public void AddLoop(int vertexIndex, int normalsIndex, int uvIndex)
{
var loop = new FaceLoop()
{
VertexIndex = vertexIndex, NormalIndex = normalsIndex
};
loop.UvIndices.Add(uvIndex);
FaceLoops.Add(loop);
}
public void CalculateNormals()
{
Normals.Clear();
for (int i = 0; i < Vertices.Count; i++)
{
Normals.Add(Vector3.Zero);
}
foreach (var submesh in Submeshes)
{
var loops = submesh.FaceLoops;
for (int i = 0; i < loops.Count; i += 3)
{
FaceLoop loop0 = loops[i];
FaceLoop loop1 = loops[i + 1];
FaceLoop loop2 = loops[i + 2];
//normal calculation
Vector3 p1 = Vertices[loop0.VertexIndex];
Vector3 p2 = Vertices[loop1.VertexIndex];
Vector3 p3 = Vertices[loop2.VertexIndex];
Vector3 U = (p2 - p1);
Vector3 V = (p3 - p1);
Vector3 normal = Vector3.Zero;
normal.X = (U.Y * V.Z) - (U.Z * V.Y);
normal.Y = (U.Z * V.X) - (U.X * V.Z);
normal.Z = (U.X * V.Y) - (U.Y * V.X);
normal = Vector3.Normalize(normal);
Normals[loop0.VertexIndex] += normal;
Normals[loop1.VertexIndex] += normal;
Normals[loop2.VertexIndex] += normal;
//set loop normal
loop0.NormalIndex = loop0.VertexIndex;
loop1.NormalIndex = loop1.VertexIndex;
loop2.NormalIndex = loop2.VertexIndex;
}
}
for (int i = 0; i < Normals.Count; i++)
{
Normals[i] = Vector3.Normalize(Normals[i]);
}
}