/// <summary>
/// Compacts the index buffer from 32 bits to 16 bits per index, if possible.
/// </summary>
/// <param name="meshData">The mesh data.</param>
/// <returns>Returns true if index buffer was actually compacted.</returns>
/// <exception cref="System.NotImplementedException"></exception>
public static unsafe bool CompactIndexBuffer(this MeshDrawData meshData)
{
// Already processed?
if (meshData.IndexBuffer == null || !meshData.IndexBuffer.Is32Bit)
{
return(false);
}
// For now, require a MeshData with only one vertex buffer and no index buffer
if (meshData.VertexBuffers.Length != 1)
{
throw new NotImplementedException();
}
var vertexBufferBinding = meshData.VertexBuffers[0];
var vertexCount = vertexBufferBinding.Count;
// Can't compact?
// Note that 65536 could be valid, but 0xFFFF is kept for primitive restart in strips.
if (vertexCount >= 65536 || !meshData.IndexBuffer.Is32Bit)
{
return(false);
}
// Create new index buffer
var indexCount = meshData.IndexBuffer.Count;
var indexBufferData = new byte[indexCount * Utilities.SizeOf <ushort>()];
fixed(byte *oldIndexBufferDataStart = &meshData.IndexBuffer.Buffer.Value.Content[0])
fixed(byte *indexBufferDataStart = &indexBufferData[0])
{
var oldIndexBufferDataPtr = (int *)oldIndexBufferDataStart;
var indexBufferDataPtr = (ushort *)indexBufferDataStart;
for (int i = 0; i < indexCount; ++i)
{
// This also works to convert 0xFFFFFFFF into 0xFFFF (primitive restart in strips).
*indexBufferDataPtr++ = (ushort)*oldIndexBufferDataPtr++;
}
meshData.IndexBuffer = new IndexBufferBindingData(new BufferData(BufferFlags.IndexBuffer, indexBufferData), false, indexCount);
}
return(true);
}
/// <summary>
/// Extracts a selection of vertices from a vertex buffer stored in this mesh data.
/// </summary>
/// <param name="meshData">The mesh data.</param>
/// <param name="vertexElementToExtract">The declaration to extract (e.g. "POSITION0"...etc.) </param>
public static T[] GetVertexBufferData <T>(this MeshDrawData meshData, params string[] vertexElementToExtract) where T : struct
{
var declaration = meshData.VertexBuffers[0].Declaration;
var offsets = declaration.EnumerateWithOffsets().Where(vertexElementOffset => vertexElementToExtract.Contains(vertexElementOffset.VertexElement.SemanticAsText)).ToList();
int expectedSize = offsets.Sum(vertexElementWithOffset => vertexElementWithOffset.Size);
var count = meshData.VertexBuffers[0].Count;
int outputSize = expectedSize * count;
int checkSize = (int)(outputSize / Utilities.SizeOf <T>()) * Utilities.SizeOf <T>();
if (checkSize != outputSize)
{
throw new ArgumentException(string.Format("Size of T is not a multiple of totalSize {0}", outputSize));
}
var output = new T[outputSize / Utilities.SizeOf <T>()];
var handleOutput = GCHandle.Alloc(output, GCHandleType.Pinned);
var ptrOutput = handleOutput.AddrOfPinnedObject();
var handleInput = GCHandle.Alloc(meshData.VertexBuffers[0].Buffer.Value.Content, GCHandleType.Pinned);
var ptrInput = handleInput.AddrOfPinnedObject();
for (int i = 0; i < count; i++)
{
foreach (var vertexElementWithOffset in offsets)
{
Utilities.CopyMemory(ptrOutput, ptrInput + vertexElementWithOffset.Offset, vertexElementWithOffset.Size);
ptrOutput = ptrOutput + vertexElementWithOffset.Size;
}
ptrInput += declaration.VertexStride;
}
handleInput.Free();
handleOutput.Free();
return(output);
}
/// <summary>
/// Determines whether the specified mesh draw data is simple.
/// A <see cref="MeshDrawData"/> is simple if:
/// * It contains only one <see cref="VertexBufferBindingData"/>, which must be simple.
/// * It contains either no <see cref="IndexBufferBindingData"/>, or a simple one.
