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UnrealEngine/Engine/Shaders/Private/RayTracing/RayTracingDecalGrid.ush
2025-05-18 13:04:45 +08:00

133 lines
3.5 KiB
HLSL

// Copyright Epic Games, Inc. All Rights Reserved.
#ifndef USE_RAY_TRACING_DECAL_GRID
#define USE_RAY_TRACING_DECAL_GRID 0
#endif
#include "../Common.ush"
#include "../Visualization.ush"
#include "/Engine/Shared/RayTracingDefinitions.h"
struct FDecalLoopCount {
uint NumDecals;
#if USE_RAY_TRACING_DECAL_GRID
uint DecalGridOffset;
#endif
};
#if USE_RAY_TRACING_DECAL_GRID
FDecalLoopCount DecalGridLookup(float3 TranslatedWorldPos)
{
FDecalLoopCount Result;
Result.NumDecals = 0;
Result.DecalGridOffset = ~0u;
if (all(RayTracingDecals.TranslatedBoundMin <= TranslatedWorldPos) && all(TranslatedWorldPos <= RayTracingDecals.TranslatedBoundMax))
{
float3 P = TranslatedWorldPos - RayTracingDecals.TranslatedBoundMin;
float3 D = RayTracingDecals.TranslatedBoundMax - RayTracingDecals.TranslatedBoundMin;
int2 UVx = int2(floor(RayTracingDecals.GridResolution * P.yz / D.yz));
int2 UVy = int2(floor(RayTracingDecals.GridResolution * P.xz / D.xz));
int2 UVz = int2(floor(RayTracingDecals.GridResolution * P.xy / D.xy));
uint DecalNx = RayTracingDecals.Grid.Load(int4(UVx, 0, 0));
uint DecalNy = RayTracingDecals.Grid.Load(int4(UVy, 1, 0));
uint DecalNz = RayTracingDecals.Grid.Load(int4(UVz, 2, 0));
uint DecalN = DecalNx;
uint DecalOffset = RayTracingDecals.GridMaxCount * (0 + 3 * (UVx.x + UVx.y * RayTracingDecals.GridResolution));
if ((RayTracingDecals.GridAxis > 2 && DecalNy < DecalN) || RayTracingDecals.GridAxis == 1)
{
DecalN = DecalNy;
DecalOffset = RayTracingDecals.GridMaxCount * (1 + 3 * (UVy.x + UVy.y * RayTracingDecals.GridResolution));
}
if ((RayTracingDecals.GridAxis > 2 && DecalNz < DecalN) || RayTracingDecals.GridAxis == 2)
{
DecalN = DecalNz;
DecalOffset = RayTracingDecals.GridMaxCount * (2 + 3 * (UVz.x + UVz.y * RayTracingDecals.GridResolution));
}
Result.DecalGridOffset = DecalOffset;
Result.NumDecals += DecalN;
}
return Result;
}
float3 DecalGridVisualize(FDecalLoopCount LoopCount, int VisualizeMode)
{
const float3 OutsideColor = 0.18;
const float3 EmptyColor = 0.36;
if (LoopCount.DecalGridOffset != ~0u)
{
switch (VisualizeMode)
{
case 2:
{
// color by unique decal list
uint H = 0;
for (int Index = 0, Num = LoopCount.NumDecals; Index < Num; Index++)
{
H = MurmurMix(H + RayTracingDecals.GridData[LoopCount.DecalGridOffset + Index]);
}
return IntToColor(H);
}
case 3:
{
// color by chosen axis
int Axis = (LoopCount.DecalGridOffset / RayTracingDecals.GridMaxCount) % 3;
if (Axis == 0) return float3(0.9, 0.2, 0.2);
if (Axis == 1) return float3(0.2, 0.9, 0.2);
if (Axis == 2) return float3(0.2, 0.2, 0.9);
return float3(0.8, 0.2, 0.8); // error
}
default:
{
// default mode - color by decal count
uint N = LoopCount.NumDecals;
if (N < 1)
{
return EmptyColor;
}
float Max = RayTracingDecals.GridMaxCount;
float t = saturate(float(N) / Max);
return BlueGreenRedColorMap(t);
}
}
}
// outside decal grid bounds
return OutsideColor;
}
uint GetDecalId(uint Index, FDecalLoopCount LoopCount)
{
if (Index >= 0)
{
return RayTracingDecals.GridData[LoopCount.DecalGridOffset + Index];
}
return Index;
}
#else
FDecalLoopCount DecalGridLookup(float3 TranslatedWorldPos)
{
uint NumDecals = min(RayTracingDecals.Count, RAY_TRACING_DECAL_COUNT_MAXIMUM);
FDecalLoopCount Result;
Result.NumDecals = NumDecals;
return Result;
}
float3 DecalGridVisualize(FDecalLoopCount LoopCount, int VisualizeMode)
{
return 0.5;
}
uint GetDecalId(uint Index, FDecalLoopCount LoopCount)
{
return Index;
}
#endif