LÖVE

Posted: **Wed Mar 04, 2015 3:36 pm**

So I'm trying to build off of the "Grid-Locked Player" Tutorial. And I've added a turret that should shoot at the player when within a certain distance of it.

Here's my code:

Code: Select all

function love.load()

	enemyImage = love.graphics.newImage("turret.png")
	enemyBullets = {}
	bulletSpeed = 250
	enemyDirection = 0
	enemyX = 200
	enemyY = 300
	enemyOriginX = enemyImage:getWidth()/2
	enemyOriginY = enemyImage:getHeight()/2
	enemyFOV = 100
	
	player = {
        grid_x = 256,
        grid_y = 256,
        act_x = 200,
        act_y = 200,
		speed = 10
	}
	
    map = {
        { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 },
        { 1, 3, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 0, 3, 1 },
        { 1, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 0, 1 },
        { 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 1 },
        { 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 1 },
        { 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 3, 3, 0, 1, 0, 1, 0, 1, 1 },
        { 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 3, 3, 0, 1, 0, 1, 0, 1, 1 },
        { 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1 },
        { 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1 },
        { 1, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1 },
        { 1, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 1 },
        { 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1 },
        { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 }
    }
end

function love.update(dt)
	enemyDirection = findRotation(enemyX,enemyY,player.grid_x,player.grid_y)
    player.act_y = player.act_y - ((player.act_y - player.grid_y) * player.speed * dt)
    player.act_x = player.act_x - ((player.act_x - player.grid_x) * player.speed * dt)
	
    for i,v in ipairs(enemyBullets) do
        v.x = v.x + (v.dx * dt)
        v.y = v.y + (v.dy * dt)
    end
	
	if player.grid_x and player.grid_y >= enemyFOV then
		local startX = enemyOriginX
		local startY = enemyOriginY
		
		local angle = math.atan2((player.act_y - startY), (player.act_x) - startX)
		
		local bulletDx = bulletSpeed * math.cos(angle)
		local bulletDy = bulletSpeed * math.sin(angle)
		
		table.insert(enemyBullets, {enemyX = startX, enemyY = startY, dx = bulletDx, dy = bulletDy})
	end
end

function love.keypressed(key)
    if key == "up" then
        if testMap(0, -1) then
            player.grid_y = player.grid_y - 32
        end
    elseif key == "down" then
        if testMap(0, 1) then
            player.grid_y = player.grid_y + 32
        end
    elseif key == "left" then
        if testMap(-1, 0) then
            player.grid_x = player.grid_x - 32
        end
    elseif key == "right" then
        if testMap(1, 0) then
            player.grid_x = player.grid_x + 32
        end
    end
end

function love.draw()
	love.graphics.draw(enemyImage,enemyX,enemyY,enemyDirection,0.05,0.05,enemyOriginX,enemyOriginY)
	love.graphics.setColor( 0, 255, 0, 200)
    love.graphics.rectangle("fill", player.act_x, player.act_y, 32, 32)
	
	love.graphics.setColor(128, 128, 128)
    for i,v in ipairs(enemyBullets) do
        love.graphics.rectangle("fill", v.x, v.y, 10, 10)
    end
		
    for y=1, #map do
        for x=1, #map[y] do
            if map[y][x] == 1 then
				love.graphics.setColor( 255, 255, 255, 200)
                love.graphics.rectangle("fill", x * 32, y * 32, 32, 32)
			elseif map[y][x] == 3 then
				love.graphics.setColor( 255, 0, 0, 200)
				love.graphics.rectangle("fill", x * 32, y * 32, 32, 32)
            end
        end
    end
end

function findRotation(x1,y1,x2,y2)
   return math.atan2(y2 - y1, x2 - x1)
end

function testMap(x, y)
    if map[(player.grid_y / 32) + y][(player.grid_x / 32) + x] == 1 then
        return false
	elseif map[(player.grid_y / 32) + y][(player.grid_x / 32) + x] == 3 then
		player.grid_y = 256
		player.grid_x = 256
    end
    return true
end

I get the error main.lua:88: bad argument #2 to ' rectangle' (number expected, got nil)

ANY HELP IS GREAT

Posted: **Wed Mar 04, 2015 5:52 pm**

You create bullets with:

Code: Select all

      table.insert(enemyBullets, {enemyX = startX, enemyY = startY, dx = bulletDx, dy = bulletDy})

but you always try to use enemyBullet[someindex].x and .y, which don't exist.

So basically just replace enemyX and enemyY with x and y.

LÖVE

bad argument #2 to ' rectangle' (number expected, got nil)

bad argument #2 to ' rectangle' (number expected, got nil)

Re: bad argument #2 to ' rectangle' (number expected, got ni