JP2006293470A - Drawing system, method therefor, and drawing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drawing system, method therefore, and drawing program capable of reducing memory capacity necessary for display without making display needlessly complicated and unnatural when displaying a translucent object. <P>SOLUTION: The drawing system comprises a Z buffer 28 for storing the respective Z values of the translucent object and background object; a frame buffer 26 for storing the respective image information corresponding to the translucent object and background object; and a translucent image writing section 114 for drawing the translucent object by writing the image information into the frame buffer 26 based on the updated Z values, after updating the respective Z values of the Z buffer 28 about each of a plurality of polygons constructing the translucent object, without accompanying the writing process to the frame butter 26. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a drawing apparatus, a method, and a drawing program for drawing a translucent three-dimensional object through which a background image can be seen.

Conventionally, various methods for drawing a translucent object using a Z buffer are known. For example, by registering translucent polygons (blending polygons) in the order table and drawing in order from the innermost translucent polygon, one or more translucent polygons overlap with other opaque polygons There is known a drawing apparatus that draws (see, for example, Patent Document 1). In addition, an opaque buffer and a translucent buffer and a common Z buffer are provided. First, an opaque polygon is drawn on the opaque buffer using the common Z buffer, and then the same Z buffer is used. A drawing device that draws a semi-transparent polygon to a semi-transparent buffer, and then draws by α blending using the image stored in the opaque buffer and the image stored in the semi-transparent buffer. (For example, refer to Patent Document 2).
Japanese Patent No. 3495189 (No. 2-9, FIG. 1-10) JP 2002-298152 A (page 5-7, FIG. 1-3)

  By the way, in the drawing apparatus disclosed in Patent Document 1, when one object is composed of a plurality of polygons, this object is displayed semi-transparently, that is, each of the plurality of polygons constituting this object is set as a semi-transparent polygon. When drawing is performed, the plurality of polygons can be seen through, and there is a problem that the display may be complicated or unnatural. For example, in many cases, semi-transparent polygons are used to display an image that allows the background to be seen through a certain object. However, when the shape and color combination of polygons constituting the object surface and the interior are complicated, these If all are displayed semi-transparently, the outline and colors displayed corresponding to the semi-transparent object are too many, and it becomes difficult to grasp the display contents when the background image is synthesized. Also, when considering each object used in a general game device that draws using polygons, the shape of each polygon is mainly determined to accurately draw the shape and color of the object surface. However, the internal shape that is not a display target may be simplified. In such a case, the shape and color may become unnatural if the internal shape is seen through.

  Further, the drawing apparatus disclosed in Patent Document 2 draws each semi-transparent polygon with respect to the semi-transparent buffer using the semi-transparent polygon as an opaque polygon, and a semi-transparent buffer is required in addition to the opaque buffer. Therefore, there is a problem that the memory capacity necessary for display increases. Also, even if you want to display a plurality of semi-transparent objects on top of each other, the semi-transparent object behind the front semi-transparent object will not be displayed. there were. For example, consider the case where two moving opaque objects intersect, and the background image can be seen through the foreground object, but no other objects that have entered between this object and the background can be seen at all. Therefore, if attention is paid to the intersecting state of the two objects, an image considerably different from the actual intersecting state of the translucent object can be obtained.

  The present invention has been created in view of the above points, and its purpose is to display a memory capacity necessary for display without making the display unnecessarily complicated or unnatural when a translucent object is displayed. It is an object to provide a drawing apparatus, method, and drawing program that can be reduced.

  In order to solve the above-described problem, the drawing apparatus of the present invention provides a background object in which an image corresponding to a translucent object that is configured by a plurality of polygons and is a target of translucent display is arranged behind the translucent object. The depth information storage means for storing the depth information of each of the translucent object and the background object, and the image for storing the image information corresponding to each of the translucent object and the background object. Information storage means and depth information update means for updating the depth information stored in the depth information storage means for each of a plurality of polygons constituting the translucent object, without writing image information to the image information storage means And the image information corresponding to the background object is written in the image information storage means. Then, after the update process by the depth information update unit is performed, the image information corresponding to the semi-transparent object is written into the image information storage unit using the depth information stored in the depth information storage unit. Transparent image writing means.

