59 lines
2.3 KiB
HLSL
59 lines
2.3 KiB
HLSL
// Shadergraph-friendly implementation of LODDitheringTransition.
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// The function as defined in Common.hlsl terminates on clip(f).
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// However, since it does not return or output anything, shadergraph
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// doesn't recognize it as code that gets used. This file can be removed
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// and replaced with a string custom function if Shader Graph ever adds
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// support for flagging custom function nodes as used, even if not
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// connected to anything.
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#ifndef SHADERGRAPH_CROSSFADE_INCLUDED
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#define SHADERGRAPH_CROSSFADE_INCLUDED
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#ifndef UNITY_MATERIAL_INCLUDED
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uint2 ComputeFadeMaskSeed(float3 V, uint2 positionSS)
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{
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uint2 fadeMaskSeed;
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// Is this a reasonable quality gate?
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#if defined(SHADER_QUALITY_HIGH)
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if (IsPerspectiveProjection())
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{
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// Start with the world-space direction V. It is independent from the orientation of the camera,
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// and only depends on the position of the camera and the position of the fragment.
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// Now, project and transform it into [-1, 1].
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float2 pv = PackNormalOctQuadEncode(V);
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// Rescale it to account for the resolution of the screen.
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pv *= _ScreenParams.xy;
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// The camera only sees a small portion of the sphere, limited by hFoV and vFoV.
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// Therefore, we must rescale again (before quantization), roughly, by 1/tan(FoV/2).
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pv *= UNITY_MATRIX_P._m00_m11;
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// Truncate and quantize.
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fadeMaskSeed = asuint((int2)pv);
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}
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else
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#endif
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{
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// Can't use the view direction, it is the same across the entire screen.
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fadeMaskSeed = positionSS;
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}
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return fadeMaskSeed;
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}
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#endif
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void LODDitheringTransitionSG_float(float3 viewDirWS, float4 screenPos, out float multiplyAlpha)
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{
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#if !defined (SHADER_API_GLES) && !defined(SHADER_STAGE_RAY_TRACING)
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float p = GenerateHashedRandomFloat(ComputeFadeMaskSeed(viewDirWS, screenPos.xy));
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float f = unity_LODFade.x - CopySign(p, unity_LODFade.x);
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multiplyAlpha = f < 0 ? 0.0f : 1.0f;
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#endif
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}
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void DoLODCrossFade_half(float3 viewDirWS, float4 screenPos, out half halfAlpha)
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{
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#if !defined (SHADER_API_GLES) && !defined(SHADER_STAGE_RAY_TRACING)
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float p = GenerateHashedRandomFloat(ComputeFadeMaskSeed(viewDirWS, screenPos.xy));
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float f = unity_LODFade.x - CopySign(p, unity_LODFade.x);
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float multiplyAlpha = f < 0 ? 0.0f : 1.0f;
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halfAlpha = (half)multiplyAlpha;
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#endif
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}
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#endif
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