GoaLitiuM/FlaxEngine
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Optimize model SDF with 8-bit storage (if possible)

Browse Source
This commit is contained in:
Wojciech Figat
2022-03-22 15:08:38 +01:00
parent 6196bb31fe
commit 18321937e4
4 changed files with 60 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

BIN
Content/Shaders/GlobalSignDistanceField.flax (Stored with Git LFS)
View File

Binary file not shown.

72
Source/Engine/Content/Assets/Model.cpp
View File

@@ -598,8 +598,35 @@ bool Model::GenerateSDF(float resolutionScale, int32 lodIndex)
const int32 mipCount = Math::Min(MipLevelsCount(resolution.X, resolution.Y, resolution.Z, true), maxMips);
if (!SDF.Texture)
SDF.Texture = GPUTexture::New();
// TODO: use 8bit format for smaller SDF textures (eg. res<100)
if (SDF.Texture->Init(GPUTextureDescription::New3D(resolution.X, resolution.Y, resolution.Z, PixelFormat::R16_Float, GPUTextureFlags::ShaderResource | GPUTextureFlags::UnorderedAccess, mipCount)))
PixelFormat format = PixelFormat::R16_UNorm;
int32 formatStride = 2;
float formatMaxValue = MAX_uint16;
typedef float (*FormatRead)(void* ptr);
typedef void (*FormatWrite)(void* ptr, float v);
FormatRead formatRead = [](void* ptr)
{
return (float)*(uint16*)ptr;
};
FormatWrite formatWrite = [](void* ptr, float v)
{
*(uint16*)ptr = (uint16)v;
};
if (resolution.MaxValue() < 8)
{
// For smaller meshes use more optimized format (gives small perf and memory gain but introduces artifacts on larger meshes)
format = PixelFormat::R8_UNorm;
formatStride = 1;
formatMaxValue = MAX_uint8;
formatRead = [](void* ptr)
{
return (float)*(uint8*)ptr;
};
formatWrite = [](void* ptr, float v)
{
*(uint8*)ptr = (uint8)v;
};
}
if (SDF.Texture->Init(GPUTextureDescription::New3D(resolution.X, resolution.Y, resolution.Z, format, GPUTextureFlags::ShaderResource | GPUTextureFlags::UnorderedAccess, mipCount)))
{
SAFE_DELETE_GPU_RESOURCE(SDF.Texture);
return true;
@@ -613,17 +640,18 @@ bool Model::GenerateSDF(float resolutionScale, int32 lodIndex)
scene.BuildBVH();
// Allocate memory for the distant field
Array<Half> voxels;
voxels.Resize(resolution.X * resolution.Y * resolution.Z);
const int32 voxelsSize = resolution.X * resolution.Y * resolution.Z * formatStride;
void* voxels = Allocator::Allocate(voxelsSize);
Vector3 xyzToLocalMul = uvwToLocalMul / Vector3(resolution);
Vector3 xyzToLocalAdd = uvwToLocalAdd;
const Vector2 encodeMAD(0.5f / SDF.MaxDistance * formatMaxValue, 0.5f * formatMaxValue);
const Vector2 decodeMAD(2.0f * SDF.MaxDistance / formatMaxValue, -SDF.MaxDistance);
// TODO: use optimized sparse storage for SDF data as hierarchical bricks
// TODO: use optimized sparse storage for SDF data as hierarchical bricks as in papers below:
// https://graphics.pixar.com/library/IrradianceAtlas/paper.pdf
// http://maverick.inria.fr/Membres/Cyril.Crassin/thesis/CCrassinThesis_EN_Web.pdf
// http://ramakarl.com/pdfs/2016_Hoetzlein_GVDB.pdf
// https://www.cse.chalmers.se/~uffe/HighResolutionSparseVoxelDAGs.pdf
// then use R8 format and brick size of 8x8x8
// 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;
@@ -640,10 +668,9 @@ bool Model::GenerateSDF(float resolutionScale, int32 lodIndex)
for (int32 i = 6; i < sampleCount; i++)
sampleDirections.Get()[i] = rand.GetUnitVector();
}
Function<void(int32)> sdfJob = [this, &resolution, &sampleDirections, &scene, &voxels, &xyzToLocalMul, &xyzToLocalAdd](int32 z)
Function<void(int32)> sdfJob = [this, &resolution, &sampleDirections, &scene, &voxels, &xyzToLocalMul, &xyzToLocalAdd, &encodeMAD, &formatStride, &formatWrite](int32 z)
{
PROFILE_CPU_NAMED("Model SDF Job");
const float encodeScale = 1.0f / SDF.MaxDistance;
float hitDistance;
Vector3 hitNormal, hitPoint;
Triangle hitTriangle;
@@ -682,7 +709,7 @@ bool Model::GenerateSDF(float resolutionScale, int32 lodIndex)
distance *= -1;
}
const int32 xAddress = x + yAddress;
voxels.Get()[xAddress] = Float16Compressor::Compress(distance * encodeScale);
formatWrite((byte*)voxels + xAddress * formatStride, distance * encodeMAD.X + encodeMAD.Y);
}
}
};
@@ -690,24 +717,24 @@ bool Model::GenerateSDF(float resolutionScale, int32 lodIndex)
// Upload data to the GPU
BytesContainer data;
data.Link((byte*)voxels.Get(), voxels.Count() * sizeof(Half));
auto task = SDF.Texture->UploadMipMapAsync(data, 0, resolution.X * sizeof(Half), data.Length(), true);
data.Link((byte*)voxels, voxelsSize);
auto task = SDF.Texture->UploadMipMapAsync(data, 0, resolution.X * formatStride, data.Length(), true);
if (task)
task->Start();
// Generate mip maps
Array<Half> voxelsMip;
void* voxelsMip = nullptr;
for (int32 mipLevel = 1; mipLevel < mipCount; mipLevel++)
{
Int3 resolutionMip = Int3::Max(resolution / 2, Int3::One);
voxelsMip.Resize(resolutionMip.X * resolutionMip.Y * resolutionMip.Z);
const int32 voxelsMipSize = resolutionMip.X * resolutionMip.Y * resolutionMip.Z * formatStride;
if (voxelsMip == nullptr)
voxelsMip = Allocator::Allocate(voxelsMipSize);
// Downscale mip
Function<void(int32)> mipJob = [this, &voxelsMip, &voxels, &resolution, &resolutionMip](int32 z)
Function<void(int32)> mipJob = [this, &voxelsMip, &voxels, &resolution, &resolutionMip, &encodeMAD, &decodeMAD, &formatStride, &formatRead, &formatWrite](int32 z)
{
PROFILE_CPU_NAMED("Model SDF Mip Job");
const float encodeScale = 1.0f / SDF.MaxDistance;
const float decodeScale = SDF.MaxDistance;
const int32 zAddress = resolutionMip.Y * resolutionMip.X * z;
for (int32 y = 0; y < resolutionMip.Y; y++)
{
@@ -726,7 +753,7 @@ bool Model::GenerateSDF(float resolutionScale, int32 lodIndex)
for (int32 dx = 0; dx < 2; dx++)
{
const int32 dxAddress = (x * 2 + dx) + dyAddress;
const float d = Float16Compressor::Decompress(voxels.Get()[dxAddress]) * decodeScale;
const float d = formatRead((byte*)voxels + dxAddress * formatStride) * decodeMAD.X + decodeMAD.Y;
distance += d;
}
}
@@ -734,23 +761,26 @@ bool Model::GenerateSDF(float resolutionScale, int32 lodIndex)
distance *= 1.0f / 8.0f;
const int32 xAddress = x + yAddress;
voxelsMip.Get()[xAddress] = Float16Compressor::Compress(distance * encodeScale);
formatWrite((byte*)voxelsMip + xAddress * formatStride, distance * encodeMAD.X + encodeMAD.Y);
}
}
};
JobSystem::Execute(mipJob, resolutionMip.Z);
// Upload to the GPU
data.Link((byte*)voxelsMip.Get(), voxelsMip.Count() * sizeof(Half));
task = SDF.Texture->UploadMipMapAsync(data, mipLevel, resolutionMip.X * sizeof(Half), data.Length(), true);
data.Link((byte*)voxelsMip, voxelsMipSize);
task = SDF.Texture->UploadMipMapAsync(data, mipLevel, resolutionMip.X * formatStride, data.Length(), true);
if (task)
task->Start();
// Go down
voxelsMip.Swap(voxels);
Swap(voxelsMip, voxels);
resolution = resolutionMip;
}
Allocator::Free(voxelsMip);
Allocator::Free(voxels);
#if !BUILD_RELEASE
auto endTime = Platform::GetTimeSeconds();
LOG(Info, "Generated SDF {}x{}x{} ({} kB) in {}ms for {}", resolution.X, resolution.Y, resolution.Z, SDF.Texture->GetMemoryUsage() / 1024, (int32)((endTime - startTime) * 1000.0), GetPath());

