//create game object
game = {dragging:false, clip:_root.game_mc};
//create object
//point p0 is its starting point in the coordinates x/y
game.myOb = {clip:game.clip.ob_mc, r:40};
game.myOb.p1 = {x:150, y:80};
//create first vector
//point p0 is its starting point in the coordinates x/y
//point p1 is its end point in the coordinates x/y
game.v1 = {p0:{x:50, y:120}, p1:{x:250, y:120}};
game.v2 = {};
//function to draw the points, lines and show text
function drawAll(v)
{
	//place ob mc
	v.clip._x = v.p1.x;
	v.clip._y = v.p1.y;
	//drawing the walls
	game.clip.p1._x = v.p1.x;
	game.clip.p1._y = v.p1.y;
	game.clip.p2._x = game.v1.p0.x;
	game.clip.p2._y = game.v1.p0.y;
	game.clip.p3._x = game.v1.p1.x;
	game.clip.p3._y = game.v1.p1.y;
	game.clip.dragger1._x = v.p1.x;
	game.clip.dragger1._y = v.p1.y;
	game.clip.dragger2._x = game.v1.p0.x;
	game.clip.dragger2._y = game.v1.p0.y;
	game.clip.dragger3._x = game.v1.p1.x;
	game.clip.dragger3._y = game.v1.p1.y;
	game.clip.v1._x = game.v1.p0.x;
	game.clip.v1._y = game.v1.p0.y;
	game.clip.v1._xscale = game.v1.vx;
	game.clip.v1._yscale = game.v1.vy;
	game.clip.v2._x = v.p1.x;
	game.clip.v2._y = v.p1.y;
	game.clip.v2._xscale = game.v2.vx;
	game.clip.v2._yscale = game.v2.vy;
	game.clip.v3._x = game.v3.p0.x;
	game.clip.v3._y = game.v3.p0.y;
	game.clip.v3._xscale = game.v3.vx;
	game.clip.v3._yscale = game.v3.vy;
}
//main function
function runMe()
{
	//check if point is dragged
	if (game.dragging)
	{
		var v = game.myOb;
		var x = Math.round(game.clip.dragger1._x);
		var y = Math.round(game.clip.dragger1._y);
		v.p1.x = x;
		v.p1.y = y;
		var v = game.v1;
		var x = Math.round(game.clip.dragger2._x);
		var y = Math.round(game.clip.dragger2._y);
		v.p0.x = x;
		v.p0.y = y;
		var x = Math.round(game.clip.dragger3._x);
		var y = Math.round(game.clip.dragger3._y);
		v.p1.x = x;
		v.p1.y = y;
		updateVector(v, true);
	}
	//start to calculate movement
	var ob = game.myOb;
	//check the wall for collisions
	var w = game.v1;
	var v = findIntersection(ob, w);
	v = updateVector(v, false);
	var pen = ob.r-v.len;
	//if we have hit the wall
	if (pen>=0)
	{
		//move object away from collision point
		game.v2.vx = v.dx*pen;
		game.v2.vy = v.dy*pen;
	}
	else
	{
		//hide this vector so the example look nicer
		game.v2.vx = 0;
		game.v2.vy = 0;
	}
	//drawing the line which shows closest distance to the wall
	game.v3 = v;
	game.v3.p0 = {};
	game.v3.p0.x = ob.p1.x-game.v3.vx;
	game.v3.p0.y = ob.p1.y-game.v3.vy;
	//draw it
	drawAll(ob);
}
//function to find all parameters for the vector
function updateVector(v, frompoints)
{
	//x and y components
	if (frompoints)
	{
		v.vx = v.p1.x-v.p0.x;
		v.vy = v.p1.y-v.p0.y;
	}
	else
	{
		v.p1.x = v.p0.x+v.vx;
		v.p1.y = v.p0.y+v.vy;
	}
	//length of vector
	v.len = Math.sqrt(v.vx*v.vx+v.vy*v.vy);
	//normalized unti-sized components
	if (v.len>0)
	{
		v.dx = v.vx/v.len;
		v.dy = v.vy/v.len;
	}
	else
	{
		v.dx = 0;
		v.dy = 0;
	}
	//right hand normal
	v.rx = -v.dy;
	v.ry = v.dx;
	//left hand normal
	v.lx = v.dy;
	v.ly = -v.dx;
	return v;
}
//find intersection point of 2 vectors
function findIntersection(v1, v2)
{
	//vector between center of ball and starting point of wall
	var v3 = {};
	v3.vx = v1.p1.x-v2.p0.x;
	v3.vy = v1.p1.y-v2.p0.y;
	//check if we have hit starting point
	var dp = v3.vx*v2.dx+v3.vy*v2.dy;
	if (dp<0)
	{
		//hits starting point
		var v = v3;
	}
	else
	{
		var v4 = {};
		v4.vx = v1.p1.x-v2.p1.x;
		v4.vy = v1.p1.y-v2.p1.y;
		//check if we have hit side or endpoint
		var dp = v4.vx*v2.dx+v4.vy*v2.dy;
		if (dp>0)
		{
			//hits ending point
			var v = v4;
		}
		else
		{
			//it hits the wall
			//project this vector on the normal of the wall
			var v = projectVector(v3, v2.lx, v2.ly);
		}
	}
	return v;
}
//project vector v1 on unit-sized vector dx/dy
function projectVector(v1, dx, dy)
{
	//find dot product
	var dp = v1.vx*dx+v1.vy*dy;
	var proj = {};
	//projection components
	proj.vx = dp*dx;
	proj.vy = dp*dy;
	return proj;
}
//calculate all parameters for the wall vectors
updateVector(game.v1, true);