Lua, Love2D, why i'm getting an error on GameObject? - lua

Question

im doing the CS50 game development course and after creating the key and locked block required when i get close to the locked block i get an error saying GameObject.lua 28: attempted to perform arithmetic on field 'y' (nil value)
here is my code for level maker
LevelMaker = Class{}
keyCollected = false
function LevelMaker.generate(width, height)
local tiles = {}
local entities = {}
local objects = {}
local tileID = TILE_ID_GROUND
-- whether we should draw our tiles with toppers
local topper = true
local tileset = math.random(20)
local topperset = math.random(20)
-- insert blank tables into tiles for later access
for x = 1, height do
table.insert(tiles, {})
end
--generate one locked box and one locked key in a random position position
local lockBoxPosition = math.random(1, width)
local keyPosition = math.random(1, width)
local keyColor = math.random(1, 4) --for reference for the color skin used
-- column by column generation instead of row; sometimes better for platformers
for x = 1, width do
local tileID = TILE_ID_EMPTY
-- lay out the empty space
for y = 1, 6 do
table.insert(tiles[y],
Tile(x, y, tileID, nil, tileset, topperset))
end
-- chance to just be emptiness (to be sure to not generate a key and locked box above a chasm)
if math.random(7) == 1 and x ~= 1 and lockBoxPosition ~= x and keyPosition ~= x then
for y = 7, height do
table.insert(tiles[y],
Tile(x, y, tileID, nil, tileset, topperset))
end
else
tileID = TILE_ID_GROUND
-- height at which we would spawn a potential jump block
local blockHeight = 4
for y = 7, height do
table.insert(tiles[y],
Tile(x, y, tileID, y == 7 and topper or nil, tileset, topperset))
end
-- chance to generate a pillar
if math.random(8) == 1 then
blockHeight = 2
-- chance to generate bush on pillar
if math.random(8) == 1 then
table.insert(objects,
GameObject {
texture = 'bushes',
x = (x - 1) * TILE_SIZE,
y = (4 - 1) * TILE_SIZE,
width = 16,
height = 16,
-- select random frame from bush_ids whitelist, then random row for variance
frame = BUSH_IDS[math.random(#BUSH_IDS)] + (math.random(4) - 1) * 7,
collidable = false
}
)
end
-- pillar tiles
tiles[5][x] = Tile(x, 5, tileID, topper, tileset, topperset)
tiles[6][x] = Tile(x, 6, tileID, nil, tileset, topperset)
tiles[7][x].topper = nil
-- chance to generate bushes
elseif math.random(8) == 1 and keyPosition ~= x then
table.insert(objects,
GameObject {
texture = 'bushes',
x = (x - 1) * TILE_SIZE,
y = (6 - 1) * TILE_SIZE,
width = 16,
height = 16,
frame = BUSH_IDS[math.random(#BUSH_IDS)] + (math.random(4) - 1) * 7,
collidable = false
}
)
end
--spawn the key
if x == keyPosition then
table.insert(objects,
GameObject {
texture = 'key-lock',
x = (x - 1) * TILE_SIZE,
y = (blockHeight+1) * TILE_SIZE,
width = 16,
height = 16,
frame = keyColor,
collidable = true,
consumable = true,
solid = false,
--key has its own function to add to the player score
onConsume = function(player, object)
gSounds['pickup']:play()
player.score = player.score + 500
keyCollected = true
end
})
end
--spawn the locked box
if x == lockBoxPosition then
table.insert(objects,
--locked box
GameObject{
texture = 'key-lock',
x = (x-1) * TILE_SIZE,
Y = (blockHeight - 1) * TILE_SIZE,
width = 16,
height = 16,
--make it a random variant
frame = keyColor + 4,
collidable = true,
hit = false,
solid = true,
lockedBox = false,
--collision function
onCollide = function(obj)
if not obj.hit then
if keyCollected then
gSounds['pickup']:play()
obj.hit = true
--spawn flag post
local flagpost = GameObject {
texture = 'flagposts',
x = obj.x + 4,
y = (blockHeight - 4) * TILE_SIZE,
width = 8,
height = 48,
frame = 1,
collidable = true,
consumable = true,
solid = false,
onConsume = function(player, object)
gSounds['pickup']:play()
player.score = player.score + 1000
--end of the level
gStateMachine:change('play', {score = player.score, lastLevelWidth = width})
end
}
--spawn flag
local flag = GameObject {
texture = 'flags',
x = obj.x + 6,
y = (blockHeight - 2) * TILE_SIZE,
width = 16,
height = 10,
frame = 1,
collidable = true,
consumable = true,
solid = false,
onConsume = function(player, object)
gSounds['pickup']:play()
player.score = player.score + 1000
--end of the level
gStateMachine:change('play', {score = player.score, lastLevelWidth = width})
end
}
--raise the flag
Timer.tween(2.0, {
[flag] = {y = ((blockHeight - 4) * TILE_SIZE) + 4}
})
gSounds['powerup-reveal']:play()
table.insert(objects, flagpost)
table.insert(objects, flag)
end
end
gSounds['empty-block']:play()
end
}
)
end
-- chance to spawn a block
if math.random(10) == 1 then
table.insert(objects,
-- jump block
GameObject {
texture = 'jump-blocks',
x = (x - 1) * TILE_SIZE,
y = (blockHeight - 1) * TILE_SIZE,
width = 16,
height = 16,
-- make it a random variant
frame = math.random(#JUMP_BLOCKS),
collidable = true,
hit = false,
solid = true,
-- collision function takes itself
onCollide = function(obj)
-- spawn a gem if we haven't already hit the block
if not obj.hit then
-- chance to spawn gem, not guaranteed
if math.random(5) == 1 then
-- maintain reference so we can set it to nil
local gem = GameObject {
texture = 'gems',
x = (x - 1) * TILE_SIZE,
y = (blockHeight - 1) * TILE_SIZE - 4,
width = 16,
height = 16,
frame = math.random(#GEMS),
collidable = true,
consumable = true,
solid = false,
-- gem has its own function to add to the player's score
onConsume = function(player, object)
gSounds['pickup']:play()
player.score = player.score + 100
end
}
-- make the gem move up from the block and play a sound
Timer.tween(0.1, {
[gem] = {y = (blockHeight - 2) * TILE_SIZE}
})
gSounds['powerup-reveal']:play()
table.insert(objects, gem)
end
obj.hit = true
end
gSounds['empty-block']:play()
end
}
)
end
end
end
local map = TileMap(width, height)
map.tiles = tiles
return GameLevel(entities, objects, map)
end
and here is GameObject
GameObject = Class{}
function GameObject:init(def)
self.x = def.x
self.y = def.y
self.texture = def.texture
self.width = def.width
self.height = def.height
self.frame = def.frame
self.solid = def.solid
self.collidable = def.collidable
self.consumable = def.consumable
self.onCollide = def.onCollide
self.onConsume = def.onConsume
self.hit = def.hit
end
function GameObject:collides(target)
return not (target.x > self.x + self.width or self.x > target.x + target.width or
target.y > self.y + self.height or self.y > target.y + target.height)
end
function GameObject:update(dt)
end
function GameObject:render()
love.graphics.draw(gTextures[self.texture], gFrames[self.texture][self.frame], self.x, self.y)
end
the issue is supossedly in line 28 of GameObject