  The drawing method of the present invention also includes depth information storage means for storing depth information of each of a translucent object that is formed of a plurality of polygons and is a target of translucent display and a background object disposed behind the translucent object. And an image information storage means for storing image information corresponding to each of the translucent object and the background object, wherein the image corresponding to the translucent object is drawn on the image corresponding to the background object. A depth information update step for updating the depth information stored in the depth information storage means for each of the plurality of polygons constituting the translucent object without the image information writing operation in the image information storage means; Image information corresponding to the background object is written to the image information storage means. After the update processing in the depth information update step is performed, the image information corresponding to the translucent object is written into the image information storage unit using the depth information stored in the depth information storage unit. A translucent image writing step.

  In addition, the drawing program of the present invention stores the depth information for storing the depth information of each of the semi-transparent object that is configured by a plurality of polygons and is the target of the semi-transparent display and the background object arranged behind the semi-transparent object. Information storage means, image information storage means for storing image information corresponding to each of the translucent object and the background object, and a plurality of translucent objects that constitute the translucent object without writing image information to the image information storage means Depth information updating means for updating the depth information stored in the depth information storage means for each of the polygons, and after the image information corresponding to the background object has been written in the image information storage means, by the depth information updating means Depth stored in depth information storage means after update processing The image information storage means using the information functions as a semi-transparent image writing means for writing image information corresponding to the semi-transparent object, and the image corresponding to the semi-transparent object is drawn on the image corresponding to the background object. Is for doing.

  Since the depth information is updated before the image information of the translucent object is written, the image information can be drawn only on the frontmost surface, thereby preventing the display from becoming complicated or unnatural. it can. In addition, since the image information corresponding to the translucent object can be written using the updated depth information after the writing of the image information corresponding to the background object is completed, an image such as a frame buffer is used for the translucent object. There is no need to prepare information storage means, and the memory capacity for display can be reduced.

  Further, the depth information updating means described above indicates that the depth information of each pixel corresponding to a plurality of polygons constituting the translucent object is closer to the viewpoint position than the depth information of other pixels having overlapping drawing positions. It is desirable to update the depth information corresponding to this drawing position. Thereby, since the depth information is updated only for the pixels on the front side of the display screen, it is possible to finally extract the frontmost surface.

  The translucent image writing means described above is configured such that when there are pixels with overlapping drawing positions among a plurality of pixels corresponding to a plurality of polygons constituting the translucent object, the plurality of pixels with the same drawing position are overlapped. It is desirable to write the image information corresponding to the translucent object using the pixel closest to the viewpoint position from among the above. As a result, even when a plurality of polygons are complexly combined to form a translucent object, translucency processing is performed using only the image information of the frontmost surface, and the rear side of this surface Therefore, it is possible to reliably prevent display from being complicated more than necessary.

  The drawing apparatus described above further includes a depth information comparison unit that compares depth information of each of the plurality of translucent objects when there are a plurality of translucent objects, and a viewpoint based on a comparison result by the depth information comparison unit. It is desirable that the update process by the depth information update unit and the image information write process by the translucent writing unit are repeatedly performed for each semi-transparent object in order from the position. Alternatively, there are a plurality of semi-transparent objects, and there is an opaque object that is configured by a plurality of polygons in addition to the background object and the plurality of semi-transparent objects, and is subject to opaque display. Compare the depth information of each of a plurality of translucent objects and opaque objects with the opaque image writing means for writing image information corresponding to the opaque object to the image information storage means using the depth information stored in the storage means. Depth information comparing means for performing the processing of writing image information by the opaque image writing means for the opaque object in order from the viewpoint position based on the comparison result by the depth information comparing means. For each translucent object It is desirable to repeat the write processing of the image information by the updating process and the semi-transparent writing means according to the depth information update unit. Thereby, when a plurality of semi-transparent objects overlap, it is possible to realize a natural display in which the plurality of semi-transparent objects can be seen through. In addition, since each translucent object is drawn only on the front side, it is possible to prevent display contents from becoming more complicated than necessary.

