public static bool pixelIsInsideTriangle(int x, int y, Vector3[] triPoints)
{
var pt1 = triPoints[0];
var pt2 = triPoints[1];
var pt3 = triPoints[2];
var barycenter = TriangleExtensions.BaryCoordinates2(x, y, pt1.ToVector2(), pt2.ToVector2(), pt3.ToVector2());
//only in the triangle if coefs are all positive.
if (barycenter.X < 0 || barycenter.X > 1f || barycenter.Y < 0 || barycenter.Y > 1f || barycenter.Z < 0 || barycenter.Z > 1f)
{
return(false);
}
return(true);
}
public static bool pixelIsInsideTriangle(int x, int y, TriangleFace triangle, Vector3[] vectors)
{
var pt1 = vectors[triangle.vertIndexList[0] - 1];
var pt2 = vectors[triangle.vertIndexList[1] - 1];
var pt3 = vectors[triangle.vertIndexList[2] - 1];
var barycenter = TriangleExtensions.BaryCoordinates2(x, y, pt1.ToVector2(), pt2.ToVector2(), pt3.ToVector2());
//only in the triangle if coefs are all positive.
if (barycenter.X < 0 || barycenter.X >= 1f || barycenter.Y < 0 || barycenter.Y >= 1f || barycenter.Z < 0 || barycenter.Z >= 1f)
{
return(false);
}
return(true);
}
//TODO should probably be Vector4
public static void drawTriangle(int triIndex, Vector3[] screenCords, Material material, double[] zbuffer, Color[] imageBuffer, int imageBufferWidth)
{
var minx = screenCords.Select(x => x.X).Min();
var miny = screenCords.Select(x => x.Y).Min();
var maxx = screenCords.Select(x => x.X).Max();
var maxy = screenCords.Select(x => x.Y).Max();
var A = screenCords[0];
var B = screenCords[1];
var C = screenCords[2];
Enumerable.Range((int)minx, (int)(maxx - minx) + 2).ToList().ForEach(x =>
{
Enumerable.Range((int)miny, (int)(maxy - miny) + 2).ToList().ForEach(y =>
{
var IsInsideTriangle = pixelIsInsideTriangle(x, y, screenCords);
var bary = TriangleExtensions.BaryCoordinates2(x, y,
A.ToVector2(), B.ToVector2(), C.ToVector2());
//compute the depth of current pixel.
var z = bary.X * A.Z + bary.Y * B.Z + bary.Z * C.Z;
if (IsInsideTriangle)
{
var flatIndex = imageBufferWidth * (int)y + (int)x;
//don't draw unless we are within bounds
//don't draw if something is already in the depth buffer for this pixel.
if (flatIndex < imageBuffer.Length && flatIndex > -1 /*&& z < depthBuffer[flatIndex]*/)
{
//only draw if nothing else is closer in the depth buffer and the shader does not ignore this pixel.
Color diffColor;
if (z < zbuffer[flatIndex] && material.Shader.FragmentToRaster(material, bary, ref diffColor))
{
imageBuffer[flatIndex] = diffColor;
zbuffer[flatIndex] = z;
}
}
}
});
});
}