SDL_Layer even slower than SDL?

Arivor · 2013-01-26T12:57:50

Hello everyone, I'm currently experimenting with SDL for some basic scrolling shooter. Since the moving background reeeally slowed things down, I went online and found "SDL_Layer". The documentation is sparse, but I thought I'd figured it out - until I tried it. With just the background in one layer and a single object in another, it's just as slow as vanilla SDL. Because of the moving background I can't use dirty rects. Unfortunately, Google was not helpful on this topic, so I presume there is something wrong with my code. Here is what I tried: SDL_Surface *screen; if ( SDL_Init(SDL_INIT_AUDIO|SDL_INIT_VIDEO) < 0 ) { fprintf(stderr, "Unable to init SDL: %s\n", SDL_GetError()); exit(1); } atexit(SDL_Quit); // Initialize screen screen = SDL_SetVideoMode(WIDTH, HEIGHT, 32, SDL_HWSURFACE | SDL_FULLSCREEN | SDL_DOUBLEBUF ); if( screen == NULL ) { fprintf(stderr, "Unable to init video: %s\n", SDL_GetError()); exit(1); } rmask = 0x00ff0000; gmask = 0x0000ff00; bmask = 0x000000ff; amask = 0xff000000; display = SDLayer_CreateRGBLayeredDisplay(SDL_HWSURFACE | SDL_FULLSCREEN, SDLAYER_FLIP, LAYERS, layer_widths, layer_heights, 32, rmask, gmask, bmask, amask); SDLayer_SetColorKey(display, SDL_SRCCOLORKEY, 0); // without this, only the topmost layer will be visible bmpBackground = SDL_LoadBMP("Background.bmp"); if(bmpBackgroundRewind == NULL) { fprintf(stderr, "Couldn't find a graphic: %s\n", SDL_GetError()); exit(1); } bmpPlayer = SDL_LoadBMP("Player.bmp"); if(bmpPlayer == NULL) { fprintf(stderr, "Couldn't find a graphic: %s\n", SDL_GetError()); exit(1); } SDL_SetColorKey(bmpPlayer, SDL_SRCCOLORKEY, SDL_MapRGB(bmpPlayer->format, 255, 0, 255)); I then enter the main loop, which repeatedly triggers the draw() function: SDL_Rect background; SDL_Rect dest; static int background_y = 0; if(++background_y >= HEIGHT) background_y=0; // draw a moving background background.x = 0; background.y = background_y; background.w = WIDTH; background.h = HEIGHT; SDLayer_Blit(bmpBackground, NULL, display, &background, 0); background.x = 0; background.y = background_y-HEIGHT; background.w = WIDTH; background.h = HEIGHT; SDLayer_Blit(bmpBackground, NULL, display, &background, 0); // draw the player dest.x = player1.x; dest.y = player1.y; dest.w = player1.w; dest.h = player1.h; SDLayer_Blit(bmpPlayer, NULL, display, &dest, 1); // draw the buffer to the screen SDLayer_Update(display); I currently disabled everything else, so it's definitely this bit which is causing the slowness. My laptop isn't the fastest one out there, but the speed I'm currently getting can't be right. Also, I have a hunch the moving background could somehow be realized with viewports and scrolling factors, but should I even bother? When the program's finished, there will be way more objects to update, and it doesn't even work smoothly for one. Or is there some alternative to blitting that I missed? Anyways, thanks in advance for any help! Sincerely Arivor

Engines and Middleware Programming

Started by Arivor January 25, 2013 01:51 PM

9 comments, last by MichaelBarth 11 years, 2 months ago

MichaelBarth

341

January 26, 2013 12:57 PM

No, SDL 2.0 isn't truly attached to OpenGL, in fact I believe it has a Direct3D backend too (need to make sure). The software renderer is still there too (and in fact has more functionality than it used to have, since now it can draw some shapes too). But yes, it will try to go with the GPU by default and resort to software rendering only as a last option.

SDL 1.2 indeed requires you to use OpenGL explicitly because by itself it'll just do software rendering.

Ah, thanks for that bit of information. I didn't know SDL 2.0 had a Direct3D backend as well. Good stuff to know.

SDL_Layer even slower than SDL?

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SDL_Layer even slower than SDL?

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