polyadvent

A game engine from scratch in C
git clone git://jb55.com/polyadvent
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shadows.glsl (1682B)


      1 
      2 float texture2DCompare(sampler2D depths, vec2 uv, float compare){
      3   float depth = texture2D(depths, uv).r;
      4   return step(compare, depth);
      5 }
      6 
      7 float texture2DShadowLerp(sampler2D depths, vec2 size, vec2 uv, float compare){
      8   vec2 texelSize = vec2(1.0)/size;
      9   vec2 f = fract(uv*size+0.5);
     10   vec2 centroidUV = floor(uv*size+0.5)/size;
     11 
     12   float lb = texture2DCompare(depths, centroidUV+texelSize*vec2(0.0, 0.0), compare);
     13   float lt = texture2DCompare(depths, centroidUV+texelSize*vec2(0.0, 1.0), compare);
     14   float rb = texture2DCompare(depths, centroidUV+texelSize*vec2(1.0, 0.0), compare);
     15   float rt = texture2DCompare(depths, centroidUV+texelSize*vec2(1.0, 1.0), compare);
     16   float a = mix(lb, lt, f.y);
     17   float b = mix(rb, rt, f.y);
     18   float c = mix(a, b, f.x);
     19   return c;
     20 }
     21 
     22 float PCF(sampler2D depths, vec2 size, vec2 uv, float compare){
     23   float result = 0.0;
     24   for(int x=-1; x<=1; x++){
     25     for(int y=-1; y<=1; y++){
     26       vec2 off = vec2(x,y)/size;
     27       result += texture2DShadowLerp(depths, size, uv+off, compare);
     28     }
     29   }
     30   return result/9.0;
     31 }
     32 
     33 vec3 shadow_strength(vec4 position, vec4 normal, vec4 v_shadow_coord) {
     34     vec3 visibility = vec3(1.0);
     35     vec4 shadow_sample = texture(shadow_map, v_shadow_coord.xy);
     36 
     37     float light_angle = dot(light_dir, normal.xyz);
     38     float bias = 0.002;
     39 
     40     bool in_shadow =
     41         shadow_sample.z < v_shadow_coord.z - bias
     42         && shadow_sample.y < 1.0;
     43 
     44     if (light_dir.z > 0.0 && in_shadow) {
     45         float factor = 1.0-abs(light_angle);
     46         // float factor = 1.0;
     47         visibility = vec3(1.0)*factor;
     48         // visibility = shadow_sample;
     49     }
     50 
     51     // visibility += normal_offset_scale;
     52 
     53 
     54     return visibility;
     55 }