progs/fpglsl/tex-multi.glsl

   1 // Multi-texture fragment shader
   2 // Brian Paul
   3
   4 // Composite second texture over first.
   5 // We're assuming the 2nd texture has a meaningful alpha channel.
   6
   7 uniform sampler2D tex1;
   8 uniform sampler2D tex2;
   9
  10 void main()
  11 {
  12    vec4 t1 = texture2D(tex1, gl_Color.xy);
  13    vec4 t2 = texture2D(tex2, gl_Color.yz);
  14    gl_FragColor = mix(t1, t2, t2.w);
  15 }