39 lines
1,005 B
HLSL
39 lines
1,005 B
HLSL
#include "common.hlsli"
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struct v2p
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{
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float4 tc0 : TEXCOORD0; // Central
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float4 tc1 : TEXCOORD1; // -1,+1
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float4 tc2 : TEXCOORD2; // -2,+2
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float4 tc3 : TEXCOORD3; // -3,+3
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float4 tc4 : TEXCOORD4; // -4,+4
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float4 tc5 : TEXCOORD5; // -5,+5
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float4 tc6 : TEXCOORD6; // -6,+6
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float4 tc7 : TEXCOORD7; // -7,+7
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};
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#define LUMINANCE_BASE 0.0001f
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float luminance(float2 tc)
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{
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float3 source = tex2D(s_image, tc);
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return dot(source, LUMINANCE_VECTOR * def_hdr);
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}
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// perform 2x2=4s convolution, working on 4x4=16p area
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// that means 256x256 source will be scaled to (256/4)x(256/4) = 64x64p
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// a): 256x256 => 64x64p with log
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// b): 64x64p => 8x8p
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// c): 8x8p => 1x1p with exp
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float4 main(v2p I) : COLOR
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{
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// first 8 bilinear samples (8x4 = 32 pixels)
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float4 final;
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final.x = luminance(I.tc0);
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final.y = luminance(I.tc1);
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final.z = luminance(I.tc2);
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final.w = luminance(I.tc3);
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// OK
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return final;
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}
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