private void DrawTriangleTrapezoid(
Vector3 topMinInterpolant,
Vector3 deltaMinInterpolant,
Vector3 topMaxInterpolant,
Vector3 deltaMaxInterpolant,
float topMinX,
float deltaMinX,
float topMaxX,
float deltaMaxX,
float minY,
float maxY)
{
int intMinY = Mathf.Clamp(Mathf.CeilToInt(minY), _policyType.MinY, _policyType.MaxY + 1),
intMaxY = Mathf.Clamp(Mathf.CeilToInt(maxY), _policyType.MinY, _policyType.MaxY + 1);
for (int intY = intMinY; intY < intMaxY; intY++)
{
float y = intY - minY,
minX = topMinX + deltaMinX * y,
maxX = topMaxX + deltaMaxX * y;
Vector3 minInterpolant = RasterVectorUtils.Add(topMinInterpolant, RasterVectorUtils.Scale(deltaMinInterpolant, y)),
maxInterpolant = RasterVectorUtils.Add(topMaxInterpolant, RasterVectorUtils.Scale(deltaMaxInterpolant, y));
if (minX > maxX)
{
Exchange(ref minX, ref maxX);
Exchange(ref minInterpolant, ref maxInterpolant);
}
if (maxX > minX)
{
int intMinX = Mathf.Clamp(Mathf.CeilToInt(minX), _policyType.MinX, _policyType.MaxX + 1),
intMaxX = Mathf.Clamp(Mathf.CeilToInt(maxX), _policyType.MinX, _policyType.MaxX + 1);
Vector3 deltaInterpolant = RasterVectorUtils.ScaleInv(RasterVectorUtils.Substract(maxInterpolant, minInterpolant), (maxX - minX));
for (int x = intMinX; x < intMaxX; x++)
{
_policyType.ProcessPixel(x, intY, minInterpolant + deltaInterpolant * (x - minX));
}
}
}
}
public void DrawTriangle(Vector3 v0, Vector3 v1, Vector3 v2, Vector2 p0, Vector2 p1, Vector2 p2)
{
_interpolants[0] = v0;
_interpolants[1] = v1;
_interpolants[2] = v2;
_points[0] = p0;
_points[1] = p1;
_points[2] = p2;
// Find the top point.
if (_points[1].y < _points[0].y && _points[1].y <= _points[2].y)
{
Exchange(ref _points[0], ref _points[1]);
Exchange(ref _interpolants[0], ref _interpolants[1]);
}
else if (_points[2].y < _points[0].y && _points[2].y <= _points[1].y)
{
Exchange(ref _points[0], ref _points[2]);
Exchange(ref _interpolants[0], ref _interpolants[2]);
}
// Find the bottom point.
if (_points[1].y > _points[2].y)
{
Exchange(ref _points[2], ref _points[1]);
Exchange(ref _interpolants[2], ref _interpolants[1]);
}
// Calculate the edge gradients.
float topMinDiffX = (_points[1].x - _points[0].x) / (_points[1].y - _points[0].y),
topMaxDiffX = (_points[2].x - _points[0].x) / (_points[2].y - _points[0].y);
Vector3 topMinDiffInterpolant = RasterVectorUtils.ScaleInv(RasterVectorUtils.Substract(_interpolants[1], _interpolants[0]), (_points[1].y - _points[0].y)),
topMaxDiffInterpolant = RasterVectorUtils.ScaleInv(RasterVectorUtils.Substract(_interpolants[2], _interpolants[0]), (_points[2].y - _points[0].y));
float bottomMinDiffX = (_points[2].x - _points[1].x) / (_points[2].y - _points[1].y),
bottomMaxDiffX = (_points[2].x - _points[0].x) / (_points[2].y - _points[0].y);
Vector3 bottomMinDiffInterpolant = RasterVectorUtils.ScaleInv(RasterVectorUtils.Substract(_interpolants[2], _interpolants[1]), (_points[2].y - _points[1].y)),
bottomMaxDiffInterpolant = RasterVectorUtils.ScaleInv(RasterVectorUtils.Substract(_interpolants[2], _interpolants[0]), (_points[2].y - _points[0].y));
DrawTriangleTrapezoid(
_interpolants[0],
topMinDiffInterpolant,
_interpolants[0],
topMaxDiffInterpolant,
_points[0].x,
topMinDiffX,
_points[0].x,
topMaxDiffX,
_points[0].y,
_points[1].y
);
DrawTriangleTrapezoid(
_interpolants[1],
bottomMinDiffInterpolant,
RasterVectorUtils.Add(_interpolants[0], RasterVectorUtils.Scale(topMaxDiffInterpolant, (_points[1].y - _points[0].y))),
bottomMaxDiffInterpolant,
_points[1].x,
bottomMinDiffX,
_points[0].x + topMaxDiffX * (_points[1].y - _points[0].y),
bottomMaxDiffX,
_points[1].y,
_points[2].y
);
}