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Revision 84ddf691

Added by Leszek Koltunski about 4 years ago

Fixes for the Projection matrix, FOV.

There was a confusion between the Projection of the Node onto the Screen, and the Projection of the Cubits on the Node.

View differences:

src/main/java/org/distorted/magic/RubikSurfaceView.java
45 45 
    // Every 1/12 the distance of min(scrWidth,scrHeight) the direction of cube rotation will reset.
46 46 
    private final static int DIRECTION_SENSITIVITY=  12;
47 47 

  		




  48
  
  
    
    private final Static4D CAMERA_POINT = new Static4D(0, 0, RubikRenderer.CAMERA_DISTANCE, 0);


  		




  
  48
  
    
    // Where did we get this sqrt(3)/2 ? From the (default, i.e. 60 degrees - see InternalOutputSurface!)


  		




  
  49
  
    
    // FOV of the projection matrix of the Node onto the Screen.


  		




  
  50
  
    
    // Take a look how the CAMERA_POINT is used in onTouchEvent - (x,y) there are expressed in sort of


  		




  
  51
  
    
    // 'half-NDC' coordinates i.e. they range from +0.5 to -0.5; thus CAMERA_POINT also needs to be


  		




  
  52
  
    
    // in 'half-NDC'. Since in this coordinate system the height of the screen is equal to 1, then the


  		




  
  53
  
    
    // Z-distance from the center of the object to the camera is equal to (scrHeight/2)/tan(FOV/2) =


  		




  
  54
  
    
    // 0.5/tan(30) = sqrt(3)/2.


  		




  
  55
  
    
    // Why is the Z-distance between the camera and the object equal to (scrHeight/2)/tan(FOV/2)?


  		




  
  56
  
    
    // Because of the way the View part of the ModelView matrix is constructed in EffectQueueMatrix.send().


  		




  
  57
  
    
    private final Static4D CAMERA_POINT = new Static4D(0, 0, (float)Math.sqrt(3)*0.5f, 0);


  		




  49
  58
  
    

  		




  50
  59
  
    
    private RubikRenderer mRenderer;


  		




  51
  60
  
    
    private RubikObjectMovement mMovement;


  		












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