   Shader question
  First problem : I have two actual materials on one texture (eg. wodden plank with metal plate on it, and a large one). I want to add specular lighting on metal, but shader will also add specular on wood which is not desireable(as wood isn''t shiny).Second problem : Metal plate that is dusty or with scars that don''t reflect light any more (if you can understand what I am saying since English isn''t my native languge). So specular would lose itself vhen changing viewing direction.My solution(theroetical) : Encode on a different texture color values where black means not reflective, and other colors mean reflective(I think it would be better to use second texture since alpha will already be used).Can this approach work? I was thinking of multiplying specular value with texel on that second texture (since black is 0.0, specular is now 0, therefore nonexistent). Please correct me if I am wrong. 
  I believe what you are looking for is a gloss map. This can be used e.g. to make parts of the metal rusty, effectively specifying the amount of the specular component that is present on a per-pixel basis.James ;  Usually the alpha of the texture is used to hold this 'shininess' amount, but if thats already in use then you could just use another texture to hold it.Since you're adding a new texture, you might be able to encode a specular power amount in as well. Then you could control how tight or diffused the specular was over the surface.Also, you might want to have a look at how Tenebrae does things: http://tenebrae.sourceforge.net/index.php?page=technical/textures.htm   [edited by - OrangyTang on February 4, 2004 7:10:03 PM];  OrangyTang: thanks for the link, it was exactly what I needed. 