Sprite trick

Questions
1

Hello again!

I have a question and i hope it is not as simple as the last one i asked. I am making a floor that is going to fill the whole screen, but instead of typing sprite, sprite, sprite all the time until you are done I began to wonder if there could be a shortcut somwhere that would give me more time instead of typing sprites all the time. So is there a way?

2

Try this

http://coolcodea.wordpress.com/2013/06/06/78-shaders-tiling-images/

3

Alternatively could you not just use a couple of for loops to do the same thing?
ie.

    local x,y = 0,0

    for i=1,32 do
        x = 0
        for j=1,32 do
              sprite("image",x,y)
              x = x + 32
        end
        y = y + 32 
    end

The next step on from this is a “tilemap” and generating a 2D array of map values (see http://www.mapeditor.org/), the above code could easily be used to draw a tilemap by looking up the value in a simple array.

4

It’s worth using the shader approach once you get a few of these tiling situations, or if you want to use a shrunk down version of the image (images are rarely exactly the right size).

The shader also works with irregular shaped objects.

Using a for loop is also going to hit your performance, a shader is way faster

5

Agreed, but what about tilemap support. I haven’t got much experience with shaders but could you use a single texture containing all your tiles and pass in a tile map array and just render a single quad that displayed a full map?

Now that would be a fast approach.

6

I’m sure you could, but you may not need a shader for that, if you set your texture mappings correctly for each vertex

7

Your probably right, I was thinking about this earlier. The only difference I can see is that if you use a mesh and set the texture coords it’ll probably be easier to setup and use than trying to use a shader and I suspect the speed increase would be negligible.

8

The real benefit of the shader is when you have fractional tiles, or an odd shaped surface, like a big triangle. Those are hard to program manually, but the shader just does them.

9

I just shared my project code for 2D map generation from a 2D table (grid) using sprite sheets.



Check it out here: http://twolivesleft.com/Codea/Talk/discussion/3058/