KR20050065251A - Interactive 3d spatial light illumination method and system - Google Patents

Abstract

Disclosed is a method and system for interactive three-dimensional spatial light illumination, comprising: converting a three-dimensional space into a plurality of polygons; Assigning an exclusive ID number to each polygon; Simulating a light source with an image extraction device and imparting a three dimensional space to obtain an image set; Analyzing a corresponding distribution for each exclusive color in the image set to transmit and calculate the amount of light received by each polygon; Switching the actual area of the light receiving area of the polygon according to the distance between the polygon and the cube, the projection ratio, and the solid angle formed between the polygon and the cube.

Description

Interactive 3D spatial light illumination method and system

The present invention relates to a method and system for interactive three-dimensional spatial light illumination, and more particularly, to a method and system for two-way three-dimensional spatial light illumination for simulating illumination and shadows in three-dimensional space.

As three-dimensional hardware graphics effects improve and three-dimensional computer game populations increase, users increasingly demand lighting models of higher quality overall three-dimensional space. For example, when a light source illuminates an object in three-dimensional space, users are more satisfied when they can see the shading effect of the object.

Conventional shadow Z-buffer shading technology has been used to create three-dimensional images with shadows for geometric objects. The shadow Z-buffer shading technique is essentially two steps: a first step of taking the accuracy of the image space into the specimen as a camera and then measuring the depth of all pixels; A second step is to use standard techniques to return the camera to the first vision point to produce a visible image. The first step usually stores the Z-buffer data generated as a result of camera processing as a shadow map, also known as light space. Thus, whether the pixels of the image are inside a shadow area covered by the shadow map produces an appropriate shadow effect. For example, if the processing result of point P defines a pixel on the image that is visible in three-dimensional space, the coordinate (x, y, z) of point P in screen space is the coordinate (x ', y) in light space. After conversion to ', z'), the coordinate values x ', y' are used as an index for shadow map inquiry to calculate a depth value comparing the coordinate values z '. If the coordinate value z 'is greater than this depth value, another object exists between the point P and the light source, closer to the light source. That is, point P is disturbed by this other object so that point P is in the shadowed area. Therefore, the luminance of point P needs to be reduced to provide the shadow effect. On the other hand, if the coordinate value z 'is smaller than this depth value, the point P is not disturbed and thus receives full illumination from the light source.

However, the shadow Z-buffer technique has to calculate the shadow effect for each pixel in image space, which creates a large operating load on the system. If an animated filmmaker wants to preview the design effects of a three-dimensional space, he has to wait a lot of time for computation and processing to get the image effect of a fully illuminated scene. If a three-dimensional space worker wants to rearrange the lighting effects for a space, he has to wait a long time during computation and processing. The prior art also provides a method of only calculating visible pixels to reduce system load. However, this method can only provide a shadow effect at a particular visual point, not all visual points. Moreover, the shadow Z-buffer technique reduces the brightness of the pixels to produce the shadow effect, but the brightness of the shadowed area may vary widely, so they cannot be accurately reduced by the mean or empirical values.

Accordingly, there is a need to provide an interactive three-dimensional spatial light illumination method and system in order to alleviate and / or eliminate the aforementioned problems.

An original object of the present invention is an interactive three-dimensional spatial light illumination method capable of simulating and calculating the illumination and shadow effects of a space according to a physical method of calculating the amount of light received by each polygon and To provide a system.

It is yet another object of the present invention to provide a method and system for interactive three-dimensional spatial light illumination that adopts the operating efficiency of a three-dimensional graphics processor to replace conventional software processes for determining whether light transmitted from a light source is received by polygons in space. To provide.

