BVH accelaration support for scene intersections (#704)

WickedEngine/wiScene_Components.cpp

@@ -928,6 +928,36 @@ namespace wi::scene
 			device->SetName(&BLASes[lod], std::string("MeshComponent::BLAS[LOD" + std::to_string(lod) + "]").c_str());
 		}
 	}
+	void MeshComponent::BuildBVH()
+	{
+		bvh_leaf_aabbs.clear();
+		uint32_t first_subset = 0;
+		uint32_t last_subset = 0;
+		GetLODSubsetRange(0, first_subset, last_subset);
+		for (uint32_t subsetIndex = first_subset; subsetIndex < last_subset; ++subsetIndex)
+		{
+			assert(subsetIndex <= 0xFF); // must fit into 8 bits userdata packing
+			const MeshComponent::MeshSubset& subset = subsets[subsetIndex];
+			if (subset.indexCount == 0)
+				continue;
+			const uint32_t indexOffset = subset.indexOffset;
+			const uint32_t triangleCount = subset.indexCount / 3;
+			for (uint32_t triangleIndex = 0; triangleIndex < triangleCount; ++triangleIndex)
+			{
+				assert(triangleIndex <= 0xFFFFFF); // must fit into 24 bits userdata packing
+				const uint32_t i0 = indices[indexOffset + triangleIndex * 3 + 0];
+				const uint32_t i1 = indices[indexOffset + triangleIndex * 3 + 1];
+				const uint32_t i2 = indices[indexOffset + triangleIndex * 3 + 2];
+				const XMFLOAT3& p0 = vertex_positions[i0];
+				const XMFLOAT3& p1 = vertex_positions[i1];
+				const XMFLOAT3& p2 = vertex_positions[i2];
+				AABB aabb = wi::primitive::AABB(wi::math::Min(p0, wi::math::Min(p1, p2)), wi::math::Max(p0, wi::math::Max(p1, p2)));
+				aabb.userdata = (triangleIndex & 0xFFFFFF) | ((subsetIndex & 0xFF) << 24u);
+				bvh_leaf_aabbs.push_back(aabb);
+			}
+		}
+		bvh.Build(bvh_leaf_aabbs.data(), (uint32_t)bvh_leaf_aabbs.size());
+	}
 	void MeshComponent::ComputeNormals(COMPUTE_NORMALS compute)
 	{
 		// Start recalculating normals:
@@ -1300,6 +1330,44 @@ namespace wi::scene
 		sphere.radius = aabb.getRadius();
 		return sphere;
 	}
+	size_t MeshComponent::GetMemoryUsageCPU() const
+	{
+		size_t size = 
+			vertex_positions.size() * sizeof(XMFLOAT3) +
+			vertex_normals.size() * sizeof(XMFLOAT3) +
+			vertex_tangents.size() * sizeof(XMFLOAT4) +
+			vertex_uvset_0.size() * sizeof(XMFLOAT2) +
+			vertex_uvset_1.size() * sizeof(XMFLOAT2) +
+			vertex_boneindices.size() * sizeof(XMUINT4) +
+			vertex_boneweights.size() * sizeof(XMFLOAT4) +
+			vertex_atlas.size() * sizeof(XMFLOAT2) +
+			vertex_colors.size() * sizeof(uint32_t) +
+			vertex_windweights.size() * sizeof(uint8_t) +
+			indices.size() * sizeof(uint32_t);
+
+		for (const MorphTarget& morph : morph_targets)
+		{
+			size +=
+				morph.vertex_positions.size() * sizeof(XMFLOAT3) +
+				morph.vertex_normals.size() * sizeof(XMFLOAT3) +
+				morph.sparse_indices_positions.size() * sizeof(uint32_t) +
+				morph.sparse_indices_normals.size() * sizeof(uint32_t);
+		}
+
+		size += GetMemoryUsageBVH();
+
+		return size;
+	}
+	size_t MeshComponent::GetMemoryUsageGPU() const
+	{
+		return generalBuffer.desc.size + streamoutBuffer.desc.size;
+	}
+	size_t MeshComponent::GetMemoryUsageBVH() const
+	{
+		return
+			bvh.allocation.capacity() +
+			bvh_leaf_aabbs.size() * sizeof(wi::primitive::AABB);
+	}
 
 	void ObjectComponent::ClearLightmap()
 	{