One Issue In OpenGL Depth Texture Fetching

最新推荐文章于 2024-11-07 16:48:12 发布

原创最新推荐文章于 2024-11-07 16:48:12 发布 · 667 阅读

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本文探讨了在深度纹理获取过程中对比度不佳的原因，并通过解析透视投影变换参数的影响，提出了两种不同z近值情况下对结果的影响分析。通常情况下，zNear设置为2.0足以区分不同颜色，但其确实影响深度纹理的呈现效果。

Problem: The color of fetched depth texture is with very poor contrast.

Reason and Solution:
    In depth texture fetching pass, projection transformation parameters DO effect the result.
    In my approach, here are two situations according to two different Z-Nears for the perspective projection transformation function:
         gluPerspective(GLfloat FOV, GLfloat aspect, GLdouble zNear, GLdouble zFar);

    By following results, it can be inferred that z-near DOES take effect on result of the fetched depth texture.

    Usually zNear = 2.0f would be enough for distinguishing different colors(actually the gray color represents depth).

First comes the original teapot scene:

/**********************************************************************************************************************************************/
Then zNear = 1.0f:

/**********************************************************************************************************************************************/
Finally Comes zNear = 6.0f: