public void DrawTriangle(double2 [] pts, double3 color, Func <double3, double3, double3> blendFunc = null)
{
int bottomIdx, midIdx, topIdx, separateIdx, coincidentIdx;
Classify3Result res = Math3.Classify3(new [] { pts [0].y, pts [1].y, pts [2].y },
out topIdx, out midIdx, out bottomIdx, out separateIdx, out coincidentIdx);
if (res == Classify3Result.AllCoincident)
{
int x = ( int )Math.Round(pts [0].x, MidpointRounding.AwayFromZero);
int y = ( int )Math.Round(pts [0].y, MidpointRounding.AwayFromZero);
Values [x, y] = blendFunc == null ? color : blendFunc(Values [x, y], color);
return;
}
else if (res == Classify3Result.HasCoincidence)
{
double2 separatePoint = pts [separateIdx];
double2 midPoint = pts [midIdx];
double2 coincidentPoint = pts [coincidentIdx];
DrawXAlignedTriangle(separatePoint, midPoint.x, coincidentPoint.x, midPoint.y, color, true, blendFunc);
}
else
{
double2 topPoint = pts [topIdx];
double2 midPoint = pts [midIdx];
double2 bottomPoint = pts [bottomIdx];
double dx = topPoint.x - bottomPoint.x;
double dy = topPoint.y - bottomPoint.y;
double ik = dx / dy;
double x2 = ik * (midPoint.y - bottomPoint.y) + bottomPoint.x;
DrawXAlignedTriangle(bottomPoint, midPoint.x, x2, midPoint.y, color, true, blendFunc);
DrawXAlignedTriangle(topPoint, midPoint.x, x2, midPoint.y, color, false, blendFunc);
}
}
public static void DrawTexturedTriangle(this HdrBuffer image, double3 [] pts, double2 [] t,
Sampler2d sampler, double tpp)
{
int bottomIdx, midIdx, topIdx, separateIdx, coincidentIdx;
Classify3Result res = Math3.Classify3(new [] { pts [0].y, pts [1].y, pts [2].y },
out topIdx, out midIdx, out bottomIdx, out separateIdx, out coincidentIdx);
if (res == Classify3Result.AllCoincident)
{
int x = ( int )Math.Round(pts [0].x, MidpointRounding.AwayFromZero);
int y = ( int )Math.Round(pts [0].y, MidpointRounding.AwayFromZero);
image.Values [x, y] = sampler.GetColor(t [0]);
return;
}
else if (res == Classify3Result.HasCoincidence)
{
double3 separatePoint = pts [separateIdx];
double3 midPoint = pts [midIdx];
double3 coincidentPoint = pts [coincidentIdx];
double2 separateT = t [separateIdx];
double2 midT = t [midIdx];
double2 coincidentT = t [coincidentIdx];
image.DrawXAlignedTexturedTriangle(separatePoint, midPoint.x, coincidentPoint.x, midPoint.y,
midPoint.z, coincidentPoint.z,
separateT, midT, coincidentT,
sampler, tpp);
//image.DrawXAlignedHollowTriangle ( separatePoint, midPoint.x, coincidentPoint.x, midPoint.y, double3.UnitY );
}
else
{
double3 topPoint = pts [topIdx];
double3 midPoint = pts [midIdx];
double3 bottomPoint = pts [bottomIdx];
double k = (midPoint.y - bottomPoint.y) / (topPoint.y - bottomPoint.y);
double x2 = k.Lerp(bottomPoint.x, topPoint.x);
double2 topT = t [topIdx];
double2 midT = t [midIdx];
double2 bottomT = t [bottomIdx];
double zInv = k.Lerp(1 / bottomPoint.z, 1 / topPoint.z);
double z2 = 1 / zInv;
double2 coincidentT = k.ZLerp(bottomT, topT, bottomPoint.z, topPoint.z, zInv);
image.DrawXAlignedTexturedTriangle(bottomPoint, midPoint.x, x2, midPoint.y,
midPoint.z, z2,
bottomT, midT, coincidentT,
sampler, tpp);
