KR100308457B1 - Rendering method of the 3D-object programmed with OpenGL interface - Google Patents

Abstract

The present invention relates to a rendering method of a 3D object programmed with an OpenGL interface that renders a 3D object programmed with the OpenGL interface as a high quality image by linking a renderman library to the OpenGL interface. Such a rendering method includes: a rendering method of rendering a 3D object and outputting it as a 2D image, the method comprising: a first step of creating a program for rendering a 3D object using an OpenGL interface; A second step of preprocessing to render the three-dimensional object; A third step of selecting a type of renderer for rendering the 3D object; A fourth step of rendering the 3D object by driving the OpenGL program when the OpenGL renderer is selected in the third step; And a fifth step of applying the OpenGL program to a renderman library and converting the renderer renderer when the renderer renderer is selected in the third step, and rendering the 3D object by driving the converted program.

Description

Rendering method of the 3D-object programmed with OpenGL interface}

The present invention relates to a rendering method using the linkage between OpenGL and Renderman, and more specifically, to the OpenGL interface, which renders a 3D object of OpenGL programmed in high definition by linking the RenderMan library to the OpenGL interface. It relates to a rendering method of a three-dimensional object.

The process of creating an image to appear on the screen from three-dimensional space in a computer is a series of processes that first design an object, place objects and light sources in a virtual three-dimensional space, determine the viewpoint of an observer, and finally create a two-dimensional image. This is a time and costly task. In particular, the rendering process for creating a two-dimensional image from the foreground of the three-dimensional space is very large time difference depending on the quality of the two-dimensional image to be obtained.

The most representative rendering methods currently used include the OpenGL renderer using the OpenGL interface (OpenGL interface) and the renderman renderer using the RenderMan interface. These two methods have advantages and disadvantages as a rendering method in which their purpose is clearly distinguished. In other words, the OpenGL renderer is a rendering method mainly used to obtain an image in real time, and is used to obtain an image having a certain quality within a short time although the image quality is poor. On the other hand, the renderman renderer is used for the purpose of obtaining a high-quality image such as a photograph, and thus has a disadvantage in that it takes a relatively long time.

In the past, these two renderers were distinguished and used according to the user's purpose, and since they were incompatible with each other, additional work was necessary, such as re-programming for each interface when using them for other purposes.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, an object of the present invention is implemented by using the OpenGL interface by integrating a program implemented using the OpenGL interface to use the renderman library. It is to provide a rendering method of a 3D object programmed with an OpenGL interface that allows a renderman renderer to render a programmed program.

1 is a flowchart illustrating a rendering method using a general OpenGL interface;

2 is a flowchart illustrating a rendering method using a general renderman interface;

3 is a flowchart illustrating a rendering method of a 3D object programmed with an OpenGL interface according to an embodiment of the present invention;

4A to 4B are diagrams for explaining the effect of a rendering method of a 3D object programmed with an OpenGL interface according to the present invention.

In order to achieve the above object, a rendering method of a 3D object in which a renderman library is linked to an OpenGL interface according to the present invention is a rendering method of rendering a 3D object and outputting it as a 2D image. A first step of creating a program for rendering a three-dimensional object; A second step of preprocessing to render the three-dimensional object; A third step of applying the OpenGL program to a renderman library and converting the OpenGL program so that a renderman renderer renders the 3D object; And a fourth step in which the renderer renderer drives the converted program to render the three-dimensional object.

Preferably, the second step of preprocessing for the rendering, the color, position, angle, degree of attenuation, the intensity of light of the light source, the color of the ambient light source and the direction of the light source such as unidirectional / bidirectional A first sub-step of setting a, a second sub-step of setting a surface characteristic and color and coordinates of the three-dimensional object to be rendered, and a texture characteristic and a coordinate, and a third sub-step of setting a viewpoint and a range of an observer. Include.

