Phong GLSL Shader - 3

GLSL Phong Shader

I have found the problem with the textures. It was as I thought, you have to copy the texture coordinates in a vertex shader. Then the texture appeared, but it was not lit very well. It seems, that the gl_FragColor-variable used to set the color of the fragment shader is always clipped to 0.0 - 1.0. So I now collect the color in a variable, then do the multiplication with the texture value (that is all you have to do if you only use GL_MODULATE as texture environment) and then put the value into gl_FragColor.

Regular fixed functionality pipeline

I also finally made some screen shots. The one at the top is with the new GLSL shader, the one to the right is with the fixed functionality pipeline. I think you can clearly see the difference, the images used exactly the same settings and were not edited.

With the Phong shader you can see three highlights in the sphere from the three light sources, whereas the fixed functionality hardly shows the strongest and it doesn't look good. Also the spot light lights the plane with the Phong shader, in the other image there is no hint of it on the plane at all. Finally near the right lower corner of the plane you can see the difference in diffuse lighting. With the Phong shader it is much more defined and clearly circular. In the fixed functionality there is not much definition remaining.

Granted, I "cheated" a bit by using a big quad, if the plane used many more vertices it wouldn't look as bad with the fixed functionality. But the basic problem remains, the spots would appear but they would be much more diffuse and highlights with high specular exponents would need a very fine geometry. And somehow I have the impression that the shader is by far a more efficient solution than creating more geometry.