In order to achieve the above objects, the bidirectional three-dimensional spatial light illumination method of the present invention comprises: selecting a three-dimensional (3D) space; Converting the three-dimensional space into a plurality of polygons, each polygon having three vertices; Assigning an exclusive ID number to each polygon corresponding to an exclusive color code to define an exclusive color for each polygon; Simulate a light source with an image extraction device and give the image a three-dimensional space defined by different colors at coordinates corresponding to the light source Using flat shading technology to enable obtaining a set; Analyzing the corresponding distribution for all exclusive colors in the image set to transmit and calculate the amount of light received by each polygon; Calculating an average amount of received light by each vertex; And simulating the image extraction device with a current view point and using the light shading and rendering effects generated by three-dimensional spatial illumination by a light source visible from the current view point. Using smooth shading technology to incorporate the amount of light received by the polygons and vertices to provide.

According to another feature of the invention, an interactive three-dimensional spatial light illumination system has a three-dimensional graphics processor for carrying out the method described above.

Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when combined with the accompanying drawings.

1 and 2 are diagrams of execution environments in accordance with a preferred embodiment of the present invention. 2 is a flow chart of a preferred embodiment according to the present invention. In order to calculate the shadow effect 31 produced by the object 3 illuminated by the light source 2, in the present embodiment, the system of the present invention uses the space provided by a plurality of polygons (step 202). The information of three-dimensional space 1 (step 201) is extracted. Referring to FIG. 3, FIG. 3 is a schematic diagram of a preferred embodiment using multiple polygons to provide a three dimensional space. The three-dimensional space is divided into four polygons A, B, C, and D. Each polygon consists of three vertices connected to one another. In addition, the feature of each polygon includes two sets of different types of vertex index information, that is, shared vertex index information and non-shared vertex information. Taking the three-dimensional space shown in FIG. 3 as an example, the corresponding polygonal feature information has two formats as follows.

Format 1 [shared vertex index information]:

Vertex array

Vertex matrix Vertex 0 V1 One V2 2 V3 3 V4 4 V5 5 V6

Index array

polygon Polygonal exponent A 0, 1, 2 B 2, 3, 4 C 0, 2, 4 D 0, 4, 5

Format 2 (unshared vertex index information):

Vertex array

Vertex matrix Vertex 0 V1 One V2 2 V3 3 V3 4 V4 5 V5 6 V1 7 V3 8 V5 9 V1 10 V5 11 V6

 Index array

polygon Polygonal exponent A 0, 1, 2 B 3, 4, 5 C 6, 7, 8 D 9, 10, 11

In addition, since an exclusive color code is set for all polygons (step 203), an exclusive ID number is first given to each polygon, and then a one-to-one switchable conversion operation is used to convert the exclusive ID number into an exclusive color code. In this embodiment, the exclusive color code uses RBGA (red, blue, green, alpha) in unsigned short 32-bit format, which is (255, 255, 255, 255). ) Is assigned a background color that is not limited to any polygon. In addition, the exclusive color code may adopt the RGB format or any format. In addition, each exclusive color distributed over each polygon is assigned to each vertex constituting each polygon in format 2 described above to form the following extended forms.

Vertex array

Vertex matrix Vertex Exclusive colors 0 V1 (0, 0, 0, 255) One V2 (1, 0, 0, 255) 2 V3 (2, 0, 0, 255) 3 V3 (3, 0, 0, 255) 4 V4 (4, 0, 0, 255) 5 V5 (5, 0, 0, 255) 6 V1 (6, 0, 0, 255) 7 V3 (7, 0, 0, 255) 8 V5 (8, 0, 0, 255) 9 V1 (9, 0, 0, 255) 10 V5 (10, 0, 0, 255) 11 V6 (11, 0, 0, 255)

Index array

polygon Polygonal exponent Exclusive ID Number A 0, 1, 2 0 B 3, 4, 5 One C 6, 7, 8 2 D 9, 10, 11 3

The light source 2 is then taken with an image extraction device, such as a camera, and flat shading technology is defined by other exclusive colors by the image extraction device from the coordinates corresponding to the light source to obtain an image set. It is used to perform the rendering process of the three-dimensional space (step 204). In this embodiment, the light source is an open light source whose energy is uniformly radiated from the center point and a cube with one unit length can be used to simulate the illumination of the light source. Each face of the cube (6 faces in total) is cut into an n × n grid, with the area of each grid being 1 / n ² of each face. Assuming that the image extraction device is located at the center of the cube, each grid of each face of the cube is equal to the pixels of the visual panel of the image extraction device, and this embodiment obtains the following six image extraction factors.