Preferably, the third step of converting the OpenGL program for rendering the renderman comprises: a first sub-step of converting the OpenGL program's coordinate system into a left-handed coordinate system; and converting the matrix representation of the OpenGL program in a row-first manner. The second sub-step, which calls the renderman functions one-to-one correspondence with the functions used in the Open-GE program, excludes light sources that the render man cannot support in the OpenGL program, and the third sub-step, which excludes projection transformations, objects, videos, etc. 4 substep, a fifth substep that calls a series of renderman functions that perform the same actions as one function used in the OpenGL program, and an addition to the OpenGL program so that the renderman renderer can use external color calculation functions. Include the sixth substep of declaring and using functions.

According to the present invention, there is provided a rendering method for rendering a three-dimensional object and outputting it as a two-dimensional image, comprising: a first step of creating a program for rendering a three-dimensional object using an OpenGL interface; A second step of preprocessing to render the three-dimensional object; A third step of selecting a type of renderer for rendering the 3D object; A fourth step of rendering the 3D object by driving the OpenGL program when the OpenGL renderer is selected in the third step; And a fifth step of applying the OpenGL program to a renderman library and converting the renderer renderer when the renderer renderer is selected in the third step, and rendering the 3D object by driving the converted program. A rendering method of a three-dimensional object programmed with an OpenGL interface is provided.

In addition, there is provided a computer-readable recording medium having recorded thereon a program for realizing a rendering method using the linkage between OpenGL and Renderman according to the present invention.

Hereinafter, referring to the accompanying drawings, a method of rendering a 3D object programmed with an OpenGL interface according to the present invention will be described in detail.

In general, in the rendering method using the OpenGL interface, as shown in FIG. 1, first, a preprocessing process such as setting a light source, an object surface characteristic, an observer viewpoint, and a range is performed. After that, the position of the object to be rendered in the three-dimensional space is set, and the OpenGL renderer renders the object, thereby generating a two-dimensional image.

In contrast, in the rendering method using the renderman interface, as shown in FIG. 2, first, the viewpoint and the range of the observer are set, the light source and the object position are set in the three-dimensional space, and then the renderman renderer renders the object. Two-dimensional image is generated. As described above, in OpenGL and Renderman, in order to render a 3D object, setting of a light source, an object surface characteristic, an observer's viewpoint and range, and an object's position in 3D space must be performed.

3 is a flowchart illustrating a method of rendering a 3D object programmed with an OpenGL interface according to an embodiment of the present invention.

First, a program for rendering a 3D object using the OpenGL interface is created (S31). Then, a preprocessing step is performed to render (S32). In this preprocessing step, the color, position, angle, attenuation degree, and light intensity of the light source are set, and whether the ambient color of the light source and the reflecting direction are unidirectional or bidirectional. In addition, the object surface characteristics and texture characteristics are set. The surface color value of the object, the coordinates of the object, the normal vector, the color, the texture coordinate, and the like are set, and the texture characteristics and the coordinates are set.

Next, when the user selects the type of renderer (S33), when the OpenGL renderer is selected, the process proceeds to step S34 to deliver the OpenGL program to the OpenGL renderer so that the general OpenGL rendering process is performed.

On the other hand, when the renderer renderer is selected in step S33, the renderer delivers the OpenGL program to the renderer renderer to render, and performs a preprocessing process for this (S35). This preprocessing process follows a predefined process for different internal graphics states between OpenGL and Renderman.

In other words, OpenGL and Renderman use different coordinates and matrix processing methods, and all the functions that can be supported are different. Therefore, in order to apply OpenGL program to the Renderman library, the differences between the two renderers must be changed. .

First, the two renderers use different coordinate systems, so if you apply the OpenGL program to Renderman Libraries, you will not get the desired image. That is, the OpenGL program uses the right hand coordinate system, whereas the renderman renderer uses the left hand coordinate system, so the right hand coordinate system in the OpenGL program must be changed to the left hand coordinate system and applied to the renderman library.

In addition, the matrix processing method used by the two renderers is different. OpenGL processes the matrix as column priority, while renderman processes the row first. Therefore, to get the correct final rendered image, we need to convert the matrix used in OpenGL to row first and then apply it to the RenderMan library.

