JP2010256985A - Drawing device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To select a suitable rendering method according to a situation of an object. <P>SOLUTION: This drawing device includes: a first storage means 104 storing vector data; a second storage means 101 storing a curved surface model rendered with the vector data and a vector data definition position; a first generation means 105 generating at least one piece of primitive data on a vector definition space; a decision means 102 deciding relation between the vector data and elements constituting the curved surface model in the vector definition space to obtain model control information; a control means 103 re-defining the vector data in reference to the model control information to obtain a re-definition curved surface mode, and deciding whether or not a plurality of elements constituting the re-definition curved surface model are present on the same plane; a second generation means 109 generating raster data in accordance with the plane when the plurality of elements are present on the same plane; and a third generation means 107 generating raster data in accordance with a curved surface when the plurality of elements are not present on the same plane. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a drawing apparatus and method for drawing a vector graphic.

  An image formed by combining geometric figure elements such as points, straight lines, curves, rectangles, and ellipses is called vector graphics. On the other hand, an image constituted by an array of points (pixels or dots) is called raster graphics.

  In general, an image displayed on a display or an image printed by a printer is raster graphics. When these devices handle vector graphics, processing (rasterization) for converting them into raster graphics is required. The rasterization processing cost is high, and a high-performance computer is required to rasterize complex vector graphics at high speed. On the other hand, since vector graphics can generate raster graphics with an appropriate resolution each time it is displayed, image quality such as contour lines is not impaired by enlargement, reduction, or deformation of the image. Therefore, artificial images with clear outlines such as illustrations and drawings are often handled as vector graphics. On the other hand, natural images such as photographs are often treated as raster graphics.

  The most familiar use of vector graphics is fonts. In early computers, raster format fonts (bitmap fonts) are used due to CPU performance limitations, but a large amount of storage capacity is required because font data must be held for each resolution. With the subsequent improvement of CPU performance, the current computer retains vector font (outline font) data that does not depend on the resolution, and generates a font with an appropriate resolution suitable for the display or printer each time. Thus, high quality fonts can always be displayed with a small storage capacity. However, even today, CPUs incorporated in mobile phones, car navigation systems, and the like have a relatively low processing capability, and there is a problem of reducing the calculation cost required for rasterizing vector graphics.

  In recent years, a GPU (graphics processor unit) has been used to solve this problem. A method for rasterizing a figure composed of straight lines and curves using a GPU has already been proposed (see, for example, Patent Document 1).

  In addition, a technique that can perform rasterization at high speed even when the geometrical shape of a figure dynamically changes is also known (for example, see Patent Document 2).

JP 2006-106705 A JP 2007-241878 A

However, when drawing a vector figure on a curved surface, there is a problem that the processing load increases and the drawing process cannot be performed at high speed.
An object of the present invention is to provide a drawing apparatus and method capable of performing drawing processing at high speed by reducing an increase in processing load due to subdivision processing or the like even when drawing a vector graphic on a curved surface. To do.

  In order to solve the above-described problems, a drawing apparatus according to the present invention includes a first storage unit that stores vector data corresponding to a vector-type graphic, a curved surface model as a guide for drawing the graphic, and the curved surface Second storage means for storing a vector data definition position corresponding to a model and indicating an area where the vector data can be rendered; and by analyzing the contour of the vector data, either a linear contour or a curved contour Vector definition referred to in order to determine the attribute value of the pixel of raster data to output the primitive data including the data corresponding to one or more, the space in which the curved surface model is defined independently defines the figure Referring to the first generation means for generating in space, the vector data definition position, and the curved surface model, the elements included in the curved surface model First determination means for determining whether each of them is on the same plane and obtaining a determination result of either a first model that is a curved surface model that can be regarded as a curved surface or a second model that is a curved surface model that can be regarded as a plane A second generation unit configured to generate an attribute value of a pixel of raster data to be output with reference to the first model and the primitive data when the first determination unit determines the first model; A third generation unit configured to generate an attribute value of a pixel of the raster data with reference to the second model and the primitive data when the first determination unit determines that the second model is the second model; It is characterized by doing.

  According to the drawing apparatus and method of the present invention, it is possible to reduce the increase in processing load due to re-division processing and the like and perform drawing processing at high speed.

The block diagram which shows the drawing apparatus which concerns on this embodiment. The figure which shows an example of a vector figure. The figure which shows an example of a vector data figure. The figure which shows the case where a convex area | region represents a figure among the triangles ((a)), and the case where a concave area | region represents a figure ((b)). The figure which shows an example of the set ((b)) of the triangle defined from a linear outline ((a)) and a curve outline. The figure which shows the state ((a)) which one of the drawing control primitives cross | intersects with a curved surface model element, or the state ((b)) contained in a drawing control primitive with a certain curved surface model element. FIG. 2 is a block diagram illustrating a curved surface vector rendering unit in FIG. 1 and a planar vector rendering unit in FIG. 1. The flowchart which shows an example of operation | movement of the model control information calculation part of FIG. The figure which shows the image of the character before a process of the input model control part of FIG. The figure which shows an example of the image of the character after the process of the input model control part of FIG. The figure which shows another example of the image of the character after the process of the input model control part of FIG. 9 is a flowchart showing a rasterizing process procedure in a comparative example. The figure which shows an example of the set ((b)) of the triangle defined from the curve outline subdivided, and the linear outline ((a)) updated in connection with it. The figure which shows an example of the linear outline divided into the triangle. The figure which shows an example of the set of the triangle ((b)) defined from the rasterized straight line outline ((a)) and curve outline in a comparative example. The figure which shows an example of the raster data produced | generated in the comparative example. The figure which shows an example of a linear outline. The figure which shows an example of the triangle data produced | generated from the linear outline in a comparative example. The figure which shows an example of the triangle point number produced | generated from the linear outline in a comparative example.

Hereinafter, a drawing apparatus and method according to embodiments of the present invention will be described in detail with reference to the drawings.
The configuration of the drawing apparatus according to the present embodiment will be described in detail with reference to FIG.
The drawing apparatus 100 according to the present embodiment includes a model storage unit 101, a model control information calculation unit 102, an input model control unit 103, a vector data storage unit 104, a drawing control primitive generation unit 105, a drawing control primitive storage unit 106, A curved surface vector rendering unit 107, a planar vector rendering unit 109, and a presentation unit 108 are included.
The vector data storage unit 104 stores vector data that is vector-format graphic data representing an arbitrary graphic. The drawing control primitive generation unit 105 reads vector data corresponding to a desired vector graphic, generates drawing control primitive data to be used for drawing vector data in the vector definition space, and draws drawing control primitive data. The data is stored in the control primitive storage unit 106.

  The model storage unit 101 stores a curved surface model (a plurality of curved surface model elements) and vector data definition positions in association with each other. The model control information calculation unit 102 extracts a desired curved surface model from the model storage unit 101, extracts desired drawing control primitive data from the drawing control primitive storage unit 106, and a curved surface vector rendering unit 107 for each curved surface model element. Model control information indicating a determination result as to whether to output drawing control primitive data to either one of the plane vector rendering unit 109 and the plane vector rendering unit 109 is calculated. The input model control unit 103 receives model control information and the same curved surface model and vector data definition position received by the model control information calculation unit 102, and either one of the curved surface vector rendering unit 107 and the planar vector rendering unit 109 is received. The surface model to be output and rendered is redefined as a redefined surface model, and it is further determined whether or not the redefined surface model is defined on the same plane. Here, the element refers to a polygon constituting the curved surface model, and for example, a triangle or a rectangle can be used.

