75 lines
2 KiB
HLSL
75 lines
2 KiB
HLSL
/*
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contributors: Inigo Quiles
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description: Add fog to the scene. See https://iquilezles.org/articles/fog/
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use: float3 raymarchFog(in <float3> pixelColor, float distanceToPoint)
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options:
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- FOG_DENSITY
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- FOG_FALLOFF
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- FOG_COLOR_COOL
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- FOG_COLOR_WARM
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*/
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#ifndef FOG_DENSITY
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#define FOG_DENSITY 0.0
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#endif
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#ifndef FOG_FALLOFF
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#define FOG_FALLOFF 0.0
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#endif
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#ifndef FOG_COLOR_COOL
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#define FOG_COLOR_COOL float3(0.5, 0.6, 0.7)
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#endif
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#ifndef FOG_COLOR_WARM
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#define FOG_COLOR_WARM float3(1.0, 0.9, 0.7)
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#endif
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#ifndef FNC_RAYMARCH_FOG
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#define FNC_RAYMARCH_FOG
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float3 raymarchFog(in float3 col, // color of pixel
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in float t) // distance to point
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{
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float fogAmount = 1.0 - exp(-t * FOG_DENSITY);
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return lerp(col, FOG_COLOR_COOL, fogAmount);
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}
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float3 raymarchColorFog(in float3 col, // color of pixel
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in float t, // distance to point
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in float3 rd, // camera to point
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in float3 lig) // sun direction
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{
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float fogAmount = 1.0 - exp(-t * FOG_DENSITY);
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float sunAmount = max(dot(rd, lig), 0.0);
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float3 fogColor = lerp(FOG_COLOR_COOL, FOG_COLOR_WARM, pow(sunAmount, 8.0));
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return lerp(col, fogColor, fogAmount);
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}
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float3 raymarchHeightFog(in float3 col, // color of pixel
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in float t, // distnace to point
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in float3 ro, // camera position
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in float3 rd) // camera to point vector
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{
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float fogAmount = (FOG_DENSITY / FOG_FALLOFF) * exp(-ro.y * FOG_FALLOFF) * (1.0 - exp(-t * rd.y * FOG_FALLOFF)) / rd.y;
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return lerp(col, FOG_COLOR_COOL, saturate(fogAmount));
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}
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float3 raymarchFog(in float3 col, in float t, in float3 ro, in float3 rd)
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{
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if (FOG_DENSITY > 0.0 && FOG_FALLOFF > 0.0) {
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return raymarchHeightFog(col, t, ro, rd);
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}
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else if (FOG_DENSITY > 0.0) {
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#ifdef LIGHT_DIRECTION
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return raymarchColorFog(col, t, rd, LIGHT_DIRECTION);
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#else
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return raymarchFog(col, t);
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#endif
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}
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else {
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return col;
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}
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}
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#endif
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