/// * StartLocation is 0.
/// * DrawCount is IndexBuffer.Count if there is an index buffer, otherwise VertexBuffers[0].Count.
/// </summary>
/// <param name="meshDrawData">The mesh draw data.</param>
/// <returns></returns>
public static bool IsSimple(this MeshDrawData meshDrawData)
{
if (meshDrawData.VertexBuffers.Length != 1)
{
return(false);
}
if (!meshDrawData.VertexBuffers[0].IsSimple())
{
return(false);
}
if (meshDrawData.IndexBuffer != null)
{
if (!meshDrawData.IndexBuffer.IsSimple())
{
return(false);
}
if (meshDrawData.DrawCount != meshDrawData.IndexBuffer.Count)
{
return(false);
}
}
else
{
if (meshDrawData.DrawCount != meshDrawData.VertexBuffers[0].Count)
{
return(false);
}
}
if (meshDrawData.StartLocation != 0)
{
return(false);
}
return(true);
}
/// <summary>
/// Generates an index buffer for this mesh data.
/// </summary>
/// <param name="meshData">The mesh data.</param>
public unsafe static void GenerateIndexBuffer(this MeshDrawData meshData)
{
// For now, require a MeshData with only one vertex buffer and no index buffer
if (meshData.VertexBuffers.Length != 1 || meshData.IndexBuffer != null)
{
throw new NotImplementedException();
}
var oldVertexBuffer = meshData.VertexBuffers[0];
var vertexStride = oldVertexBuffer.Declaration.VertexStride;
var indexMapping = GenerateIndexMapping(oldVertexBuffer);
var vertices = indexMapping.Vertices;
// Generate vertex buffer
var vertexBufferData = new byte[oldVertexBuffer.Declaration.VertexStride * indexMapping.Vertices.Length];
fixed(byte *oldVertexBufferDataStart = &oldVertexBuffer.Buffer.Value.Content[oldVertexBuffer.Offset])
fixed(byte *vertexBufferDataStart = &vertexBufferData[0])
{
var vertexBufferDataCurrent = vertexBufferDataStart;
for (int i = 0; i < vertices.Length; ++i)
{
Utilities.CopyMemory((IntPtr)vertexBufferDataCurrent, new IntPtr(&oldVertexBufferDataStart[vertexStride * vertices[i]]), vertexStride);
vertexBufferDataCurrent += vertexStride;
}
meshData.VertexBuffers[0] = new VertexBufferBindingData(new BufferData(BufferFlags.VertexBuffer, vertexBufferData), oldVertexBuffer.Declaration, indexMapping.Vertices.Length);
}
// Generate index buffer
var indexBufferData = new byte[indexMapping.Indices.Length * Utilities.SizeOf <int>()];
fixed(int *indexDataStart = &indexMapping.Indices[0])
fixed(byte *indexBufferDataStart = &indexBufferData[0])
{
Utilities.CopyMemory((IntPtr)indexBufferDataStart, (IntPtr)indexDataStart, indexBufferData.Length);
meshData.IndexBuffer = new IndexBufferBindingData(new BufferData(BufferFlags.IndexBuffer, indexBufferData), true, indexMapping.Indices.Length);
}
}
/// <summary>
/// Generates the tangents and binormals for this mesh data.
/// Tangents and bitangents will be encoded as float4:
/// float3 for tangent and an additional float for handedness (1 or -1),
/// so that bitangent can be reconstructed.