  When it is determined that the redefined surface model element is not defined on the same plane, the surface vector rendering unit 107 receives the rendering control primitive data and the redefined surface model, and outputs raster data as a final output. Generate. When it is determined that the redefined surface model element is defined on the same plane, the plane vector rendering unit 109 receives the rendering control primitive data and the redefined surface model, and outputs raster data as a final output. Generate. The presentation unit 108 displays the received raster data on the screen.

[Vector data storage unit 104]
The vector data storage unit 104 stores one or more vector data corresponding to one or more types of vector graphics. The vector data is vector-format graphic data representing an arbitrary vector-format graphic to be rasterized (referred to as a vector graphic; an example of the vector graphic is shown in FIG. 2), and indicates an arbitrary graphic including an area to be rasterized. The coordinates of the start point, control point, and end point, the type of vector graphic (for example, font, picture), the connection relationship of each point (start point, control point, and end point) constituting the vector graphic, and internal rasterization Information indicating the area. Even if the information on which side of a straight line or curve is to be inside the figure is not defined for each straight line or curve, the outline of the vector data can be determined by deciding which side of the straight line or curve is the internal area. The internal area can be defined simultaneously with the line analysis. An example of the vector graphic is shown in FIG. 2, and the connection relation between each point included in the vector data corresponding to the vector graphic of FIG. 2 is shown in FIG.
The vector data is not limited to the above format, and may include other data generally used in the graphics field such as color information and alpha value.

[Drawing control primitive generation unit 105]
The drawing control primitive generation unit 105 refers to the vector data stored in the vector data storage unit 104, extracts vector data to be drawn, and draws the drawing control primitive data from the extracted vector data into the vector definition space. At least one is generated. The vector definition space is a space that is independent of the space where the curved surface model is defined, and is defined in a certain range of the space where the vector data to be rendered is defined by unique position coordinates (or texture coordinates). Is. The vector definition space is a two-dimensional space in which each axis is defined in the range from 0 to 1, for example. The vector definition space is a space that is referred to in order to determine pixel attribute values of raster data output from rendering units 107 and 109 described later. The pixel attribute value is usually a plurality of values indicating position coordinates in the vector definition space, color information of each pixel, transparency, and the like. The raster data is image data having the same resolution as the resolution of the image finally presented on the presentation unit 108. The curved surface model will be described in detail in the model storage unit 101 described later.
The drawing control primitive data is data used to draw vector data on a curved surface model, and is data including, for example, a point coordinate forming a triangle or a convex polygon and a line connecting the point coordinates. The drawing control primitive data represented by the drawing control primitive data is a figure generated by analyzing the start point, the control point, and the end point of the vector data. It may contain polygon groups. In the present embodiment, the case where the drawing control primitive includes a triangle group and a polygon group will be described as an example. In FIG. 3, the straight line of the figure or the end point of the parametric curve is represented by a black circle, and the control point of the parametric curve is represented by a white circle.
The drawing control primitive generation unit 105 generates drawing control primitive data including data corresponding to a curved outline (for example, FIG. 5B) and a straight line outline (for example, FIG. 15) as a result of contour analysis of the vector data. To do. The rendering control primitive data is equivalent to the vector data in reproducing the vector graphic. The drawing control primitive generated from the curve contour is a set of polygons (here, triangles) defined by connecting the three points of the start point and end point of the parametric curve of the curve contour and the control point. Each triangle circumscribes a parametric curve, and the curve is always present inside the triangle. The example of FIG. 3 is a set of triangles defined by connecting the three points of the start point, the end point, and the control point included in FIG. Further, a triangle defined from a curved contour represents a convex region of a curved line defined inside (referred to as a convex curved contour) as shown in FIG. 4B, and a triangular shape defined in FIG. 4A. Are composed of two types, one representing a concave region (referred to as a concave curve contour). As for the triangle defined from the curved contour, only the pixels belonging to the convex region of the curve among the pixels inside the triangle are rasterized.

A straight line outline is defined as a polygon obtained by ignoring control points and connecting the start and end points of straight lines and curves included in vector data with line segments. For example, the straight line outline is a figure shown in FIG. Further, this straight line outline is triangulated. Specifically, an arbitrary vertex (referred to as a pivot) is selected from a plurality of vertices of a polygon constituting the straight line outline. Then, the pivot and all other vertices are connected by a straight line, and a plurality of triangles having the pivot as one vertex are generated so that the two vertices to be connected are sides of one triangle. The plurality of triangles are used as drawing control primitives generated from the straight outline. The two vertices connected here mean two vertices connected by polygon sides.
A more detailed method for generating primitive data for drawing control from vector data in this way is described in, for example, the above-mentioned Japanese Patent Application Laid-Open No. 2007-241878, and detailed description thereof is omitted here.

However, the method for generating the drawing control primitive data is not limited to this. For example, the triangle defined from the curved contour is composed of the concave curved contour and the convex curved contour as described above. . The linear contour may be defined according to these two types of curved contours, for example. In this case, the straight contour ignores the control point in the convex curve contour and connects the start point and the end point, and the concave curve contour connects the start point, the control point, and the end point in this order. It is a set of polygonal outlines obtained by connecting minutes. FIG. 5A is an example of the linear contours connected in this way. As can be seen from FIG. 5 (a), the number of polygons constituting the straight contour is not limited to one (in this example, it is composed of three polygons). Each polygon may contain self-intersections and holes.
In this case, information indicating the rasterized area inside the figure (for example, a triangle) is determined by, for example, two types of curved contours described above. With these two types of curve contours, it is possible to indicate which of the regions inside the triangle, which is divided by the curve determined by the start point, the control point, and the end point, is the region to be rasterized.

  The drawing control primitive data is defined in the vector definition space as described above. In this case, the normalization of the triangle is performed so that the rendering control primitive data is all included in the range in which the vector definition space is defined, and the smallest rectangle covering the triangle group is the largest. Specifically, the rectangle is the smallest rectangle that covers all the drawing control primitives, each side is parallel to any axis in the vector definition space, and two sides intersect perpendicularly, After determining the magnification when expanding so that the longer of the two sides of the rectangle becomes the longest length that can fit in the vector definition space, the rectangle is expanded and normalized while maintaining the aspect ratio of the rectangle. can do. Unlike this method, for example, the drawing control primitive data generated by the drawing control primitive generation unit 105 are all included in the vector definition space, and each side of the rectangle is parallel to any axis of the vector definition space. Considering the smallest rectangle, it is possible to normalize with the magnification when the rectangle is enlarged within the range included in the vector definition space while maintaining the aspect ratio of the rectangle. However, the present invention is not limited to this method, and other normalization methods common in the graphics field may be used.

[Drawing control primitive storage unit 106]
The drawing control primitive storage unit 106 receives and stores drawing control primitive data from the drawing control primitive generation unit 105.

[Model storage unit 101]
The model storage unit 101 stores a curved surface model including a plurality of curved surface model elements including parameters at each vertex, and a vector data definition position corresponding to the curved surface model. The curved surface model element is indicated by a polygon having three or more sides, for example, a triangle. A curved surface model is expressed by a set of a plurality of curved surface model elements. The vector data definition position indicates at which position of the curved surface model the vector data is rendered in order to reproduce the vector graphic based on the primitive data. That is, the vector data definition position indicates in which area of the curved surface model the area defined in the vector definition space is rendered. The curved surface model here is used as a guide for drawing vector graphics. The model storage unit 101 may store a plurality of curved surface models configured by curved surface model elements.

