[SDL] correct way of map scrolling

[Stefan Hendriks]

>
> But it looks like you're using a full pre-rendered map instead of
> something generated more dynamically, so that wouldn't work as well
> for you.

Who said i was drawing everything and then move the viewport?

I'd say, use the viewport to know what to draw, and then calculate the
tile x and y positions accoring to your camera positions.

The only question that remains is :
- is the camera X,Y position pixel per pixel
or:
- is it per tile?

Ie, tilesize = 32 pixels;


More likely in pseudo code:

Map tiles[x][y];

void draw_tile(tile , x, y) {

  int drawX = x - cameraX;
  int drawY = y - camerayY;

 blit(screen, drawX, drawY);
}


// this draws tiles per tile:
for (int x = cameraX; x < screenwidthXinTiles; x++) {
 for (int y = camerayY; y < screenwdithYinTiles; y++) {
  draw_tile(tiles[x][y],
 }
}

// and this by pixel:
for (int x = (cameraX / 32); x < screenwidthXinTiles; x++) {
 for (int y = (camerayY / 32); y < screenwdithYinTiles; y++) {
  draw_tile(tiles[x][y],
 }
}


-- 
Stefan Hendriks
-----------------------
http://www.fundynamic.nl