private void DrawTriangle(VertexPT [] triVs)
{
if (culling != Culling.None)
{
// Cull by normal
//double3 n = GetPerspectiveTriangleNormal ( new double3 [] { triVs [0].P, triVs [1].P, triVs [2].P },
// culling == Culling.Ccw ? CycleDir.Ccw : CycleDir.Cw );
//if ( ( n & double3.UnitZ ) >= 0 )
// return;
// Cull by order
CycleDir triOrder = GetPerspectiveTriangleOrder(new double3 [] { triVs [0].P, triVs [1].P, triVs [2].P });
if ((triOrder == CycleDir.Ccw && culling == Culling.Ccw) ||
(triOrder == CycleDir.Cw && culling == Culling.Cw))
{
return;
}
}
VertexPT [][] vss = ClipTriangleByZ(
triVs,
nearZ, 1);
foreach (VertexPT [] clippedVs in vss)
{
DrawClippedAndCulledTriangle(clippedVs [0], clippedVs [1], clippedVs [2]);
}
}
double3 GetPerspectiveTriangleNormal(double3 [] pts, CycleDir cycleDir)
{
for (int i = 0; i < pts.Length; i++)
{
double z = pts [i].z <= 0 ? 1e-5 : pts [i].z;
pts [i].xy /= z;
}
if (cycleDir == CycleDir.Cw)
{
return(((pts [1] - pts [0]) * (pts [2] - pts [1])).Normalized);
}
else
{
return(((pts [2] - pts [1]) * (pts [1] - pts [0])).Normalized);
}
}
