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- Shader "Hidden/Post FX/Grain Generator"
- {
- CGINCLUDE
-
- #pragma exclude_renderers d3d11_9x
- #pragma target 3.0
- #include "UnityCG.cginc"
- #include "Common.cginc"
-
- float _Phase;
-
- // Implementation based on Timothy Lottes' "Large Grain"
- // Reference code: https://www.shadertoy.com/view/4sSXDW
- // Other article of interest: http://devlog-martinsh.blogspot.fr/2013/05/image-imperfections-and-film-grain-post.html
- float Noise(float2 n, float x)
- {
- n += x;
- return frac(sin(dot(n.xy, float2(12.9898, 78.233))) * 43758.5453);
- }
-
- float Step1(float2 uv, float n)
- {
- float b = 2.0, c = -12.0;
- return (1.0 / (4.0 + b * 4.0 + abs(c))) * (
- Noise(uv + float2(-1.0, -1.0), n) +
- Noise(uv + float2( 0.0, -1.0), n) * b +
- Noise(uv + float2( 1.0, -1.0), n) +
- Noise(uv + float2(-1.0, 0.0), n) * b +
- Noise(uv + float2( 0.0, 0.0), n) * c +
- Noise(uv + float2( 1.0, 0.0), n) * b +
- Noise(uv + float2(-1.0, 1.0), n) +
- Noise(uv + float2( 0.0, 1.0), n) * b +
- Noise(uv + float2( 1.0, 1.0), n)
- );
- }
-
- float Step2(float2 uv, float n)
- {
- float b = 2.0, c = 4.0;
- return (1.0 / (4.0 + b * 4.0 + abs(c))) * (
- Step1(uv + float2(-1.0, -1.0), n) +
- Step1(uv + float2( 0.0, -1.0), n) * b +
- Step1(uv + float2( 1.0, -1.0), n) +
- Step1(uv + float2(-1.0, 0.0), n) * b +
- Step1(uv + float2( 0.0, 0.0), n) * c +
- Step1(uv + float2( 1.0, 0.0), n) * b +
- Step1(uv + float2(-1.0, 1.0), n) +
- Step1(uv + float2( 0.0, 1.0), n) * b +
- Step1(uv + float2( 1.0, 1.0), n)
- );
- }
-
- float Step3BW(float2 uv)
- {
- return Step2(uv, frac(_Phase));
- }
-
- float3 Step3(float2 uv)
- {
- float a = Step2(uv, 0.07 * frac(_Phase));
- float b = Step2(uv, 0.11 * frac(_Phase));
- float c = Step2(uv, 0.13 * frac(_Phase));
- return float3(a, b, c);
- }
-
- float4 FragGrain(VaryingsDefault i) : SV_Target
- {
- float grain = Step3BW(i.uv * float2(192.0, 192.0));
- return float4(grain.xxx, 1.0);
- }
-
- float4 FragGrainColored(VaryingsDefault i) : SV_Target
- {
- float3 grain = Step3(i.uv * float2(192.0, 192.0));
- return float4(grain, 1.0);
- }
-
- ENDCG
-
- SubShader
- {
- Cull Off ZWrite Off ZTest Always
-
- Pass
- {
- CGPROGRAM
-
- #pragma vertex VertDefault
- #pragma fragment FragGrain
-
- ENDCG
- }
-
- Pass
- {
- CGPROGRAM
-
- #pragma vertex VertDefault
- #pragma fragment FragGrainColored
-
- ENDCG
- }
- }
- }
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