An example of how IL's conditional shader compilation system could work.

Example Shader

#version 1
required-version: 140 // GLSL version
name: "Example Shader"
description: "A simple example shader, which shows how you could have conditional compilation based on whether or not texture coordinates are available."

#vertex-shader
#array-attrib position vec3 in_Position
#if drawable.texcoord
#array-attrib texcoord vec2 in_Texcoord
out vec2 texcoord;
#endif
#matrix MVP mvp

void main()
{
    gl_Position = mvp * vec4(in_Position, 1.0);
#if drawable.texcoord
    texcoord = in_Texcoord;
#endif
}

#fragment-shader
#fragdata accumulation vec3 out_Color
#if drawable.texcoord
in vec2 texcoord;
#texture color0 sampler2D tex
#elif lighting.ambient
#constant lighting.ambient vec3 color
#endif

void main()
{
#if drawable.texcoord
    out_Color = texture(tex, texcoord);
#elif lighting.ambient
    out_Color = color;
#else
    out_Color = vec3(.5, .5, .5);
#endif
}