  Hereinafter, a drawing apparatus according to an embodiment to which the present invention is applied will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a configuration of a drawing apparatus according to an embodiment. The drawing device shown in FIG. 1 draws and displays images of three-dimensional objects, which are various objects arranged in a virtual three-dimensional space, and operates as a game device using a computer, for example. . The drawing apparatus shown in FIG. 1 includes a CPU 10 for operating as a computer, a ROM 12, a RAM 14, an external storage device 16, an input device 18, an image processing device 20, a display device 22, and a video memory 24.

  The CPU 10 executes a program stored in the ROM 12, RAM 14, or external storage device 16, thereby performing a 3D object drawing process as the game progresses. The external storage device 16 can be realized by using a DVD and a DVD reading device, but may be realized by using a hard disk device or other devices (for example, a large-capacity semiconductor memory). The external storage device 16 stores various data (for example, texture data) necessary for drawing in addition to programs necessary for the progress of the game, display of the three-dimensional object, and the like.

  The input device 18 is used by a user (player) to input instructions. Usually, a controller that gives instructions to game devices is often used as the input device 18, but a keyboard, mouse, or the like that performs various inputs in a general computer may be used as the input device 18.

  The image processing device 20 performs processing related to image drawing and display in accordance with instructions from the CPU 10. For example, it is assumed that each three-dimensional object appearing in the virtual three-dimensional space as the game progresses is composed of a plurality of polygons, and the CPU 10 has drawing conditions including a virtual viewpoint position and lighting arrangement. When set, the image processing apparatus 20 performs a perspective projection conversion process based on the viewpoint position, and performs a texture mapping process including a rendering process corresponding to a three-dimensional object that can be viewed from the viewpoint position, to perform each tertiary An image of the original object is drawn and written to the video memory 24, and the written data that has been written is read and displayed on the display device 22. In the present embodiment, it is assumed that background objects, opaque objects, and translucent objects exist as objects to be drawn. The background object may be included in the opaque object.

  The video memory 24 is used for drawing and display by the image processing apparatus 20, and includes a frame buffer 26 and a Z buffer 28. The frame buffer 26 stores the image information of each of the background object, the opaque object, and the translucent object that can be viewed from the viewpoint position for each pixel in the frame unit. For example, if the display rate is 1/60 seconds, the display contents of the frame buffer 26 for one frame are updated every 1/60 seconds. Further, RGB data corresponding to each pixel is used as the image information. It should be noted that at least two frame buffers 26 are provided for drawing and display, and when display is performed on the display device 22 using one frame buffer 26, the other frame buffer 26 is used for the next display. You may make it perform drawing processing using. The same applies to the Z buffer 28.

  The Z buffer 28 stores Z values as depth information of background objects, opaque objects, and translucent objects. In the present embodiment, the direction in which the distance from the viewpoint position increases when each three-dimensional object is viewed from the viewpoint position is defined as the Z direction, and the position along the Z direction is defined as the Z value. The larger the Z value, the closer to the display screen, and the smaller the Z value, the closer to the front of the display screen. Therefore, when opaque objects overlap in the Z direction and there are two pixels with different Z values corresponding to the same display value, display is performed for pixels arranged with a small Z value on the near side. Is called. In the above-described example, the Z value is large corresponding to the back side (the side far from the viewpoint position) of the display screen, and the Z value is small corresponding to the front side (the side close to the viewpoint position) of the display screen. However, the Z value may be small corresponding to the back side of the display screen and may be large corresponding to the near side of the display screen.

  FIG. 2 is a diagram showing details of a drawing processing unit realized by the drawing apparatus shown in FIG. As shown in FIG. 2, the drawing processing unit 100 includes a background image writing unit 110, an opaque image writing unit 112, a translucent image writing unit 114, a Z value comparison unit 118, a drawing order setting unit 120, and a drawing condition setting unit 122. I have. Each component included in the drawing processing unit 100 is a functional block realized by the CPU 10 and the image processing apparatus 20 shown in FIG. 1 and extracts those related to the drawing operation of the present invention.