/// More info at http://www.terathon.com/code/tangent.html
/// </summary>
/// <param name="meshData">The mesh data.</param>
public static unsafe void GenerateTangentBinormal(this MeshDrawData meshData)
{
if (!meshData.IsSimple())
{
throw new ArgumentException("meshData is not simple.");
}
if (meshData.PrimitiveType != PrimitiveType.TriangleList &&
meshData.PrimitiveType != PrimitiveType.TriangleListWithAdjacency)
{
throw new NotImplementedException();
}
var vertexBufferBinding = meshData.VertexBuffers[0];
var indexBufferBinding = meshData.IndexBuffer;
var indexData = indexBufferBinding != null ? indexBufferBinding.Buffer.Value.Content : null;
var oldVertexStride = vertexBufferBinding.Declaration.VertexStride;
var bufferData = vertexBufferBinding.Buffer.Value.Content;
// TODO: Usage index in key
var offsetMapping = vertexBufferBinding.Declaration
.EnumerateWithOffsets()
.ToDictionary(x => x.VertexElement.SemanticAsText, x => x.Offset);
var positionOffset = offsetMapping["POSITION"];
var uvOffset = offsetMapping[VertexElementUsage.TextureCoordinate];
var normalOffset = offsetMapping[VertexElementUsage.Normal];
// Add tangent to vertex declaration
var vertexElements = vertexBufferBinding.Declaration.VertexElements.ToList();
if (!offsetMapping.ContainsKey(VertexElementUsage.Tangent))
{
vertexElements.Add(VertexElement.Tangent <Vector4>());
}
vertexBufferBinding.Declaration = new VertexDeclaration(vertexElements.ToArray());
var newVertexStride = vertexBufferBinding.Declaration.VertexStride;
// Update mapping
offsetMapping = vertexBufferBinding.Declaration
.EnumerateWithOffsets()
.ToDictionary(x => x.VertexElement.SemanticAsText, x => x.Offset);
var tangentOffset = offsetMapping[VertexElementUsage.Tangent];
var newBufferData = new byte[vertexBufferBinding.Count * newVertexStride];
var tangents = new Vector3[vertexBufferBinding.Count];
var bitangents = new Vector3[vertexBufferBinding.Count];
fixed(byte *indexBufferStart = indexData)
fixed(byte *oldBuffer = &bufferData[vertexBufferBinding.Offset])
fixed(byte *newBuffer = &newBufferData[0])
{
var indexBuffer32 = indexBufferBinding != null && indexBufferBinding.Is32Bit ? (int *)indexBufferStart : null;
var indexBuffer16 = indexBufferBinding != null && !indexBufferBinding.Is32Bit ? (short *)indexBufferStart : null;
var indexCount = indexBufferBinding != null ? indexBufferBinding.Count : vertexBufferBinding.Count;
for (int i = 0; i < indexCount; i += 3)
{
// Get indices
int index1 = i + 0;
int index2 = i + 1;
int index3 = i + 2;
if (indexBuffer32 != null)
{
index1 = indexBuffer32[index1];
index2 = indexBuffer32[index2];
index3 = indexBuffer32[index3];
}
else if (indexBuffer16 != null)
{
index1 = indexBuffer16[index1];
index2 = indexBuffer16[index2];
index3 = indexBuffer16[index3];
}
int vertexOffset1 = index1 * oldVertexStride;
int vertexOffset2 = index2 * oldVertexStride;
int vertexOffset3 = index3 * oldVertexStride;
// Get positions
var position1 = (Vector3 *)&oldBuffer[vertexOffset1 + positionOffset];
var position2 = (Vector3 *)&oldBuffer[vertexOffset2 + positionOffset];
var position3 = (Vector3 *)&oldBuffer[vertexOffset3 + positionOffset];
// Get texture coordinates
var uv1 = (Vector3 *)&oldBuffer[vertexOffset1 + uvOffset];
var uv2 = (Vector3 *)&oldBuffer[vertexOffset2 + uvOffset];
var uv3 = (Vector3 *)&oldBuffer[vertexOffset3 + uvOffset];
// Calculate position and UV vectors from vertex 1 to vertex 2 and 3
var edge1 = *position2 - *position1;
var edge2 = *position3 - *position1;
var uvEdge1 = *uv2 - *uv1;
var uvEdge2 = *uv3 - *uv1;
var t = Vector3.Normalize(uvEdge2.Y * edge1 - uvEdge1.Y * edge2);
var b = Vector3.Normalize(uvEdge1.X * edge2 - uvEdge2.X * edge1);
// Contribute to every vertex
tangents[index1] += t;
tangents[index2] += t;
tangents[index3] += t;
bitangents[index1] += b;
