/// <summary>Unmanaged buffer of iMeshIndexer wrapped into a Span you can write your vertices</summary>
public static Span <T> getBuffer <T>(this iMeshIndexer indexer) where T : unmanaged
{
sMeshIndexerSetup setup = indexer.getSetup();
int expected = setup.bytesPerVertex;
int actual = Marshal.SizeOf <T>();
if (expected != actual)
{
throw new ArgumentException($"Vertex size mismatch; indexer expects { expected } bytes / vertex, yet sizeof( { typeof( T ).FullName } ) is { actual }");
}
unsafe
{
return(new Span <T>((void *)indexer.getPointer(), (int)setup.verticesPerBatch));
}
}
static BoundingBox loadStlImpl(iMeshIndexer indexer, Stream stream, int trianglesCount, int trianglesPerBatch, float?minCosAngle)
{
Stopwatch sw;
if (logTime)
{
sw = Stopwatch.StartNew();
}
var bbox = loadStlTriangles(indexer, stream, trianglesCount, trianglesPerBatch);
if (logTime)
{
ConsoleLogger.logDebug("Loading STL and indexing vertices: {0}", sw.Elapsed.print());
}
if (minCosAngle.HasValue)
{
if (logTime)
{
sw.Restart();
}
indexer.generateNormals(minCosAngle.Value);
if (logTime)
{
ConsoleLogger.logDebug("Generating normals: {0}", sw.Elapsed.print());
}
}
if (logTime)
{
sw.Restart();
}
indexer.optimizeMesh(eMeshOptimizerFlags.All);
if (logTime)
{
ConsoleLogger.logDebug("Optimizing the mesh: {0}", sw.Elapsed.print());
}
return(bbox);
}
static BoundingBox loadStlTriangles(iMeshIndexer indexer, Stream stream, int trianglesCount, int trianglesPerBatch)
{
Memory <StlTriangle> buffer = new Memory <StlTriangle>(new StlTriangle[trianglesPerBatch]);
BoundingBox? box = null;
Span <Vector3> indexerBuffer = indexer.getBuffer <Vector3>();
while (trianglesCount > 0)
{
int batch = Math.Min(trianglesCount, trianglesPerBatch);
// Read into the buffer, it's over an array in managed memory
Memory <StlTriangle> slice = buffer.Slice(0, batch);
stream.Read(MemoryMarshal.AsBytes(slice.Span));
// Copy the batch to native memory
copyBatch(indexerBuffer, slice.Span);
// Update the box. Using the data from native memory because it has better locality, we only consume 72% of the source data, the rest is normals and BS.
BoundingBox bb = BoundingBox.compute(indexerBuffer.Slice(0, batch * 3));
if (box.HasValue)
{
box = BoundingBox.union(box.Value, bb);
}
else
{
box = bb;
}
// Index these vertices
indexer.commitBatch((uint)batch * 3);
trianglesCount -= batch;
}
return(box.Value);
}
