Java PConstants.PI屬性代碼示例

/**
 * ( begin auto-generated from PVector_angleBetween.xml )
 *
 * Calculates and returns the angle (in radians) between two vectors.
 *
 * ( end auto-generated )
 *
 * @webref pvector:method
 * @usage web_application
 * @param v1 the x, y, and z components of a PVector
 * @param v2 the x, y, and z components of a PVector
 * @brief Calculate and return the angle between two vectors
 */
static public float angleBetween(PVector v1, PVector v2) {

  // We get NaN if we pass in a zero vector which can cause problems
  // Zero seems like a reasonable angle between a (0,0,0) vector and something else
  if (v1.x == 0 && v1.y == 0 && v1.z == 0 ) return 0.0f;
  if (v2.x == 0 && v2.y == 0 && v2.z == 0 ) return 0.0f;

  double dot = v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
  double v1mag = Math.sqrt(v1.x * v1.x + v1.y * v1.y + v1.z * v1.z);
  double v2mag = Math.sqrt(v2.x * v2.x + v2.y * v2.y + v2.z * v2.z);
  // This should be a number between -1 and 1, since it's "normalized"
  double amt = dot / (v1mag * v2mag);
  // But if it's not due to rounding error, then we need to fix it
  // http://code.google.com/p/processing/issues/detail?id=340
  // Otherwise if outside the range, acos() will return NaN
  // http://www.cppreference.com/wiki/c/math/acos
  if (amt <= -1) {
    return PConstants.PI;
  } else if (amt >= 1) {
    // http://code.google.com/p/processing/issues/detail?id=435
    return 0;
  }
  return (float) Math.acos(amt);
}
 

/**
 * This function draws the progress bar graphical
 * component of the popup.
 */
private void drawProgressBar()
{
	//draw progress bar
	window.noFill();
	
	window.strokeWeight(3);
	
	turn = (int)(System.currentTimeMillis() - poisonStamp) / 1000;
	for(int x = 0; x < 3; ++x)
	{
		window.stroke(randomColours[randomIndex[x]][0],
					  randomColours[randomIndex[x]][1], 
					  randomColours[randomIndex[x]][2]);
		
		//arcs 1
		if(x >= turn)
		{
			if(x == turn)
				currentVel[x] -= 5.0f;
			if(currentVel[x] < maxVel)
				currentVel[x] = maxVel;
			
			float angle = PConstants.PI * 2 * (float)(System.currentTimeMillis() - poisonStamp) / currentVel[x];
			float radius = (barRadius + (10 * x)) * (1 - (x == turn ? ((float)(System.currentTimeMillis() - poisonStamp) % (Settings.commandWaitTime / 3) / (float)(Settings.commandWaitTime / 3)) : 0));
			window.arc(window.width / 2, (window.height / 2) + 60, 
					   radius,
					   radius, 
				       x % 2 == 0 ? (float)((-PConstants.PI / 6.0) + angle) : (float)((-PConstants.PI / 6.0) - angle), 
					   x % 2 == 0 ? (float)((PConstants.PI / 6.0) + angle) : (float)((PConstants.PI / 6.0) - angle));
			window.arc(window.width / 2, (window.height / 2) + 60,
					   radius,
					   radius, 
					   x % 2 == 0 ? (float)((-PConstants.PI / 6.0) + angle + PConstants.PI) : (float)((-PConstants.PI / 6.0) - angle - PConstants.PI), 
					   x % 2 == 0 ? (float)((PConstants.PI / 6.0) + angle + PConstants.PI) : (float)((PConstants.PI / 6.0) - angle - PConstants.PI));
		}
	}
	
	window.strokeWeight(1);
}
 

public void mouseEvent(processing.event.MouseEvent event) {
 
  switch (event.getAction()) {

    case MouseEvent.DRAG:
      //Calc distance dragged 
      float dx = prevX - event.getX();
      float dy = prevY - event.getY();

      if (_parent.mouseButton == PConstants.LEFT
              && !event.isControlDown()) {
        //Rotation about the z-axis, on the graph not world axis.
        PVector relX = VectorUtils.rotateArbitaryAxis(getRelativePosition(),
                new PVector(0, 1, 0), -dx * PConstants.PI / 100);
        _position = PVector.add(relX, _lookat);

        float dAngle = dy * PConstants.PI / 100;
        PVector r = getRelativePosition();

        //The next sections is slightly tricky, to get a better understanding
        //render the vector A in the draw routine below, this shows the axis 
        //the camera is rotated about.

        //now need to get an axis to rotate about that will allow
        //the camera to orbit over the top and bottom of lookat point
        A = new PVector(0, 0, 1);
        //now we get the angle between the z axis and the r vector projected
        //into the x-z plane only so no y comp and add 90deg
        float angle = (float) Math.atan2(r.x, r.z) + PConstants.PI / 2;
        //now rotate the axis A so it is orthogonal to r
        A = VectorUtils.rotateArbitaryAxis(A, new PVector(0, 1, 0), angle);
        //As we now have an axis that is always orthogonal to our relative
        //position going through the lookat point, we rotate the camera
        //position around it.
        PVector relY = VectorUtils.rotateArbitaryAxis(r, A, dAngle);

        //Strange things happen when the new relative position gets to 0,0,0 and flips
        //to the other side, the scene flips the z and x axis(comment out this check 
        //to see) so basically we dont want to apply any changes if the sign has changed
        if (Math.signum(r.x) == Math.signum(relY.x)
                && Math.signum(r.z) == Math.signum(relY.z)) {
          _position = PVector.add(relY, _lookat);
        }

      }
      if (_parent.mouseButton == PConstants.RIGHT
              || (_parent.mouseButton == PConstants.LEFT && event.isControlDown())) {
        PVector newPos = PVector.add(_position, PVector.mult(getEyeVector(), dy * 20));
        PVector relPos = PVector.sub(newPos, _lookat);

        if (relPos.mag() < _nearLimit || relPos.mag() > _farLimit) {
          newPos = _position;
        }

        _position = newPos;
      }

      prevX = event.getX();
      prevY = event.getY();
      break;
    case MouseEvent.MOVE:
      //Keep track of previous mouse pos
      //so a distance dragged can be calculated
      prevX = event.getX();
      prevY = event.getY();
      break;
  }

}