bitangents[index2] += b;
bitangents[index3] += b;
}
var oldVertexOffset = 0;
var newVertexOffset = 0;
for (int i = 0; i < vertexBufferBinding.Count; ++i)
{
Utilities.CopyMemory(new IntPtr(&newBuffer[newVertexOffset]), new IntPtr(&oldBuffer[oldVertexOffset]), oldVertexStride);
var normal = *(Vector3 *)&oldBuffer[oldVertexOffset + normalOffset];
var target = ((float *)(&newBuffer[newVertexOffset + tangentOffset]));
var tangent = -tangents[i];
var bitangent = bitangents[i];
// Gram-Schmidt orthogonalize
*((Vector3 *)target) = Vector3.Normalize(tangent - normal * Vector3.Dot(normal, tangent));
// Calculate handedness
target[3] = Vector3.Dot(Vector3.Cross(normal, tangent), bitangent) < 0.0f ? -1.0f : 1.0f;
oldVertexOffset += oldVertexStride;
newVertexOffset += newVertexStride;
}
}
vertexBufferBinding.Offset = 0;
vertexBufferBinding.Buffer = new BufferData(BufferFlags.VertexBuffer, newBufferData);
}
public unsafe static void SortMeshPolygons(this MeshDrawData meshData, Vector3 viewDirectionForSorting)
{
// need to have alreade an vertex buffer
if (meshData.VertexBuffers == null)
{
throw new ArgumentException();
}
// For now, require a MeshData with an index buffer
if (meshData.IndexBuffer == null)
{
throw new NotImplementedException("The mesh Data needs to have index buffer");
}
if (meshData.VertexBuffers.Length != 1)
{
throw new NotImplementedException("Sorting not implemented for multiple vertex buffers by submeshdata");
}
if (viewDirectionForSorting == Vector3.Zero)
{
// By default to -Z if sorting is set to null
viewDirectionForSorting = -Vector3.UnitZ;
}
const int PolySize = 3; // currently only triangle list are supported
var polyIndicesSize = PolySize * Utilities.SizeOf <int>();
var vertexBuffer = meshData.VertexBuffers[0];
var oldIndexBuffer = meshData.IndexBuffer;
var vertexStride = vertexBuffer.Declaration.VertexStride;
// Generate the sort list
var sortList = new List <KeyValuePair <int, Vector3> >();
var pointList = new List <Vector3>();
fixed(byte *vertexBufferPointerStart = &vertexBuffer.Buffer.Value.Content[vertexBuffer.Offset])
fixed(byte *indexBufferPointerStart = &oldIndexBuffer.Buffer.Value.Content[oldIndexBuffer.Offset])
{
for (var i = 0; i < oldIndexBuffer.Count / PolySize; ++i)
{
// fill the point list of the polygon vertices
pointList.Clear();
for (var u = 0; u < PolySize; ++u)
{
var curIndex = *(int *)(indexBufferPointerStart + Utilities.SizeOf <int>() * (i * PolySize + u));
var pVertexPos = (Vector3 *)(vertexBufferPointerStart + vertexStride * curIndex);
pointList.Add(*pVertexPos);
}
// compute the bary-center
var accu = Vector3.Zero;
foreach (var pt in pointList) //linq do not seems to work on Vector3 type, so compute the mean by hand ...
{
accu += pt;
}
var center = accu / pointList.Count;
// add to the list to sort
sortList.Add(new KeyValuePair <int, Vector3>(i, center));
}
}
// sort the list
var sortedIndices = sortList.OrderBy(x => Vector3.Dot(x.Value, viewDirectionForSorting)).Select(x => x.Key).ToList(); // TODO have a generic delegate for sorting
// re-write the index buffer
var newIndexBufferData = new byte[oldIndexBuffer.Count * Utilities.SizeOf <int>()];
fixed(byte *newIndexDataStart = &newIndexBufferData[0])
fixed(byte *oldIndexDataStart = &oldIndexBuffer.Buffer.Value.Content[0])
{
var newIndexBufferPointer = newIndexDataStart;
foreach (var index in sortedIndices)
{
Utilities.CopyMemory((IntPtr)(newIndexBufferPointer), (IntPtr)(oldIndexDataStart + index * polyIndicesSize), polyIndicesSize);
newIndexBufferPointer += polyIndicesSize;
}
}
meshData.IndexBuffer = new IndexBufferBindingData(new BufferData(BufferFlags.IndexBuffer, newIndexBufferData), oldIndexBuffer.Is32Bit, oldIndexBuffer.Count);
}
/// <summary>
/// Transform a vertex buffer positions, normals, tangents and bitangents using the given matrix.