  It is assumed that a parameter indicating a corresponding position in the vector definition space is defined at each vertex of the curved surface model element. For example, the use of texture coordinates can be considered for this parameter. With this parameter, the position coordinates of the curved surface model element in the space where the curved surface is represented correspond to the vector data definition position in the vector definition space, so define the curved surface model element (here, a triangle) in the vector definition space. It is possible to easily determine the positional relationship between the vector data to be rendered in the vector definition space and the curved surface model element in the vector definition space. Further, when the curved surface model element is a triangle, the normal vector of the curved surface model element can be determined by the three vertices that generate the triangle.

The data to be stored is not limited to these. Other information commonly used for rendering in the graphics field, such as camera parameters that represent the position of the viewpoint and the direction of the line of sight during rendering, and whether to project in parallel projection or projection projection, is the model storage unit. 101 may be stored. In this case, information including transparency and color for each curved surface model element in the space where the curved surface model is represented is also included in the above-described parameters.
In the present embodiment, a case where the curved surface model element is configured by a triangle will be described as an example. When this is applied to a general polygon, for example, there is a method of dividing the polygon into a set of triangles. As for the division method, for example, the method described in “M. Doberg, M. Van Kriveld, M. Obermarz, O. Schwartzkop, Tetsuo Asano Translation: Computer Geometry Computer Science: Algorithms and Applications, Modern Science Co., Ltd.” It is possible to use.

[Model control information calculation unit 102]
The model control information calculation unit 102 extracts a desired curved surface model and vector data definition position from the model storage unit 101, extracts desired drawing control primitive data from the drawing control primitive storage unit 106, and stores each surface model element. It is determined whether or not the final input curved surface model element is used, and model control information, which is a determination result indicating the relationship with the vector graphic, is calculated for each curved surface model element.
Here, the determination method of model control information is demonstrated in detail using FIG.
The drawing control represented by the curved surface model elements (here, the internal area 601 of the polygon 2 which is a triangle) stored in the model storage unit 101 and the drawing control primitive data stored in the drawing control primitive storage unit 106 The following determination is made for each curved surface model element at the vector data definition position with respect to an arbitrary figure included in the primitive for use (here, the internal region 602 of the polygon 1 that is a triangle).
(A) Whether the triangles intersect each other
(B) Whether one triangle is completely included in the inner region of the other triangle (for example, in FIG. 6, the inner region 603 of the polygon 2 is completely included in the inner region 604 of the polygon 1. ing)
The above two points are individually determined for each triangle. As this determination method, for example, the method described in “Eiichiro Nakamae, Tomoyoshi Nishida: 3D Computer Graphics, pp 63-72, Shosodo” can be used, and detailed description thereof is omitted here. The determination at this time is performed in the vector definition space. In order to make the determination, it is examined how triangles constituting the curved surface model are defined in the vector definition space. Since the vertex for each curved surface model element holds a parameter indicating the corresponding position in the vector definition space, each curved surface model element can be defined in the vector definition space. Note that the vector definition space at this time is a two-dimensional space.
As a result of the above judgment, if the triangles intersect or one triangle is completely included in the inner area of the other triangle, the final judgment result is “true”, otherwise As “false”, the determination result of “true” and “false” is output to the input model control unit 103 as model control information for each curved surface model element at the vector data definition position. That is, a curved surface model element whose model control information is “true” can be said to be a curved surface model element including an area where vector data is drawn. For example, the model control information may indicate “true” or “false” for each curved surface model element using a flag, and may output the flag for each curved surface model element to the input model control unit 103.
Note that the determination does not necessarily have to be performed according to the above-described procedure, and an arbitrary figure (inner area 602 of polygon 1) in which a curved surface model element (inner areas 601 and 603 of polygon 2) is included in the drawing control primitive. 604) or any one of the arbitrary figures included in the curved surface model element and the drawing control primitive may be determined to be completely included in the other internal region. That is, the model control information calculation unit 102 only needs to be able to determine whether the area occupied by the curved model element in the vector definition space overlaps the area occupied by the drawing control primitive. Further, depending on the use, it may be replaced by simple determination. For example, it is checked whether or not the vertex for each curved surface model element is included in the internal area of an arbitrary graphic included in the drawing control primitive. This makes it possible to determine the positional relationship between the curved surface model element and the drawing control primitive faster than the normal determination.
Note that the curved surface model stored in the model storage unit 101 used for the determination by the model control information calculation unit 102 is not rewritten.
When the model control information calculation unit 102 receives a desired curved surface model and vector data definition position from the model storage unit 101, the model control information calculation unit 102 sends the same data as the received curved surface model and vector data definition position to the input model control unit 103. To the model storage unit 101.

[Input model control unit 103]
The input model control unit 103 receives model control information indicating a determination result for each curved surface model element from the model control information calculation unit 102, and receives from the model storage unit 101 the same curved surface model and model model information received by the model control information calculation unit 102. A new curved surface model including a curved surface model element that receives a vector data definition position and the determination result included in the model control information is “true” is redefined, and a redefined curved surface model (hereinafter referred to as a redefined curved surface model). For each curved surface model element (hereinafter referred to as a redefined curved surface model element) that is a component of (), it is determined whether all the redefined curved surface model elements included in the redefined curved surface model are defined on the same plane. Since the redefined curved surface model element is a curved surface model extracted from the curved surface model received from the model storage unit 101 and the determination result included in the model control information is “true”, The defined curved surface model element is used as an input to the next rendering process. Therefore, subsequent processing is not performed for curved surface model elements whose determination result included in the model control information calculated by the model control information calculation unit 102 is “false”. That is, the input model control unit 103 sets a curved surface model element whose determination result is “true” as a redefined curved surface model element.

Also, the input model control unit 103 determines whether the redefined surface model is a plane for the redefined surface model, that is, whether all the redefined surface model elements included in the redefined surface model are on the same plane. Judge whether or not. The plane part can be determined, for example, by examining whether the normal vector directions of the redefined surface model elements included in the redefined surface model in the space where the surface model is defined are almost the same. is there. Whether or not the directions of the normal vectors are almost the same can be determined by the following procedure. Note that the lengths of normal vectors to be treated below are adjusted so as to be all unit vectors.
1) One arbitrary redefined surface model element is selected from the redefined surface model, and the normal vector is defined as a reference normal vector _Vb .
2) An inner product of the normal vector of the redefined surface model element other than the redefined surface model element selected in the above “1)” and V _b is obtained, and it is determined whether the value takes a value close to 1.0. . For example, it is determined whether or not the difference between the calculated inner product and 1.0 is a value within a threshold defined in advance by the user.
3) The determination of “2)” above is performed for all the redefined curved surface model elements, and if all the inner products obtained are within the threshold value, the redefined curved surface model constitutes a plane and the redefined curved surface The model is output to the plane vector rendering unit 109. In other cases, that is, when there is a redefined curved surface model element in which the difference between the calculated inner product and 1.0 exceeds the threshold value, the redefined curved surface model is determined to be a curved surface by assuming that the redefined curved surface model does not constitute a plane. The data is output to the vector rendering unit 107. The normal vector is calculated in advance for each curved surface model stored in the model storage unit 101 and stored in the model storage unit 101, and the input model control unit 103 refers to the value of the normal vector to refer to the curved surface model. It may be determined whether or not is a plane, or the input model control unit 103 may calculate a normal vector of the curved surface model element from the position coordinates of each vertex of the curved surface model element.

