/// <summary>
/// Calculates a the ShadowVolume for a certain lightPosition.
/// </summary>
/// <param name="light">The light that is used for casting the ShadowVolume.</param>
/// <param name="world">The object to world space matrix.</param>
/// <param name="recalcFaceNormals">Recalculates the face normals. This is just necessary if the vertices
/// of the mesh are manipulated by the CPU like for SoftwareSkinning.</param>
/// <returns>The ShadowVolume in form of an Mesh.</returns>
public Mesh Calculate(Light light, Matrix4 world, bool recalcFaceNormals)
{
// Init variables
int j = 0;
// Calculate the object space light vector
this.world = world;
Vector4 osLight = light.Vector4 * Matrix4.Invert(world);
// calc the method to use
if (method == StencilMethod.Automatic)
{
currentMethod = CalcMethod(light, world);
}
else
{
currentMethod = method;
}
SetTechnique(currentMethod);
// for all subsets of the mesh add the silohuette
for (int iSubSet = 0; iSubSet < mesh.SubSets.Count; iSubSet++)
{
SubSet subset = mesh.SubSets[iSubSet];
SubSet shadow = shadowVolume.SubSets[iSubSet];
// get indices and positions
PositionStream positionStream = (PositionStream)subset.VertexUnit[typeof(PositionStream)];
// recalc face normals
if (recalcFaceNormals)
{
faceNormals[iSubSet] = subset.CalcFaceNormals();
}
shadow.IndexBufferStart = j;
CalcVisibilityInfo(ref j, iSubSet, osLight);
if (indexStream.ElementSize == 2)
{
AddShadowVolume16(ref j, iSubSet, light, positionStream.Size / 2);
}
else
{
AddShadowVolume32(ref j, iSubSet, light, positionStream.Size / 2);
}
shadow.PrimitiveCount = (j - shadow.IndexBufferStart) / 3;
}
indexStream.Upload();
return(shadowVolume);
}
//---------------------------------------------------------------
#endregion
//---------------------------------------------------------------
//---------------------------------------------------------------
#region Methods
//---------------------------------------------------------------
private void UpdateMetaInfo()
{
faceNormals = new Vector3[mesh.SubSets.Count][];
backface = new bool[mesh.SubSets.Count][];
edges = new Edge[mesh.SubSets.Count][];
this.shadowVolume = new Mesh();
int maxIndex = 0;
for (int iSubSet = 0; iSubSet < mesh.SubSets.Count; iSubSet++)
{
maxIndex = System.Math.Min(mesh.SubSets[iSubSet].VertexUnit.Size, maxIndex);
}
indexStream = IndexStream.Create(1024 * 16, maxIndex);
for (int iSubSet = 0; iSubSet < mesh.SubSets.Count; iSubSet++)
{
SubSet subSet = mesh.SubSets[iSubSet];
faceNormals[iSubSet] = subSet.CalcFaceNormals();
backface[iSubSet] = new bool[subSet.PrimitiveCount];
edges[iSubSet] = subSet.CalcEdges();
shadowVolume.SubSets.Add(new SubSet(subSet.VertexUnit, indexStream));
}
}
