Added topology convert utility function.

src/amalgamated.cpp

@@ -20,4 +20,5 @@
 #include "shader_dxbc.cpp"
 #include "shader_dx9bc.cpp"
 #include "shader_spirv.cpp"
+#include "topology.cpp"
 #include "vertexdecl.cpp"

src/topology.cpp

@@ -0,0 +1,215 @@
+/*
+ * Copyright 2011-2016 Branimir Karadzic. All rights reserved.
+ * License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
+ */
+
+#include <bx/debug.h>
+#include <bx/radixsort.h>
+
+#include "config.h"
+#include "topology.h"
+
+namespace bgfx
+{
+	template<typename IndexT>
+	static uint32_t toplogyConvertTriListFlipWinding(void* _dst, uint32_t _dstSize, const IndexT* _indices, uint32_t _numIndices)
+	{
+		if (NULL == _dst)
+		{
+			return _numIndices;
+		}
+
+		IndexT* dst = (IndexT*)_dst;
+		IndexT* end = &dst[_dstSize/sizeof(IndexT)];
+		for (uint32_t ii = 0; ii < _numIndices && dst < end; ii += 3, dst += 3)
+		{
+			const IndexT* tri = &_indices[ii];
+			IndexT i0 = tri[0], i1 = tri[1], i2 = tri[2];
+
+			dst[0] = i0;
+			dst[1] = i2;
+			dst[2] = i1;
+		}
+
+		return _numIndices;
+	}
+
+	template<typename IndexT, typename SortT>
+	static uint32_t toplogyConvertTriListToLineList(void* _dst, uint32_t _dstSize, const IndexT* _indices, uint32_t _numIndices, IndexT* _temp, SortT* _tempSort)
+	{
+		// Create all line pairs and sort indices.
+		IndexT* dst = _temp;
+		for (uint32_t ii = 0; ii < _numIndices; ii += 3)
+		{
+			const IndexT* tri = &_indices[ii];
+			IndexT i0 = tri[0], i1 = tri[1], i2 = tri[2];
+
+			if (i0 > i1) { bx::xchg(i0, i1); }
+			if (i1 > i2) { bx::xchg(i1, i2); }
+			if (i0 > i1) { bx::xchg(i0, i1); }
+			BX_CHECK(i0 < i1 < i2, "");
+
+			dst[0] = i0; dst[1] = i1;
+			dst[2] = i1; dst[3] = i2;
+			dst[4] = i0; dst[5] = i2;
+			dst += 6;
+		}
+
+		// Sort all line pairs.
+		SortT* sorted = (SortT*)_temp;
+		bx::radixSort(sorted, _tempSort, _numIndices);
+
+		uint32_t num = 0;
+
+		// Remove all line pair duplicates.
+		if (NULL == _dst)
+		{
+			SortT last = sorted[0];
+			for (uint32_t ii = 1; ii < _numIndices; ++ii)
+			{
+				if (last != sorted[ii])
+				{
+					num += 2;
+					last = sorted[ii];
+				}
+			}
+			num += 2;
+		}
+		else
+		{
+			dst = (IndexT*)_dst;
+			IndexT* end = &dst[_dstSize/sizeof(IndexT)];
+			SortT  last = sorted[0];
+			for (uint32_t ii = 1; ii < _numIndices && dst < end; ++ii)
+			{
+				if (last != sorted[ii])
+				{
+					union Un { SortT key; struct { IndexT i0; IndexT i1; } u16; } un = { last };
+					dst[0] = un.u16.i0;
+					dst[1] = un.u16.i1;
+					dst += 2;
+					last = sorted[ii];
+				}
+			}
+
+			if (dst < end)
+			{
+				union Un { SortT key; struct { IndexT i0; IndexT i1; } u16; } un = { last };
+				dst[0] = un.u16.i0;
+				dst[1] = un.u16.i1;
+				dst += 2;
+			}
+
+			num = uint32_t(dst - (IndexT*)_dst);
+		}
+
+		return num;
+	}
+
+	template<typename IndexT, typename SortT>
+	static uint32_t toplogyConvertTriListToLineList(void* _dst, uint32_t _dstSize, const IndexT* _indices, uint32_t _numIndices, bx::AllocatorI* _allocator)
+	{
+		IndexT* temp     = (IndexT*)BX_ALLOC(_allocator, _numIndices*2*sizeof(IndexT)*2);
+		SortT*  tempSort = (SortT*)&temp[_numIndices*2];
+		uint32_t num = toplogyConvertTriListToLineList(_dst, _dstSize, _indices, _numIndices, temp, tempSort);
+		BX_FREE(_allocator, temp);
+		return num;
+	}
+
+	template<typename IndexT>
+	static uint32_t toplogyConvertTriStripToTriList(void* _dst, uint32_t _dstSize, const IndexT* _indices, uint32_t _numIndices)
+	{
+		IndexT* dst = (IndexT*)_dst;
+		IndexT* end = &dst[_dstSize/sizeof(IndexT)];
+
+		for (uint32_t ii = 0, num = _numIndices-2; ii < num && dst < end; ++ii)
+		{
+			IndexT i0 = _indices[ii+0];
+			IndexT i1 = _indices[ii+1];
+			IndexT i2 = _indices[ii+2];
+			if (i0 != i1
+			&&  i1 != i2)
+			{
+				dst[0] = i0;
+				dst[1] = i1;
+				dst[2] = i2;
+				dst += 3;
+			}
+		}
+
+		return uint32_t(dst - (IndexT*)_dst);
+	}
+
+	template<typename IndexT>
+	static uint32_t toplogyConvertLineStripToLineList(void* _dst, uint32_t _dstSize, const IndexT* _indices, uint32_t _numIndices)
+	{
+		IndexT* dst = (IndexT*)_dst;
+		IndexT* end = &dst[_dstSize/sizeof(IndexT)];
+
+		IndexT i0 = _indices[0];
+
+		for (uint32_t ii = 1; ii < _numIndices && dst < end; ++ii)
+		{
+			IndexT i1 = _indices[ii];
+			if (i0 != i1)
+			{
+				dst[0] = i0;
+				dst[1] = i1;
+				dst += 2;
+
+				i0 = i1;
+			}
+		}
+
+		return uint32_t(dst - (IndexT*)_dst);
+	}
+
+	uint32_t toplogyConvert(TopologyConvert::Enum _conversion, void* _dst, uint32_t _dstSize, const void* _indices, uint32_t _numIndices, bool _index32, bx::AllocatorI* _allocator)
+	{
+		switch (_conversion)
+		{
+		case TopologyConvert::TriStripToTriList:
+			if (_index32)
+			{
+				return toplogyConvertTriStripToTriList(_dst, _dstSize, (const uint32_t*)_indices, _numIndices);
+			}
+
+			return toplogyConvertTriStripToTriList(_dst, _dstSize, (const uint16_t*)_indices, _numIndices);
+
+		case TopologyConvert::TriListFlipWinding:
+			if (_index32)
+			{
+				return toplogyConvertTriListFlipWinding(_dst, _dstSize, (const uint32_t*)_indices, _numIndices);
+			}
+
+			return toplogyConvertTriListFlipWinding(_dst, _dstSize, (const uint16_t*)_indices, _numIndices);
+
+		case TopologyConvert::TriListToLineList:
+			if (NULL == _allocator)
+			{
+				return 0;
+			}
+
+			if (_index32)
+			{
+				return toplogyConvertTriListToLineList<uint32_t, uint64_t>(_dst, _dstSize, (const uint32_t*)_indices, _numIndices, _allocator);
+			}
+
+			return toplogyConvertTriListToLineList<uint16_t, uint32_t>(_dst, _dstSize, (const uint16_t*)_indices, _numIndices, _allocator);
+
+		case TopologyConvert::LineStripToLineList:
+			if (_index32)
+			{
+				return toplogyConvertLineStripToLineList(_dst, _dstSize, (const uint32_t*)_indices, _numIndices);
+			}
+
+			return toplogyConvertLineStripToLineList(_dst, _dstSize, (const uint16_t*)_indices, _numIndices);
+
+		default:
+			break;
+		}
+
+		return 0;
+	}
+
+} //namespace bgfx

