Dying on SDL_Flip.

It seems my SDL program dies whenever I flip pages.

Code:

screen = SDL_SetVideoMode(800, 600, 16, 
                          SDL_SWSURFACE | SDL_DOUBLEBUF);
SDL_WM_SetCaption("Fight", NULL);
...
SDL_Flip(screen);

Am I doing something wrong? I haven't drawn anything on screen yet.

nevermind, i figured it out. it was an unrelated pointer thing.

Not sure about SDL - I wrote my own flip code in assembly.

Simply retrieve a pointer from DirectX to the buffer and primary surface.

Code:

push ds
push esi
push edi


lds   esi,[SecondaryBuffer]
les   edi,[PrimaryBuffer]
mov ecx,[size]
rep  movsd

pop edi
pop esi
pop ds

A faster way would be MMX except that MMX does not allow memory to memory transfers. Besides that the only faster way I know of is REP STOSQ which is only available on the Intel IA-64 Itanium CPU.

When not in fullscreen mode...
you don't need SDL_DOUBLEBUFF
you should'nt use SDL_Flip

use SDL_UpdateRect

*rummages for reference*

God this book is small....

Code:

Prototype
void SDL_UpdateRect(SDL_Surface *screen, Sint32 x, Sint32 y, Sint32 w, Sint32 h);

also

void SDL_UpdateRects(SDL_Surface *screen, int numrects, SDL_Rect *rects);

Ex.1 for a 800x600 window:

SDL_UpdateRect(screen, 0, 0, 800, 600)

Ex.2 for a 800x600 window:


SDL_Rect rect;
rect.x = 0;
rect.y = 0;
rect.w = 800;
rect.h = 600;
SDL_UpdateRects(screen, 1, &rect)

Also, i suggest using macros for screen hieght/width because they are used so often... and its alot easier to change and... yeah.