/* Simple program: Move N sprites around on the screen as fast as possible */ #include #include #include "SDL.h" #define NUM_SPRITES 100 #define MAX_SPEED 1 SDL_Surface *sprite; int numsprites; SDL_Rect *sprite_rects; SDL_Rect *positions; SDL_Rect *velocities; int sprites_visible; int debug_flip; Uint16 sprite_w, sprite_h; /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */ static void quit(int rc) { SDL_Quit(); exit(rc); } int LoadSprite(char *file) { SDL_Surface *temp; /* Load the sprite image */ sprite = SDL_LoadBMP(file); if (sprite == NULL) { fprintf(stderr, "Couldn't load %s: %s", file, SDL_GetError()); return (-1); } /* Set transparent pixel as the pixel at (0,0) */ if (sprite->format->palette) { SDL_SetColorKey(sprite, (SDL_SRCCOLORKEY | SDL_RLEACCEL), *(Uint8 *) sprite->pixels); } /* Convert sprite to video format */ temp = SDL_DisplayFormat(sprite); SDL_FreeSurface(sprite); if (temp == NULL) { fprintf(stderr, "Couldn't convert background: %s\n", SDL_GetError()); return (-1); } sprite = temp; /* We're ready to roll. :) */ return (0); } void MoveSprites(SDL_Surface * screen, Uint32 background) { int i, nupdates; SDL_Rect area, *position, *velocity; nupdates = 0; /* Erase all the sprites if necessary */ if (sprites_visible) { SDL_FillRect(screen, NULL, background); } /* Move the sprite, bounce at the wall, and draw */ for (i = 0; i < numsprites; ++i) { position = &positions[i]; velocity = &velocities[i]; position->x += velocity->x; if ((position->x < 0) || (position->x >= (screen->w - sprite_w))) { velocity->x = -velocity->x; position->x += velocity->x; } position->y += velocity->y; if ((position->y < 0) || (position->y >= (screen->h - sprite_w))) { velocity->y = -velocity->y; position->y += velocity->y; } /* Blit the sprite onto the screen */ area = *position; SDL_BlitSurface(sprite, NULL, screen, &area); sprite_rects[nupdates++] = area; } if (debug_flip) { if ((screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF) { static int t = 0; Uint32 color = SDL_MapRGB(screen->format, 255, 0, 0); SDL_Rect r; r.x = (sin((float) t * 2 * 3.1459) + 1.0) / 2.0 * (screen->w - 20); r.y = 0; r.w = 20; r.h = screen->h; SDL_FillRect(screen, &r, color); t += 2; } } /* Update the screen! */ if ((screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF) { SDL_Flip(screen); } else { SDL_UpdateRects(screen, nupdates, sprite_rects); } sprites_visible = 1; } /* This is a way of telling whether or not to use hardware surfaces */ Uint32 FastestFlags(Uint32 flags, int width, int height, int bpp) { const SDL_VideoInfo *info; /* Hardware acceleration is only used in fullscreen mode */ flags |= SDL_FULLSCREEN; /* Check for various video capabilities */ info = SDL_GetVideoInfo(); if (info->blit_hw_CC && info->blit_fill) { /* We use accelerated colorkeying and color filling */ flags |= SDL_HWSURFACE; } /* If we have enough video memory, and will use accelerated blits directly to it, then use page flipping. */ if ((flags & SDL_HWSURFACE) == SDL_HWSURFACE) { /* Direct hardware blitting without double-buffering causes really bad flickering. */ if (info->video_mem * 1024 > (height * width * bpp / 8)) { flags |= SDL_DOUBLEBUF; } else { flags &= ~SDL_HWSURFACE; } } /* Return the flags */ return (flags); } int main(int argc, char *argv[]) { SDL_Surface *screen; Uint8 *mem; int width, height; Uint8 video_bpp; Uint32 videoflags; Uint32 background; int i, done; SDL_Event event; Uint32 then, now, frames; /* Initialize SDL */ if (SDL_Init(SDL_INIT_VIDEO) < 0) { fprintf(stderr, "Couldn't initialize SDL: %s\n", SDL_GetError()); return (1); } numsprites = NUM_SPRITES; videoflags = SDL_SWSURFACE | SDL_ANYFORMAT; width = 640; height = 480; video_bpp = 