  The background image writing unit 110 performs processing for writing image information of each pixel constituting the background object into the frame buffer 26. The background object is realized using a two-dimensional object, but a three-dimensional object may be used. Also, the Z value corresponding to the background object is set to a sufficiently large value.

  The opaque image writing unit 112 writes image information corresponding to the opaque object to the frame buffer 26 based on the Z value stored in the Z buffer 28. Specifically, for each pixel (target pixel) corresponding to each polygon constituting the opaque object, the opaque image writing unit 112 uses the Z value of the target pixel when another pixel exists at the same display position. Is smaller than the Z value of the other pixels, the content of the Z buffer 28 is updated using the Z value of the pixel of interest and the content of the frame buffer 26 is updated using the image information of the pixel of interest. When the Z value of the pixel is larger than the Z values of the other pixels, the contents of the Z buffer 28 and the frame buffer 26 are not updated. Further, when there is no other pixel at the same display position as the target pixel, the opaque image writing unit 112 updates the contents of the Z buffer 28 using the Z value of the target pixel and uses the image information of the target pixel. The contents of the frame buffer 26 are updated.

  The translucent image writing unit 114 writes the image information corresponding to the translucent object to the frame buffer 26 based on the Z value stored in the Z buffer 28. Specifically, the translucent image writing unit 114 has two operation modes. On the other hand, when there is another pixel at the same display position for each pixel (target pixel) corresponding to each polygon constituting the translucent object without the image information writing operation to the frame buffer 26. This is a Z buffer update mode in which only the contents of the Z buffer 28 are updated using the Z value of the pixel of interest when the Z value of the pixel is smaller than the Z values of the other pixels. On the other hand, after the operation of the Z buffer update mode is completed, the image information corresponding to the translucent object is written to the frame buffer 26 using the Z value for each pixel stored in the Z buffer 28. The frame buffer update mode to be performed. At the time when the operation of the Z buffer update mode is finished, among the pixels corresponding to the plurality of polygons constituting the opaque object, the Z value of the pixel closest to the viewpoint position is stored in the Z buffer 28 for the pixels whose display positions overlap. Has been. Therefore, when image information is written to the frame buffer 26 in the frame buffer update mode using the Z buffer 28 in which the Z value has been written in this way, an image having the smallest Z value for each display position is obtained. Drawing using information is performed. Note that drawing of image information corresponding to a translucent object is performed using, for example, an alpha blending method.

  When there are a plurality of semi-transparent objects and opaque objects in the display range, the Z value comparison unit 118 compares the Z values corresponding to the objects. This comparison operation is performed to check the relative position of each object in the Z direction, that is, which object is located behind the background, and is performed for all the pixels included in each object. There is no need.

  When there are a plurality of semi-transparent objects and opaque objects in the display range, the drawing order setting unit 120 determines whether the image by the semi-transparent image writing unit 114 or the opaque image writing unit 112 is based on the comparison result by the Z value comparison unit 118. The order of the objects to perform the information writing operation, that is, the drawing operation is determined.

  The drawing condition setting unit 122 sets various drawing conditions. Various drawing conditions include a virtual viewpoint position, an arrangement of illumination necessary for rendering processing, and the like. In addition, the various drawing conditions include designation of validity / invalidity of updating the contents of the frame buffer 26 and the Z buffer 28. When the operation of the Z buffer update mode is performed by the translucent image writing unit 114, the content update of the Z buffer 28 is enabled (Z buffer write on), and the content update of the frame buffer 26 is disabled (frame buffer write) The drawing conditions to be turned off are set. Further, when the operation of the frame buffer update mode is performed by the translucent image writing unit 114, the content update of the Z buffer 28 is disabled (Z buffer write off) and the content update of the frame buffer 26 is enabled (frame The drawing conditions for setting buffer writing on) are set.