/// </summary>
/// <param name="meshDrawDatas">The mesh draw datas.</param>
/// <param name="can32BitIndex">A flag stating if 32 bit index buffers.</param>
public unsafe static MeshDrawData MergeDrawData(IList <MeshDrawData> meshDrawDatas, bool can32BitIndex)
{
if (meshDrawDatas.Count == 0)
{
throw new ArgumentException("Need at least 1 MeshDrawData.", "meshDrawDatas");
}
if (meshDrawDatas.Count == 1)
{
return(meshDrawDatas[0]);
}
// Check that vertex buffer declarations are matching
var firstMeshDrawData = meshDrawDatas[0];
if (!firstMeshDrawData.IsSimple())
{
throw new InvalidOperationException("Can only merge simple MeshDrawData.");
}
var firstVertexBuffer = firstMeshDrawData.VertexBuffers[0];
var hasIndexBuffer = IsIndexed(meshDrawDatas);
int totalVertexCount = 0;
int totalIndexCount = 0;
//TODO: extend to non-simple vertex declarations, fill with default values it missing declarations etc. ?
for (int i = 0; i < meshDrawDatas.Count; i++)
{
var meshDrawData = meshDrawDatas[i];
// This should not happen anymore
if (i != 0)
{
if (!meshDrawData.IsSimple())
{
throw new InvalidOperationException("Can only merge simple MeshDrawData.");
}
if (meshDrawData.VertexBuffers.Length != firstMeshDrawData.VertexBuffers.Length)
{
throw new InvalidOperationException("Non-matching vertex buffer declarations.");
}
if (!meshDrawData.VertexBuffers[0].Declaration.Equals(firstMeshDrawData.VertexBuffers[0].Declaration))
{
throw new InvalidOperationException("Non-matching vertex buffer declarations.");
}
}
if (meshDrawData.PrimitiveType != PrimitiveType.TriangleList)
{
throw new InvalidOperationException("Can only merge TriangleList.");
}
// Update vertex/index counts
totalVertexCount += meshDrawData.VertexBuffers[0].Count;
if (hasIndexBuffer)
{
if (meshDrawData.IndexBuffer != null)
{
totalIndexCount += meshDrawData.IndexBuffer.Count;
}
else
{
totalIndexCount += meshDrawData.VertexBuffers[0].Count;
}
}
}
// Allocate vertex buffer
var result = new MeshDrawData {
PrimitiveType = PrimitiveType.TriangleList
};
var destBufferData = new byte[firstVertexBuffer.Declaration.VertexStride * totalVertexCount];
result.VertexBuffers = new VertexBufferBindingData[] {
new VertexBufferBindingData(
new BufferData(BufferFlags.VertexBuffer, destBufferData),
firstVertexBuffer.Declaration,
totalVertexCount,
firstVertexBuffer.Stride)
};
// Copy vertex buffers
fixed(byte *destBufferDataStart = &destBufferData[0])
{
var destBufferDataCurrent = destBufferDataStart;
foreach (MeshDrawData meshDrawData in meshDrawDatas)
{
var sourceBuffer = meshDrawData.VertexBuffers[0].Buffer.Value;
fixed(byte *sourceBufferDataStart = &sourceBuffer.Content[0])
{
Utilities.CopyMemory((IntPtr)destBufferDataCurrent, (IntPtr)sourceBufferDataStart, sourceBuffer.Content.Length);
destBufferDataCurrent += sourceBuffer.Content.Length;
}
}
}
if (hasIndexBuffer)
{
var use32BitIndex = can32BitIndex && totalVertexCount > ushort.MaxValue; // 65535 = 0xFFFF is kept for primitive restart in strip
// Allocate index buffer
destBufferData = new byte[(use32BitIndex ? sizeof(uint) : sizeof(ushort)) * totalIndexCount];
result.IndexBuffer = new IndexBufferBindingData(
new BufferData(BufferFlags.IndexBuffer, destBufferData),
use32BitIndex,
totalIndexCount);
// Copy index buffers
