progs/glsl/CH11-bumpmap.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
  11 varying vec3 LightDir;
  12 varying vec3 EyeDir;
  13
  14 uniform vec3  SurfaceColor;    // = (0.7, 0.6, 0.18)
  15 uniform float BumpDensity;     // = 16.0
  16 uniform float BumpSize;        // = 0.15
  17 uniform float SpecularFactor;  // = 0.5
  18
  19 void main()
  20 {
  21     vec3 litColor;
  22     vec2 c = BumpDensity * gl_TexCoord[0].st;
  23     vec2 p = fract(c) - vec2(0.5);
  24
  25     float d, f;
  26     d = p.x * p.x + p.y * p.y;
  27     f = inversesqrt(d + 1.0);
  28
  29     if (d >= BumpSize)
  30         { p = vec2(0.0); f = 1.0; }
  31
  32     vec3 normDelta = vec3(p.x, p.y, 1.0) * f;
  33     litColor = SurfaceColor * max(dot(normDelta, LightDir), 0.0);
  34     vec3 reflectDir = reflect(LightDir, normDelta);
  35
  36     float spec = max(dot(EyeDir, reflectDir), 0.0);
  37     spec *= SpecularFactor;
  38     litColor = min(litColor + spec, vec3(1.0));
  39
  40     gl_FragColor = vec4(litColor, 1.0);
  41 }