8; debug_flip = 0; while (argc > 1) { --argc; if (strcmp(argv[argc - 1], "-width") == 0) { width = atoi(argv[argc]); --argc; } else if (strcmp(argv[argc - 1], "-height") == 0) { height = atoi(argv[argc]); --argc; } else if (strcmp(argv[argc - 1], "-bpp") == 0) { video_bpp = atoi(argv[argc]); videoflags &= ~SDL_ANYFORMAT; --argc; } else if (strcmp(argv[argc], "-fast") == 0) { videoflags = FastestFlags(videoflags, width, height, video_bpp); } else if (strcmp(argv[argc], "-hw") == 0) { videoflags ^= SDL_HWSURFACE; } else if (strcmp(argv[argc], "-flip") == 0) { videoflags ^= SDL_DOUBLEBUF; } else if (strcmp(argv[argc], "-debugflip") == 0) { debug_flip ^= 1; } else if (strcmp(argv[argc], "-fullscreen") == 0) { videoflags ^= SDL_FULLSCREEN; } else if (isdigit(argv[argc][0])) { numsprites = atoi(argv[argc]); } else { fprintf(stderr, "Usage: %s [-bpp N] [-hw] [-flip] [-fast] [-fullscreen] [numsprites]\n", argv[0]); quit(1); } } /* Set video mode */ screen = SDL_SetVideoMode(width, height, video_bpp, videoflags); if (!screen) { fprintf(stderr, "Couldn't set %dx%d video mode: %s\n", width, height, SDL_GetError()); quit(2); } /* Load the sprite */ if (LoadSprite("icon.bmp") < 0) { quit(1); } /* Allocate memory for the sprite info */ mem = (Uint8 *) malloc(4 * sizeof(SDL_Rect) * numsprites); if (mem == NULL) { SDL_FreeSurface(sprite); fprintf(stderr, "Out of memory!\n"); quit(2); } sprite_rects = (SDL_Rect *) mem; positions = sprite_rects; sprite_rects += numsprites; velocities = sprite_rects; sprite_rects += numsprites; sprite_w = sprite->w; sprite_h = sprite->h; srand(time(NULL)); for (i = 0; i < numsprites; ++i) { positions[i].x = rand() % (screen->w - sprite_w); positions[i].y = rand() % (screen->h - sprite_h); positions[i].w = sprite->w; positions[i].h = sprite->h; velocities[i].x = 0; velocities[i].y = 0; while (!velocities[i].x && !velocities[i].y) { velocities[i].x = (rand() % (MAX_SPEED * 2 + 1)) - MAX_SPEED; velocities[i].y = (rand() % (MAX_SPEED * 2 + 1)) - MAX_SPEED; } } background = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00); /* Print out information about our surfaces */ printf("Screen is at %d bits per pixel\n", screen->format->BitsPerPixel); if ((screen->flags & SDL_HWSURFACE) == SDL_HWSURFACE) { printf("Screen is in video memory\n"); } else { printf("Screen is in system memory\n"); } if ((screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF) { printf("Screen has double-buffering enabled\n"); } if ((sprite->flags & SDL_HWSURFACE) == SDL_HWSURFACE) { printf("Sprite is in video memory\n"); } else { printf("Sprite is in system memory\n"); } /* Run a sample blit to trigger blit acceleration */ { SDL_Rect dst; dst.x = 0; dst.y = 0; dst.w = sprite->w; dst.h = sprite->h; SDL_BlitSurface(sprite, NULL, screen, &dst); SDL_FillRect(screen, &dst, background); } if ((sprite->flags & SDL_HWACCEL) == SDL_HWACCEL) { printf("Sprite blit uses hardware acceleration\n"); } if ((sprite->flags & SDL_RLEACCEL) == SDL_RLEACCEL) { printf("Sprite blit uses RLE acceleration\n"); } /* Loop, blitting sprites and waiting for a keystroke */ frames = 0; then = SDL_GetTicks(); done = 0; sprites_visible = 0; while (!done) { /* Check for events */ ++frames; while (SDL_PollEvent(&event)) { switch (event.type) { case SDL_MOUSEBUTTONDOWN: SDL_WarpMouse(screen->w / 2, screen->h / 2); break; case SDL_KEYDOWN: /* Any keypress quits the app... */ case SDL_QUIT: done = 1; break; default: break; } } MoveSprites(screen, background); } SDL_FreeSurface(sprite); free(mem); /* Print out some timing information */ now = SDL_GetTicks(); if (now > then) { printf("%2.2f frames per second\n", ((double) frames * 1000) / (now - then)); } SDL_Quit(); return (0); }