//private void DrawTriangle ( VertexPT [] triVs ) {
// VertexPT [][] vss = ClipTriangleByZ (
// triVs,
// nearZ, 1 );
// foreach ( VertexPT [] clippedVs in vss ) {
// if ( culling != Culling.None ) {
// //double3 n = GetPerspectiveTriangleNormal ( new double3 [] { clippedVs [0].P, clippedVs [1].P, clippedVs [2].P },
// // culling == Culling.Ccw ? CycleDir.Ccw : CycleDir.Cw );
// //if ( ( n & double3.UnitZ ) >= 0 )
// // return;
// CycleDir triOrder = GetPerspectiveTriangleOrder ( new double3 [] { clippedVs [0].P, clippedVs [1].P, clippedVs [2].P } );
// if ( ( triOrder == CycleDir.Ccw && culling == Culling.Ccw ) ||
// ( triOrder == CycleDir.Cw && culling == Culling.Cw ) )
// return;
// }
// DrawClippedAndCulledTriangle ( clippedVs [0], clippedVs [1], clippedVs [2] );
// }
//}
void DrawClippedAndCulledTriangle(VertexPT v0, VertexPT v1, VertexPT v2)
{
double tpp = GetTexelsPerPixel(v0.P, v1.P, v2.P, v0.T, v1.T, v2.T,
image.Size.width, image.Size.height,
sampler.Map.Width, sampler.Map.Height);
// Transform to screen space
double2 halfWh = new double2(image.Size.width / 2, image.Size.height / 2);
v0.P.xy /= v0.P.z;
v1.P.xy /= v1.P.z;
v2.P.xy /= v2.P.z;
double3 screenP0 = new double3(halfWh + (v0.P.xy ^ halfWh), v0.P.z);
double3 screenP1 = new double3(halfWh + (v1.P.xy ^ halfWh), v1.P.z);
double3 screenP2 = new double3(halfWh + (v2.P.xy ^ halfWh), v2.P.z);
// Invert vertically
screenP0.y = image.Size.height - screenP0.y;
screenP1.y = image.Size.height - screenP1.y;
screenP2.y = image.Size.height - screenP2.y;
image.DrawTexturedTriangle(new [] { screenP0, screenP1, screenP2 },
new [] { v0.T, v1.T, v2.T }, sampler, tpp);
//image.DrawTriangle ( new [] { screenP0, screenP1, screenP2 }, color );
}
VertexPT [] TransformVertices(VertexPT [] vs, double4x4 m)
{
VertexPT [] tVs = new VertexPT [vs.Length];
for (int i = 0; i < vs.Length; i++)
{
tVs [i] = new VertexPT(m.Transform(vs [i].P), vs [i].T);
}
return(tVs);
}
VertexPT [][] ClipTriangleByZ(VertexPT [] vs, double z, int insideSign)
{
// Warning: this algorithm generally does not preserve cw/ccw order
Debug.Assert(insideSign == 1 || insideSign == -1);
List <VertexPT> vsInside = new List <VertexPT> (vs);
List <VertexPT> vsOutside = new List <VertexPT> ();
for (int i = 0; i < vsInside.Count; i++)
{
if (vsInside [i].P.z.CompareTo(z) != insideSign)
{
vsOutside.Add(vsInside [i]);
vsInside.RemoveAt(i--);
}
}
if (vsOutside.Count == 0)
{
return new VertexPT [][] { ( VertexPT [] )vs.Clone() }
}
;
else if (vsOutside.Count == 3)
{
return new VertexPT [][] {}
}
;
else if (vsOutside.Count == 2)
{
VertexPT [] newVs = new VertexPT [3];
newVs [0] = vsInside [0];
double k1 = (z - vsOutside [0].P.z) / (vsInside [0].P.z - vsOutside [0].P.z);
double k2 = (z - vsOutside [1].P.z) / (vsInside [0].P.z - vsOutside [1].P.z);
newVs [1] = new VertexPT(
k1.Lerp(vsOutside [0].P, vsInside [0].P),
k1.Lerp(vsOutside [0].T, vsInside [0].T)
);
newVs [2] = new VertexPT(
k2.Lerp(vsOutside [1].P, vsInside [0].P),
k2.Lerp(vsOutside [1].T, vsInside [0].T)
);
return(new VertexPT [][] { newVs });
}
else if (vsOutside.Count == 1)
{
double k1 = (z - vsOutside [0].P.z) / (vsInside [0].P.z - vsOutside [0].P.z);
double k2 = (z - vsOutside [0].P.z) / (vsInside [1].P.z - vsOutside [0].P.z);
VertexPT v1 = new VertexPT(
k1.Lerp(vsOutside [0].P, vsInside [0].P),
k1.Lerp(vsOutside [0].T, vsInside [0].T)
);
VertexPT v2 = new VertexPT(
k2.Lerp(vsOutside [0].P, vsInside [1].P),
k2.Lerp(vsOutside [0].T, vsInside [1].T)
);
return(new VertexPT [][] {
new VertexPT [] { vsInside [0], v1, v2 },
new VertexPT [] { vsInside [0], vsInside [1], v2 }
});
}
throw new ArgumentException("Invalid vertex data.");
}