src/topology.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright 2011-2016 Branimir Karadzic. All rights reserved.
+ * License: https://github.com/bkaradzic/bgfx#license-bsd-2-clause
+ */
+
+#ifndef BGFX_TOPOLOGY_H_HEADER_GUARD
+#define BGFX_TOPOLOGY_H_HEADER_GUARD
+
+#include <bgfx/bgfx.h>
+#include <bx/allocator.h>
+
+namespace bgfx
+{
+	///
+	struct TopologyConvert
+	{
+		enum Enum
+		{
+			TriListFlipWinding,
+			TriListToLineList,
+			TriStripToTriList,
+			LineStripToLineList,
+
+			Count
+		};
+	};
+
+	/// Converts topology from triangle list to line list.
+	///
+	/// @param[in] _conversion
+	/// @param[in] _dst
+	/// @param[in] _dstSize
+	/// @param[in] _indices
+	/// @param[in] _numIndices
+	/// @param[in] _index32
+	///
+	/// @returns
+	///
+	uint32_t toplogyConvert(TopologyConvert::Enum _conversion, void* _dst, uint32_t _dstSize, const void* _indices, uint32_t _numIndices, bool _index32, bx::AllocatorI* _allocator);
+
+} // namespace bgfx
+
+#endif // BGFX_TOPOLOGY_H_HEADER_GUARD