Face Front Left Back Right Top Bottom View direction (0, 0, -1) (-1, 0, 0) (0, 0, 1) (1, 0, 0) (0, 1, 0) (0, -1, 0) Up vector (0, 1, 0) (0, 1, 0) (0, 1, 0) (0, 1, 0) (0, 0, 1) (0, 0, -1) Right axis (1, 0, 0) (0, 0, -1) (-1, 0, 0) (0, 0, -1) (1, 0, 0) (1, 0, 0) Field of View 90 Aspect ratio 1.0 Near Plane 0.5 View-port size (n, n)

Therefore, the image extracting apparatus of the present embodiment uses the polygon data derived from the format 2 according to the above-described parameters to perform the flat shading technique and the rendering process, and then records the final rendering result.

The amount of light received by the differential regions of all polygons can then be transferred and calculated by analyzing the corresponding distribution for all exclusive colors in the image (step 205). 4, FIG. 4 is a flow chart of a preferred embodiment of calculating the amount of light received by polygons. This embodiment collects the color distributions of all pixels according to six variables (step 401); In order to obtain a projection area in the cube projected by the light modification area of each polygon (step 403), the displayed colors are converted into the corresponding exclusive ID numbers of each polygon (step 402). For example, in the collected result, there are k pixels with a color of RGBA (0, 0, 0, 255) according to the above-described formats; RGBA (0, 0, 0, 255) corresponds to polygon A shown in FIG. 3, and the projection area of the light receiving area of polygon A on the cube is represented by the following [Equation 1]:

[Equation 1]

In addition, the present embodiment can calculate the actual area of the light receiving area of the polygon according to the distance between the polygon and the cube as the projection ratio (Equation 2) (step 404):

[Equation 2]

Where 'dist' is the distance between the polygon's center of gravity and the light source, Is the solid angle formed between the polygon and the cube. if, If all are zero, the actual area of the light receiving area of polygon A is as follows:

As a result, the amount of light received by the differential region of the polygon is given by Equation 3 below (step 405):

[Equation 3]

× dot

Where A _lighting is the actual area of the polygonal light receiving area, A _total is the total area of the polygon, N is the normal vector of the polygon, L is the vector for the center of gravity of the polygon, and I is the Strength. This embodiment takes advantage of the feature that the center of gravity of the polygon must be inside the polygon providing light energy received by any point in the polygonal region.

In order to make the final imaging result flat and smooth, the system needs to calculate the average received energy of each vertex and generate the final vertex color (step 206). In a data structure that uses polygons to provide an object or space, sometimes many vertices may be shared by many other polygons; For example, vertex V5 shown in FIG. 5 is shared by polygons B, C, and D. However, in order for these vertices to receive different amounts of light in different polygons and to flatten and smooth the image, this embodiment averages all the different amounts of light for each shared vertex, and then the final color. Calculate the characteristics determined by this average and vertex of the received light to produce the over luminance.

Finally, the image extraction apparatus returns to the current point of view for observing the three-dimensional space, and a three-dimensional spatial illumination of the light source, in which a smooth shading technique observes the amount of light of the polygons from the current point of view. It is used to integrate with the vertices that provide the shading and presentation effects generated from (step 207).

As described above, the present invention can simulate and calculate lighting and shading effects according to the physical effects of actual light illumination, so that the actual received received for every polygon to improve the imaging quality produced by the geometric pattern Light is obtained. In addition, the present invention utilizes a three-dimensional graphics processor that provides a great functional capability that replaces conventional software processes.

Although the present invention has been described in connection with the preferred embodiments, it should be understood that many other modifications and variations are possible without departing from the spirit and scope of the invention as claimed below.

1 is a diagram of an execution environment of a preferred embodiment according to the present invention.

2 is a flow chart of a preferred embodiment according to the present invention.