Also, there are some that are only supported by OpenGL and not by the Renderman renderer. In other words, in OpenGL, you can define the light source anywhere in the program, but in the case of RenderMan, it is only possible at the beginning. In addition, projection transforms, objects, and videos that are only supported in OpenGL and not supported in Renderman are applied to the Renderman library except in the OpenGL program. In other words, OpenGL has two matrices internally for view and projection, but since Renderman has only one model view matrix for this purpose, it converts the two matrices into one. Two-dimensional points or lines used in OpenGL are not supported by RenderMan and are therefore excluded from rendering objects. Also, the three-dimensional buffer or composite buffer used to support video in OpenGL is excluded from this video because Renderman does not support it.

In addition, Renderman can use an external color calculation function to support shadows on objects, which OpenGL does not support. Therefore, we declare an additional function in the OpenGL program so that we can use the external color calculation functions supported by the Renderman library.

Among the above-mentioned contents, the contents of the preprocessing for renderman rendering are shown in Table 1, and the limitations of the OpenGL program for renderman rendering are shown in Table 2.

Item Preprocessing Content Coordinate system OpenGL uses the right hand coordinate system, while Renderman uses the left hand coordinate system. Therefore, it changes the coordinate system of OpenGL program. procession OpenGL stores the matrix in a column-first manner, while RenderMan stores the matrix in a row-first manner. Thus, the matrix representation of OpenGL programs is changed to the row-first mode as appropriate. Internal Graphics State Only Supported by OpenGL Limitations exclude light sources, projection transformations, usable objects, and video support that are not supported by the Renderman structure. Effects Only Supported by Renderman Declare an additional function (glShader) in your OpenGL program so that you can use the external color calculation functions supported by RenderMan.

Item Contents Light source The declaration of the light source must be done at the beginning of the program. That is, it must be declared before glEnable (LIGHTi). Viewpoint, projection transformation View and projection transformations use only the Model View matrix. modelling Points or lines are excluded from the rendering object. video Stereoscopic and composite buffers used for various effects in animation cannot be used.

In order to use the Renderman renderer effectively in OpenGL programs, additional functions must be added. This function is called the glShader function, which supports the functions provided by Renderman for calculating the color of the object surface, the deformation of the object surface, the exterior of the object, and the interior of the object.

After performing the preprocessing process for rendering the renderman as described above, the renderman renderer renders a 3D object created by the OpenGL program (S36) and outputs a 2D image (S37).

4A to 4B are diagrams for explaining the effect of the rendering method according to the present invention. 4A is a diagram illustrating a two-dimensional image output when an OpenGL program is rendered using an OpenGL renderer, and FIG. 4B is an output when a program converted and applied to a renderman library is rendered using a renderman renderer. It is a figure which shows the two-dimensional image which becomes.

While the invention has been described above based on the preferred embodiments thereof, these embodiments are intended to illustrate rather than limit the invention. It will be apparent to those skilled in the art that various changes, modifications, or adjustments to the above embodiments can be made without departing from the spirit of the invention. Therefore, the protection scope of the present invention will be limited only by the appended claims, and should be construed as including all such changes, modifications or adjustments.

As described above, since the rendering program written using the OpenGL interface can be rendered by the OpenGL renderer and the renderman renderer, the user can render more precisely using the OpenGL interface that is easier to learn from the user's perspective. This has the benefit of increasing the reusability of the program.

In addition, the process of rendering to obtain a high quality image is a time-consuming task. In particular, since the user has to go through several trials and errors to obtain the desired image, the time is inevitably increased. According to the present invention, it is necessary to obtain a high-quality image because it is possible to obtain a high-quality image by correcting the foreground while finally checking a rough image by using OpenGL rendering in a relatively fast time, and finally rendering the image with a renderer renderer. There is an advantage to save time.

