/* ToDo:
 - pmouseX/Y doesn't work correctly during pause.  PApplet has dmouse & emouse.
 pmouse is set each time thru the draw loop so should probably be set whenever
 loop() is called.
 */
class Nav {
  float cameraX0, cameraY0, cameraZ0, targetX0, targetY0, targetZ0;
  PApplet parent0;
  Camera camera1;
  Camera camera2;

  Nav(PApplet parent, float cameraX, float cameraY, float cameraZ, float targetX, float targetY, float targetZ) {
    cameraX0 = cameraX;
    cameraY0 = cameraY;
    cameraZ0 = cameraZ;
    targetX0 = targetX;
    targetY0 = targetY;
    targetZ0 = targetZ;
    parent0 = parent;

    reset();
  }

  void setTransform() {
    setTransform(true);
  }
  void setTransform(boolean checkMouse) {
    if (checkMouse && mousePressed) {
      float dx = mouseX - pmouseX, dy = mouseY - pmouseY;
      mousepause = true;
      if (keyPressed && key==CODED) {
        switch(keyCode) {
        case SHIFT:
          camera1.zoom(radians(dy) / 2);
          break;
        case ALT:
          camera1.track(-dx, -dy);
          break;
          /*
        case CONTROL:
           reset();
           break;
           */
        }
      }
      else {
        camera1.tumble(radians(-dx), radians(-dy));
      }
    } else {
      mousepause = false;  
    }
    camera1.feed();
  }
  void showAxes(float axisLength, PFont font) {
    //pushMatrix(); 

    stroke(0,255,0);
    line(0,0,0,axisLength,0,0);
    line(0,0,0,0,axisLength,0);
    line(0,0,0,0,0,axisLength);
    //PFont font = loadFont("AlBayan-24.vlw");
    //textAlign(LEFT);
    textSize(4);
    fill(0,255,0,100);

    billboard.BeginBillboard(axisLength*1.125,0,0);
    text("X",0,0,0);
    billboard.EndBillboard();

    billboard.BeginBillboard(0,axisLength*1.125,0);
    text("Y",0,0,0);
    billboard.EndBillboard();
    billboard.BeginBillboard(0,0,axisLength*1.125);
    text("Z",0,0,0);
    billboard.EndBillboard();

    //popMatrix();
  }


  void reset() {
    camera1 = new Camera(parent0, cameraX0, cameraY0, cameraZ0, targetX0, targetY0, targetZ0);
    camera2 = new Camera(parent0);
    //camera2.look(PI,0);
  }

}


class BillBoard
{
  //from http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Contribution_3DOpenGL;action=display;num=1116313488
  //see http://campbellhoge.us/cchoge/billboard/ 
  PGraphics3D m_engine;
  PMatrix m_inv;

  // From setup() call billboard = new Billboard( (PGraphics3)(this.g));
  BillBoard( PGraphics3D engine )
  {
    m_engine = engine;
  }

  // x, y, and z are the local coordinates of the object
  // you want to billboard  
  void BeginBillboard( float x, float y, float z )
  {
    m_inv = m_engine.cameraInv;
    float[] in = new float[4];
    float[] out = new float[4];

    in[0] = x; 
    in[1] = y; 
    in[2] = z; 
    in[3] = 1;
    m_engine.camera.mult( in,out );

    pushMatrix();

    applyMatrix( m_inv.m00, m_inv.m01, m_inv.m02, m_inv.m03,
    m_inv.m10, m_inv.m11, m_inv.m12, m_inv.m13,
    m_inv.m20, m_inv.m21, m_inv.m22, m_inv.m23,
    m_inv.m30, m_inv.m31, m_inv.m32, m_inv.m33 );

    translate( out[0], out[1], out[2] );
  }

  void EndBillboard()
  {
    popMatrix();
  }
}