Refactor smooth normal and welding

include/nbl/asset/utils/CPolygonGeometryManipulator.h

@@ -9,6 +9,7 @@
 
 #include "nbl/asset/ICPUPolygonGeometry.h"
 #include "nbl/asset/utils/CGeometryManipulator.h"
+#include "nbl/asset/utils/CVertexHashGrid.h"
 
 namespace nbl::asset
 {
@@ -17,15 +18,31 @@ namespace nbl::asset
 class NBL_API2 CPolygonGeometryManipulator
 {
 	public:
-		//vertex data needed for CSmoothNormalGenerator
-		struct SSNGVertexData
-		{
-			uint32_t index;									     //offset of the vertex into index buffer
-			uint32_t hash;											       //
-			float wage;												         //angle wage of the vertex
-			hlsl::float32_t3 position;							   //position of the vertex in 3D space
-			hlsl::float32_t3 parentTriangleFaceNormal; //
-		};
+
+    struct SSNGVertexData
+    {
+      uint64_t index;									     //offset of the vertex into index buffer
+			uint32_t hash;
+      hlsl::float32_t3 weightedNormal;
+			// TODO(kevinyu): Should we separate this from SSNGVertexData, and store it in its own vector in VertexHashGrid? Similar like how hashmap work. Or keep it intrusive?
+      hlsl::float32_t3 position;							   //position of the vertex in 3D space
+
+			hlsl::float32_t3 getPosition() const
+			{
+				return position;
+			}
+
+			void setHash(uint32_t hash)
+			{
+				this->hash = hash;
+			}
+
+			uint32_t getHash() const
+			{
+				return hash;
+			};
+
+    };
 
 		using VxCmpFunction = std::function<bool(const SSNGVertexData&, const SSNGVertexData&, const ICPUPolygonGeometry*)>;
 
@@ -247,7 +264,7 @@ class NBL_API2 CPolygonGeometryManipulator
 				VxCmpFunction vxcmp = [](const CPolygonGeometryManipulator::SSNGVertexData& v0, const CPolygonGeometryManipulator::SSNGVertexData& v1, const ICPUPolygonGeometry* buffer) 
 				{ 
 					static constexpr float cosOf45Deg = 0.70710678118f;
-					return dot(v0.parentTriangleFaceNormal,v1.parentTriangleFaceNormal) > cosOf45Deg;
+					return dot(normalize(v0.weightedNormal),normalize(v1.weightedNormal)) > cosOf45Deg;
 				});
 
