Spherical Coordinated Camera

noamnav

hello there,

trying to create my own class for spherical movement of camera (based on mouse movement), i am experiencing a problem setting the up vector for the camera: when scrolling the camera on the up and down the matrix (x and y) seem to flip.

don't seem to have this problem with the horizontal scroll.

help anyone?

thanks

float camX, camY, camZ;
float camRad = width*20;
float camTheta, camPhi;
float camDragX, camDragY;
float newCamX = 50;
float newCamY = 600;
boolean moveCam = false;
PVector up;

void cam() {                                                                                            //camera
  camPhi   = map(newCamX, 0, width, PI, -PI);                              //phi is the horizontal angle 0-2PI    
  camTheta = map(newCamY, 0, height, HALF_PI, -HALF_PI);        //theta is the vertical angle 0-PI
  up    = new PVector (sin(camPhi), cos(camPhi));


  camX = camRad*sin(camTheta)*sin(camPhi);
  camY = camRad*sin(camTheta)*cos(camPhi);  
  camZ = camRad*cos(camTheta);

  camera(camX, camY, camZ, 0, 0, 0, up.x, up.y, up.z);
}

void mousePressed() {
  if (mouseButton == RIGHT) {
    camDragX = mouseX - newCamX;
    camDragY = mouseY - newCamY;
    moveCam = true;
  }
}

void mouseDragged() {
  if (mouseButton == RIGHT) {
    if (moveCam) {
      newCamX = mouseX - camDragX;
      newCamY = mouseY - camDragY;
    }
  }
}

void mouseReleased() {
  moveCam = false;
}

void mouseWheel(MouseEvent event) {
  float zoom = event.getCount();
  zoom = zoom*50;
  camRad += zoom;
}

void setup () {
  size (500, 500, P3D);
  colorMode(HSB, 360, 1, 1, 1);  
}


void draw() {
  background (0, 0, 1);  
  drawAxis();
  cam();
  fill(1,0,0);
  ellipse (width/2, height/2, 250, 250);
}

void drawAxis() {
  stroke (0, 1, 1);
  line (0, 0, 0, 1000, 0, 0);
  stroke (90, 1, 1);
  line (0, 0, 0, 0, 1000, 0);
  stroke (210, 1, 1);
  line (0, 0, 0, 0, 0, 1000);
  noStroke();
}

koogs

Highlight code, press ctrl-o

koogs

Have you seen the peasycam library?

noamnav

yes i am aware of it, but in this exercise i'm trying to develop my own class.

Chrisir

When you rotate up

The image is upsidedown

Not a bug only logical - camera turns

You can compensate by saying up.y = -1 or something - test it

Chrisir

Probably with if....camTheta....

noamnav

solved, by adding:

if (camZ<0) up.mult(-1);

(before the camera command)

this works and generates a 3d spherical coordinates with the Z axis facing up, though there's obviously something i'm missing in the math which forces me to introduce the condition.

thanks for the help