public static Triangle[] ToTriangles(Quad quad)
{
Triangle[] tris = new Triangle[2];
VertexDeclaration quadDecl = quad.p0.VertexDeclaration;
tris[0] = new Triangle();
tris[1] = new Triangle();
for (int i = 0; i < 3; ++i)
{
tris[0][i] = new Vertex(quadDecl);
tris[1][i] = new Vertex(quadDecl);
}
tris[0].p0.FromArray(quad[0].ToArray());
tris[0].p1.FromArray(quad[1].ToArray());
tris[0].p2.FromArray(quad[2].ToArray());
tris[1].p0.FromArray(quad[0].ToArray());
tris[1].p1.FromArray(quad[2].ToArray());
tris[1].p2.FromArray(quad[3].ToArray());
return tris;
}
private void PopulateMesh()
{
int offset = 0;
tris = new Triangle[triCount];
int triPos = 0;
for (int i = 0; i < polyVertexCount.Length; ++i)
{
IPoly poly;
if (polyVertexCount[i] == 3)
poly = new Triangle();
else
poly = new Quad();
for (int j = 0; j < polyVertexCount[i]; ++j)
{
float[] datArray = new float[_vertexDeclaration.Stride];
int index = 0;
foreach (KeyValuePair<string, Semantic> inputSemantic in semantics)
{
var channel = _vertexDeclaration.GetChannel(inputSemantic.Key);
index = indices[(semantics.Count * offset) + inputSemantic.Value.Offset];
float[] sourceData = sources[inputSemantic.Value.SourceName].data;
int sourceStride = sources[inputSemantic.Value.SourceName].stride;
PopulateArray(sourceData, index * sourceStride, datArray, channel.Offset, channel.Stride);
}
poly[j] = new Vertex(_vertexDeclaration);
poly[j].FromArray(datArray);
++offset;
}
if (polyVertexCount[i] == 4)
{
Triangle[] quadTris = PrimitiveHelper.ToTriangles(poly as Quad);
quadTris.CopyTo(tris, triPos);
triPos += 2;
}
else
{
tris[triPos] = (Triangle)poly;
++triPos;
}
}
}
private float[] GenerateTangents(Triangle tri, int vertexNum)
{
int posOffset = _vertexDeclaration.GetChannel("VERTEX").Offset;
int texOffset = _vertexDeclaration.GetChannel("TEXCOORD").Offset;
int p1 = (vertexNum + 1) % 3;
int p2 = (vertexNum + 2) % 3;
Vector3 vec1 = VectorMethods.FromArray3(tri[p1].Data, posOffset);
vec1 -= VectorMethods.FromArray3(tri[vertexNum].Data, posOffset);
Vector3 vec2 = VectorMethods.FromArray3(tri[p2].Data, posOffset);
vec2 -= VectorMethods.FromArray3(tri[vertexNum].Data, posOffset);
Vector2 tc1 = VectorMethods.FromArray2(tri[p1].Data, texOffset) - VectorMethods.FromArray2(tri[vertexNum].Data, texOffset);
Vector2 tc2 = VectorMethods.FromArray2(tri[p2].Data, texOffset) - VectorMethods.FromArray2(tri[vertexNum].Data, texOffset);
Vector3 bitangent = (tc2.Y * vec1) - (tc1.Y * vec2);
Vector3 tangent = (-tc2.X * vec1) + (tc1.X * vec2);
float[] tangents = new float[6];
tangent.ToArray().CopyTo(tangents, 0, 0);
bitangent.ToArray().CopyTo(tangents, 0, 3);
return tangents;
}
