/// <summary>
/// Performs the specified operation on the provided meshes.
/// </summary>
/// <param name="first">The first mesh</param>
/// <param name="second">The second mesh</param>
/// <param name="operation">The mesh opration to perform on the two meshes</param>
/// <returns>A triangular mesh resulting from performing the specified operation. If the resulting mesh is empty, will return null.</returns>
public static Mesh3 PerformCSG(Mesh3 first, Mesh3 second, CSGOperations operation)
{
Mesh3 finalResult = null;
unsafe
{
InteropMesh a = new InteropMesh();
InteropMesh b = new InteropMesh();
Vector3[] aTransformed = first.GetTransformedVertices();
Vector3[] bTransformed = second.GetTransformedVertices();
InteropMesh *result;
fixed(Vector3 *aVerts = &aTransformed[0], bVerts = &bTransformed[0])
{
fixed(int *aTris = &first.TriangleIndices[0], bTris = &second.TriangleIndices[0])
{
a.vertsArrayLength = first.Vertices.Length * 3;
a.triArrayLength = first.TriangleIndices.Length;
a.vertices = (double *)aVerts;
a.triangleIndices = aTris;
b.vertsArrayLength = second.Vertices.Length * 3;
b.triArrayLength = second.TriangleIndices.Length;
b.vertices = (double *)bVerts;
b.triangleIndices = bTris;
try
{
result = performCSG(ref a, ref b, operation);
}
catch (SEHException ex)
{
ArgumentException e = new ArgumentException("Carve has thrown an error. Possible reason is corrupt or self-intersecting meshes", ex);
throw e;
}
}
}
if (result->vertsArrayLength == 0)
{
freeMesh(result);
return(null);
}
Vector3[] vertices = new Vector3[result->vertsArrayLength / 3];
int[] triangleIndices = new int[result->triArrayLength];
// Copy the results back in parallel
Parallel.For(0, vertices.Length, i =>
{
vertices[i] = new Vector3(result->vertices[3 * i], result->vertices[3 * i + 1], result->vertices[3 * i + 2]);
});
Parallel.For(0, triangleIndices.Length, i =>
{
triangleIndices[i] = result->triangleIndices[i];
});
// If none of the vertices had colors, return whatever we have
if (!first.HasColours && !second.HasColours)
{
finalResult = new Mesh3(vertices, triangleIndices);
freeMesh(result);
}
else // Assign colors to the resulting mesh
{
uint[] colors = new uint[vertices.Length];
uint grayCode = 4286611584; // The uint value of the color gray (representing no color)
// Assign the default gray to all vertices
Parallel.For(0, colors.Length, i =>
{
colors[i] = grayCode;
});
#region Worst practices of parallel coding
/**
* The procedure for color matching is creating a map of (vertex=>color) and then
* comparing all vertices of the resulting mesh (in parallel) with this map and
* assigning colors as necessary
*/
if (first.HasColours)
{
ConcurrentDictionary <Vector3, uint> firstMap = new ConcurrentDictionary <Vector3, uint>();
// Create vertex to color map
Parallel.For(0, aTransformed.Length, i =>
{
firstMap[aTransformed[i]] = first.VertexColours[i];
});
// Assign colors
Parallel.For(0, vertices.Length, i =>
{
if (firstMap.ContainsKey(vertices[i]))
{
colors[i] = firstMap[vertices[i]];
}
});
}
if (second.HasColours)
{
ConcurrentDictionary <Vector3, uint> secondMap = new ConcurrentDictionary <Vector3, uint>();
Parallel.For(0, bTransformed.Length, i =>
{
secondMap[bTransformed[i]] = second.VertexColours[i];
});
Parallel.For(0, vertices.Length, i =>
{
if (secondMap.ContainsKey(vertices[i]))
{
colors[i] = secondMap[vertices[i]];
}
});
}
#endregion
finalResult = new Mesh3(vertices, triangleIndices, colors);
}
} // end-unsafe
Matrix3 transform = first.Transform.Invert();
finalResult = new Mesh3(finalResult.Vertices.Select(x => transform.Transform(x - first.Position)).ToArray(),
finalResult.TriangleIndices, finalResult.VertexColours);
finalResult.Position = first.Position;
finalResult.Transform = first.Transform;
return(finalResult);
}