fixed(byte *destBufferDataStart = &destBufferData[0])
{
var destBufferDataCurrent = destBufferDataStart;
var offset = 0;
foreach (MeshDrawData meshDrawData in meshDrawDatas)
{
var indexBuffer = meshDrawData.IndexBuffer;
byte[] sourceBufferContent = null;
var is32Bit = false;
if (indexBuffer != null)
{
sourceBufferContent = indexBuffer.Buffer.Value.Content;
is32Bit = indexBuffer.Is32Bit;
}
if (offset != 0 || (use32BitIndex != meshDrawData.IndexBuffer.Is32Bit))
{
if (use32BitIndex)
{
sourceBufferContent = CreateIntIndexBuffer(offset, meshDrawData.IndexBuffer.Count, sourceBufferContent, is32Bit);
}
else
{
sourceBufferContent = CreateShortIndexBuffer(offset, meshDrawData.IndexBuffer.Count, sourceBufferContent, is32Bit);
}
}
fixed(byte *sourceBufferDataStart = &sourceBufferContent[0])
{
Utilities.CopyMemory((IntPtr)destBufferDataCurrent, (IntPtr)sourceBufferDataStart,
sourceBufferContent.Length);
destBufferDataCurrent += sourceBufferContent.Length;
}
offset += meshDrawData.VertexBuffers[0].Count;
}
}
result.DrawCount = totalIndexCount;
}
else
{
result.DrawCount = totalVertexCount;
}
return(result);
}
/// <summary>
/// Generates the index buffer with dominant edge and vertex informations.
/// Each triangle gets its indices expanded to 12 control points, with 0 to 2 being original triangle,
/// 3 to 8 being dominant edges and 9 to 11 being dominant vertices.
/// </summary>
/// <param name="meshData">The mesh data.</param>
public static unsafe void GenerateIndexBufferAEN(this MeshDrawData meshData)
{
// For now, require a MeshData with only one vertex buffer and one index buffer
if (meshData.VertexBuffers.Length != 1 || meshData.IndexBuffer == null)
{
throw new NotImplementedException();
}
// More info at http://developer.download.nvidia.com/whitepapers/2010/PN-AEN-Triangles-Whitepaper.pdf
// This implementation might need some performance improvements
var indexBuffer = meshData.IndexBuffer;
var triangleCount = indexBuffer.Count / 3;
var newIndices = new int[triangleCount * 12];
var positionMapping = GenerateIndexMapping(meshData.VertexBuffers[0], "POSITION");
var dominantEdges = new Dictionary <EdgeKeyAEN, EdgeAEN>();
var dominantVertices = new Dictionary <int, int>();
fixed(byte *indexBufferStart = &indexBuffer.Buffer.Value.Content[indexBuffer.Offset])
{
var oldIndices = (int *)indexBufferStart;
var triangleIndices = stackalloc int[3];
var positionIndices = stackalloc int[3];
// Step 2: prepare initial data
for (int i = 0; i < triangleCount; ++i)
{
triangleIndices[0] = oldIndices[i * 3 + 0];
triangleIndices[1] = oldIndices[i * 3 + 1];
triangleIndices[2] = oldIndices[i * 3 + 2];
positionIndices[0] = positionMapping.Indices[triangleIndices[0]];
positionIndices[1] = positionMapping.Indices[triangleIndices[1]];
positionIndices[2] = positionMapping.Indices[triangleIndices[2]];
newIndices[i * 12 + 0] = triangleIndices[0];
newIndices[i * 12 + 1] = triangleIndices[1];
newIndices[i * 12 + 2] = triangleIndices[2];
newIndices[i * 12 + 3] = triangleIndices[0];
newIndices[i * 12 + 4] = triangleIndices[1];
newIndices[i * 12 + 5] = triangleIndices[1];
newIndices[i * 12 + 6] = triangleIndices[2];
newIndices[i * 12 + 7] = triangleIndices[2];
newIndices[i * 12 + 8] = triangleIndices[0];
newIndices[i * 12 + 9] = triangleIndices[0];
newIndices[i * 12 + 10] = triangleIndices[1];