  The Z buffer 28 described above is a depth information storage unit, the frame buffer 26 is an image information storage unit, the translucent image writing unit 114 is a depth information updating unit and a translucent image writing unit, and the opaque image writing unit 112 is an opaque image. The Z value comparison unit 118 corresponds to the writing means, and corresponds to the depth information comparison means.

  The drawing apparatus according to the present embodiment has such a configuration. Next, the operation is performed when there is only one semi-transparent object and when there are a plurality of semi-transparent objects and opaque objects. Separately described.

[When there is only one translucent object]
FIG. 3 is a flowchart showing the operation procedure of the drawing process when only one translucent object (object A) exists in addition to the background. Also, the description will be given focusing on the drawing operation for displaying the object A over the background.

  First, the drawing condition setting unit 122 determines the viewpoint position and the illumination arrangement as drawing conditions in order to draw the image information of the object A on the background image information (step 100). The viewpoint position is used for perspective projection conversion necessary for writing image information of the object A as a three-dimensional object in the planar frame buffer 26. The arrangement of illumination is used for rendering processing necessary for creating image information.

  Next, the drawing condition setting unit 122 designates frame buffer write-on (content update valid for the frame buffer 26) (step 101) and designates Z-buffer write on (content update valid for the Z buffer 28) (step 101). 102). The background image writing unit 110 performs background object drawing processing based on these drawing conditions (step 103). Specifically, since frame buffer writing on and Z buffer writing on are designated, the background image writing unit 110 writes the image information into the frame buffer 26 while updating the Z value of the Z buffer 28 as necessary. As a result, the background object is drawn.

  Next, the drawing condition setting unit 122 designates frame buffer writing off (content update invalidity of the frame buffer 26) (step 104). Note that the Z buffer write-on state designated in step 102 is maintained for the Z buffer 28. The translucent image writing unit 114 performs drawing processing of the object A based on these drawing conditions (step 105). Specifically, since frame buffer writing off and Z buffer writing on are designated, the translucent image writing unit 114 updates the Z value of the Z buffer 28 without writing image information to the frame buffer 26. Only do.

  Next, the drawing condition setting unit 122 designates frame buffer write-on (step 106), and designates Z-buffer write off (content update invalid in the Z buffer 28) (step 107). The translucent image writing unit 114 performs the drawing process for the object A based on these drawing conditions (step 108). Specifically, since frame buffer write-on and Z-buffer write-off are designated, the translucent image writing unit 114 does not update the Z value of the Z buffer 28 and does not update the Z value stored in the Z buffer 28. The image information is written to the frame buffer 26 using the value. In the example described above, Z buffer write-off is designated in step 107, but the content of the Z buffer 28 is not updated even if Z buffer write on is designated (the content of the Z buffer 28 has already been updated in step 105). Therefore, the Z buffer write-off designation in step 107 may not be performed. In addition, writing of image information of the object A to the frame buffer 26 (writing of RGB data in pixel units) is performed by combining the background RGB data and the RGB data of the object A (semi-transparent object) using an alpha blending method. This is performed by calculating new RGB data and writing the calculated RGB data in the frame buffer 26. In this way, the drawing process for the object A, which is a translucent object, is completed. This drawing process is performed at each frame rate (or at a time interval twice the frame rate when writing and reading are alternately performed using the two frame buffers 26).

  FIG. 4 is an explanatory diagram of polygons constituting the object A. The object A shown in FIG. 4 has a shape in which a cube and a rectangular parallelepiped are combined. For simplicity, it is assumed that each surface of the cube and the rectangular parallelepiped is composed of one polygon.

