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Trying new meshlet gen approach

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Dynamitos
2024-04-05 10:41:59 +02:00
parent 7eedaf61ba
commit 505e7d6547
19 changed files with 219 additions and 216 deletions
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src/Engine/Graphics/Meshlet.cpp
+80 -47
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@@ -5,62 +5,95 @@
using namespace Seele;
struct Triangle
{
StaticArray<uint32, 3> indices;
};
int findIndex(Meshlet& current, uint32 index)
{
for (uint32 i = 0; i < current.numVertices; ++i)
{
if (current.uniqueVertices[i] == index)
{
return i;
}
}
if (current.numVertices == Gfx::numVerticesPerMeshlet)
{
return -1;
}
current.uniqueVertices[current.numVertices] = index;
return current.numVertices++;
}
void completeMeshlet(Array<Meshlet>& meshlets, Meshlet& current)
{
meshlets.add(current);
current = {
.numVertices = 0,
.numPrimitives = 0,
};
}
void addTriangle(Array<Meshlet>& meshlets, Meshlet& current, Triangle tri)
{
int f1 = findIndex(current, tri.indices[0]);
int f2 = findIndex(current, tri.indices[1]);
int f3 = findIndex(current, tri.indices[2]);
if (f1 == -1 || f2 == -1 || f3 == -1)
{
completeMeshlet(meshlets, current);
f1 = findIndex(current, tri.indices[0]);
f2 = findIndex(current, tri.indices[1]);
f3 = findIndex(current, tri.indices[2]);
}
current.primitiveLayout[current.numPrimitives * 3 + 0] = uint8(f1);
current.primitiveLayout[current.numPrimitives * 3 + 1] = uint8(f2);
current.primitiveLayout[current.numPrimitives * 3 + 2] = uint8(f3);
current.numPrimitives++;
if (current.numPrimitives == Gfx::numPrimitivesPerMeshlet)
{
completeMeshlet(meshlets, current);
}
}
void Meshlet::build(const Array<Vector>& positions, const Array<uint32>& indices, Array<Meshlet>& meshlets)
{
Meshlet current = {
.numVertices = 0,
.numPrimitives = 0,
};
auto findIndex = [&current](uint32 index) -> int {
for (uint32 i = 0; i < current.numVertices; ++i)
Array<Triangle> triangles(indices.size() / 3);
for (size_t i = 0; i < triangles.size(); ++i)
{
triangles[i].indices[0] = indices[i * 3 + 0];
triangles[i].indices[1] = indices[i * 3 + 1];
triangles[i].indices[2] = indices[i * 3 + 2];
}
while (!triangles.empty())
{
uint32 best = 0;
float lowestSurface = std::numeric_limits<float>::max();
AABB newAABB;
for (uint32 i = 0; i < triangles.size(); ++i)
{
if (current.uniqueVertices[i] == index)
AABB adjusted = current.boundingBox;
adjusted.adjust(positions[triangles[i].indices[0]]);
adjusted.adjust(positions[triangles[i].indices[1]]);
adjusted.adjust(positions[triangles[i].indices[2]]);
float surface = adjusted.surfaceArea();
if (surface < lowestSurface)
{
return i;
lowestSurface = surface;
best = i;
newAABB = adjusted;
}
}
if (current.numVertices == Gfx::numVerticesPerMeshlet)
{
return -1;
}
current.uniqueVertices[current.numVertices] = index;
return current.numVertices++;
};
auto completeMeshlet = [&positions, &meshlets, &current]() {
for (uint32 i = 0; i < current.numVertices; ++i)
{
current.boundingBox.adjust(positions[current.uniqueVertices[i]]);
}
meshlets.add(current);
current = {
.numVertices = 0,
.numPrimitives = 0,
};
};
for (size_t faceIndex = 0; faceIndex < indices.size() / 3; ++faceIndex)
{
int f1 = findIndex(indices[faceIndex * 3 + 0]);
int f2 = findIndex(indices[faceIndex * 3 + 1]);
int f3 = findIndex(indices[faceIndex * 3 + 2]);
if (f1 == -1 || f2 == -1 || f3 == -1)
{
completeMeshlet();
f1 = findIndex(indices[faceIndex * 3 + 0]);
f2 = findIndex(indices[faceIndex * 3 + 1]);
f3 = findIndex(indices[faceIndex * 3 + 2]);
}
current.primitiveLayout[current.numPrimitives * 3 + 0] = uint8(f1);
current.primitiveLayout[current.numPrimitives * 3 + 1] = uint8(f2);
current.primitiveLayout[current.numPrimitives * 3 + 2] = uint8(f3);
current.numPrimitives++;
if (current.numPrimitives == Gfx::numPrimitivesPerMeshlet)
{
completeMeshlet();
}
}
if (current.numVertices > 0)
{
completeMeshlet();
current.boundingBox = newAABB;
addTriangle(meshlets, current, triangles[best]);
triangles.removeAt(best);
}
}