Spawning Enemies

[J4awesome]

Hi,
I new to love2d and I was wondering if there is a very simple way to spawn an enemy.The enemy need to be on the top of the screen and slowly coming down.I would also like for there to be about 2-3 enemies at a time.The size of the window for my game is 400x400.
Any help is great

[MadByte]

Welcome J4awesome!

Something to read about "Tables"
Something about "numeric for loops"

There are tons of ways to use tables to hold multiple objects. Here is one:

Code: Select all

local enemies = {}

function newEnemy(x,y)
  local enemy = {}
  enemy.x = x
  enemy.y = y
  enemy.width = 64
  enemy.height = 64
  enemy.removed = false
  table.insert(enemies, enemy)
end


function love.load()
  newEnemy(0, 0)
  newEnemy(100, 100)
  newEnemy(200, 200)
end


function love.update(dt)
  for i=#enemies, 1, -1 do
    local enemy = enemies[i]
    if not enemy.removed then
      -- update enemy
    else table.remove(enemies, i) end
  end
end


function love.draw()
  for i=#enemies, 1, -1 do
    local enemy = enemies[i]
    -- draw stuff
    love.graphics.rectangle("line", enemy.x, enemy.y, enemy.width, enemy.height)
  end
end


function love.keypressed(key)
  if key == "escape" then love.event.quit() end
  if key == "space" and #enemies > 0 then enemies[#enemies].removed = true end
end

spawnEnemies.love

(490 Bytes) Downloaded 232 times

I didn't added the movement because I'm sure you'll easily find out how to do it, anyway if you really want some help with it - go here.
Please read the Lua pil article before asking what exactly happens here. If you afterwards still got questions feel free to ask

[J4awesome]

Hi,
I used your script in my game and I worked good.But the only thing is I couldn't figure out how to make the enemies move down to the bottom of the screen and hide itself.

[Doctory]

Hi,
I used your script in my game and I worked good.But the only thing is I couldn't figure out how to make the enemies move down to the bottom of the screen and hide itself.

You could do this:

Code: Select all

  for k, v in ipairs(enemies)  do
  	v.height = v.height + 100 * dt
  end

Put this in love.update.

[J4awesome]

I tried everything you told me to do but the 'enemies' are just staying there doing nothing.I sent to my main lua file to see if you know what the problem is.

P.S-If the game looks rushed it's because i'm doing a 24 hour game challenge with my friend

[monkeyman]

You could do this:

Code: Select all

  for k, v in ipairs(enemies)  do
  	v.height = v.height + 100 * dt
  end

Put this in love.update.

Small typo, v.y not v.height.

Code: Select all

  for k, v in ipairs(enemies)  do
    v.y = v.y + 100 * dt
  end

I tried everything you told me to do but the 'enemies' are just staying there doing nothing.I sent to my main lua file to see if you know what the problem is.

P.S-If the game looks rushed it's because i'm doing a 24 hour game challenge with my friend

Here are two .love files, the first is Madbyte's code with Doctory's update suggestion, the second is a small game I worked on a while ago to test out a similar problem. The enemies spawn at the top of the screen at a random x coordinate within the screen bounds, and you have to shoot them before they hit the ground. Arrow keys to move and spacebar to shoot. Hopefully going over the code will help with your problem.

Edit: By the way that's some of the first code I ever wrote, and it's not particularly elegant. The enemy.update and enemy.spawn functions are what you should look at, ignore the other stuff.

[Ref]

Could just check Modog's code over on 'Programs and Demos' or my code farther down the post.