private void ScanLine(int sx, int ex, int y, float sz, float ez)
{
for (int x = sx; x <= ex; x++)
{
float z = Mathf.Reciprocal(LerpZ(sx, ex, x, sz, ez));
Vector4 pa = _a.position;
Vector4 pb = _b.position;
Vector4 pc = _c.position;
//计算每个像素的重心坐标
float t = ((pb.y - pc.y) * x + (pc.x - pb.x) * y + (pb.x * pc.y - pc.x * pb.y)) / ((pb.y - pc.y) * pa.x + (pc.x - pb.x) * pa.y + (pb.x * pc.y - pc.x * pb.y));
float s = ((pa.y - pc.y) * x + (pc.x - pa.x) * y + (pa.x * pc.y - pc.x * pa.y)) / ((pa.y - pc.y) * pb.x + (pc.x - pa.x) * pb.y + (pa.x * pc.y - pc.x * pa.y));
float w = 1 - t - s;
//插值color和uv
Color4 c = _a.color * t + _b.color * s + _c.color * w;
TexCoord uv = _a.uv * t + _b.uv * s + _c.uv * w;
Fragment fragment = new Fragment(x, y, z, c, uv);
fragments.Add(fragment);
}
}
public Color4 Sample(TexCoord uv)
{
byte r = 255;
byte g = 255;
byte b = 255;
byte a = 255;
int x = (int)(uv.u * _bitmapData.Width);
int y = (int)(uv.v * _bitmapData.Height) * _bitmapData.Stride;
if (_bitmapData.PixelFormat == PixelFormat.Format24bppRgb)
{
unsafe
{
int p = y + (x * 3);
byte *ptr = (byte *)_bitmapData.Scan0.ToPointer();
r = ptr[p + 2];
g = ptr[p + 1];
b = ptr[p + 0];
}
}
else if (_bitmapData.PixelFormat == PixelFormat.Format32bppArgb)
{
unsafe
{
int p = y + (x * 4);
byte *ptr = (byte *)_bitmapData.Scan0.ToPointer();
r = ptr[p * 4 + 3];
g = ptr[p * 4 + 2];
b = ptr[p * 4 + 1];
a = ptr[p * 4 + 0];
}
}
return(new Color4(r, g, b, a));
}