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Minor sdf imporvements

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This commit is contained in:
Wojtek Figat
2024-05-24 12:41:39 +02:00
parent 7c83481d6f
commit f326fa611f
3 changed files with 17 additions and 19 deletions
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29
Source/Engine/Tools/ModelTool/ModelTool.cpp
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@@ -18,6 +18,7 @@
#include "Engine/Content/Assets/Model.h"
#include "Engine/Content/Content.h"
#include "Engine/Serialization/MemoryWriteStream.h"
#include "Engine/Engine/Units.h"
#if USE_EDITOR
#include "Engine/Core/Utilities.h"
#include "Engine/Core/Types/StringView.h"
@@ -85,7 +86,7 @@ bool ModelTool::GenerateModelSDF(Model* inputModel, ModelData* modelData, float
return true;
Float3 size = bounds.GetSize();
ModelBase::SDFData sdf;
sdf.WorldUnitsPerVoxel = 10 / Math::Max(resolutionScale, 0.0001f);
sdf.WorldUnitsPerVoxel = METERS_TO_UNITS(0.1f) / Math::Max(resolutionScale, 0.0001f); // 1 voxel per 10 centimeters
Int3 resolution(Float3::Ceil(Float3::Clamp(size / sdf.WorldUnitsPerVoxel, 4, 256)));
Float3 uvwToLocalMul = size;
Float3 uvwToLocalAdd = bounds.Minimum;
@@ -96,7 +97,6 @@ bool ModelTool::GenerateModelSDF(Model* inputModel, ModelData* modelData, float
sdf.LocalBoundsMax = bounds.Maximum;
sdf.ResolutionScale = resolutionScale;
sdf.LOD = lodIndex;
// TODO: maybe apply 1 voxel margin around the geometry?
const int32 maxMips = 3;
const int32 mipCount = Math::Min(MipLevelsCount(resolution.X, resolution.Y, resolution.Z, true), maxMips);
PixelFormat format = PixelFormat::R16_UNorm;
@@ -169,21 +169,20 @@ bool ModelTool::GenerateModelSDF(Model* inputModel, ModelData* modelData, float
// https://www.cse.chalmers.se/~uffe/HighResolutionSparseVoxelDAGs.pdf
// Brute-force for each voxel to calculate distance to the closest triangle with point query and distance sign by raycasting around the voxel
const int32 sampleCount = 12;
Array<Float3> sampleDirections;
sampleDirections.Resize(sampleCount);
constexpr int32 sampleCount = 12;
Float3 sampleDirections[sampleCount];
{
RandomStream rand;
sampleDirections.Get()[0] = Float3::Up;
sampleDirections.Get()[1] = Float3::Down;
sampleDirections.Get()[2] = Float3::Left;
sampleDirections.Get()[3] = Float3::Right;
sampleDirections.Get()[4] = Float3::Forward;
sampleDirections.Get()[5] = Float3::Backward;
sampleDirections[0] = Float3::Up;
sampleDirections[1] = Float3::Down;
sampleDirections[2] = Float3::Left;
sampleDirections[3] = Float3::Right;
sampleDirections[4] = Float3::Forward;
sampleDirections[5] = Float3::Backward;
for (int32 i = 6; i < sampleCount; i++)
sampleDirections.Get()[i] = rand.GetUnitVector();
sampleDirections[i] = rand.GetUnitVector();
}
Function<void(int32)> sdfJob = [&sdf, &resolution, &backfacesThreshold, &sampleDirections, &scene, &voxels, &xyzToLocalMul, &xyzToLocalAdd, &encodeMAD, &formatStride, &formatWrite](int32 z)
Function<void(int32)> sdfJob = [&sdf, &resolution, &backfacesThreshold, sampleDirections, &sampleCount, &scene, &voxels, &xyzToLocalMul, &xyzToLocalAdd, &encodeMAD, &formatStride, &formatWrite](int32 z)
{
PROFILE_CPU_NAMED("Model SDF Job");
Real hitDistance;
@@ -203,7 +202,7 @@ bool ModelTool::GenerateModelSDF(Model* inputModel, ModelData* modelData, float
// Raycast samples around voxel to count triangle backfaces hit
int32 hitBackCount = 0, hitCount = 0;
for (int32 sample = 0; sample < sampleDirections.Count(); sample++)
for (int32 sample = 0; sample < sampleCount; sample++)
{
Ray sampleRay(voxelPos, sampleDirections[sample]);
if (scene.RayCast(sampleRay, hitDistance, hitNormal, hitTriangle))
@@ -218,7 +217,7 @@ bool ModelTool::GenerateModelSDF(Model* inputModel, ModelData* modelData, float
float distance = (float)minDistance;
// TODO: surface thickness threshold? shift reduce distance for all voxels by something like 0.01 to enlarge thin geometry
// if ((float)hitBackCount > (float)hitCount * 0.3f && hitCount != 0)
if ((float)hitBackCount > (float)sampleDirections.Count() * backfacesThreshold && hitCount != 0)
if ((float)hitBackCount > (float)sampleCount * backfacesThreshold && hitCount != 0)
{
// Voxel is inside the geometry so turn it into negative distance to the surface
distance *= -1;

