public bool ClosestRayIntersection(Ray ray, Vector3 modelBase, float ignoreDistance, out Vector3 intersection)
{
bool intersects = false;
intersection = Vector3.Zero;
float minDistSquared = float.MaxValue;
float ignoreDistanceSquared = ignoreDistance * ignoreDistance;
Vector3 where = Vector3.Zero;
// Iterate over the triangles
for (int i = 0; i < triangles.Count; i++)
{
TriangleVertices t = triangles[i];
if (RayIntersectsTriangle(ray, t.Vertices, modelBase, ref where))
{
float distSquared = (where - ray.Origin).LengthSquared;
if (distSquared > ignoreDistanceSquared && distSquared < minDistSquared)
{
minDistSquared = distSquared;
intersection = where;
intersects = true;
}
}
}
return(intersects);
}
public List <TriangleVertices> Build()
{
List <TriangleVertices> triangles = new List <TriangleVertices>();
try {
for (int ind = 0, indexSet = 0; ind < indexDataList.Count; ind++, indexSet++)
{
int vertexSet = (int)indexDataVertexDataSetList[ind];
IndexData indexData = (IndexData)indexDataList[indexSet];
OperationType opType = operationTypes[indexSet];
int iterations = 0;
switch (opType)
{
case OperationType.TriangleList:
iterations = indexData.indexCount / 3;
break;
case OperationType.TriangleFan:
case OperationType.TriangleStrip:
iterations = indexData.indexCount - 2;
break;
}
// locate position element & the buffer to go with it
VertexData vertexData = (VertexData)vertexDataList[vertexSet];
VertexElement posElem =
vertexData.vertexDeclaration.FindElementBySemantic(VertexElementSemantic.Position);
HardwareVertexBuffer posBuffer = vertexData.vertexBufferBinding.GetBuffer(posElem.Source);
try {
IntPtr posPtr = posBuffer.Lock(BufferLocking.ReadOnly);
IntPtr idxPtr = indexData.indexBuffer.Lock(BufferLocking.ReadOnly);
unsafe {
byte *pBaseVertex = (byte *)posPtr.ToPointer();
ushort *p16Idx = null;
uint * p32Idx = null;
// counters used for pointer indexing
int count16 = 0;
int count32 = 0;
if (indexData.indexBuffer.Type == IndexType.Size16)
{
p16Idx = (ushort *)idxPtr.ToPointer();
}
else
{
p32Idx = (uint *)idxPtr.ToPointer();
}
float *pReal = null;
int triStart = triangles.Count;
// iterate over all the groups of 3 indices
triangles.Capacity = triStart + iterations;
uint[] index = new uint[3];
for (int t = 0; t < iterations; t++)
{
Vector3[] v = new Vector3[3];
TriangleVertices tri = new TriangleVertices(v);
bool broken = false;
for (int i = 0; i < 3; i++)
{
// Standard 3-index read for tri list or first tri in strip / fan
if (opType == OperationType.TriangleList || t == 0)
{
if (indexData.indexBuffer.Type == IndexType.Size32)
{
index[i] = p32Idx[count32++];
}
else
{
index[i] = p16Idx[count16++];
}
}
else
{
// Strips and fans are formed from last 2 indexes plus the
// current one for triangles after the first
if (indexData.indexBuffer.Type == IndexType.Size32)
{
index[i] = p32Idx[i - 2];
}
else
{
index[i] = p16Idx[i - 2];
}
// Perform single-index increment at the last tri index
if (i == 2)
{
if (indexData.indexBuffer.Type == IndexType.Size32)
{
count32++;
}
else
{
count16++;
}
}
}
// Retrieve the vertex position
if (index[i] >= posBuffer.VertexCount)
{
log.InfoFormat("TriangleListBuilder.Build: Error: index[i] {0} is not less than posBuffer.VertexCount {1}, iteration t {2}",
index[i], posBuffer.VertexCount, t);
broken = true;
break;
}
Debug.Assert(index[i] < posBuffer.VertexCount);
byte *pVertex = pBaseVertex + (index[i] * posBuffer.VertexSize);
pReal = (float *)(pVertex + posElem.Offset);
v[i].x = *pReal++;
v[i].y = *pReal++;
v[i].z = *pReal++;
}
if (!broken)
{
// Put the points in in counter-clockwise order
if (((v[0].x - v[2].x) * (v[1].y - v[2].y) - (v[1].x - v[2].x) * (v[0].y - v[2].y)) < 0)
{
// Clockwise, so reverse points 1 and 2
Vector3 tmp = v[1];
v[1] = v[2];
v[2] = tmp;
}
// Debug.Assert(((v[0].x - v[2].x) * (v[1].y - v[2].y) - (v[1].x - v[2].x) * (v[0].y - v[2].y)) >= 0);
// Add to the list of triangles
triangles.Add(new TriangleVertices(v));
}
} // for iterations
} // unsafe
}
finally {
// unlock those buffers!
indexData.indexBuffer.Unlock();
posBuffer.Unlock();
}
}
return(triangles);
}
catch (Exception e) {
log.ErrorFormat("TriangleListBuilder.Build: Exception raised during triangle building: {0}", e.Message);
triangles.Clear();
return(triangles);
}
}
