Problem with drawing moving sprites.

[Moonkis]

I'm doing an endless runner kind of thing, but with Wizards and Goblins and shoot em' up elements. I'm quite new to Lua and trying to get the hang of it. The goblins comes swarming from the right to the left in 400px per second. I'v noticed that they shift back a little whenever they move. it looks like they take 3 steps forward and one back each frame, which is really weird.

This intensifies whenever there are higher entity counts on screen (32~ entities). Have anyone else had this problem? I'm not sure how to solve it. I'm uploading the .love files so you guys can see what I mean.

EDIT:

Move with WASD and shoot with spacebar!


EDIT 2:

This seems only to happen when shooting bullets, I adjusted the spawner to spawn in the interval of 0.01 which spawns enough goblins to always update and render 136 objects.

EDIT 3:

If I remove the check inside bullet that sets the alive status to false ( causing it to not get removed from a table ) then the problem disapears. I think it is how I remove objects from the game ... is it a bad idea to call table.remove?

[Doctory]

Incorrect game packaging
It should be a .zip, not .rar.

[Moonkis]

Incorrect game packaging
It should be a .zip, not .rar.

Fixed it! Try download it again

[Doctory]

Incorrect game packaging
It should be a .zip, not .rar.

Fixed it! Try download it again

Take out all the files from Dungeon Pew Pew folder and put it in the zip.

[davisdude]

I haven't looked at it yet, but I'd be willing to put money on the fact that it's your drawings. How they're made to quads or whatever. That's probably it.

*(On a side note, if that's not the problem, don't expect any money)

[Moonkis]

I think so too, hopefully someone could explain what I'm doing wrong!

I updated the .love file! HOPEFULLY this is correct!

Thanks in advance!

[Doctory]

Yes, it works now. I see no problem what so ever here, it may be your computer.

[Moonkis]

Yes, it works now. I see no problem what so ever here, it may be your computer.

Have you tried spamming bullets (Holding spacebar)? Its then the problem arises. I "kind" of fixed this, by basically move the table.remove(...) into it's own loop which runs after the update-loop.

Is table.remove a bad idea to call WHEN iterating over the loop itself?

I'v basically isolated the problem to this piece of code (in EntityManager.update(dt))

Code: Select all

	for i, e in pairs(EntityManager.objects) do
		if e.update then
			e:update(dt)
                        if e:isAlive() == false then
                           table.remove(EntityManager.objects, i)
                        end
		end
	end

[davisdude]

It depends on how you're iterating. If you have a loop that starts at the end and iterates until the beginning adding -1 each time, it's harmless. Now if you have a normal for-loop, you're really messing it up. Here's what I mean:

Code: Select all

Fruits = {
     { Color = { 255, 0, 0, 255 }, Taste = 'Great!', Size = 64 }, -- Apple
     { Color = { 255, 255, 0, 255 }, Taste = 'Awful', Size = 32 }, -- Lemon
     { Color = { 255, 0, 255, 255 }, Taste = 'Great!', Size = 2 } }, -- Grape
}

function FruitLoop( Table ) -- Yes, intentional pun here. :)
     for a = 1, #Table do
          local Fruit = Table[a]
          if Fruit.Taste = 'Great!' then
               table.remove( Table, a )
          end
     end
end

What happens here is the original Fruits[2] (lemon) is not even touched in the first iteration. Here's how the table would look during this:

Code: Select all

a = 1
#Fruits = 3
Fruits[1] has a taste of 'Great!' so it's removed. Now the table is
Fruits = {
     { Color = { 255, 255, 0, 255 }, Taste = 'Awful', Size = 32 }, -- Lemon, 1st index
     { Color = { 255, 0, 255, 255 }, Taste = 'Great!', Size = 2 } }, -- Grape, 2nd index
}

a = 2 (Accessing Grape)
#Fruits = 2
Notices that Grape tastes great too, and removes it.

To fix this problem, iterate like this:

Code: Select all

function FruitLoop( Table ) -- Yes, intentional pun here. :)
     for a = #Table, 1, -1 do -- Starts accessing at 3. Goes until 1, removing 1 from the index each time.
          local Fruit = Table[a]
          if Fruit.Taste = 'Great!' then
               table.remove( Table, a )
          end
     end
end

[Moonkis]

It depends on how you're iterating. If you have a loop that starts at the end and iterates until the beginning adding -1 each time, it's harmless. Now if you have a normal for-loop, you're really messing it up. Here's what I mean:

Code: Select all

Fruits = {
     { Color = { 255, 0, 0, 255 }, Taste = 'Great!', Size = 64 }, -- Apple
     { Color = { 255, 255, 0, 255 }, Taste = 'Awful', Size = 32 }, -- Lemon
     { Color = { 255, 0, 255, 255 }, Taste = 'Great!', Size = 2 } }, -- Grape
}

function FruitLoop( Table ) -- Yes, intentional pun here. :)
     for a = 1, #Table do
          local Fruit = Table[a]
          if Fruit.Taste = 'Great!' then
               table.remove( Table, a )
          end
     end
end

What happens here is the original Fruits[2] (lemon) is not even touched in the first iteration. Here's how the table would look during this:

Code: Select all

a = 1
#Fruits = 3
Fruits[1] has a taste of 'Great!' so it's removed. Now the table is
Fruits = {
     { Color = { 255, 255, 0, 255 }, Taste = 'Awful', Size = 32 }, -- Lemon, 1st index
     { Color = { 255, 0, 255, 255 }, Taste = 'Great!', Size = 2 } }, -- Grape, 2nd index
}

a = 2 (Accessing Grape)
#Fruits = 2
Notices that Grape tastes great too, and removes it.

To fix this problem, iterate like this:

Code: Select all

function FruitLoop( Table ) -- Yes, intentional pun here. :)
     for a = #Table, 1, -1 do -- Starts accessing at 3. Goes until 1, removing 1 from the index each time.
          local Fruit = Table[a]
          if Fruit.Taste = 'Great!' then
               table.remove( Table, a )
          end
     end
end

Why isn't Fruit[2] touched here? Shouldn't it? Also I'm using a generic loop (think what it's called)

Code: Select all

for i, v in pairs(table) do
  -- code
end

EDIT:

Oh, is it because that a = 1 then we remove an item, the table is resized, which means lemon is now at index 1, and we move onto index 2, thus "skipping" lemon?