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SDL Question

Started by LatchGameDev Apr 13, 2012 at 5:22 AM 1 reply 1.7k views

Original Post

Apr 13, 2012 at 5:22 AM

This is my work around but it makes my program so slow


 // I take the small square tile i want out of the tile_sheet and blit it onto temp_tile
 apply_surface( 0, 0, tile_sheet, temp_tile, &clip);
 
 // I save the SDL_Surface as tile.bmp
 SDL_SaveBMP(temp_tile, "Graphics\\tile.bmp");
 
 // Lastly I load the bmp into a different SDL_Surface called tile
 tile = load_image("Graphics\\tile.bmp");

Like I said the above works but is so darn slow. Ideally what I'd like to do is set the clipped part of tilesheet into a seperate SDL_Surface and have it save like...


 // I take the small square tile i want out of the tile_sheet and blit it onto temp_tile
 apply_surface( 0, 0, tile_sheet, temp_tile, &clip);
 
 tile = temp_tile;

Also the apply_surface function is from http://lazyfoo.net/S...son06/index.php

Wooh

Apr 13, 2012 at 12:12 PM

If you just want to copy the surface you can use SDL_DisplayFormat (or SDL_DisplayFormatAlpha)
tile = SDL_DisplayFormat(temp_tile);

If you don't want to use temp_tile at all you could just create a new surface with the same format as tile_sheet and blit the part you want.

tile = SDL_CreateRGBSurface(tile_sheet->flags, clip.w, clip.h, tile_sheet->format->BitsPerPixel, tile_sheet->format->Rmask, tile_sheet->format->Gmask, tile_sheet->format->Bmask, tile_sheet->format->Amask);
 apply_surface( 0, 0, tile_sheet, tile, &clip);

Copying/creating surfaces are slow so try to avoid doing it each frame update. If you only do it at loading/setup time it shouldn't be a problem.

LatchGameDev

Author

LatchGameDev

Apr 13, 2012 at 4:27 PM

Thank you, Thank you, Thank you
I'm only copying surfaces when i'm loaded/reloading the map and it was taking 44 seconds to load my map before. I used your first suggestion and it reduced the time to less then a second!

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