spaceshooter.p8

pico-8 cartridge // http://www.pico-8.com
version 34
__lua__
function _init()
	t=0

 ship = {
		h=4, 
		sp=1,
		x = 63,
		y = 100,
		p = 0,
		imm = false,
		t = 0,
		box = {x1=0, y1=0,
									x2=7, x2=7}
		}

 bullets = {}
 enemies = {}
 expl = {}
 stars = {}

 for i=1,128 do
 	add(stars, {
 		x=rnd(128),
 		y=rnd(128),
 		s=rnd(2)+1
 	})
 end


	start()
end

function start()
	_update = update_game
	_draw = draw_game
end

function game_over()
	_update = update_over
	_draw = draw_over
end

function update_over()
end
function draw_over()
	cls()
	print("game_over!", 40, 50,4)
end


function explode(_x,_y)
	add(expl, {x=_x,y=_y,t=0})
end

function fire()
	local b = {
		sp=3,
		x=ship.x,
		y=ship.y,
		dx=0,
		dy=-3,
		box = {x1=2, y1=2,
									x2=5, x2=5}
	}
	add(bullets,b)
end

function draw_game()
	cls()

	for st in all(stars) do
		pset(st.x, st.y, 6)
	end
	--bullets
	for b in all(bullets) do
		spr(b.sp, b.x, b.y)
		--draw_coll(b)
	end

	for ex in all(expl) do
		circ(ex.x,ex.y,ex.t/3,8+ex.t%3)
	end

	--enemies
	for e in all(enemies) do
		spr(e.sp, e.x, e.y)
		--draw_coll(e)
	end
	--ship
	if not ship.imm or t%8<4 then
		spr(ship.sp,ship.x,ship.y)
	end
	--draw_coll(ship)

	-- ui drawing
	for i=1,4 do
		if i<=ship.h then
		 spr(33,80+6*i,3)
		else
		 spr(34,80+6*i,3)
		end
	end

end

function update_game()
	t=t+1
	if ship.imm then
		ship.t += 1
		if ship.t>30 then
			ship.imm=false
			ship.t=0
		end
	end

	for st in all(stars) do
		st.y += st.s
		if st.y >= 128 then
			st.y = 0
			st.x = rnd(128)
		end
	end

	for ex in all(expl) do
		ex.t+=1
		if ex.t == 13 then
			del(expl, ex)
		end
	end

	--enemy logic
	if #enemies <= 0 then
		respawn()
	end
	for e in all(enemies) do
		e.m_y +=1.2
		e.x = e.r*sin(e.d*t/50) + e.m_x
		e.y = e.r*cos(t/50) + e.m_y
		if coll(ship,e) and not
					ship.imm then
			ship.imm = true
			ship.h -= 1
			ship.y += 4
			if ship.h <= 0 then
				game_over()
			end

		end

		if e.y > 150 then
			del(enemies,e)
		end

	end

	for b in all(bullets) do
		b.x+=b.dx
		b.y+=b.dy
		if b.x < 0 or b.x > 128 or
		 b.y < 0 or b.y > 128 then
			del(bullets, b)
		end
		for e in all(enemies) do
			if coll(b,e) then
				del(enemies,e)
				ship.p+=1
				explode(e.x,e.y)
			end
		end

	end

	if(t%8<4) then
		ship.sp=1
	else
		ship.sp=2
	end

	local shooting = false
	if btn(❎) then
		fire()
		shooting = true
		ship.y+=0.5
 end

	if not shooting then
		if btn(0) then ship.x-=1 end
		if btn(1) then ship.x+=1 end
		if btn(2) then ship.y-=1 end
		if btn(3) then ship.y+=1 end
	end

end
-->8
function coll(a,b)
	--todo
	local box_a = abs_box(a)
	local box_b = abs_box(b)

	if box_a.x1 > box_b.x2 or
				box_a.y1 > box_b.y2 or
				box_b.x1 > box_a.x2 or
				box_b.y1 > box_b.y2 then
		return false
	else
		return true
	end
end

function draw_coll(o)
	local o_box = abs_box(o)
	rect(o_box.x1, o_box.y1,
						o_box.x2, o_box.y2,
						11)
end

function abs_box(s)
 -- returns the position of the
 -- collision box
	local box = {}
	box.x1 = s.box.x1 + s.x
	box.y1 = s.box.y1 + s.y
	box.x2 = s.box.x2 + s.x
	box.y2 = s.box.x2 + s.y
	return box
end
-->8
function respawn()
	local n = flr(rnd(9))+2
	for i=1,4 do
		local d = -1
		if rnd(1)<0.5 then d=1 end
	 add(enemies, {
	 	sp=17,
	 	m_x=10+i*16,
	 	m_y=i*4-10,
	 	d=d,
	 	x=-32,
	 	y=-32,
	 	r=10,
	 	box = {x1=0, y1=0,
	 								x2=7, x2=7}
	 	})
	end
end
__gfx__
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