7
Source/Engine/Renderer/GlobalSignDistanceFieldPass.cpp
View File

@@ -38,9 +38,9 @@ PACK_STRUCT(struct ModelRasterizeData
Vector3 VolumeToUVWMul;
float MipOffset;
Vector3 VolumeToUVWAdd;
float MaxDistance;
float DecodeMul;
Vector3 VolumeLocalBoundsExtent;
float Padding0;
float DecodeAdd;
});
PACK_STRUCT(struct Data
@@ -379,7 +379,8 @@ bool GlobalSignDistanceFieldPass::Render(RenderContext& renderContext, GPUContex
modelData.VolumeToUVWMul = volumeToUVWMul;
modelData.VolumeToUVWAdd = volumeToUVWAdd;
modelData.MipOffset = (float)mipLevelIndex;
modelData.MaxDistance = sdf.MaxDistance;
modelData.DecodeMul = 2.0f * sdf.MaxDistance;
modelData.DecodeAdd = -sdf.MaxDistance;
_modelsBuffer->Write(modelData);
_modelsTextures.Add(sdf.Texture->ViewVolume());

6
Source/Shaders/GlobalSignDistanceField.shader
View File

@@ -15,9 +15,9 @@ struct ModelRasterizeData
float3 VolumeToUVWMul;
float MipOffset;
float3 VolumeToUVWAdd;
float MaxDistance;
float DecodeMul;
float3 VolumeLocalBoundsExtent;
float Padding0;
float DecodeAdd;
};
META_CB_BEGIN(0, Data)
@@ -73,7 +73,7 @@ float DistanceToModelSDF(float minDistance, ModelRasterizeData modelData, Textur
BRANCH if (minDistance <= distanceToVolume) return distanceToVolume;
// Sample SDF
float volumeDistance = modelSDFTex.SampleLevel(SamplerLinearClamp, volumeUV, modelData.MipOffset).x * modelData.MaxDistance;
float volumeDistance = modelSDFTex.SampleLevel(SamplerLinearClamp, volumeUV, modelData.MipOffset).x * modelData.DecodeMul + modelData.DecodeAdd;
// Combine distance to the volume with distance to the surface inside the model
float result = CombineDistanceToSDF(volumeDistance, distanceToVolume);