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To convert from world space coordinates to screen coordinates, it's a matter of simple the substraction of the top-left coordinates of the camera to the object/tile position. ScreenX = ObjectX - CameraX; ScreenY = ObjectY - CameraY; However, when it comes down to determine the visibility of tiles, since they're stored in a 2D array where each tile has the same size, you can easily know wich ranges in the array are visible by translating the world coordinates into tile coordinates TileMinX = CameraX / TileSize; TileMaxX = (CameraX + ScreenWidth) / TileSize; TileMinY = CameraY / TileSize; TileMaxY = (CameraY + ScreenHeight) / TileSize; So those are the coordinates wich you need to render on screen. Of course, depending on the scroll values, it might interesting to add 1 to the MaxX so you also render tiles that are in between. Code example for a simple scroller: #define MAX_WIDTH Whatever #define MAX_HEIGHT Whatever #define MAX_TILES Whatever #define TILE_SIZE Whatever unsigned short LevelWidth; unsigned short LevelHeight; unsigned short Level[MAX_HEIGHT][MAX_WIDTH]; SDL_Surface * Tileset[MAX_TILES]; void RenderMap(SDL_Surface * Output, int CameraX, int CameraY) { // Determine ranges int MinX = CameraX / TILE_SIZE; int MinY = CameraY / TILE_SIZE; int MaxX = (CameraX+Output->width) / TILE_SIZE + 1; int MaxY = (CameraY+Output->height) / TILE_SIZE + 1; // Clip if out of range if (MinX < 0) MinX = 0; if (MinY < 0) MinY = 0; if (MaxX >= LevelWidth) MaxX = LevelWidth - 1; if (MaxY >= LevelHeight) MaxY = LevelHeight - 1; // Iterate through the level array for (int y = MinY; y < MaxY; y++) { for (int x = MinX; x < MaxX; x++) { // Determine if the tile we're about to draw is the transparent tile. If so, skip. if (Level[y][x] == 0) continue; // Render RenderImage(Tileset[Level[y][x]], Output, x * TILE_SIZE - CameraX, y * TILE_SIZE - CameraY); } } } void RenderImage(SDL_Surface * Input, SDL_Surface * Output, int x, int y) { .... }