3 is a schematic diagram of a preferred embodiment using multiple polygons to provide a three dimensional space.

4 is a flow chart of a preferred embodiment of calculating the amount of light received by the polygon of FIG.

Claims (10)

(A) selecting a three dimensional (3D) space; (B) converting the three-dimensional space into a plurality of polygons in which each polygon has three vertices; (C) assigning an exclusive ID number to each polygon corresponding to an exclusive color code to define an exclusive color for each polygon; (D) Simulate a light source with an image extraction device and create a three-dimensional space in which the image extraction device is defined with different colors at coordinates corresponding to the light source. Using flat shading technology to enable imparting and obtaining an image set; (E) analyzing the corresponding distribution for all exclusive colors in the image set to deliver and calculate the amount of light received by each polygon; (F) calculating an average amount of received light by each vertex; And (G) Simulate the image extraction device with a current view point, and a rendering and rendering effect generated by three-dimensional spatial illumination by a light source visible from the current view point. Using a smooth shading technology to incorporate the amount of light received by the polygons and vertices to provide. The method of claim 1, All polygons are: Shared vertex index data (A) in which all vertices are defined as vertex indexes; And A method for interactive three-dimensional spatial light illumination, wherein all vertices have unshared vertex index data defined as different vertex indexes for different polygons. The method of claim 1, And said exclusive color code uses a short 32-bit format of RGBA unsigned. The method of claim 1, And wherein the exclusive color code uses an RGB format. The method of claim 1, Step (D) is: A cube with one unit length is adopted to simulate the results when a light source is placed in the cube, all sides of the cube are divided into n × n grids, and the area of each grid is all sides 1 / n ² , wherein the image extraction device obtains each of six sets of images corresponding to six sides of the cube. The method of claim 5, Step (E) is: (E1) analyzing a plurality of exclusive colors in the image; (E2) converting the plurality of exclusive colors into a corresponding exclusive ID number to obtain polygons corresponding to the exclusive ID numbers; (E3) calculating a projection area on the cube projected by the light receiving area of each polygon; (E4) switching the actual area of the light receiving area of the polygon according to the distance between the polygon and the cube, the projection ratio, and the solid angle formed between the polygon and the cube; (E5) further comprising calculating the amount of light received by the differential area of the polygon. The method of claim 6, In the step (E3), k pixels are comparable to the exclusive colors of the polygon, and the projection area of the light receiving area of the polygon is calculated by the following equation (1). . [Equation 1] The method of claim 6, In the step (E4), the solid angle formed between the polygon and the cube is and the two-dimensional three-dimensional spatial light illumination, characterized in that the actual area of the light receiving area of the polygon is calculated by the following equation (2). Way. [Equation 2] here, 'dist': Distance between polygon center of gravity and light source The method of claim 6, In the step (E5), the amount of light received by the discriminating region of the polygon is the following [Equation 3] bidirectional three-dimensional spatial light illumination method. [Equation 3] × dot here, A _lighting : the actual area of the light receiving area of the polygon, A _total : total area of the polygon, N is the normal vector of the polygon, L is the vector for the center of gravity of the polygon, I: intensity of light source In an interactive three-dimensional spatial light illumination system equipped with a three-dimensional graphics processor: Means for selecting a three-dimensional (3D) space; Means for converting the three-dimensional space into a plurality of polygons, each polygon having three vertices; Means for assigning an exclusive ID number to each polygon corresponding to an exclusive color code to define an exclusive color for each polygon; Simulate a light source with an image extraction device and give the image a three-dimensional space defined by different colors at coordinates corresponding to the light source Means for using flat shading technology to enable obtaining a set; Means for analyzing a corresponding distribution for all exclusive colors in the image set to transmit and calculate the amount of light received by each polygon; Means for calculating an average amount of received light by each vertex; And Simulate the image extraction device with a current view point and provide light shading and rendering effects generated by three-dimensional spatial illumination by a light source visible from the current view point. And means for using smooth shading technology to incorporate the amount of light received by the polygons and vertices to achieve the same.