image.DrawXAlignedTexturedTriangle(topPoint, midPoint.x, x2, midPoint.y,
midPoint.z, z2,
topT, midT, coincidentT,
sampler, tpp);
//image.DrawXAlignedHollowTriangle ( bottomPoint, midPoint.x, x2, midPoint.y, double3.UnitX );
//image.DrawXAlignedHollowTriangle ( topPoint, midPoint.x, x2, midPoint.y, double3.UnitX );
//double3 white = new double3 ( 1, 1, 1 );
//Func <double3, double3, double3> blendFunc = ( bg, fg ) => bg == white ? double3.UnitX : ( bg == double3.UnitY ? double3.UnitZ : double3.UnitY );
//image.DrawYSteppingLine ( bottomPoint, new double2 ( midPoint.x, midPoint.y ), double3.UnitX, true, false, blendFunc );
//image.DrawYSteppingLine ( bottomPoint, new double2 ( x2, midPoint.y ), double3.UnitX, false, false, blendFunc );
//image.DrawYSteppingLine ( topPoint, new double2 ( midPoint.x, midPoint.y ), double3.UnitX, true, true, blendFunc );
//image.DrawYSteppingLine ( topPoint, new double2 ( x2, midPoint.y ), double3.UnitX, false, true, blendFunc );
}
}
public static Classify3Result Classify3 <T> (T [] vals, out int highIdx, out int midIdx, out int lowIdx,
out int separateIdx, out int coincidentIdx)
where T : IComparable <T>
{
Classify3Result res = Classify3Result.Distinct;
separateIdx = 0;
coincidentIdx = 0;
int cmp10 = vals [1].CompareTo(vals [0]);
int cmp02 = vals [0].CompareTo(vals [2]);
if (cmp10 == 1) // 1 > 0
{
if (cmp02 == 1) // 1 > 0 > 2
{
highIdx = 1;
midIdx = 0;
lowIdx = 2;
}
else if (cmp02 == -1) // 1 > 0 < 2 => 1 >= 2 > 0 || 2 > 1 > 0
{
lowIdx = 0;
int cmp12 = vals [1].CompareTo(vals [2]);
if (cmp12 == 0) // 1 == 2 => 1 == 2 > 0
{
res = Classify3Result.HasCoincidence;
midIdx = 1;
highIdx = 1;
separateIdx = 0;
coincidentIdx = 2;
}
else if (cmp12 == 1) // 1 > 2 > 0
{
midIdx = 2;
highIdx = 1;
}
else /*if ( cmp12 == -1 )*/ // 2 > 1 > 0
{
midIdx = 1;
highIdx = 2;
}
}
else /*if ( cmp02 == 0 )*/ // 0 == 2 => 1 > 0 == 2
{
res = Classify3Result.HasCoincidence;
highIdx = 1;
midIdx = 0;
lowIdx = 0;
separateIdx = 1;
coincidentIdx = 2;
}
}
else if (cmp10 == -1) // 1 < 0
{
if (cmp02 == 1) // 0 > 2 => 1 <= 2 < 0 || 2 < 1 < 0
{
highIdx = 0;
int cmp12 = vals [1].CompareTo(vals [2]);
if (cmp12 == 0) // 1 == 2 => 1 == 2 < 0
{
res = Classify3Result.HasCoincidence;
midIdx = 1;
lowIdx = 1;
separateIdx = 0;
coincidentIdx = 2;
}
else if (cmp12 == 1) // 1 > 2 => 2 < 1 < 0
{
midIdx = 1;
lowIdx = 2;
}
else /*if ( cmp12 == -1 )*/ // 1 < 2 => 1 < 2 < 0
{
midIdx = 2;
lowIdx = 1;
}
}
else if (cmp02 == -1) // 0 < 2 => 1 < 0 < 2
{
highIdx = 2;
midIdx = 0;
lowIdx = 1;
}
else /*if ( cmp02 == 0 )*/ // 0 == 2 => 1 < 0 == 2
{
res = Classify3Result.HasCoincidence;
highIdx = 0;
midIdx = 0;
lowIdx = 1;
separateIdx = 1;
coincidentIdx = 2;
}
}
else /*if ( cmp10 == 0 )*/ // 1 == 0
{
res = Classify3Result.HasCoincidence;
midIdx = 0;
separateIdx = 2;
coincidentIdx = 1;
int cmp21 = vals [2].CompareTo(vals [1]);
if (cmp21 == -1) // 2 < 1 => 2 < 1 == 0
{
highIdx = 0;
lowIdx = 2;
}
else if (cmp21 == 1) // 2 > 1 => 2 > 1 == 0
{
highIdx = 2;
lowIdx = 0;
}
else /*if ( cmp21 == 0 )*/ // 2 == 0 => 2 == 1 == 0
{
res = Classify3Result.AllCoincident;
highIdx = 0;
lowIdx = 0;
}
}
return(res);
}
