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贴图方式总结及备忘

实践之后才会觉得书中的每句话都富有含意,总结以备忘.
1. Light Mapping,光照贴图,准确地说是漫反射光照贴图,所以也有简称反射贴图的.
<Realtime Rendering>定义如下: For static lighting in an environment, the diffuse component on any surface remains the same from any angle. Because of this view-independence, the contribution of light to a surface could be captured in a texture structure attached to a surface. By using a seperate, precomputed texture that captured the lighting contributions, and multiplying it with the underlying surface, one can achieve Phong-like shading.
Reference: http://www.flipcode.com/articles/article_lightmapping.shtml

2.AphaMapping,Alpha贴图,Before testing and replacing the Z-buffer value, there needs to be a test of the alpha value. If alpha is 0, then nothing further is done for the pixel. If this additional test is not done, the tree's background color will not affect the pixel's color, but will potentially affect the z-value, which can lead to rendering errors.

3.Gloss mapping: A gloss map is a texture that changes the contribution of the specular component over the surface.

4.Cube Map:
A. Reflective surface need mapping locations on the object's surface to the appropriate reflected direction in the 360 degree environment surrounding the object.
B.The texturing enable priority is cube map, 3D, 2D, and finally 1D.
C.立方图非常适用于实现环境,反射和光照效果,立方图还可以把纹理环绕到球体上,使纹理单元均匀地分布于它的各个面上.

5.Shere Env Map
A.Also called reflection mapping
B.All EM start with a ray from the viewer to a point on the reflector. This ray is then reflected with respect to the normal at that point. Instead of finding the intersection with the closest surface, as ray tracing does, EM uses the direction of the reflection vector as an index to an image containing the environment.
C.Shere EM is view-dependent meaning that a different sphere map texture image is required for each different eye position. Additionally, sphere mapping is subject to unsightly "speckle" artifacts at the glancing edges of sphere mapped objects.

6.Dot3 Bump Map
A.

References: <Realtime Rendering>
http://developer.nvidia.com/object/cube_map_ogl_tutorial.html
游戏编程精粹5.6

posted on 2006-11-02 23:58 linghuye 阅读(1125) 评论(0)  编辑 收藏 引用 所属分类: 3D图形学研究置顶项目

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