Claims (8)

In the rendering method for rendering a three-dimensional object to output a two-dimensional image, A first step of creating a program for rendering a three-dimensional object using the OpenGL interface; A second step of preprocessing to render the three-dimensional object; A third step of applying the OpenGL program to a renderman library and converting the OpenGL program so that a renderman renderer renders the 3D object; And And a fourth step of the renderer renderer driving the converted program to render the 3D object. The method of claim 1, wherein the second step of preprocessing for rendering, A first sub-step of setting the color, position, angle, attenuation degree, intensity of light of the light source, and setting the state of the light source such that the color of the ambient light of the light source and the direction in which the light is reflected are unidirectional / bidirectional, A second substep of setting surface characteristics and colors and coordinates, and texture characteristics and coordinates of the three-dimensional object to be rendered; and And a third substep of setting a viewpoint and a range of an observer. The method of claim 1 or 2, wherein the third step of converting the OpenGL program for rendering the renderman, A first substep of converting the coordinate system of the OpenGL program to the left-hand coordinate system; The second substep of converting the matrix representation of the OpenGL program to the row first method, The third substep of excluding light sources, projection transformations, objects, movies, etc. that renderman cannot support in the OpenGL program, The fourth substep of calling renderman functions that correspond one-to-one with the functions used in the OpenGL program, A fifth substep of calling a series of renderman functions that perform the same operation as one function used in an OpenGL program, and A rendering method of a 3D object incorporating a RenderMan library in an OpenGL interface, comprising a sixth step of declaring and using an additional function in an OpenGL program to use an external color calculation function supported by a RenderMan renderer. In the rendering method for rendering a three-dimensional object to output a two-dimensional image, A first step of creating a program for rendering a three-dimensional object using the OpenGL interface; A second step of preprocessing to render the three-dimensional object; A third step of selecting a type of renderer for rendering the 3D object; A fourth step of rendering the 3D object by driving the OpenGL program when the OpenGL renderer is selected in the third step; And If a renderer renderer is selected in the third step, the OpenGL program is applied to a renderman library and converted, and the renderman renderer includes a fifth step of driving the converted program to render the 3D object. Rendering method of 3D object programmed with OpenGL interface. The method of claim 4, wherein the second step of preprocessing for rendering, A first sub-step of setting the color, position, angle, attenuation degree, intensity of light of the light source, and setting the state of the light source such that the color of the ambient light of the light source and the direction in which the light is reflected are unidirectional / bidirectional, A second substep of setting surface characteristics and colors and coordinates, and texture characteristics and coordinates of the three-dimensional object to be rendered; and A rendering method by applying an OpenGL program to the renderman library, the method comprising a third substep of setting an observer's viewpoint and range. The method of claim 4 or 5, wherein in the fifth step, converting the OpenGL program for renderman rendering, A first substep of converting the coordinate system of the OpenGL program to the left-hand coordinate system; The second substep of converting the matrix representation of the OpenGL program to the row first method, The third substep of excluding light sources, projection transformations, objects, movies, etc. that renderman cannot support in the OpenGL program, The fourth substep of calling renderman functions that correspond one-to-one with the functions used in the OpenGL program, A fifth substep of calling a series of renderman functions that perform the same operation as one function used in an OpenGL program, and A method of rendering an OpenGL program applied to the Renderman library, including a sixth sub-step of declaring and using an additional function in the OpenGL program so that an external color calculation function supported by the Renderman renderer can be used. On your computer, A first step of creating a program for rendering a three-dimensional object using the OpenGL interface; A second step of preprocessing to render the three-dimensional object; A third step of applying the OpenGL program to a renderman library and converting the OpenGL program so that a renderman renderer renders the 3D object; And A computer-readable program that records a program for realizing a rendering method of a 3D object linked to a renderman library on an OpenGL interface including a fourth step in which the renderman renderer drives the converted program to render the 3D object. Record carrier. On your computer, A first step of creating a program for rendering a three-dimensional object using the OpenGL interface; A second step of preprocessing to render the three-dimensional object; A third step of selecting a type of renderer for rendering the 3D object; A fourth step of rendering the 3D object by driving the OpenGL program when the OpenGL renderer is selected in the third step; And If the renderman renderer is selected in the third step, the openGL program is applied to the renderman library and converted, and the renderman renderer includes a fifth step of driving the converted program to render the 3D object. A computer-readable recording medium storing a program for realizing a rendering method of a three-dimensional object programmed by an interface.