[Curved surface vector rendering unit 107]
The curved surface vector rendering unit 107 receives the rendering control primitive data from the rendering control primitive storage unit 106, receives the redefined curved surface model determined not to constitute a plane from the input model control unit 103, and receives the redefined curved surface model and Raster data as final output is generated from the drawing control primitive data and sent to the presentation unit 108. Regarding the drawing control primitive data received by the curved surface vector rendering unit 107 from the drawing control primitive storage unit 106, for example, when the model control information calculation unit 102 extracts the drawing control primitive data from the drawing control primitive storage unit 106, The drawing control primitive storage unit 106 passes the same drawing control primitive data to the curved surface vector rendering unit 107 and the planar vector rendering unit 109. As another example, the model control information calculation unit 102 may directly pass the drawing control primitive data extracted from the drawing control primitive storage unit 106 to the curved surface vector rendering unit 107 and the plane vector rendering unit 109. As yet another example, when the input model control unit 103 determines that the redefined curved surface model is not on the same plane, the determination result is returned to the model control information calculation unit 102, and the model control information calculation unit 102 If the primitive data for drawing control is passed to the curved surface vector rendering unit 107 and it is determined that the redefined curved surface model is on the same plane, the determination result is returned to the model control information calculating unit 102 and the model control information calculating unit 102 May pass the primitive data for drawing control to the plane vector rendering unit 109.

Next, the operation of each block included in the curved surface vector rendering unit 107 will be described in detail.
The curved surface vector rendering unit 107 includes a drawing parameter calculation unit 701, a drawing attribute control information calculation unit 202, a raster data generation unit 703, and a raster data storage unit 704 as shown in the left diagram of FIG. 7.

[Drawing Parameter Calculation Unit 701]
The drawing parameter calculation unit 701 receives from the input model control unit 103 a redefined curved surface model that is determined not to constitute a plane, and calculates drawing parameters by a method described later. The drawing parameters are the positions in the vector definition space for each pixel occupied by each curved surface model element (here, the redefined curved surface model element) when the curved surface model (here, the redefined curved surface model) is projected onto the screen. It is a parameter indicating information including coordinates, color information, and transparency.
In addition to the redefined curved surface model, the drawing parameter calculation unit 701 reads camera parameters and a projection method if necessary. In this case, the drawing parameter calculation unit 701 defines parameters indicating which positions in the vector definition space each pixel of the raster data generated by the raster data generation unit 703 described later corresponds to, and what color is defined. It is calculated whether it should be done. As a result, the position coordinates of each pixel in the vector definition space (hereinafter referred to as corresponding position), the color information of each pixel, and pixel attribute information (hereinafter referred to as pixel attribute information) such as transparency are determined and rendered. Parameter. That is, the drawing parameter calculation unit 701 calculates a drawing parameter for each pixel.

In the present embodiment, for example, texture coordinates are used as unique position coordinates in the vector definition space. When using the texture coordinates, the drawing parameter calculation unit 701 calculates the correspondence between the curved surface model and the vector definition space by using a texture mapping method generally used in the graphics field. The position can be calculated.
How to calculate the corresponding position (for example, texture coordinates) of each pixel, the color information of each pixel, and the transparency can be performed by a method similar to the rendering method when rendering the curved surface model. For example, it can be obtained by approximating a curved surface model with a set of fine triangular faces and calculating which triangular face each pixel attribute information is determined on. This calculation method is the same as the method for determining pixel attribute information when rendering a triangular surface, and since it is a common method in the graphics field, description thereof is omitted. Further, the method for determining the pixel attribute information from the curved surface model is not limited to this. For example, a half line is extended from each pixel in the direction of the line of sight when rendering, and the corresponding position (for example, texture coordinates) of the intersection of the curved model and the half line, color information, transparency, etc. are used as pixel attribute information. Further, the present invention is not limited to this method, and other methods that can calculate pixel attribute information for each pixel may be used.
Further, the drawing parameters corresponding to the vector definition space are not limited to the above format, and other data generally used in the graphics field may be used or included. For example, it may be a uniquely defined value that is substituted as a parameter in a formula determined in advance. Moreover, what changed this parameter using the parameter calculated from curved surface models, such as a curvature, may be included.

[Drawing determination information calculation unit 702]
The drawing determination information calculation unit 702 receives drawing control primitive data from the drawing control primitive storage unit 106, receives drawing parameters from the drawing parameter calculation unit 701, and calculates drawing determination information. The drawing determination information is information for determining whether or not the corresponding position of each pixel is included in the closed region formed by the vector data, and is a drawing determination variable described later. Examples of the method for determining the corresponding position include the following methods.

1) One arbitrary graphic data (here, a triangle) included in the drawing control primitive data is read.
2) It is checked whether this graphic data or a part of this graphic data includes the corresponding position of each pixel calculated by the drawing parameter calculation unit 701.
3) If the corresponding position is included in the internal area of the graphic data, the drawing determination variable is set to 1.
Here, the drawing determination variable is a variable for determining whether or not to write a pixel to the output raster data. Also, the determination process differs depending on whether the read drawing control primitive is a triangle generated from a straight line outline or a triangle generated from a curved outline.
In the case of a triangle generated from a straight outline, 1 is added to the drawing determination variable if the corresponding position of each pixel is included within the triangle.
On the other hand, in the case of a triangle generated from a curved contour, processing differs depending on the generation rule in the drawing control primitive generation unit 105. The first condition is “true” if the corresponding position of each pixel is included in the triangle, and is a common condition regardless of the generation rule. The second condition differs depending on the rule for generating primitive data for drawing control. If a straight line contour is generated by linking the start and end points of a straight line and a curve included in vector data ignoring control points, the corresponding position of each pixel is included in the convex area of the curve. “True”. In addition, when switching whether or not to include a control point when generating a straight contour by two types of curved contours, that is, in a convex curved contour, the control point is ignored and the two points of the start point and the end point are connected, and in the concave curved contour When connecting the three points of the start point, the control point, and the end point in this order, and connecting these line segments to generate a straight outline, the convex region of the convex curve (the curved convex region represents a figure) or concave If it is included in one of the concave areas of the curve (the curved concave area represents a figure), it is “true” as being included in a part of the triangle. When these two conditions are “true”, 1 is added to the drawing determination variable. Although 1 is added here, it may not be 1 if it is an odd number.

By repeating the above 1) to 3) until determination is made for all graphic data (here, triangles) included in all drawing control primitive data, the corresponding position of each pixel becomes the drawing control primitive or drawing control. The number of times determined to be included in a part of the primitive is obtained. In the present embodiment, this drawing determination variable is used as drawing determination information.
For example, when the drawing control primitive is composed of triangles generated from three straight outlines, and the corresponding position of each pixel corresponds to the inside of two of the triangles, the drawing determination variable is 2. Further, the vector data holds information such as color information and alpha value, and if necessary, the color information and alpha value at the corresponding position of each pixel may be calculated together.