2
Source/Shaders/GI/DDGI.hlsl
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@@ -213,11 +213,11 @@ float3 SampleDDGIIrradiance(DDGIData data, Texture2D<snorm float4> probesData, T
float2 uv = GetDDGIProbeUV(data, cascadeIndex, probeIndex, octahedralCoords, DDGI_PROBE_RESOLUTION_DISTANCE);
float2 probeDistance = probesDistance.SampleLevel(SamplerLinearClamp, uv, 0).rg * 2.0f;
float probeDistanceMean = probeDistance.x;
float probeDistanceMean2 = probeDistance.y;
// Visibility weight (Chebyshev)
if (biasedPosToProbeDist > probeDistanceMean)
{
float probeDistanceMean2 = probeDistance.y;
float probeDistanceVariance = abs(Square(probeDistanceMean) - probeDistanceMean2);
float chebyshevWeight = probeDistanceVariance / (probeDistanceVariance + Square(biasedPosToProbeDist - probeDistanceMean));
weight *= max(chebyshevWeight * chebyshevWeight * chebyshevWeight, 0.05f);

5
Source/Shaders/GlobalSignDistanceField.hlsl
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@@ -223,7 +223,6 @@ GlobalSDFHit RayTraceGlobalSDF(const GlobalSDFData data, Texture3D<float> tex, T
float4 cascadePosDistance = data.CascadePosDistance[cascade];
float voxelSize = data.CascadeVoxelSize[cascade];
float voxelExtent = voxelSize * 0.5f;
float cascadeMinStep = voxelSize;
float3 worldPosition = trace.WorldPosition + trace.WorldDirection * (voxelSize * cascadeTraceStartBias);
// Hit the cascade bounds to find the intersection points
@@ -270,7 +269,7 @@ GlobalSDFHit RayTraceGlobalSDF(const GlobalSDFData data, Texture3D<float> tex, T
stepDistance *= cascadeMaxDistance;
// Detect surface hit
float minSurfaceThickness = voxelExtent * saturate(stepTime / (voxelExtent * 2.0f));
float minSurfaceThickness = voxelExtent * saturate(stepTime / voxelSize);
if (stepDistance < minSurfaceThickness)
{
// Surface hit
@@ -293,7 +292,7 @@ GlobalSDFHit RayTraceGlobalSDF(const GlobalSDFData data, Texture3D<float> tex, T
}
// Move forward
stepTime += max(stepDistance * trace.StepScale, cascadeMinStep);
stepTime += max(stepDistance * trace.StepScale, voxelSize);
}
hit.StepsCount += step;
}