  FIG. 5 is a diagram showing the contents of the frame buffer 26 and the Z buffer 28 before the object A is drawn. FIG. 5A shows the contents of the frame buffer 26, and FIG. 5B shows the contents of the Z buffer 28. As shown in FIG. 5A, the frame buffer 26 stores the image information of the background object written in step 103. As shown in FIG. 5B, the Z buffer 28 stores a uniform Z value corresponding to each pixel constituting the background object. The Z value of the background object does not necessarily have to be uniform, and a Z value corresponding to the content of the background object may be set, but for the sake of simplicity, a uniform Z value is set. And

  FIG. 6 is a diagram showing the contents of the frame buffer 26 and the Z buffer 28 when the drawing process of the object A in step 105 is completed. 6A shows the contents of the frame buffer 26, and FIG. 6B shows the contents of the Z buffer 28. Since the drawing condition for frame buffer writing off is set in step 104, the content of the frame buffer 26 is maintained the same as before (image information of the background object) as shown in FIG. On the other hand, as shown in FIG. 6B, since the Z value of the Z buffer 28 is updated in accordance with the contents of the object A, the Z of the pixel corresponding to the foremost side (side closer to the viewpoint position) is finally reached. The Z value is updated using the value.

  FIG. 7 is a diagram showing the contents of the frame buffer 26 and the Z buffer 28 when the drawing process of the object A in step 108 is completed. FIG. 7A shows the contents of the frame buffer 26 and FIG. 7B shows the contents of the Z buffer 28. Since the drawing condition for frame buffer write-on is set in step 106, as shown in FIG. 7A, the contents of the frame buffer 26 are updated, and the image information of the background object is displayed at the display position where the object A exists. And the image information of the object A are synthesized by the alpha blending method, and new image information is generated and stored in the frame buffer 26. Further, since the drawing condition for Z-buffer write-off is set in step 107, the content of the Z-buffer 28 is not updated as shown in FIG. 7B.

  As described above, since the Z value of the Z buffer 28 is updated before the image information of the translucent object is written to the frame buffer 26, the image information can be drawn only on the frontmost surface, and the display can be performed. It can be prevented from becoming complicated or unnatural. In addition, after the writing of the image information corresponding to the background object to the frame buffer 26 is completed, the image information corresponding to the translucent object can be written to the same frame buffer 26 using the Z value that has been updated. There is no need to prepare a dedicated frame buffer for the translucent object, and the memory capacity for display can be reduced.

[When there are multiple semi-transparent objects and opaque objects]
FIG. 8 is a flowchart showing the operation procedure of the drawing process when there are a plurality of semi-transparent objects and opaque objects. Further, the description will be given focusing on a drawing operation for displaying a semi-transparent object or an opaque object on the background. Since each operation of Step 100 to Step 103 is the same as that shown in FIG. 3, the operation after Step 110 performed after Step 103 will be described.

  The Z value comparison unit 118 compares the Z values of a translucent object and an opaque object (which may be included in either case) displayed superimposed on the background object, and a drawing order setting unit 120. Sorts these objects in order from the back of the screen (in order of distance from the viewpoint position) based on the comparison result (step 110).

  Next, the drawing order setting unit 120 selects the innermost object (step 111), and determines whether or not a semi-transparent display is performed on this object, that is, whether or not it is a semi-transparent object ( Step 112). If the selected object is a translucent object, an affirmative determination is made, and then the drawing condition setting unit 122 designates frame buffer writing off (step 113). Note that the Z buffer write-on state designated in step 102 is maintained for the Z buffer 28. The translucent image writing unit 114 performs drawing processing of an object that is a translucent object based on these drawing conditions (step 114). Specifically, since frame buffer writing off and Z buffer writing on are designated, the translucent image writing unit 114 updates the Z value of the Z buffer 28 without writing image information to the frame buffer 26. Only do.

  Next, the drawing condition setting unit 122 designates frame buffer writing on (step 115), and the translucent image writing unit 114 performs object drawing processing based on the designated drawing condition (step 116). Specifically, since frame buffer write-on is designated, the translucent image writing unit 114 uses the Z value stored in the Z buffer 28 to write image information to the frame buffer 26 (processing by the alpha blending method). )I do.

  On the other hand, if the selected object is an opaque object, a negative determination is made in step 112, and then the opaque image writing unit 112 writes the image information into the frame buffer 26 while updating the contents of the Z buffer 28. An opaque object drawing process is performed (step 117).

