| #include <stdio.h> #include <stdlib.h> #include "SDL.h" void Slock(SDL_Surface *screen) { if ( SDL_MUSTLOCK(screen) ) { if ( SDL_LockSurface(screen) < 0 ) { return; } } } void Sulock(SDL_Surface *screen) { if ( SDL_MUSTLOCK(screen) ) { SDL_UnlockSurface(screen); } } void DrawPixel(SDL_Surface *screen, int x, int y, Uint8 R, Uint8 G, Uint8 B) { Uint32 color = SDL_MapRGB(screen->format, R, G, B); switch (screen->format->BytesPerPixel) { case 1: // Assuming 8-bpp { Uint8 *bufp; bufp = (Uint8 *)screen->pixels + y*screen->pitch + x; *bufp = color; } break; case 2: // Probably 15-bpp or 16-bpp { Uint16 *bufp; bufp = (Uint16 *)screen->pixels + y*screen->pitch/2 + x; *bufp = color; } break; case 3: // Slow 24-bpp mode, usually not used { Uint8 *bufp; bufp = (Uint8 *)screen->pixels + y*screen->pitch + x * 3; if(SDL_BYTEORDER == SDL_LIL_ENDIAN) { bufp[0] = color; bufp[1] = color >> 8; bufp[2] = color >> 16; } else { bufp[2] = color; bufp[1] = color >> 8; bufp[0] = color >> 16; } } break; case 4: // Probably 32-bpp { Uint32 *bufp; bufp = (Uint32 *)screen->pixels + y*screen->pitch/4 + x; *bufp = color; } break; } } void DrawScene(SDL_Surface *screen) { Slock(screen); for(int x=0;x<640;x++) { for(int y=0;y<480;y++) { DrawPixel(screen, x,y,y/2,y/2,x/3); } } Sulock(screen); SDL_Flip(screen); } int main(int argc, char *argv[]) { if ( SDL_Init(SDL_INIT_AUDIO|SDL_INIT_VIDEO) < 0 ) { printf("Unable to init SDL: %s\n", SDL_GetError()); exit(1); } atexit(SDL_Quit); SDL_Surface *screen; screen=SDL_SetVideoMode(640,480,32,SDL_HWSURFACE|SDL_DOUBLEBUF); if ( screen == NULL ) { printf("Unable to set 640x480 video: %s\n", SDL_GetError()); exit(1); } int done=0; while(done == 0) { SDL_Event event; while ( SDL_PollEvent(&event) ) { if ( event.type == SDL_QUIT ) { done = 1; } if ( event.type == SDL_KEYDOWN ) { if ( event.key.keysym.sym == SDLK_ESCAPE ) { done = 1; } } } DrawScene(screen); } return 0; } |
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