[Raster data generation unit 703]
The raster data generation unit 703 receives the drawing determination information (drawing determination variable) and the drawing parameters from the drawing determination information calculation unit 702, and uses pixel attribute information to write the screen display raster data. Whether to do this is determined for each pixel, and raster data is generated. When the pixel drawing determination variable is an odd number, the raster data generation unit 703 generates a pixel attribute value corresponding to the corresponding position based on the drawing parameter, and writes the pixel to the raster data. At this time, if there is color information or alpha value calculated from vector data, the corresponding part such as color information or alpha value of pixel attribute information already calculated is replaced with a value calculated from vector data, or already Processing such as blending with the color information or alpha value of the calculated pixel attribute information may be performed. The drawing determination variable is an odd number. Rasterized all areas inside the figure of the curve defined in the drawing control primitive data generated from the straight line outline and the drawing control primitive data generated from the curve outline. The case is equivalent to the pixel being written an odd number of times. If this is replaced with the generation of stencil data disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2007-241878, the bit inversion of the stencil data is performed an odd number of times, resulting in a value other than 0 and being determined to be inside the figure. Will be equal. This can obtain the same result as the stencil data of the above-mentioned Japanese Patent Application Laid-Open No. 2007-241878.

[Raster data storage unit 704]
The raster data storage unit 704 receives raster data from the raster data generation unit 703, stores it, and sends it to the presentation unit 108. However, the configuration of the raster data is not limited to this format, and may include other data generally used in the graphics field.

[Planar vector rendering unit 109]
The plane vector rendering unit 109 extracts the drawing control primitive data from the drawing control primitive storage unit 106 with reference to the drawing control primitive data, receives from the input model control unit 103 the redefined curved surface model determined to constitute the plane, and redefines it. Raster data that is the final output is generated from the curved surface model and drawing control primitive data, and is sent to the presentation unit 108.
Next, the operation of each block included in the plane vector rendering unit 109 will be described in detail.
The plane vector rendering unit 109 includes a stencil data generation unit 705 and a plane rendering result data generation unit 706 as shown in the diagram on the right side of FIG.

[Stencil data generation unit 705]
The stencil data generation unit 705 receives drawing control primitive data from the drawing control primitive storage unit 106, receives a redefined curved surface model determined to constitute a plane from the input model control unit 103, and draws drawing control primitive data. Stencil data is generated by rasterizing pixels inside the control primitive. The generated stencil data is sent to the planar rendering result data generation unit 706.
Stencil data is image data having the same resolution as that finally presented to the presentation unit 108. A numerical value of about several bits is assigned to each pixel of the stencil data, and each pixel is initialized to 0 prior to drawing every frame.
The stencil data generation unit 705 reads and rasterizes the drawing control primitive data generated from the straight contour stored in the drawing control primitive storage unit 106 and the drawing control primitive data generated from the curved contour.

  Specifically, for example, with respect to drawing control primitive data generated from a straight outline, pixels in the internal area of each drawing control primitive are rasterized. With respect to the drawing control primitive generated from the curved contour, the pixels belonging to the convex region of the curved line among the pixels inside the triangle are rasterized. At this time, the pixel value of the stencil data corresponding to the rasterized pixel is bit-inverted for each triangle. With respect to this method, for example, the method disclosed in Japanese Patent Application Laid-Open No. 2007-241878 can be applied.

  For example, as a rasterization method, it is conceivable to perform rasterization based on a non-zero rule. At this time, among the rasterized pixels, each point constituting the triangle which is a rendering control primitive is incremented (+1) by adding the value of the pixel included in the triangle when rotated clockwise, to the triangle when rotated counterclockwise. Decrement (-1) the value of the contained pixel. With respect to the drawing control primitive generated from the straight outline, all the pixels in the inner area of each drawing control primitive are rasterized. For the drawing control primitive generated from the curved contour, only the pixels belonging to the convex region of the curved line among the pixels inside the triangle are rasterized.

[Plane rendering result data generation unit 706]
The planar rendering result data generation unit 706 receives the stencil data from the stencil data generation unit 705, generates raster data to be output while referring to the stencil data, and sends the raster data to the presentation unit 108. The raster data to be output is generated by rasterizing the pixels occupied by the redefined surface model when the redefined surface model is projected onto the screen. However, among these pixels, rasterization is limited only to locations where the pixel value is other than zero.
This raster data is image data having the same resolution as that finally presented to the presentation unit 108, and each pixel of the raster data is assigned a numerical value of several bits for each of a plurality of color components (for example, RGBA). It has been.

[Presentation unit 108]
The presentation unit 108 receives raster data from the curved surface vector rendering unit 107 or the planar vector rendering unit 109 and displays it on the screen as necessary.

Note that the results output from the plane vector rendering unit 109 and the curved surface vector rendering unit 107 may be stored in the raster data storage unit 704 in an image format generally used in the graphics field such as bitmap, JPEG, or GIF. Alternatively, the output result or stored data may be transferred through the network.
Further, in FIG. 1, the model storage unit 101, the vector data storage unit 104, and the drawing control primitive storage unit 106 are shown as different blocks, but these may be configured together on a single memory, You may divide and comprise on a plurality of different memories.
In this embodiment, the vector definition space is, for example, a two-dimensional space in which each axis is defined in the range from 0 to 1, but the vector definition space is not limited to this format. Each axis may be defined in a range other than 0 to 1.
In addition, the model control information calculation unit 102 has a curved surface model element at a vector data definition position with respect to the drawing control primitive data received from the drawing control primitive storage unit 106 and the curved surface model received from the model storage unit 101. It is not necessary to determine whether or not to make the final input curved surface model element every time. In this case, the model control information calculation unit 102 sets the model control information so that all the received curved surface model elements are redefined curved surface model elements, and sends the model control information to the input model control unit 103. At this time, the input model control unit 103 refers to the model control information and defines a redefined curved surface model element for the curved surface model element received from the model storage unit 101. That is, in this case, all the curved surface model elements received from the model storage unit 101 are defined as redefined curved surface model elements. The input model control unit 103 determines whether or not the redefined curved surface model element is in the same plane. Thereby, it is possible to reduce the processing cost for the intersection determination of the curved surface model element and the drawing control primitive and the determination of the inclusion.

  According to the embodiment described above, when rendering vector data, it is determined in vector data units whether a curved surface model is defined on the same plane, and if plane rendering with low cost can be used, By switching to use, it is possible to select a rendering method that is suitable for the situation of the object even when objects that need to use curved surface rendering and objects that can be planar rendering are mixed. It improves the processing efficiency when rendering vector data.

(First modification)
In this modification, the model control information calculation unit 102 determines whether the triangle intersects and one triangle is completely included in the inner area of the other triangle. This is different from the above embodiment. In the above embodiment, since the rendering control primitive is a determination target for the curved surface model element, when a rendering method is selected in units of vector data, an extra region may be a determination target depending on the shape of the vector data. In the present modification, the contour of the vector graphic is set as the determination target for the curved surface model element, so that a triangle can be selected according to the vector data. Only blocks that perform operations different from those in the above embodiment will be described below.

The drawing control primitive generation unit 105 sends the vector data together with the drawing control primitive data to the drawing control primitive storage unit 106.
The drawing control primitive storage unit 106 stores drawing control primitive data and vector data received from the drawing control primitive generation unit 105.

