Celestia Forums

Please take a look at the area marked with red in the image below:
it acquires some ugly noise if i enable Open GL 2.0. Compare with the pic
above it... To the right are the relevant parts of the surface, spec and
bumpmap shown in 100%.

What is happening here?

- rthorvald

If you look carefully at the top image, you can see that the noise is also visible in the top image. What I believe is happening is that you have some compression artifacts in your bump map. These ordinarily don't interfered with final appearance of the surface. However, in the OpenGL 2.0, the normal map (generated automatically from the bump map) is used for specular reflections as well as diffuse light. Specular highlights will reveal noise in normal maps much more readily that diffuse reflection. What I would recommend is to use a PNG normal map instead of a bump map (and this is only one of the many reasons to prefer normal maps over bump maps.)

--Chris

chris wrote:... is used for specular reflections as well as diffuse light. Specular highlights will reveal noise in normal maps much more readily that diffuse reflection. What I would recommend is to use a PNG normal map instead of a bump map (and this is only one of the many reasons to prefer normal maps over bump maps

Thanks! I??ll look into this, then.

- rthorvald