feat: translate clusterlod to C# and restructure to Ghost.Graphics.Meshlet

This commit is contained in:
2026-03-16 16:01:57 +00:00
parent e831b71a79
commit 301a6d1c45
14 changed files with 1076 additions and 2 deletions

View File

@@ -0,0 +1,199 @@
using System;
using Ghost.MeshOptimizer;
using Misaki.HighPerformance;
namespace Ghost.Graphics.Meshlet;
internal struct Cluster
{
public nuint vertices;
public UnsafeList<uint> indices;
public int group;
public int refined;
public ClodBounds bounds;
}
public unsafe static class ClodBuilder
{
private const float CONST_SIMPLIFY_RATIO_DEFAULT = 0.5f;
private const float CONST_SIMPLIFY_THRESHOLD_DEFAULT = 0.85f;
private const float CONST_SIMPLIFY_ERROR_MERGE_PREVIOUS_DEFAULT = 1.0f;
private const float CONST_SIMPLIFY_ERROR_MERGE_ADDITIVE_DEFAULT = 0.0f;
private const float CONST_SIMPLIFY_ERROR_FACTOR_SLOPPY_DEFAULT = 2.0f;
public static nuint Build(ClodConfig config, ClodMesh mesh, void* outputContext, ClodOutputDelegate outputCallback, Allocator allocator = Allocator.Persistent)
{
if (mesh.vertexAttributesStride % (nuint)sizeof(float) != 0)
throw new ArgumentException("vertexAttributesStride must be a multiple of sizeof(float)");
var locks = new UnsafeList<byte>((int)mesh.vertexCount, allocator);
locks.Resize(mesh.vertexCount);
for (int i = 0; i < (int)mesh.vertexCount; i++)
locks[i] = 0;
// Generate position-only remap
var remap = new UnsafeList<uint>((int)mesh.vertexCount, allocator);
remap.Resize(mesh.vertexCount);
Api.meshopt_generatePositionRemap(remap.Ptr, mesh.vertexPositions, mesh.vertexCount, mesh.vertexPositionsStride);
// Set up protect bits on UV seams
if (mesh.attributeProtectMask != 0)
{
nuint maxAttributes = mesh.vertexAttributesStride / sizeof(float);
for (nuint i = 0; i < mesh.vertexCount; i++)
{
uint r = remap[(int)i];
for (nuint j = 0; j < maxAttributes; j++)
{
if ((r != i) && ((mesh.attributeProtectMask & (1u << (int)j)) != 0))
{
if (mesh.vertexAttributes[i * maxAttributes + j] != mesh.vertexAttributes[r * maxAttributes + j])
{
locks[(int)i] |= (byte)Api.meshopt_SimplifyVertex_Protect;
}
}
}
}
}
// Initial clusterization
var clusters = ClodInternal.Clusterize(config, mesh, mesh.indices, mesh.indexCount, allocator);
// Compute initial bounds
for (int i = 0; i < (int)clusters.Length; i++)
{
clusters[i].bounds = ClodBoundsHelper.ComputeBounds(mesh, clusters[i].indices, 0.0f);
}
var pending = new UnsafeList<int>((int)clusters.Length, allocator);
pending.Resize((nuint)clusters.Length);
for (int i = 0; i < (int)clusters.Length; i++)
pending[i] = i;
int depth = 0;
while (pending.Length > 1)
{
var groups = ClodInternal.Partition(config, mesh, clusters, pending, remap, allocator);
pending.Clear();
// Lock boundaries
ClodInternal.LockBoundary(locks, groups, clusters, remap, mesh.vertexLock);
for (int i = 0; i < (int)groups.Length; i++)
{
var merged = new UnsafeList<uint>(groups[i].Length * (int)config.MaxTriangles * 3, allocator);
for (int j = 0; j < (int)groups[i].Length; j++)
{
var clusterIndices = clusters[groups[i][j]].indices;
for (int k = 0; k < (int)clusterIndices.Length; k++)
merged.Add(clusterIndices[k]);
}
nuint targetSize = ((nuint)merged.Length / 3) * (nuint)config.SimplifyRatio * 3;
var bounds = ClodBoundsHelper.MergeBounds(clusters, groups[i]);
float error = 0.0f;
var simplified = ClodSimplify.Simplify(config, mesh, merged, locks, targetSize, &error, allocator);
if (simplified.Length > (nuint)(merged.Length * config.SimplifyThreshold))
{
bounds.error = float.MaxValue;
OutputGroup(config, mesh, clusters, groups[i], bounds, depth, outputContext, outputCallback, allocator);
merged.Dispose();
simplified.Dispose();
continue;
}
bounds.error = Math.Max(bounds.error * config.SimplifyErrorMergePrevious, error) + error * config.SimplifyErrorMergeAdditive;
int refined = OutputGroup(config, mesh, clusters, groups[i], bounds, depth, outputContext, outputCallback, allocator);
// Discard old clusters
for (int j = 0; j < (int)groups[i].Length; j++)
{
clusters[groups[i][j]].indices.Dispose();
}
// Clusterize simplified mesh
var split = ClodInternal.Clusterize(config, mesh, simplified.Ptr, simplified.Length, allocator);
for (int j = 0; j < (int)split.Length; j++)
{
split[j].refined = refined;
split[j].bounds = bounds;
clusters.Add(split[j]);
pending.Add((int)clusters.Length - 1);
}
split.Dispose();
merged.Dispose();
simplified.Dispose();
}
// Cleanup groups
for (int i = 0; i < (int)groups.Length; i++)
groups[i].Dispose();
groups.Dispose();
depth++;
}
if (pending.Length > 0)
{
var cluster = clusters[pending[0]];
var bounds = cluster.bounds;
bounds.error = float.MaxValue;
OutputGroup(config, mesh, clusters, pending, bounds, depth, outputContext, outputCallback, allocator);
}
// Cleanup
for (int i = 0; i < (int)clusters.Length; i++)
clusters[i].indices.Dispose();
clusters.Dispose();
locks.Dispose();
remap.Dispose();
pending.Dispose();
return (nuint)clusters.Length;
}
private static int OutputGroup(
ClodConfig config,
ClodMesh mesh,
UnsafeList<Cluster> clusters,
UnsafeList<int> group,
ClodBounds simplified,
int depth,
void* outputContext,
ClodOutputDelegate outputCallback,
Allocator allocator
)
{
var groupClusters = new UnsafeList<ClodCluster>((int)group.Length, allocator);
groupClusters.Resize((nuint)group.Length);
for (int i = 0; i < (int)group.Length; i++)
{
ref var srcCluster = ref clusters[group[i]];
ref var dstCluster = ref groupClusters[i];
dstCluster.refined = srcCluster.refined;
dstCluster.bounds = (config.OptimizeBounds && srcCluster.refined != -1)
? ClodBoundsHelper.ComputeBounds(mesh, srcCluster.indices, srcCluster.bounds.error)
: srcCluster.bounds;
dstCluster.indices = srcCluster.indices.Ptr;
dstCluster.indexCount = (nuint)srcCluster.indices.Length;
dstCluster.vertexCount = srcCluster.vertices;
}
var clodGroup = new ClodGroup { Depth = depth, Simplified = simplified };
int result = outputCallback != null
? outputCallback(outputContext, clodGroup, (ClodCluster*)groupClusters.Ptr, (nuint)groupClusters.Length)
: -1;
groupClusters.Dispose();
return result;
}
}