Best way?

What is the best way to cycle through tiles for a tile-based game?

currently i am using this method

For X = 0 to 100
For Y = 0 to 100
bitblt blah blah, X*16,Y*16 (tiles are 16pixels wide/tall)
Next Y
Next X

is that the best way/ fastest?

just seeing if there are any tips to improve speed

Figure out the tile taht is in the upper left corner of the screen, and start your Bltting from that point. For example, say you had you 100x100 tile map, but the tile in the top left is at 12, 12, and you know that only 10 tiles will fit on the screen at once(just as an example), your loop would look like:

Code:

---

for i = 12 to 22
  for j = 12 to 22
    bitblt
  next j
next i

---

Have a variable for x, and y, and then just as the height and width of tiles on the screen.

Z.

It would be a bit faster to:

VB Code:

For X = 0 to 1600 Step 16
    For Y = 0 to 1600 Step 16
        BitBlt blah blah, X,Y (tiles are 16pixels wide/tall) 
    Next Y 
Next X

hmm..
thanks for the STEP idea.. i gotta try that..

as for the other post.. yeah.. i already do that ;)

any other improvement tips?

If you can, try to remove the inner loop. Itll save a tiny bit of time(read, a few clock cycles).

Z.

Well, I don't see how we could remove the inner loop :)

Anyway, if you have the tiles in an array, here's how I optimized my loop:

VB Code:

Dim X As Long, Y As Long
    Dim DestX As Long, DestY As Long
    Dim TileX As Long, TileY As Long
    
    DestX = ViewX + ScreenTileX
    DestY = ViewY + ScreenTileY
    
    'Loop trough all tiles and draw them
    For X = ViewX To DestX
        For Y = ViewY To DestY
            Blt imgTiles, Backbuffer, TileX, TileY, Map(X, Y).SrcX, Map(X, Y).SrcY, TileSize, TileSize
            
            TileY = TileY + TileSize
        Next Y
        
        TileX = TileX + TileSize
        TileY = 0
    Next X

See, no slow multiplications :D

ViewX/Y is the coordinates of the screen (top/left). The map's SrcX/Y are the coordinates of each tile in the tiles image. This blt function is a wrapper function but you get the idea :)

Something I forgot, TileSize is the size of the tile (duh) and ScreenTileX/Y is the width and height of the map, in tiles :)