newIndices[i * 12 + 11] = triangleIndices[2];
// Step 2b/2c: Build dominant vertex/edge list
for (int j = 0; j < 3; ++j)
{
dominantVertices[positionIndices[j]] = triangleIndices[j];
var edge = new EdgeAEN(
triangleIndices[((j + 0) % 3)],
triangleIndices[((j + 1) % 3)],
positionIndices[((j + 0) % 3)],
positionIndices[((j + 1) % 3)]);
dominantEdges[new EdgeKeyAEN(edge)] = edge;
edge = edge.Reverse();
dominantEdges[new EdgeKeyAEN(edge)] = edge;
}
}
// Step3: Find dominant vertex/edge
for (int i = 0; i < triangleCount; ++i)
{
triangleIndices[0] = oldIndices[i * 3 + 0];
triangleIndices[1] = oldIndices[i * 3 + 1];
triangleIndices[2] = oldIndices[i * 3 + 2];
positionIndices[0] = positionMapping.Indices[triangleIndices[0]];
positionIndices[1] = positionMapping.Indices[triangleIndices[1]];
positionIndices[2] = positionMapping.Indices[triangleIndices[2]];
for (int j = 0; j < 3; ++j)
{
// Dominant edge
int vertexKey;
if (dominantVertices.TryGetValue(positionIndices[j], out vertexKey))
{
newIndices[i * 12 + 9 + j] = vertexKey;
}
// Dominant vertex
EdgeAEN edge;
var edgeKey = new EdgeKeyAEN(positionIndices[((j + 0) % 3)], positionIndices[((j + 1) % 3)]);
if (dominantEdges.TryGetValue(edgeKey, out edge))
{
newIndices[i * 12 + 3 + j * 2 + 0] = edge.Index0;
newIndices[i * 12 + 3 + j * 2 + 1] = edge.Index1;
}
}
}
}
// Generate index buffer
var indexBufferData = new byte[triangleCount * 12 * Utilities.SizeOf <int>()];
fixed(int *indexDataStart = &newIndices[0])
fixed(byte *indexBufferDataStart = &indexBufferData[0])
{
Utilities.CopyMemory((IntPtr)indexBufferDataStart, (IntPtr)indexDataStart, indexBufferData.Length);
meshData.IndexBuffer = new IndexBufferBindingData(new BufferData(BufferFlags.IndexBuffer, indexBufferData), true, triangleCount * 12);
}
meshData.DrawCount = triangleCount * 12;
meshData.PrimitiveType = PrimitiveType.PatchList.ControlPointCount(12);
}
/// <summary>
/// Split the mesh if it has strictly more than 65535 vertices (max index = 65534) on a plaftorm that does not support 32 bits indices.
/// </summary>
/// <param name="meshDrawData">The mesh to analyze.</param>
/// <param name="can32bitIndex">A flag stating if 32 bit indices are allowed.</param>
/// <returns>A list of meshes.</returns>
public unsafe static List <MeshDrawData> SplitMesh(MeshDrawData meshDrawData, bool can32bitIndex)
{
if (meshDrawData.IndexBuffer == null)
{
return new List <MeshDrawData> {
meshDrawData
}
}
;
if (!meshDrawData.IndexBuffer.Is32Bit) // already 16 bits buffer
{
return new List <MeshDrawData> {
meshDrawData
}
}
;
var verticesCount = meshDrawData.VertexBuffers[0].Count;
if (verticesCount <= ushort.MaxValue) // can be put in a 16 bits buffer - 65535 = 0xFFFF is kept for primitive restart in strip
{
meshDrawData.CompactIndexBuffer();
return(new List <MeshDrawData> {
meshDrawData
});
}
// now, we only have a 32 bits buffer that is justified because of a large vertex buffer
if (can32bitIndex) // do nothing
{
return new List <MeshDrawData> {
meshDrawData
}
}
;
// TODO: handle primitives other than triangle list
if (meshDrawData.PrimitiveType != PrimitiveType.TriangleList)
{
return new List <MeshDrawData> {
meshDrawData
}
}
;
// Split the mesh
var finalList = new List <MeshDrawData>();
fixed(byte *indicesByte = &meshDrawData.IndexBuffer.Buffer.Value.Content[0])