  After the object drawing process in step 116 or 117 is completed in this way, the drawing order setting unit 120 determines whether or not there is another object that is not drawn (step 118). If it exists, an affirmative determination is made, and then the next object is selected (step 119). Thereafter, the process returns to step 112, and the drawing operation relating to the newly selected object is repeated. If there is no other object that is not drawn, a negative determination is made in step 118, and a series of drawing operations for a plurality of objects is terminated.

  In this way, by rearranging semi-transparent objects and opaque objects and drawing in order from the object at the back of the screen, even if multiple semi-transparent objects overlap, these multiple semi-transparent objects It is possible to realize a natural display in which the image appears transparent. In addition, since each translucent object is drawn only on the front side, it is possible to prevent display contents from becoming more complicated than necessary.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, the content of the video memory 24 is rewritten by performing perspective projection conversion or the like using the image processing apparatus 20, but the CPU 10 may directly perform these processes. Further, each configuration of the drawing processing unit 100 shown in FIG. 2 may be realized by dedicated hardware.

It is a figure which shows the structure of the drawing apparatus of one Embodiment. It is a figure which shows the detail of the drawing process part implement | achieved by the drawing apparatus shown in FIG. It is a flowchart which shows the operation | movement procedure of the drawing process in case only one translucent object other than a background exists. It is explanatory drawing of the polygon which comprises a semi-transparent object. It is a figure which shows the content of the frame buffer and Z buffer before drawing of a semi-transparent object. It is a figure which shows the content of the frame buffer and Z buffer at the time of the completion | finish of the drawing process of the object in step 105 of FIG. It is a figure which shows the content of the frame buffer and Z buffer at the time of the completion | finish of the drawing process of the object in step of FIG. It is a flowchart which shows the operation | movement procedure of the drawing process in case there exist two or more translucent objects and opaque objects.

Explanation of symbols

10 CPU
12 ROM
14 RAM
16 External storage device 18 Input device 20 Image processing device 22 Display device 24 Video memory 26 Frame buffer 28 Z buffer 100 Drawing processing unit 110 Background image writing unit 112 Opaque image writing unit 114 Translucent image writing unit 118 Z value comparison unit 120 Drawing Order setting section 122 Drawing condition setting section

Claims (11)

