Pickups in PICO-8

pico8_pickups.p8

-- Or if you don't want to bother with drawing each pickup with every tile aviable to you, you can make them "objects".

--For this, create an array, that will hold all our pickups:
pickupCollection = {}

-- and a function that you can call to add pickups.
-- we include a _type so later you can differentiate them
-- by checking the this. For ex: _type = 1 is a healing item, _type = 2 is a bomb etc...
function add_pickup(_xPosition, _yPosition, _type)
	-- we create a local variable to hold the item
	local pickup = {
		-- holds x position
		x = _xPosition,
		-- holds y position
		y = _yPosition,
		type = _type
	}
	-- now that we have the data we need
	-- add it to the global array that holds them
	add(pickupCollection, pickup)
end

-- now you can add a pickup anywhere by calling
-- add_pickup(xPosYouWant, yPosYouWant, typeYouWant)

-- after all this we just need to handle the collision
-- and the logic inside our _update() or a function that is called
-- from _update()

-- Loop through all of them, one-by-one they are checked from the array
-- and put into the item variable. We do a backwards for loop so you can
-- delete items and nothing can shift over to screw you
for i=#pickupCollection,1,-1 do
	local item = pickupCollection[i]
	-- handle collision. If you are tiled based, then what sugarvoid sent works
	-- but we don't need an mget() cuz we know the exact position. If you are
	-- doing AABB collision, put it here instead	
	if item.x == player.x and item.y == player.y then
		-- let's check the types I mention to know what to do
		if item.type == 1 then
			-- heal the player for ex
			player.lives += 1	
		elseif item.type == 2 then
			-- here you can do another one
		end
		-- if we picked up the item, delete it from the array
		del(pickupCollection, item)	
	end
end

-- now all you need is to draw them somewhere on the screen
-- so inside _draw() or a function called from _draw()
-- usually I align my pickups in a row on the spritesheet.
-- if you can do that, you can use _type to grab the sprite you need
-- ex: you have item starting from id:16 then the first item is 16, second
-- is 17, third 18 ... etc. This is just 16 + (pickup.type-1)
for pickup in all(pickupCollection) do
	-- if you are doing tile based, then multiply x,y by 8
	-- so they are tiled aligned. Remember tiles are 8x8 
	spr(16 + (pickup.type-1), pickup.x*8, pickup.y*8)
	-- if not, then just draw them normally on their position
end

-- bam you are set

Development Video explaining all this: https://www.youtube.com/watch?v=Vd9DPIzlFGg