The model control information calculation unit 102 extracts a desired curved surface model and vector data definition position from the model storage unit 101, extracts desired vector data from the drawing control primitive storage unit 106, and performs determination for each curved surface model element. Then, model control information indicating the determination result for each curved surface model element is sent to the input model control unit 103. Note that the model control information calculation unit 102 may receive vector data from the vector data storage unit 104.
The determination method is composed of all points including control points that appear when the outline of a vector data figure (for example, FIG. 3) indicating the connection relationship between the control points, start points, and end points included in the vector data is traced. It is determined whether the polygon and the curved surface model element intersect with each other, or whether one of the polygon and the curved surface model element is completely included in the other internal region. The polygon may be obtained from the drawing control primitive storage unit 106. For example, a drawing control primitive (triangle) defined by a curved contour and a drawing control primitive (polygon) defined by a straight contour may be similarly determined as polygons used for the above-described determination. As a specific determination method for the above-described determination, for example, the method described in “Eihachiro Nakamae, Tomomi Nishida: 3D Computer Graphics, pp 63-72, Shosodo” can be used. The detailed description in is omitted.
However, the determination method is not limited to this, and it is only necessary to check whether or not the area occupied by the curved surface model in the vector definition space overlaps the area occupied by the vector graphic (for example, the graphic of FIG. 2). Distinguish between the case where they intersect each other and the case where either one of polygons or curved surface model elements formed by tracking the outline of a vector data figure (for example, the figure in FIG. 3) is included in the other There is no need, and since primitive data for drawing control is defined, the determination can also be made by a method such as the flowchart shown in FIG.

In step S801, a curved surface model element (generally a polygon, for example, a triangle) that has not yet been determined from the curved surface model is selected. Next, in step S802, the position of each vertex of the curved surface model element in the vector definition space is set as the corresponding position of the drawing determination information calculation unit 702, and the drawing determination variable is processed in the same procedure as described above for the drawing determination information calculation unit 702. Is calculated. If the drawing determination variable is an odd number, a part of the curved surface model element is always in the internal area of the vector data figure, so the model control information becomes “true” and the process proceeds to step S806. If the drawing determination variable is an even number, the process proceeds to step S803.
In step S803, it is checked whether at least one of the vertices and control points of the vector data figure is included in the internal area of the curved surface model element. If any one of the vertices and control points of the vector data figure is included in the internal area of the curved surface model element, the model control information becomes “true” and the process proceeds to step S806. If neither the vertex nor the control point of the vector data figure is included in the internal area of the curved surface model element, the process proceeds to step S804. In step S804, it is checked whether each ridge line constituting the triangle defined by the curved contour or each ridge line constituting the straight line contour intersects with the ridge line constituting the curved surface model element. If they intersect, the model control information becomes “true” and the process proceeds to step S806. Otherwise, the process proceeds to step S805, and the model control information becomes “false”.
In step S807, it is checked whether or not all the curved surface model elements included in the curved surface model have been determined. If all the curved surface model elements have been determined, the process ends. Since there is a curved surface model that has not been determined yet. If there is, the process returns to step S801 and the above-described processing is performed in the same manner.

With the above processing, an image in which the present embodiment and the first modification are applied to the input model control unit 103 will be described with reference to FIGS. 9A to 9C.
FIG. 9A shows a state in which the control process is not performed before the rendering process for the character “next”. FIGS. 9B and 9C are the control processes after the application of the embodiment and after the application of the first modification, respectively. Shows the state of the It can be seen that the data to be rendered is reduced after application of the embodiment shown in FIG. 9B than in the state before the control processing shown in FIG. 9A. Further, after the application of the first modification shown in FIG. 9C, the ridge line of the drawing control primitive generated from the contour line of the vector graphic and the curved line contour is to be determined, so that the vector data constituting the “next” character is included in the vector data. Rendering can be performed together, and the data can be greatly reduced.

  Further, when considering the balance between the processing cost and the triangle to be reduced, the processing of S802 and S804 can be changed. In S <b> 802, the drawing determination variable is calculated in the same procedure as the description of the drawing determination information calculation unit 702, with the position of each vertex of the curved surface model element in the vector definition space as the corresponding position of the drawing determination information calculation unit 702. However, a drawing control primitive generated from a straight outline is used for the determination at this time. If the drawing determination variable is an odd number, the model control information is “true” because a part of the curved surface model is always inside the polygon surrounded by the straight outline. When the drawing determination variable is an even number, it is further checked whether at least one corresponding position is included in the drawing control primitive generated from the curved contour. If it is included, the model control information is “true”. If the model control information is “true”, the process proceeds to step S806. If the model control information is “false”, the process proceeds to step S803. Otherwise, it is “false”. In step S803, the same process as described above is performed. In step S804, it is checked whether each ridge line of the drawing control primitive intersects with a ridge line constituting the curved surface model. If they intersect, the model control information becomes “true” and the process proceeds to step S806. Otherwise, the process proceeds to step S805, and the model control information is “false”.

  According to the first modification shown above, the outline of the vector data is targeted for determination, and therefore a triangle can be selected according to the vector data. For this reason, the accuracy and determination speed of selecting a rendering method are improved.

(Second modification)
In the above embodiment, in the input model control unit 103, the curved surface vector rendering unit 107 and the plane are determined depending on whether or not all the curved surface model elements included in the curved model whose model control information is “true” are defined on the same plane. The vector rendering unit 109 determines which of the curved surface models is input. Therefore, a curved surface model in which a portion that can be regarded as a plane and a portion that can be regarded as a curved surface are mixed must be determined as a curved surface model that is not on the same plane. In this modification, even for a curved surface model in which a portion that can be regarded as a plane and a portion that can be regarded as a curved surface are mixed, the curved surface model that can be regarded as a plane and the curved surface model that can be regarded as a curved surface are separated and different rendering methods are applied.

[Input model control unit 103]
The input model control unit 103 receives a curved surface model and a vector data definition position from the model storage unit 101, receives model control information indicating a determination result for each curved surface model element from the model control information calculation unit 102, and forms curved surface models It is determined whether the model elements are on the same plane, and are classified into a curved surface model that can be regarded as a plane and a curved surface model that can be regarded as a curved surface. Below, the classification method of the curved surface model in this modification is demonstrated.
First, an arbitrary curved surface model element (triangle) Tc is selected from the curved surface model. Next, it is checked whether the curved surface model elements adjacent to the curved surface model element are defined on the same plane as Tc. If they are not on the same plane, the process ends for the curved surface model element. If they are on the same plane, it is assumed that the curved surface model element belongs to the group of Tc, and it is checked whether the curved surface model element adjacent to the curved surface model element is defined on the same plane as Tc. This is recursively performed until the processing for all curved surface model elements is completed. After the processing is completed, if there is a curved surface model element that does not yet belong to the group in the curved surface model, an arbitrary curved surface model element is selected again from the curved surface model elements, and the above-described procedure is repeated. This is repeated until all the curved surface model elements are processed.

  As a result of the above processing, a curved surface model element whose model control information is “true” includes a group of curved surface model elements that can be regarded as zero or more planes, and other curved surface model elements, that is, curved surface model elements that are regarded as curved surfaces. are categorized. Among these, the curved surface model elements of a group that can be regarded as a plane are sent to the planar vector rendering unit 109, and other curved surface model elements are sent to the curved surface vector rendering unit 107.

  According to the second modified example described above, when a curved surface model element including vector data in a curved surface model can be partially regarded as a flat surface, a separate rendering method is performed by separating the flat surface portion and the curved surface portion. By applying it, the rendering efficiency of vector data is improved.

(Comparative example)
Hereinafter, as a comparative example with the embodiment of the present invention, techniques described in Japanese Patent Application Laid-Open Nos. 2006-106705 and 2007-241878 will be described.
As described above, a GPU (graphics processor unit) is used to reduce the calculation cost required for rasterizing vector graphics. First, the technique disclosed in Japanese Patent Laid-Open No. 2006-106705 for rasterizing a vector graphic composed of straight lines and curves as shown in FIG. 2 using the GPU will be described.

