110 lines
3.2 KiB
HLSL
110 lines
3.2 KiB
HLSL
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#include "MomentOutput.hlsl"
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// DONTBLOWUP is NOT part of the original paper, this is a hack i had to do to make this implementation usable
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//#define ABSORPTION_EPSILON max(REAL_MIN, 1e-5)
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#if _MOMENT_HALF_PRECISION
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//#define DONTBLOWUP HALF_MIN
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#define DONTBLOWUP HALF_EPS
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#else
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//#define DONTBLOWUP FLT_MIN
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#define DONTBLOWUP FLT_EPS
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#endif
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float4 _WrappingZoneParameters;
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/*! This function implements complex multiplication.*/
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float2 Multiply(float2 LHS, float2 RHS) {
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return float2(LHS.x * RHS.x - LHS.y * RHS.y, LHS.x * RHS.y + LHS.y * RHS.x);
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}
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// if ROV, set to the stored moments from the rasterizer order view and write the new moments back
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// no ROVs so only single precision works - needs further changes for quantized to read/write moments
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MomentOutput GenerateMoments(float vd, float t)
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{
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t = max(t, DONTBLOWUP); // we have a blowup issue when t (1 - alpha) is close to 0, empirically it happens above 0.99 alpha so let's lock it around there (no visual issues, at that point its pretty indiscernable from opaque)
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// Return early if the surface is fully transparent
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clip(0.9999999f - t);
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float a = -log(t);
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float d = WarpDepth(vd);
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MomentOutput output;
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output.b0 = a;
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#ifdef _TRIGONOMETRIC
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float p = mad(d, _WrappingZoneParameters.y, _WrappingZoneParameters.y);
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float2 c;
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sincos(p, c.y, c.x);
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float2 c2 = Multiply(c, c);
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output.b1 = float4(c, c2) * a;
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#ifdef _MOMENT8
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output.b2 = float4(Multiply(c, c2), Multiply(c2, c2)) * a;
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#elif defined(_MOMENT6)
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output.b2 = Multiply(c, c2) * a;
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#endif
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#else // not _TRIGONOMETRIC
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float d2 = d * d;
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float d4 = d2 * d2;
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#if _MOMENT_HALF_PRECISION // QUANTIZE (ROVs ONLY)
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#ifdef _MOMENT8
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float4 b_even = (float4) 0;
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float4 b_odd = (float4) 0;;
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offsetMoments(b_even, b_odd, -1.0);
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b_even *= output.b0;
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b_odd *= output.b0;
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float d6 = d4 * d2;
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float4 b_even_new = float4(d2, d4, d6, d6 * d2);
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float4 b_odd_new = float4(d, d2 * d, d4 * d, d6 * d);
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float4 b_even_new_q, b_odd_new_q;
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#elif defined(_MOMENT6)
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float3 b_even = (float3) 0;
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float3 b_odd = (float3) 0;
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offsetMoments(b_even, b_odd, -1.0);
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b_even *= output.b0;
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b_odd *= output.b0;
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float3 b_even_new = float3(d2, d4, d4 * d2);
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float3 b_odd_new = float3(d, d2 * d, d4 * d);
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float3 b_even_new_q, b_odd_new_q;
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#else // _MOMENT4
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float2 b_even = (float2) 0;
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float2 b_odd = (float2) 0;
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offsetMoments(b_even, b_odd, -1.0);
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b_even *= output.b0;
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b_odd *= output.b0;
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float2 b_even_new = float2(d2, d4);
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float2 b_odd_new = float2(d, d2 * d);
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float2 b_even_new_q, b_odd_new_q;
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#endif
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quantizeMoments(b_even_new_q, b_odd_new_q, b_even_new, b_odd_new);
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// combine moments
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b_even += b_even_new_q * a;
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b_odd += b_odd_new_q * a;
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// go back to interval [0, 1]
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b_even /= a;
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b_odd /= a;
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offsetMoments(b_even, b_odd, 1.0);
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output.b1 = float4(b_odd.x, b_even.x, b_odd.y, b_even.y);
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#ifdef _MOMENT8
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output.b2 = float4(b_odd.z, b_even.z, b_odd.w, b_even.w);
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#elif defined(_MOMENT6)
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output.b2 = float2(b_odd.z, b_even.z);
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#endif
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#else // _MOMENT_SINGLE_PRECISION
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output.b1 = float4(d, d2, d2 * d, d4) * a;
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#ifdef _MOMENT8
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output.b2 = output.b1 * d4;
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#elif defined(_MOMENT6)
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output.b2 = output.b1.xy * d4;
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#endif
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#endif // precision end
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#endif // TRIGONOMETRIC end
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return output;
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}
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