If you start the following program, you can drag the filled area with the mouse in some positions, where only parts of the polygon are filled.
You can start it in JAVA2D-Mode and it works - in P3D it doesnt...
Anyone knows why? There is no error-message.


import processing.opengl.*;

void setup(){
 size(800,800, OPENGL);
}
void draw(){
 background(0);
 stroke(255);
 fill(100);

 float d = int(mouseX);
 float xl = 20;
 float xr = 40;
 float xh = 50;
 float y2 = 400;
 float yh = int(mouseY);

 beginShape(POLYGON);
 vertex(xl,height);      
 bezierVertex(xl, y2, d,yh, d,yh);      
 bezierVertex(d, yh, xr, y2, xr, height);      
 bezierVertex(xr, height, xl, height, xl, height);
 endShape();
}