A flowchart of this rasterization method is shown in FIG. As can be seen from this figure, the processing of the method disclosed in Japanese Patent Application Laid-Open No. 2006-106705 comprises two stages of processing: CPU pre-processing and GPU main processing. First, the CPU divides the vector-style figure into a collection of triangles, and then rasterizes each triangle by the GPU. The processing unit of the GPU is a triangle, and a vector figure composed of straight lines and curves as shown in FIG. 2 cannot be directly handled. Therefore, the processing unit is divided into two steps.
In the first step S1001, vector data is read from a storage medium such as an HDD or a RAM, and a process for analyzing the contour line is performed. For example, the vector format data representing the vector graphic of FIG. 2 includes points and straight lines as shown in the vector data graphic shown in FIG. In FIG. 3, the straight line of the figure or the end point of the parametric curve is represented by a black circle, and the control point of the parametric curve is represented by a white circle. In step S1001, such a vector data figure is analyzed to generate two types of contour data as shown in FIG.
In this specification, as described above, the contour line data in FIG. 5A is expressed as “straight line contour”, and the contour line data in FIG. 5B is expressed as “triangle defined from the curved contour”. ing. In the following description, the drawing control primitive data is assumed to be triangle data, and the drawing control primitive is assumed to be a triangle.
Returning to the flowchart of FIG. In step S1002, a process is performed to check whether there is an overlap in the triangle defined from the curved contour generated in the previous step. As a result, if an overlap is found, the process proceeds to step S1003, and a process of subdividing the larger area of the two overlapping triangles is performed.
Since the straight contour is also changed due to the influence of this processing, in the next step S1004, processing for updating the straight contour is performed. Thereafter, the process returns to step S1002 to check again whether there is an overlap. If there is no overlap, the process proceeds to step S1005. As long as there is an overlap in the triangle defined from the curved contour, the processing of steps S1002 to S1004 is repeated.

For example, in the case of a set of triangles defined from the curved contour shown in FIG. 5B, it can be seen that the triangles a and b and the triangles c and d overlap in step S1002. In step S1003, the triangles a and c are subdivided into two triangles a0 and a1, and c0 and c1, respectively, as shown in FIG. In step S1004, a process for updating the linear contour is performed as shown in FIG.
In step S1005, a process of dividing each polygon constituting the straight contour into triangles is performed. For example, the three polygons in FIG. 11A are divided into a collection of triangles as shown in FIG.
The above processes (steps S1001 to S1005) are all executed as preprocessing by the CPU.
In step S1006, the triangles (FIG. 13B) defined from the triangles (FIG. 12) and the curved contours constituting the straight line contour are rasterized by the GPU. At this time, with respect to the triangle constituting the straight outline, as shown in FIG. 13A, all pixels inside the triangle are rasterized.
On the other hand, for the triangle defined from the curved contour, as shown in FIG. 13B, among the pixels inside the triangle, the concave region of the concave curved contour or the convex region of the convex curved contour is rasterized. Is done.
Triangular rasterization results defined from the straight and curved contours obtained in this way are stored together with the frame buffer inside the GPU. For example, FIGS. 13A and 13B are stored in the frame buffer as raster data as shown in FIG.

  In the conventional rasterization method using the GPU, a curve is approximated using a plurality of triangles, so that there is a problem that the image looks rough when enlarged. In addition, in order to rasterize more smoothly, the approximation accuracy of a curve must be increased using a large number of triangles, and an increase in storage capacity and processing cost is inevitable. On the other hand, according to the method disclosed in Japanese Patent Application Laid-Open No. 2006-106705, processing is performed in units of pixels in the vicinity of the curve, not in units of triangles, so that the curve can always be rasterized smoothly regardless of resolution. In addition, the storage capacity and the processing cost do not depend on the resolution and are always small.

However, the rasterizing method disclosed in Japanese Patent Laid-Open No. 2006-106705 has the following two problems.
The first problem is the high cost of preprocessing. In particular, the cost of the triangle overlap determination defined from the curved contour in step S1002 in FIG. 10 and the triangulation of the straight contour in step S1005 are high.
The cost of the preprocessing is not a big problem if the geometric shape of the figure does not change with time. This is because once pre-processing is performed, it is not necessary to perform pre-processing again thereafter. However, when the geometrical shape of a figure changes dynamically, the preprocessing must be performed again each time, which often becomes a bottleneck of the entire rasterization process.
The second problem is using alpha blending for anti-aliasing. Here, anti-aliasing is a process of removing jaggy (stepped jagged edges) appearing on the contour line of a rasterized figure. Alpha blending is a process of translucently synthesizing two pixel values using a coefficient called alpha value.
As widely known, in order to use alpha blending, all figures must be sorted by depth value (depth sort), and rasterized in order from the figure located at the back. Depth sorting is a very expensive process and often becomes a bottleneck of the entire rasterization process.

Japanese Patent Application Laid-Open No. 2007-241878 proposes a method for solving these two problems.
In the above Japanese Unexamined Patent Publication No. 2007-241878, a polygon obtained by simply connecting the start and end points of a straight line and a curve included in vector data with a line segment is defined as a straight line outline. For example, the linear contour analyzed from the vector data figure of FIG. 3 becomes three polygons P0, P1, and P2 as shown in FIG. As for the triangle defined from the curved contour, the same one as in the above Japanese Patent Laid-Open No. 2006-106705 is used.
An arbitrary point (pivot) is selected for each polygon forming the obtained straight outline. Then, a triangle is generated that connects the pivot and all two connecting points not including the pivot. The two points connected here mean two points connected by a side of the polygon.
For example, in the three polygons P0, P1, and P2 in FIG. 15, when points 0, 23, and 28 are selected as pivots, triangles as shown in FIG. 16 are generated. Since triangles are overlapped and it is difficult to grasp the shape of the triangles only with this figure, FIG. 17 shows the numbers of three points constituting the triangles generated from the three polygons P0, P1, and P2.
Note that FIG. 17 is only a supplement for easy understanding of the description, and does not represent the triangle data itself. The actual triangle data is composed of position coordinates of three points constituting each triangle, texture coordinates, connection relations, and the like.

Next, a process of generating stencil data is performed by rasterizing the pixels inside the triangle. The stencil data is image data having the same resolution as that finally presented.
First, triangle data generated from a straight outline and triangle data generated from a curved outline are read and rasterized. At this time, for the triangle of the straight outline, all the pixels inside the triangle are rasterized, and the pixel values of the stencil data corresponding to these pixel positions are bit-inverted.
On the other hand, for triangles defined from curved contours, pixels belonging to the convex region of the curve among the pixels inside the triangle are rasterized, and pixel values of stencil data corresponding to these pixel positions are bit-inverted. .
As a result, the pixel value is bit-inverted an odd number of times inside the graphic, and the pixel value is bit-inverted an even number of times outside the graphic.

Since the pixel to be filled can be determined by the above processing, the drawing result can be generated by painting the corresponding pixel of the raster data for drawing.
In the above Japanese Patent Laid-Open No. 2007-241878, since the triangulation of the straight contour is not performed, if the connection relation of the triangle data does not change even if the vertex of the vector data is moved, the corresponding vertex coordinates of the triangle data are simply rewritten. There is no need to recreate the triangle data. Therefore, even if the geometrical shape of the figure changes dynamically, it can be rasterized at high speed.
Also, a subpixel-accurate image of the raster data for drawing is prepared, the color of the figure is assigned to a part of the subpixel based on the coverage data, and is synthesized when the final raster data for drawing is generated. This enables anti-aliasing that does not require alpha blending.

