1 | #version 100 |
---|
2 | precision mediump int; |
---|
3 | precision mediump float; |
---|
4 | |
---|
5 | uniform sampler2D inRTT; |
---|
6 | uniform sampler2D inLum; |
---|
7 | uniform vec2 texelSize; |
---|
8 | |
---|
9 | varying vec2 uv; |
---|
10 | const vec4 BRIGHT_LIMITER = vec4(0.6, 0.6, 0.6, 0.0); |
---|
11 | |
---|
12 | const float MIDDLE_GREY = 0.72; |
---|
13 | const float FUDGE = 0.001; |
---|
14 | const float L_WHITE = 1.5; |
---|
15 | |
---|
16 | /** Tone mapping function |
---|
17 | @note Only affects rgb, not a |
---|
18 | @param inColour The HDR colour |
---|
19 | @param lum The scene lumninence |
---|
20 | @returns Tone mapped colour |
---|
21 | */ |
---|
22 | vec4 toneMap(in vec4 inColour, in float lum) |
---|
23 | { |
---|
24 | // From Reinhard et al |
---|
25 | // "Photographic Tone Reproduction for Digital Images" |
---|
26 | |
---|
27 | // Initial luminence scaling (equation 2) |
---|
28 | inColour.rgb *= MIDDLE_GREY / (FUDGE + lum); |
---|
29 | |
---|
30 | // Control white out (equation 4 nom) |
---|
31 | inColour.rgb *= (1.0 + inColour.rgb / L_WHITE); |
---|
32 | |
---|
33 | // Final mapping (equation 4 denom) |
---|
34 | inColour.rgb /= (1.0 + inColour.rgb); |
---|
35 | |
---|
36 | return inColour; |
---|
37 | } |
---|
38 | |
---|
39 | void main(void) |
---|
40 | { |
---|
41 | vec4 accum = vec4(0.0, 0.0, 0.0, 0.0); |
---|
42 | |
---|
43 | accum += texture2D(inRTT, uv + texelSize * vec2(-1.0, -1.0)); |
---|
44 | accum += texture2D(inRTT, uv + texelSize * vec2( 0.0, -1.0)); |
---|
45 | accum += texture2D(inRTT, uv + texelSize * vec2( 1.0, -1.0)); |
---|
46 | accum += texture2D(inRTT, uv + texelSize * vec2(-1.0, 0.0)); |
---|
47 | accum += texture2D(inRTT, uv + texelSize * vec2( 0.0, 0.0)); |
---|
48 | accum += texture2D(inRTT, uv + texelSize * vec2( 1.0, 0.0)); |
---|
49 | accum += texture2D(inRTT, uv + texelSize * vec2(-1.0, 1.0)); |
---|
50 | accum += texture2D(inRTT, uv + texelSize * vec2( 0.0, 1.0)); |
---|
51 | accum += texture2D(inRTT, uv + texelSize * vec2( 1.0, 1.0)); |
---|
52 | |
---|
53 | // take average of 9 samples |
---|
54 | accum *= 0.1111111111111111; |
---|
55 | |
---|
56 | // Reduce bright and clamp |
---|
57 | accum = max(vec4(0.0, 0.0, 0.0, 1.0), accum - BRIGHT_LIMITER); |
---|
58 | |
---|
59 | // Sample the luminence texture |
---|
60 | vec4 lum = texture2D(inLum, vec2(0.5, 0.5)); |
---|
61 | |
---|
62 | // Tone map result |
---|
63 | gl_FragColor = toneMap(accum, lum.r); |
---|
64 | } |
---|