/// <summary>
/// Computes the premultiplied value of specified color
/// </summary>
/// <param name="color">Color value</param>
/// <returns></returns>
public static Color Premultiply(Color color)
{
return(new Color(Color4.Premultiply(color.RawColor)));
}
private void RasterizeTriangle(Triangle <TPixelShaderInput> tri, MemoryResources resources, IPixelShader <TPixelShaderInput> pixelShader, OutputMerger outputMerger, int outputWidth, int outputHeight, Color4[,] colorBuffer, float[,] wBuffer)
{
var posA = tri.A.TransformedPosition;
var posB = tri.B.TransformedPosition;
var posC = tri.C.TransformedPosition;
var bitmapCoordA = MapNdcToScreen(posA.X, posA.Y, outputWidth, outputHeight);
var bitmapCoordB = MapNdcToScreen(posB.X, posB.Y, outputWidth, outputHeight);
var bitmapCoordC = MapNdcToScreen(posC.X, posC.Y, outputWidth, outputHeight);
// Triangle bounds (in [-1, 1] space)
var boundsLeft = Math.Min(bitmapCoordA.X, Math.Min(bitmapCoordB.X, bitmapCoordC.X));
var boundsTop = Math.Min(bitmapCoordA.Y, Math.Min(bitmapCoordB.Y, bitmapCoordC.Y));
var boundsRight = Math.Max(bitmapCoordA.X, Math.Max(bitmapCoordB.X, bitmapCoordC.X));
var boundsBottom = Math.Max(bitmapCoordA.Y, Math.Max(bitmapCoordB.Y, bitmapCoordC.Y));
if (boundsLeft == boundsRight || boundsTop == boundsBottom)
{
return;
}
for (var j = boundsTop; j <= boundsBottom; ++j)
{
if (j < 0 || outputHeight <= j)
{
continue;
}
for (var i = boundsLeft; i <= boundsRight; ++i)
{
if (i < 0 || outputWidth <= i)
{
continue;
}
if (!Helper.PointInTriangle(new Point(i, j), bitmapCoordA, bitmapCoordB, bitmapCoordC))
{
continue;
}
var pixCoord = MapScreenToNdc(i, j, outputWidth, outputHeight);
var interpolated = InterpolatePoint(tri.A, tri.B, tri.C, pixCoord, out var outOfRange);
//if (outOfRange) {
// continue;
//}
var pos = interpolated.TransformedPosition;
if (pos.Z < -1 || 1 < pos.Z || pos.Y < -1 || 1 < pos.Y || pos.X < -1 || 1 < pos.X)
{
continue;
}
var depthTestPassed = outputMerger.IsDepthTestPassed(pos.W, wBuffer[i, j]);
if (!depthTestPassed && colorBuffer[i, j].Alpha.Equals(1))
{
continue;
}
var pixel = pixelShader.Transform(resources, interpolated, out var discarded);
if (discarded)
{
continue;
}
pixel = Color4.Premultiply(pixel);
if (depthTestPassed)
{
wBuffer[i, j] = pos.W;
colorBuffer[i, j] = outputMerger.Blend(colorBuffer[i, j], pixel);
}
else if (colorBuffer[i, j].Alpha < 1)
{
colorBuffer[i, j] = outputMerger.Blend(pixel, colorBuffer[i, j]);
}
}
}
}