However, the techniques described in Japanese Patent Application Laid-Open Nos. 2006-106705 and 2007-241878 cannot be applied as they are when rendering a figure on a curved surface.
In general, rendering polygon data on a curved surface is realized by adding vertices to the original polygon data by dividing the polygon data into fine polygon data groups and moving the vertices. Even when vector data is rendered on a curved surface using the method disclosed in Japanese Patent Application Laid-Open No. 2007-241878, it is necessary to subdivide the triangle data generated by the method disclosed in Japanese Patent Application Laid-Open No. 2007-241878. is there.
There are various methods for re-dividing the triangle data. However, the processing cost of the method of re-division so as to obtain a drawing result that is sufficiently along the curved surface, that is, rendered on the curved surface, is high.
Since the triangle data for drawing the vector data is subdivided, it is necessary to redo the subdivision process every time the geometric shape of the figure changes. For this reason, it is impossible to cope with the dynamic geometrical shape change which is a problem of the above-mentioned Japanese Patent Application Laid-Open No. 2006-106705 and the advantage of the above-mentioned Japanese Patent Application Laid-Open No. 2007-241878.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 100 ... Drawing apparatus, 101 ... Model storage part, 102 ... Model control information calculation part, 103 ... Input model control part, 104 ... Vector data storage part, 105 ... For drawing control Primitive generator 106, rendering control primitive storage 107, curved surface vector rendering unit 108, presentation unit 109, plane vector rendering unit 601, 603, polygon 2 Internal region, 602, 604... Polygon 1 internal region, 701... Drawing parameter calculation unit, 702 .. Drawing determination information calculation unit, 703 .. Raster data generation unit, 704 .. Raster data Storage unit, 705, stencil data generation unit, 706, plane rendering result data generation unit.

Claims (11)

First storage means for storing vector data corresponding to a vector format figure;
A second storage means for storing a curved surface model as a guide for drawing the graphic, and a vector data definition position corresponding to the curved surface model and indicating an area where the vector data can be rendered;
By performing contour analysis on the vector data, primitive data including data corresponding to at least one of a linear contour and a curved contour is defined and output independently of the space in which the curved surface model is defined. First generation means for generating in a vector definition space referred to in order to determine pixel attribute values of raster data;
A curved surface that can be regarded as a first model or a plane that is a curved surface model that can be regarded as a curved surface by determining whether each element included in the curved surface model is on the same plane with reference to the vector data definition position and the curved surface model First determination means for obtaining a determination result of one of the second models as models;
A second generation unit configured to generate pixel attribute values of raster data to be output with reference to the first model and the primitive data when the first determination unit determines that the first model is included;
A third generation unit configured to generate an attribute value of a pixel of the raster data with reference to the second model and the primitive data when the first determination unit determines that the second model is the second model; A drawing apparatus comprising the drawing apparatus. For each of the elements, it further comprises second determination means for calculating where the element is in the vector definition space and determining the relationship between the element and data corresponding to the graphic in the vector definition space,
The first determination unit refers to the determination result of the second determination unit for each element, determines an element to be adopted from the plurality of elements, generates a redefined curved surface model including the element to be adopted, Determining whether the first model and the second model are on the same plane for each element included in the redefined curved surface model, obtaining a determination result of either the first model or the second model;
The second generation means refers to the first model determined from the redefined curved surface model and the primitive data, generates attribute values of pixels of raster data to be output,
The said 3rd production | generation means produces | generates the attribute value of the pixel of the said raster data with reference to the said 2nd model and the said primitive data determined from the said redefined surface model. Drawing device.   The drawing apparatus according to claim 2, wherein the second determination unit determines a relationship between the element and the vector data.   The drawing apparatus according to claim 3, wherein the second determination unit determines whether an area occupied by the element in the vector definition space overlaps an area occupied by a graphic indicated by vector data.   The drawing apparatus according to claim 2, wherein the second determination unit determines a relationship between the element and the primitive data.   The drawing apparatus according to claim 5, wherein the second determination unit determines whether an area occupied by the element in the vector definition space overlaps an area occupied by a primitive represented by the primitive data.   The first determination means separates into a plurality of elements constituting the curved surface and a plurality of elements constituting the plane based on a determination result of whether or not the plurality of elements are part of the curved surface model constituting the plane. The plurality of elements constituting the curved surface are sent to the second generation means, and the plurality of elements constituting the plane are sent to the third generation means. The drawing apparatus according to item 1. The second generation means includes
Calculating means for calculating drawing parameters including a corresponding position in the vector definition space, color information, and transparency for each pixel occupied by elements of the curved surface model when the curved surface model is projected onto a screen;
It is determined whether or not the corresponding position is included in the primitive data, and if the primitive data including the corresponding position is primitive data generated from the straight line outline, a first value is added to the drawing determination variable of the corresponding position. If the primitive data including the corresponding position is primitive data generated from the curved contour, and the corresponding position is included in the convex region of the curved contour, a third value that adds the first value to the drawing determination variable A determination means;
4. The fourth generation unit according to claim 1, further comprising: a fourth generation unit configured to generate an attribute value of a pixel corresponding to the corresponding position based on the drawing parameter if the drawing determination variable is an odd number. 8. The drawing apparatus according to any one of 7 above. The second generation means includes
Calculating means for calculating drawing parameters including a corresponding position in the vector definition space, color information, and transparency for each pixel occupied by elements of the curved surface model when the curved surface model is projected onto a screen;
It is determined whether or not the corresponding position is included in the primitive data, and if the primitive data including the corresponding position is primitive data generated from the straight line outline, a first value is added to the drawing determination variable of the corresponding position. If the primitive data including the corresponding position is primitive data generated from the curved contour, and the corresponding position is included in one of the convex region and the concave region of the curved contour, the drawing determination variable includes the first data. Third determination means for adding one value;
4. The fourth generation unit according to claim 1, further comprising: a fourth generation unit configured to generate an attribute value of a pixel corresponding to the corresponding position based on the drawing parameter if the drawing determination variable is an odd number. 8. The drawing apparatus according to any one of 7 above. The third generation means includes fifth generation means for generating stencil data by rasterizing pixels with reference to the primitive data and the second model;
10. The drawing apparatus according to claim 1, further comprising: a sixth generation unit configured to generate the output raster data with reference to the stencil data. Stores vector data corresponding to vector format figures,
A curved surface model as a guide for drawing the figure, and a vector data definition position corresponding to the curved surface model and indicating an area where the vector data can be rendered;
By performing contour analysis on the vector data, primitive data including data corresponding to at least one of a linear contour and a curved contour is defined and output independently of the space in which the curved surface model is defined. Generate in the vector definition space referenced to determine the pixel attribute value of the raster data,
A curved surface that can be regarded as a first model or a plane that is a curved surface model that can be regarded as a curved surface by determining whether each element included in the curved surface model is on the same plane with reference to the vector data definition position and the curved surface model Obtain the first judgment result of either one of the models, the second model,
If it is determined that the first model is based on the first determination result, the attribute value of the pixel of the raster data to be output is generated with reference to the first model and the primitive data.
When it is determined that the second model is based on the first determination result, an attribute value of a pixel of the raster data is generated with reference to the second model and the primitive data. .

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