Unlimited coordinates system / unlimited map

[dusoft]

Hi,

Probably this idea is not new, but I have tried to use out of window (screen resolution) coordinates in love.graphics (e.g. line, rectangle etc.) and it works. (think using negative coordinates that are to the left and top of 0,0 or coordinates to the right/bottom of window width/height)

So I was thinking, since Love2D is able to draw out of visible coordinate system, this could work in coordination with:

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love.graphics.translate

(to move around the map to make desired coordinate window visible)

and

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love.graphics.scale

(to zoom in/out)

as kind of flat map system, right?

Does anyone know, if this has been tried before? And also, if this has any performance impact/consequences?

[s-ol]

This is exactly how probably 90% of maps are drawn (number made up).

There is a performance impact if you draw a huge, complicated map of course, but in this case you need to optimize whatever way you do it.
If you optimize you can still keep this approach but roughly figure out the range that will end up on your screen and only invest time drawing that.

[dusoft]

great!

will

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love.graphics.setScissor

be respected impact-wise in terms of not drawing anything else beside the selected rectangle?

[s-ol]

great!

will

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love.graphics.setScissor

be respected impact-wise in terms of not drawing anything else beside the selected rectangle?

no, offscreen contents are scissored automatically afaik (the performance difference will be negligible or nonexistent).

Whats more important is not trying to draw things in the first place, or even better, not even reading the data in Lua.
For example, lets say you're drawing a tilemap:

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love.graphics.translate(-camera.x, -camera.y)
for x=1,1000 do
  for y=1,1000 do
    tiles[x][y]:draw()
  end
end

of course this is not how it usually looks for real, but you get the idea, and probably why you don't want to do that.
Heres a better approach, performance-wise:

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love.graphics.translate(-camera.x, -camera.y)
local width, height = love.graphics.getDimensions()
local sx = math.floor(camera.x / TILEWIDTH)
local sy = math.floor(camera.x / TILEWIDTH)
local ex = math.ceil((camera.x + width) / TILEWIDTH)
local ey = math.ceil((camera.x + height) / TILEWIDTH)
for x=sx,ex do
  for y=sy,ey do
    tiles[x][y]:draw()
  end
end

do you get why and how this works?

Keep in mind that you don't even need to think about this until your game starts to lag, or you are thinking about bringing it to some platform where it lags.

[dusoft]

Cool, thanks, I understand.