Mouse On Sphere In Perspective

mouse-sphere-perspective.pde

float distToCam = 1040; //1900
float w=1200, h=1200, wd2=w/2, hd2=h/2, wdh=w/h;

void settings() {
  fullScreen(P3D);
}

void setup() {
  surface.setSize(1200, 1200);
  surface.setLocation(360, 0);
  hint(DISABLE_DEPTH_TEST);
}

void draw() {
  perspective(atan(hd2/distToCam)*2, wdh, distToCam, 10000);
  camera(0, 0, -distToCam, 0, 0, 0, 0, 1, 0);
  scale(-1, 1, 1); //flip horizontal

  //sphere
  background(0);
  fill(100);
  stroke(255);
  sphere(hd2);
  
  //mouse/box
  pushMatrix();
  PVector p = getMouseOnSphereInPerspective();
  translate(p.x, p.y, p.z);
  fill(255, 0, 0);
  noStroke();
  ellipse(-10, -10, 20, 20);  
  popMatrix();
}

PVector getMouseOnSphereInPerspective() {
  float r = wd2;
  float cx = wd2;
  float cy = wd2;
  float mx = mouseX;
  float my = mouseY;
  float d = dist(mx, my, cx, cy);
  float a = d/r * PI/2;
  float x1 = sin(a);
  float y1 = cos(a);
  float x = (mx - cx) / d * x1;
  float y = (my - cy) / d * x1;
  float z = y1;
  return new PVector(x*r, y*r, z*r);
}

dit werkt bij distToCam is 1040. Maar om goed beeld op de globe te hebben moet distToCam op 1900 staan en dan werkt de muisfunctie niet goed meer.