-- 点与四边形碰撞
function hitQuad(x, y, lt--[[ {x,y} --]], lb--[[ {x,y} --]], rt--[[ {x,y} --]], rb--[[ {x,y} --]]) 
	local a = (lt.x - lb.x) * (y - lb.y) - (lt.y - lb.y) * (x - lb.x);
	local b = (rt.x - lt.x) * (y - lt.y) - (rt.y - lt.y) * (x - lt.x);
	local c = (rb.x - rt.x) * (y - rt.y) - (rb.y - rt.y) * (x - rt.x);
	local d = (lb.x - rb.x) * (y - rb.y) - (lb.y - rb.y) * (x - rb.x);
	if ((a > 0 and b > 0 and c > 0 and d > 0) or (a < 0 and b < 0 and c < 0 and d < 0)) then
		return true;
	end
	return false;
end

-- 点与矩形碰撞
function testPoint(x0,y0,w0,h0,x1,y1)
    return x1 >= x0 and x1 <= x0 + w0 and y1>=y0 and y1 < y0 + h0
end

-- 矩形碰撞
function testRect(x0,y0,w0,h0,x1,y1,w1,h1)
    return x0<x1+w1 and y0<y1+h1 and x0+w0>x1 and y0+h0>y1
end

-- 圆形碰撞
function testCircle(x0,y0,r0,x1,y1,r1)
    return math.sqrt(math.pow(math.abs(x0-x1),2)+math.pow(math.abs(y0-y1),2)) < r0+r1
end

-- 点与圆形碰撞
function testCircle(x0,y0,x1,y1,r1)
    return math.sqrt(math.pow(math.abs(x0-x1),2)+math.pow(math.abs(y0-y1),2)) < r1
end

function rotate(ox,oy,x,y,r)
    r=math.rad(r)
	return (x - ox)*math.cos(r) - (y - oy)*math.sin(r) + ox,(x - ox)*math.sin(r) + (y - oy)*math.cos(r) + oy
end