/**********************************************
***********************************************
**                                           **
** Flash Collision Detection Functions       **
**                                           **
** ----------------------------------------- **
**   This file declares collision detection  **
** functions for several different types of  **
** collisions involving circles, rects, etc  **
** ----------------------------------------- **
**                                           **
**                                 Jermo2004 **
**                                           **
***********************************************
**********************************************/




//
// this function tests for the intersection of 2 circles
// returns a boolean value of true if there is a collision
//
// usage:  circleTest( [X1] , [Y1] , [Radius1] , [X2] , [Y2] , [Radius2] )
//
// test collision between a dot and a circle using a radius of 0 for the dot
//
//////////////////////////////////////////////////////////////////////////////
_root.circleHit = function(nAX, nAY, nAR, nBX, nBY, nBR)
{
	var xDist = (nAX - nBX);
	var yDist = (nAY - nBY);
	var nDist = Math.sqrt((xDist * xDist) + (yDist * yDist));
	return (nDist < (nAR + nBR));
}





//
// this function tests for the intersection of a circle with a rectangle
// returns a boolean value of true if there is a collision
//
// usage:  circleIntersectRect( [CircleX] , [CircleY] , [CircleRadius] , 
//                              [RectLeft] , [RectTop] , [RectRight] , [RectBottom] )
//
///////////////////////////////////////////////////////////////////////////////////////
_root.circleIntersectRect = function(nCX, nCY, nCR, nRLeft, nRTop, nRRight, nRBottom)
{
	var nCloseX = 0;  //holds the closest X position inside the rectangle
	var nCloseY = 0;  //holds the closest Y position inside the rectangle

	// determine the closest X position inside the rect
	// and if the X is totally out of range, return false
	if (nCX >= (nRLeft - nCR) && nCX <= (nRRight + nCR))
	{
		if (nCX >= nRLeft && nCX <= nRRight)
			nCloseX = nCX;
		else if (nCX < nRLeft)
			nCloseX = nRLeft;
		else
			nCloseX = nRRight;
	}
	else
		return false;

	// determine the closest Y position inside the rect
	// and if the Y is totally out of range, return false
	if (nCY >= (nRTop - nCR) && nCY <= (nRBottom + nCR))
	{
		if (nCY >= nRTop && nCY <= nRBottom)
			nCloseY = nCY;
		else if (nCY < nRTop)
			nCloseY = nRTop;
		else
			nCloseY = nRBottom;
	}
	else
		return false;

	//do a collision detection with the closest dot on the rectangle with the circle
	return _root.circleHit(nCX, nCY, nCR, nCloseX, nCloseY, 0);
}