-- collision example
-- andy c

function _init()
 -- create player object named block, each object in this example will need an x and a y
	block = {}
	block.x = 64
	block.y = 64
	-- create 6 walls
	walla = {}
	walla.x = ceil(rnd(120))
	walla.y = ceil(rnd(120))
	wallb = {}
	wallb.x = ceil(rnd(120))
	wallb.y = ceil(rnd(120))
	wallc = {}
	wallc.x = ceil(rnd(120))
	wallc.y = ceil(rnd(120))
	walld = {}
	walld.x = ceil(rnd(120))
	walld.y = ceil(rnd(120))
	walle = {}
	walle.x = ceil(rnd(120))
	walle.y = ceil(rnd(120))
	wallf = {}
	wallf.x = ceil(rnd(120))
	wallf.y = ceil(rnd(120))
	-- add the walls to the wall table
	walls = {walla, wallb, wallc, walld, walle, wallf} 
-- here's an inspirational quote: "wall-e" - wall-e
end

function collision(wall)
-- basically if it overlaps on two axis, it's a collision
	if(block.x < wall.x + 8 and 
		block.x + 8 > wall.x and
		block.y < wall.y + 8 and
		block.y + 8 > wall.y)then
		return true
	end
end

function _update()
 -- basically, move the coordinate, and test a collision for every object in the table. 
 -- if any of them return true, move back the coordinate to where it was
	-- left
	if (btn(0) and block.x > 0) then
		block.x -= 1
		for i in all(walls) do
			if (collision(i)) then
			 block.x += 1
			end
		end
	end
	-- right
	if (btn(1) and block.x < 120) then
		block.x += 1
		for i in all(walls) do
			if (collision(i)) then
			 block.x -= 1
			end
		end
	end
	-- up
	if (btn(2) and block.y > 0) then
		block.y -= 1
		for i in all(walls) do
			if (collision(i)) then
			 block.y += 1
			end
		end
	end
	-- down
	if (btn(3) and block.y < 120) then
		block.y += 1
		for i in all(walls) do
			if (collision(i)) then
			 block.y -= 1
			end
		end
	end
end

function _draw()
-- iterate through the table and draw a blue square for each block. draw a red square for the player
	cls()
	spr(1,block.x,block.y)
	for i in all(walls) do
		spr(2,i.x,i.y)
	end
end