progs/glsl/CH11-bumpmaptex.frag

   1 //
   2 // Fragment shader for procedural bumps
   3 //
   4 // Authors: John Kessenich, Randi Rost
   5 //
   6 // Copyright (c) 2002-2006 3Dlabs Inc. Ltd.
   7 //
   8 // See 3Dlabs-License.txt for license information
   9 //
  10 // Texture mapping/modulation added by Brian Paul
  11 //
  12
  13 varying vec3 LightDir;
  14 varying vec3 EyeDir;
  15
  16 uniform float BumpDensity;     // = 16.0
  17 uniform float BumpSize;        // = 0.15
  18 uniform float SpecularFactor;  // = 0.5
  19
  20 sampler2D Tex;
  21
  22 void main()
  23 {
  24     vec3 ambient = vec3(0.25);
  25     vec3 litColor;
  26     vec2 c = BumpDensity * gl_TexCoord[0].st;
  27     vec2 p = fract(c) - vec2(0.5);
  28
  29     float d, f;
  30     d = p.x * p.x + p.y * p.y;
  31     f = inversesqrt(d + 1.0);
  32
  33     if (d >= BumpSize)
  34         { p = vec2(0.0); f = 1.0; }
  35
  36     vec3 SurfaceColor = texture2D(Tex, gl_TexCoord[0].st).xyz;
  37
  38     vec3 normDelta = vec3(p.x, p.y, 1.0) * f;
  39     litColor = SurfaceColor * (ambient + max(dot(normDelta, LightDir), 0.0));
  40     vec3 reflectDir = reflect(LightDir, normDelta);
  41
  42     float spec = max(dot(EyeDir, reflectDir), 0.0);
  43     spec *= SpecularFactor;
  44     litColor = min(litColor + spec, vec3(1.0));
  45
  46     gl_FragColor = vec4(litColor, 1.0);
  47 }