/*
* Solves the system [a] + [b]s = [u] + [v]t
* [a - u] = [v]t - [b]s
*/
private static void SolveLinearSystem2(Point2Float a, Vector2Float b, out float s, Point2Float u, Vector2Float v, out float t)
{
Vector2Float constants = a - u;
double det_denom = Vector2Float.Determinant(v, -b);
double det_v = Vector2Float.Determinant(constants, -b);
double det_b = Vector2Float.Determinant(v, constants);
t = (float)(det_v / det_denom);
s = (float)(det_b / det_denom);
}
public override void Render(EffectConfigToken parameters, RenderArgs dstArgs, RenderArgs srcArgs, Rectangle[] rois, int startIndex, int length)
{
BlendEffectConfigToken token = parameters as BlendEffectConfigToken;
Point2Float start = new Point2Float();
Point2Float end = new Point2Float();
Point2Float p;
Point2Float q;
if (token.blendDirection == BlendDirection.BL_TR)
{
start = new Point2Float(bounds.Left - 0.5f, bounds.Bottom + 0.5f);
end = new Point2Float(bounds.Right + 0.5f, bounds.Top - 0.5f);
}
else if (token.blendDirection == BlendDirection.BR_TL)
{
start = new Point2Float(bounds.Right, bounds.Bottom);
end = new Point2Float(bounds.Left, bounds.Top);
}
else if (token.blendDirection == BlendDirection.TL_BR)
{
start = new Point2Float(bounds.Left, bounds.Top);
end = new Point2Float(bounds.Right, bounds.Bottom);
}
else if (token.blendDirection == BlendDirection.TR_BL)
{
start = new Point2Float(bounds.Right, bounds.Top);
end = new Point2Float(bounds.Left, bounds.Bottom);
}
if (token.blendDirection == BlendDirection.BL_TR || token.blendDirection == BlendDirection.TR_BL)
{
p = new Point2Float(bounds.Right, bounds.Bottom);
q = new Point2Float(bounds.Left, bounds.Top);
}
else
{
p = new Point2Float(bounds.Left, bounds.Bottom);
q = new Point2Float(bounds.Right, bounds.Top);
}
Vector2Float lineDir = Vector2Float.Normalize(p - q);
for (int i = startIndex; i < length; ++i)
{
Rectangle rect = rois[i];
for (int y = rect.Top; y < rect.Bottom; ++y)
{
for (int x = rect.Left; x < rect.Right; ++x)
{
Point2Float current = new Point2Float(x, y) + new Vector2Float(0.5f, 0.5f);
Vector2Float dir = Vector2Float.Normalize(end - current);
float distToCross = 0;
float dist_ignore = 0;
SolveLinearSystem2(current, dir, out distToCross, p, Vector2Float.Normalize(q - p), out dist_ignore);
Point2Float center = new Point2Float(bounds.Left + bounds.Width / 2, bounds.Top + bounds.Height / 2);
Vector2Float distToCenter = current - center;
distToCenter.X /= bounds.Width / 2;
distToCenter.Y /= bounds.Height / 2;
Point2Float from2;
if (Math.Abs(distToCenter.X) > Math.Abs(distToCenter.Y))
{
from2 = new Point2Float(start.X, end.Y);
}
else
{
from2 = new Point2Float(end.X, start.Y);
}
float distToStart = 0;
float dist_ignore2 = 0;
SolveLinearSystem2(current, -dir, out distToStart, from2, Vector2Float.Normalize(from2 - start), out dist_ignore2);
if (distToCross > 0)
{
float t = distToStart / (distToStart + distToCross);
ColorBgra pixle = srcArgs.Surface.GetPoint(x, y);
pixle.A = (byte)(t * pixle.A);
//pixle.R = (byte)(255 * t);
//pixle.G = 0; // (byte)(from2.Y);
//pixle.B = 0;
dstArgs.Surface.SetPoint(x, y, pixle);
}
else
{
dstArgs.Surface.SetPoint(x, y, srcArgs.Surface.GetPoint(x, y));
}
}
}
}
}