In a drawing apparatus that draws an image corresponding to a semi-transparent object that is composed of a plurality of polygons and that is a target of semi-transparent display on an image corresponding to a background object arranged behind the semi-transparent object,
Depth information storage means for storing depth information of each of the translucent object and the background object;
Image information storage means for storing image information corresponding to each of the translucent object and the background object;
Depth information updating means for updating depth information stored in the depth information storage means for each of the plurality of polygons constituting the translucent object without an image information writing operation in the image information storage means; ,
After the image information corresponding to the background object is written in the image information storage unit and after the update process by the depth information update unit is performed, the depth information stored in the depth information storage unit is used. Translucent image writing means for writing image information corresponding to the translucent object to the image information storage means,
A drawing apparatus comprising: In claim 1,
The depth information update means indicates that the depth information of each pixel corresponding to the plurality of polygons constituting the translucent object is closer to the viewpoint position than the depth information of other pixels having overlapping drawing positions. In some cases, the drawing apparatus updates the depth information corresponding to the drawing position. In claim 1 or 2,
The translucent image writing means may include a plurality of pixels having overlapping drawing positions when there are overlapping pixels in the plurality of pixels corresponding to the plurality of polygons constituting the translucent object. A drawing apparatus, wherein image information corresponding to the translucent object is written using a pixel closest to the viewpoint position from the inside. In any one of Claims 1-3,
A depth information comparison unit that compares depth information of each of the plurality of translucent objects when there are a plurality of the translucent objects;
An update process by the depth information update unit and an image information write process by the translucent writing unit are repeatedly performed for each of the semi-transparent objects in order from the viewpoint position based on the comparison result by the depth information comparing unit. A drawing apparatus characterized by. In any one of Claims 1-3,
There are a plurality of the semi-transparent objects, and there is an opaque object that is made up of a plurality of polygons and is an object of opaque display in addition to the background object and the plurality of the semi-transparent objects,
Opaque image writing means for writing image information corresponding to the opaque object to the image information storage means using the depth information stored in the depth information storage means;
Depth information comparison means for comparing depth information of each of the plurality of translucent objects and opaque objects;
The opaque information is written by the opaque image writing means for the opaque object in order from the viewpoint position based on the comparison result by the depth information comparison means, and the semi-transparent object A drawing apparatus, wherein an updating process by the depth information updating unit and an image information writing process by the translucent writing unit are repeatedly performed for each transparent object. Depth information storage means for storing depth information of a translucent object composed of a plurality of polygons and a background object arranged behind the translucent object, the translucent object, and the translucent object In a drawing apparatus comprising image information storage means for storing image information corresponding to each of the background objects, in a drawing method for drawing an image corresponding to the translucent object on an image corresponding to the background object,
A depth information update step of updating the depth information stored in the depth information storage means for each of the plurality of polygons constituting the translucent object without an image information writing operation to the image information storage means; ,
After the image information corresponding to the background object is written in the image information storage means, and after the update process in the depth information update step is performed, the depth information stored in the depth information storage means is used. A translucent image writing step of writing image information corresponding to the translucent object to the image information storage means;
A drawing method comprising: In claim 6,
A depth information comparison step of comparing depth information of each of the plurality of translucent objects when there are a plurality of the translucent objects;
Based on the comparison result in the depth information comparison step, the update processing by the depth information update step and the image information writing processing by the translucent writing step are repeatedly performed for each of the semi-transparent objects in order from the viewpoint position. A drawing method characterized by. In claim 6,
There are a plurality of the semi-transparent objects, and there is an opaque object that is made up of a plurality of polygons and is an object of opaque display in addition to the background object and the plurality of the semi-transparent objects,
An opaque image writing step of writing image information corresponding to the opaque object to the image information storage means using the depth information stored in the depth information storage means;
A depth information comparison step of comparing depth information of each of the plurality of translucent objects and the opaque object;
The opaque information is written in the order of increasing distance from the viewpoint position based on the comparison result in the depth information comparison step, and the opaque information is written in the opaque image writing step. A rendering method characterized by repeatedly performing update processing by the depth information update step and image information write processing by the translucent writing step for each transparent object. Computer
Depth information storage means for storing depth information of a translucent object composed of a plurality of polygons and subject to translucent display and a background object arranged behind the translucent object;
Image information storage means for storing image information corresponding to each of the translucent object and the background object;
Depth information updating means for updating depth information stored in the depth information storage means for each of the plurality of polygons constituting the translucent object without writing image information to the image information storage means; ,
After the image information corresponding to the background object is written in the image information storage unit and after the update process by the depth information update unit is performed, the depth information stored in the depth information storage unit is used. Translucent image writing means for writing image information corresponding to the translucent object to the image information storage means,
A drawing program for performing an image by superimposing an image corresponding to the translucent object on an image corresponding to the background object. In claim 9,
When a plurality of the translucent objects exist, the computer further functions as a depth information comparison unit that compares depth information of the plurality of translucent objects, and a viewpoint position based on a comparison result by the depth information comparison unit A drawing program that repeatedly performs update processing by the depth information update unit and image information write processing by the translucent writing unit for each of the semi-transparent objects in order from a distance from In claim 9,
There are a plurality of the semi-transparent objects, and there is an opaque object that is made up of a plurality of polygons and is an object of opaque display in addition to the background object and the plurality of the semi-transparent objects,
An opaque image writing unit that writes image information corresponding to the opaque object to the image information storage unit using the depth information stored in the depth information storage unit, and a plurality of the translucent objects Further functioning as depth information comparison means for comparing the respective depth information of the opaque object,
Based on the comparison result by the depth information comparison unit, the image information is written by the opaque image writing unit for the opaque object in order from the viewpoint position, and for each semi-transparent object for the semi-transparent object. A drawing program for repeatedly performing update processing by the depth information update means and image information write processing by the translucent writing means.

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