public QuadraticCurveSegment[] Split(double t)
{
var p = new List<Point>();
var q = new List<Point>();
var _p = new List<Point>();
p.Add(Start);
p.Add(ControlPoint);
p.Add(End);
q.Add(p[0]);
q.Add(p[1]);
q.Add(p[2]);
while (p.Count > 1)
{
_p = new List<Point>();
for(int i = 0; i < p.Count - 1; i++)
{
var pt = Point.Lerp(t, p[i], p[i + 1]);
q.Add(pt);
_p.Add(pt);
}
p = _p;
}
var a = new QuadraticCurveSegment(q[0], q[3], q[5]) { Convex = Convex };
var b = new QuadraticCurveSegment(q[5], q[4], q[2]) { Convex = Convex };
return new QuadraticCurveSegment[] { a, b };
}
private static void AddQuadraticCurveSegment(QuadraticCurveSegment quadraticCurveSegment, List<PolygonPoint> points, BufferGenerator vertexBufferGenerator, BufferGenerator indexBufferGenerator, ref int indexCount, float r, float g, float b, int subDiffs = 0)
{
if(subDiffs < 2)
{
var splits = quadraticCurveSegment.Split(0.5);
AddQuadraticCurveSegment(splits[0], points, vertexBufferGenerator, indexBufferGenerator, ref indexCount, r, g, b, subDiffs + 1);
AddQuadraticCurveSegment(splits[1], points, vertexBufferGenerator, indexBufferGenerator, ref indexCount, r, g, b, subDiffs + 1);
return;
}
float sign;
quadraticCurveSegment.Split(0.5);
if (quadraticCurveSegment.Convex)
{
sign = 1f;
points.Add(new PolygonPoint(quadraticCurveSegment.End.X, quadraticCurveSegment.End.Y));
}
else
{
sign = -1f;
points.Add(new PolygonPoint(quadraticCurveSegment.ControlPoint.X, quadraticCurveSegment.ControlPoint.Y));
points.Add(new PolygonPoint(quadraticCurveSegment.End.X, quadraticCurveSegment.End.Y));
}
AddVertex(vertexBufferGenerator, (float)quadraticCurveSegment.Start.X, (float)quadraticCurveSegment.Start.Y, 0f, 0f, r, g, b, sign);
AddVertex(vertexBufferGenerator, (float)quadraticCurveSegment.End.X, (float)quadraticCurveSegment.End.Y, 1f, 1f, r, g, b, sign);
AddVertex(vertexBufferGenerator, (float)quadraticCurveSegment.ControlPoint.X, (float)quadraticCurveSegment.ControlPoint.Y, 0.5f, 0f, r, g, b, sign);
indexBufferGenerator.WriteUInt((uint)indexCount++, (uint)indexCount++, (uint)indexCount++);
}