/* ********************************************************************************* */
public static void Create_Control_Point(
PointX Prev, PointX CornerPnt, PointX Next, PointX CtrlPnt) {
PointX before = new PointX(Prev), after = new PointX(Next);
before.Subtract(CornerPnt);
before.Normalize();
after.Subtract(CornerPnt);
after.Normalize();
before.Add(after); // this now divides the angle between the two lines
before.Normalize(); // this gives us normalized output
// CtrlPnt.CopyFrom(before);
double x0, y0, sin, cos;
double d =
(after.x * before.y)
- (after.y * before.x); // winding order: d=(x-x1)*(y2-y1)-(y-y1)*(x2-x1)
if (d > 0) {
sin = Sin90; // 90 degrees
cos = Cos90;
} else {
sin = Sin270; // 270 degrees
cos = Cos270;
}
x0 = (before.x * cos) - (before.y * sin); // precalculated all to constants
y0 = (before.y * cos) + (before.x * sin);
CtrlPnt.Assign(x0, y0); // result is one point, 1 unit long, 'tangent' to the corner.
/*
position = sign((Bx - Ax) * (Y - Ay) - (By - Ay) * (X - Ax))// alternative: cross product
*/
}
/* ********************************************************************************* */
public static void Cubic_Spline_Chunk(
PointX p0, PointX p1, PointX p2, PointX p3, double FractAlong, PointX result) {
// B(t) = (1-t)^3*P0 + 3*(1-t)^2*t*P1 + 3*(1-t)*t^2*P2 + t^3*P3
double MinusFract = 1.0 - FractAlong;
double Wgt0 = Math.pow(MinusFract, 3); // * P0;
double Wgt1 = 3 * FractAlong * Math.pow(MinusFract, 2); // * P1;
double Wgt2 = 3 * MinusFract * Math.pow(FractAlong, 2); // * P2;
double Wgt3 = Math.pow(FractAlong, 3); // * P3;
double XLoc = (p0.x * Wgt0) + (p1.x * Wgt1) + (p2.x * Wgt2) + (p3.x * Wgt3);
double YLoc = (p0.y * Wgt0) + (p1.y * Wgt1) + (p2.y * Wgt2) + (p3.y * Wgt3);
result.Assign(XLoc, YLoc);
}
/* ********************************************************************************* */
public static void Test(Graphics2D gr) {
double Factor = 150;
PointX p0 = new PointX(1 * Factor, 1 * Factor),
ctr = new PointX(2 * Factor, 2 * Factor),
p1 = new PointX(3 * Factor, 0.5 * Factor);
int len = 256;
PointX[] results = new PointX[len];
for (int cnt = 0; cnt < len; cnt++) {
results[cnt] = new PointX();
}
Cheap_Spline(gr, p0, ctr, p1, results);
PointX[] raw = new PointX[10];
p0.Assign(0, 0);
PointX prevpnt = p0, pnt = p0;
for (int cnt = 0; cnt < raw.length; cnt++) {
prevpnt = pnt;
pnt =
new PointX(
60 + cnt * 80, 200 + (cnt % 2) * 80 + (Globals.RandomGenerator.nextDouble() * 100));
raw[cnt] = pnt;
gr.setColor(Globals.ToColorWheel(Globals.RandomGenerator.nextDouble()));
gr.drawLine((int) prevpnt.x, (int) prevpnt.y, (int) pnt.x, (int) pnt.y);
}
int NumSubLines = 8;
results = new PointX[NumSubLines * (raw.length - 1) + 1];
for (int pcnt = 0; pcnt < results.length; pcnt++) {
results[pcnt] = new PointX();
}
Cubic_Spline(gr, raw, NumSubLines, results);
if (true) {
pnt = results[0];
len = results.length;
gr.setColor(Color.red);
for (int cnt = 1; cnt < len; cnt++) {
prevpnt = pnt;
pnt = results[cnt];
// gr.setColor(Globals.ToColorWheel(Globals.RandomGenerator.nextDouble()));
gr.drawLine((int) prevpnt.x, (int) prevpnt.y, (int) pnt.x, (int) pnt.y);
}
}
}