{
var indicesUint = (uint *)indicesByte;
var splitInfos = new List <SplitInformation>();
var currentSplit = new SplitInformation();
currentSplit.StartTriangleIndex = 0;
var currentIndexUintPtr = indicesUint;
for (int triangleIndex = 0; triangleIndex < meshDrawData.IndexBuffer.Count / 3; ++triangleIndex)
{
var verticesToAdd = 0;
var index0 = *currentIndexUintPtr++;
var index1 = *currentIndexUintPtr++;
var index2 = *currentIndexUintPtr++;
if (!currentSplit.UsedIndices.Contains(index0))
{
++verticesToAdd;
}
if (!currentSplit.UsedIndices.Contains(index1))
{
++verticesToAdd;
}
if (!currentSplit.UsedIndices.Contains(index2))
{
++verticesToAdd;
}
if (currentSplit.UsedIndices.Count + verticesToAdd > 65535) // append in the same group
{
splitInfos.Add(currentSplit);
currentSplit = new SplitInformation();
currentSplit.StartTriangleIndex = triangleIndex;
}
AddTriangle(currentSplit, index0, index1, index2, triangleIndex);
}
if (currentSplit.UsedIndices.Count > 0)
{
splitInfos.Add(currentSplit);
}
foreach (var splitInfo in splitInfos)
{
var triangleCount = splitInfo.LastTriangleIndex - splitInfo.StartTriangleIndex + 1;
var newMeshDrawData = new MeshDrawData
{
PrimitiveType = PrimitiveType.TriangleList,
DrawCount = 3 * triangleCount,
VertexBuffers = new VertexBufferBindingData[meshDrawData.VertexBuffers.Length]
};
// vertex buffers
for (int vbIndex = 0; vbIndex < meshDrawData.VertexBuffers.Length; ++vbIndex)
{
var stride = meshDrawData.VertexBuffers[vbIndex].Stride;
if (stride == 0)
{
stride = meshDrawData.VertexBuffers[vbIndex].Declaration.VertexStride;
}
var newVertexBuffer = new byte[splitInfo.UsedIndices.Count * stride];
fixed(byte *vertexBufferPtr = &meshDrawData.VertexBuffers[vbIndex].Buffer.Value.Content[0])
fixed(byte *newVertexBufferPtr = &newVertexBuffer[vbIndex])
{
//copy vertex buffer
foreach (var index in splitInfo.UsedIndices)
{
Utilities.CopyMemory((IntPtr)(newVertexBufferPtr + stride * splitInfo.IndexRemapping[index]), (IntPtr)(vertexBufferPtr + stride * index), stride);
}
}
newMeshDrawData.VertexBuffers[vbIndex] = new VertexBufferBindingData
{
Offset = 0,
Count = splitInfo.UsedIndices.Count,
Buffer = new BufferData(BufferFlags.VertexBuffer, newVertexBuffer),
Declaration = meshDrawData.VertexBuffers[vbIndex].Declaration,
Stride = 0
};
}
// index buffer
var newIndexBuffer = new byte[sizeof(ushort) * 3 * triangleCount];
fixed(byte *newIndexBufferPtr = &newIndexBuffer[0])
{
var newIndexBufferUshortPtr = (ushort *)newIndexBufferPtr;
var currentIndexPtr = &indicesUint[3 * splitInfo.StartTriangleIndex];
for (int triangleIndex = 0; triangleIndex < triangleCount; ++triangleIndex)
{
var index0 = *currentIndexPtr++;
var index1 = *currentIndexPtr++;
var index2 = *currentIndexPtr++;
var newIndex0 = splitInfo.IndexRemapping[index0];
var newIndex1 = splitInfo.IndexRemapping[index1];
var newIndex2 = splitInfo.IndexRemapping[index2];
*newIndexBufferUshortPtr++ = newIndex0;
*newIndexBufferUshortPtr++ = newIndex1;
*newIndexBufferUshortPtr++ = newIndex2;
}
}
newMeshDrawData.IndexBuffer = new IndexBufferBindingData
{
Offset = 0,
Count = triangleCount * 3,
Buffer = new BufferData(BufferFlags.IndexBuffer, newIndexBuffer),
Is32Bit = false
};
finalList.Add(newMeshDrawData);
}
}
return(finalList);
}