 #if 0 // TODO: REDO

include/nbl/asset/utils/CVertexHashGrid.h

@@ -0,0 +1,212 @@
+#ifndef _NBL_ASSET_C_VERTEX_HASH_MAP_H_INCLUDED_
+#define _NBL_ASSET_C_VERTEX_HASH_MAP_H_INCLUDED_
+
+#include "nbl/core/declarations.h"
+
+namespace nbl::asset
+{
+
+template <typename T>
+concept HashGridVertexData = requires(T obj, T const cobj, uint32_t hash) {
+		{ cobj.getHash() } -> std::same_as<uint32_t>;
+		{ obj.setHash(hash) } -> std::same_as<void>;
+		{ cobj.getPosition() } -> std::same_as<hlsl::float32_t3>;
+};
+
+template <HashGridVertexData VertexData>
+class CVertexHashGrid
+{
+public:
+
+	using vertex_data_t = VertexData;
+	using collection_t = core::vector<VertexData>;
+	struct BucketBounds
+	{
+		collection_t::const_iterator begin;
+		collection_t::const_iterator end;
+	};
+
+	CVertexHashGrid(size_t _vertexCount, uint32_t _hashTableMaxSize, float _cellSize) :
+		m_sorter(createSorter(_vertexCount)),
+		m_hashTableMaxSize(_hashTableMaxSize),
+		m_cellSize(_cellSize)
+	{
+		assert((core::isPoT(m_hashTableMaxSize)));
+
+		m_vertices.reserve(_vertexCount);
+	}
+
+	//inserts vertex into hash table
+	void add(VertexData&& vertex)
+	{
+		vertex.setHash(hash(vertex));
+		m_vertices.push_back(vertex);
+	}
+
+	void validate()
+	{
+		const auto oldSize = m_vertices.size();
+		m_vertices.resize(oldSize*2u);
+		auto finalSortedOutput = std::visit( [&](auto& sorter) { return sorter(m_vertices.data(), m_vertices.data() + oldSize, oldSize, KeyAccessor()); },m_sorter );
+
+		if (finalSortedOutput != m_vertices.data())
+			m_vertices.erase(m_vertices.begin(), m_vertices.begin() + oldSize);
+		else
+			m_vertices.resize(oldSize);
+	}
+
+	const collection_t& vertices() const { return m_vertices; }
+
+	collection_t& vertices(){ return m_vertices; }
+
+	inline uint32_t getVertexCount() const { return m_vertices.size(); }
+
+	template <typename Fn>
+	void iterateBroadphaseCandidates(const VertexData& vertex, Fn fn) const
+	{
+		std::array<uint32_t, 8> neighboringCells;
+		const auto cellCount = getNeighboringCellHashes(neighboringCells.data(), vertex);
+
+		//iterate among all neighboring cells
+		for (uint8_t i = 0; i < cellCount; i++)
+		{
+			const auto& neighborCell = neighboringCells[i];
+			BucketBounds bounds = getBucketBoundsByHash(neighborCell);
+			for (; bounds.begin != bounds.end; bounds.begin++)
+			{
+				const vertex_data_t& neighborVertex = *bounds.begin;
+				if (&vertex != &neighborVertex)
+					if (!fn(neighborVertex)) break;
+			}
+		}
+
+	};
+
+private:
+	struct KeyAccessor
+	{
+		_NBL_STATIC_INLINE_CONSTEXPR size_t key_bit_count = 32ull;
+
+		template<auto bit_offset, auto radix_mask>
+		inline decltype(radix_mask) operator()(const VertexData& item) const
+		{
+			return static_cast<decltype(radix_mask)>(item.getHash() >> static_cast<uint32_t>(bit_offset)) & radix_mask;
+		}
+	};
+
+	static constexpr uint32_t primeNumber1 = 73856093;
+	static constexpr uint32_t primeNumber2 = 19349663;
+	static constexpr uint32_t primeNumber3 = 83492791;
+
+	static constexpr uint32_t invalidHash = 0xFFFFFFFF;
+
+	using sorter_t = std::variant<
+		core::LSBSorter<KeyAccessor::key_bit_count, uint16_t>,
+		core::LSBSorter<KeyAccessor::key_bit_count, uint32_t>,
+		core::LSBSorter<KeyAccessor::key_bit_count, size_t>>;
+	sorter_t m_sorter;
+
+	static sorter_t createSorter(size_t vertexCount)
+	{
+		if (vertexCount < (0x1ull << 16ull))
+			return core::LSBSorter<KeyAccessor::key_bit_count, uint16_t>();
+		if (vertexCount < (0x1ull << 32ull))
+			return core::LSBSorter<KeyAccessor::key_bit_count, uint32_t>();
+		return core::LSBSorter<KeyAccessor::key_bit_count, size_t>();
+	}
+
+	collection_t m_vertices;
+	const uint32_t m_hashTableMaxSize;
+	const float m_cellSize;
+
+	uint32_t hash(const VertexData& vertex) const
+	{
+		const hlsl::float32_t3 position = floor(vertex.getPosition() / m_cellSize);
+
+		return	((static_cast<uint32_t>(position.x) * primeNumber1) ^
+			(static_cast<uint32_t>(position.y) * primeNumber2) ^
+			(static_cast<uint32_t>(position.z) * primeNumber3))& (m_hashTableMaxSize - 1);
+	}
+
+	uint32_t hash(const hlsl::uint32_t3& position) const
+	{
+		return	((position.x * primeNumber1) ^
+			(position.y * primeNumber2) ^
+			(position.z * primeNumber3))& (m_hashTableMaxSize - 1);
+	}
+
+	uint8_t getNeighboringCellHashes(uint32_t* outNeighbors, const VertexData& vertex) const
+	{
+		hlsl::float32_t3 cellfloatcoord = floor(vertex.getPosition() / m_cellSize - hlsl::float32_t3(0.5));
+		hlsl::uint32_t3 baseCoord = hlsl::uint32_t3(static_cast<uint32_t>(cellfloatcoord.x), static_cast<uint32_t>(cellfloatcoord.y), static_cast<uint32_t>(cellfloatcoord.z));
+
+		uint8_t neighborCount = 0;
+
+		outNeighbors[neighborCount] = hash(baseCoord);
+		neighborCount++;
+
+		auto addUniqueNeighbor = [&neighborCount, outNeighbors](uint32_t hashval)
+		{
+			if (std::find(outNeighbors, outNeighbors + neighborCount, hashval) == outNeighbors + neighborCount)
+			{
+				outNeighbors[neighborCount] = hashval;
+				neighborCount++;
+			}
+		};
+
+		addUniqueNeighbor(hash(baseCoord + hlsl::uint32_t3(0, 0, 1)));
+		addUniqueNeighbor(hash(baseCoord + hlsl::uint32_t3(0, 1, 0)));
+		addUniqueNeighbor(hash(baseCoord + hlsl::uint32_t3(1, 0, 0)));
+		addUniqueNeighbor(hash(baseCoord + hlsl::uint32_t3(1, 1, 0)));
+		addUniqueNeighbor(hash(baseCoord + hlsl::uint32_t3(1, 0, 1)));
+		addUniqueNeighbor(hash(baseCoord + hlsl::uint32_t3(0, 1, 1)));
+		addUniqueNeighbor(hash(baseCoord + hlsl::uint32_t3(1, 1, 1)));
+
+		return neighborCount;
+	}
+
+	BucketBounds getBucketBoundsByHash(uint32_t hash) const
+	{
+		if (hash == invalidHash)
+			return { m_vertices.end(), m_vertices.end() };
+
+		const auto skipListBound = std::visit([&](auto& sorter)
+		{
+			auto hashBound = sorter.getHashBound(hash);
+			return std::pair<collection_t::const_iterator, collection_t::const_iterator>(m_vertices.begin() + hashBound.first, m_vertices.begin() + hashBound.second);
+		}, m_sorter);
+
+		auto begin = std::lower_bound(
+			skipListBound.first, 
+			skipListBound.second, 
+			hash,
+			[](const VertexData& vertex, uint32_t hash)
+			{
+				return vertex.hash < hash;
+			});
+
+		auto end = std::upper_bound(
+			skipListBound.first, 
+			skipListBound.second, 
+			hash, 
+			[](uint32_t hash, const VertexData& vertex)
+			{
+				return hash < vertex.hash;
+			});
+
+		const auto beginIx = begin - m_vertices.begin();
+		const auto endIx = end - m_vertices.begin();
+		//bucket missing
+		if (begin == end)
+			return { m_vertices.end(), m_vertices.end() };
+
+		//bucket missing
+		if (begin->hash != hash)
+			return { m_vertices.end(), m_vertices.end() };
+
+		return { begin, end };
+	}
+};
+
+}
+#endif