/// <summary>
/// Calculate the volume of an entity's subentity at the given index (default 0). This is not the most robust funciton
/// but does fine with plain meshes and meshes with skeletal animation.
/// </summary>
/// <param name="entity">The entity to calculate the sub entity volume of.</param>
/// <param name="subEntityIndex">The index of the sub entity.</param>
/// <returns>The volume in engine units.</returns>
public static unsafe float calculateVolume(this Entity entity, ushort subEntityIndex = 0)
{
float volume = 0.0f;
using (MeshPtr mesh = entity.getMesh())
{
SubMesh subMesh = mesh.Value.getSubMesh(subEntityIndex);
using (VertexData vertexData = subMesh.vertexData.clone(true))
{
if (entity.hasSkeleton())
{
entity.animateVertexData(vertexData, subEntityIndex);
}
VertexDeclaration vertexDeclaration = vertexData.vertexDeclaration;
VertexBufferBinding vertexBinding = vertexData.vertexBufferBinding;
VertexElement positionElement = vertexDeclaration.findElementBySemantic(VertexElementSemantic.VES_POSITION);
HardwareVertexBufferSharedPtr positionHardwareBuffer = vertexBinding.getBuffer(positionElement.getSource());
int vertexSize = positionHardwareBuffer.Value.getVertexSize().ToInt32();
byte *vertexBuffer = (byte *)positionHardwareBuffer.Value.lockBuf(HardwareBuffer.LockOptions.HBL_NORMAL);
IndexData indexData = subMesh.indexData;
int numIndices = indexData.IndexCount.ToInt32();
byte * currentVertex;
Vector3 *v0, v1, v2; //Each vertex
using (var indexBuffer = indexData.IndexBuffer)
{
switch (indexBuffer.Value.getType())
{
case HardwareIndexBuffer.IndexType.IT_16BIT:
short *shortIndexBuffer = (short *)indexBuffer.Value.lockBuf(HardwareBuffer.LockOptions.HBL_READ_ONLY);
for (int i = 0; i < numIndices; i += 3)
{
currentVertex = vertexBuffer + vertexSize * shortIndexBuffer[i];
positionElement.baseVertexPointerToElement(currentVertex, (float **)&v0);
currentVertex = vertexBuffer + vertexSize * shortIndexBuffer[i + 1];
positionElement.baseVertexPointerToElement(currentVertex, (float **)&v1);
currentVertex = vertexBuffer + vertexSize * shortIndexBuffer[i + 2];
positionElement.baseVertexPointerToElement(currentVertex, (float **)&v2);
volume += Geometry.SignedVolumeOfTetrahedron(*v0, *v1, *v2);
}
break;
case HardwareIndexBuffer.IndexType.IT_32BIT:
int *intIndexBuffer = (int *)indexData.IndexBuffer.Value.lockBuf(HardwareBuffer.LockOptions.HBL_READ_ONLY);
for (int i = 0; i < numIndices; i += 3)
{
currentVertex = vertexBuffer + vertexSize * intIndexBuffer[i];
positionElement.baseVertexPointerToElement(currentVertex, (float **)&v0);
currentVertex = vertexBuffer + vertexSize * intIndexBuffer[i];
positionElement.baseVertexPointerToElement(currentVertex, (float **)&v1);
currentVertex = vertexBuffer + vertexSize * intIndexBuffer[i];
positionElement.baseVertexPointerToElement(currentVertex, (float **)&v2);
volume += Geometry.SignedVolumeOfTetrahedron(*v0, *v1, *v2);
}
break;
}
indexBuffer.Value.unlock();
}
positionHardwareBuffer.Value.unlock();
positionHardwareBuffer.Dispose();
}
return(volume);
}
}
/// <summary>
/// Perform skeletal animation on a given entity copying the results to vertexData. Used for volume calculations.
/// </summary>
/// <param name="entity"></param>
/// <param name="vertexData"></param>
/// <param name="subEntityIndex"></param>
private static void animateVertexData(this Entity entity, VertexData vertexData, ushort subEntityIndex)
{
Entity_animateVertexData(entity.OgreObject, vertexData.OgreObject, subEntityIndex);
}
