[SDL] Performance issues

[Edward Byard]

Yes I am using converted surfaces. I'm using hardware surfaces too. Forgot to mention I'm using SDL_image libs...

Here's some code...

    Screen = SDL_SetVideoMode(SCREEN_WIDTH,SCREEN_HEIGHT,16,SDL_HWSURFACE|SDL_DOUBLEBUF);

    if (Screen==NULL)
    {
        printf("Can't set video mode: ", SDL_GetError(), "\n");
        return 0;
    }
    // load up some graphics...LoadGraphic converts surfaces using SDL_DisplayFormat...

    Background = LoadGraphic("graphics/bgnd.tga");
      Temp = LoadGraphic("graphics/strip.tga");
    DrawImage(Background,0,0,SCREEN_WIDTH,SCREEN_HEIGHT,Screen,0,0,255);

                    SDL_Rect DstRect;
                    SDL_Rect SrcRect;
                    DstRect.x = 165;
                    DstRect.y = 245;
                    DstRect.h = 100;
                    DstRect.w = Graphic ->w;

                    SrcRect.x = 0;
                    SrcRect.y = Graphic ->h;
                    SrcRect.h = 100;
                    SrcRect.w = Graphic ->w;
                    while (SrcRect.y!=-4)
                    {
                        DrawImage(Graphic ,SrcRect.x,SrcRect.y,SrcRect.w,SrcRect.h,Screen,DstRect.x,DstRect.y,255);
                        SDL_UpdateRect(Screen,0,0,0,0);
                        SrcRect.y -= 4;
                    }
....and this runs dead slow - I'm updating the Screen (which is also a Rect)

It's not going to be anything stupid like frame rates is it? It's going very slowly so I guessed not...I want it to just zoom by...not crawl..

Thanks
Ed

Paulo Pinto <pjmlp at progtools.org> wrote: Hi,

have you done the usual stuff?

By that I mean, are you converting your surfaces
before displaying them?

http://www.libsdl.org/cgi/docwiki.cgi/SDL_5fDisplayFormat

Are you enabling hardware surfaces?

Cheers,
Paulo

Edward Byard wrote:
> Hi Folks,
> 
> I'm pretty new to video programming, but have many years of experience 
> on embedded systems (mechanical control systems mostly).
> 
> Anyway, I'm writing a slot machine simulator, and am having problems 
> getting performance out of the system. Basically, I'm using SDL_ 
> BlitSurface to blit a portion of an image to a rectangle, and it's 
> pretty slow (800x600,16bpp,double-buffered).
> 
> Now, am I missing something? I have a background image, which I then 
> place the aforementioned rectangle on. I don't re-draw the background at 
> all - just update the rectangle. Is this making any sense?
> 
> If someone can help, I'd appreciate it...
> 
> Thanks
> Ed
> 
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