1 /* Simple program: Move N sprites around on the screen as fast as possible */
2
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <string.h>
6 #include <ctype.h>
7 #include <math.h>
8 #include <time.h>
9
10 #include "SDL.h"
11
12 #define NUM_SPRITES 100
13 #define MAX_SPEED 1
14
15 SDL_Surface *sprite;
16 int numsprites;
17 SDL_Rect *sprite_rects;
18 SDL_Rect *positions;
19 SDL_Rect *velocities;
20 int sprites_visible;
21 int debug_flip;
22 Uint16 sprite_w, sprite_h;
23
24 /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
quit(int rc)25 static void quit(int rc)
26 {
27 SDL_Quit();
28 exit(rc);
29 }
30
LoadSprite(char * file)31 int LoadSprite(char *file)
32 {
33 SDL_Surface *temp;
34
35 /* Load the sprite image */
36 sprite = SDL_LoadBMP(file);
37 if ( sprite == NULL ) {
38 fprintf(stderr, "Couldn't load %s: %s", file, SDL_GetError());
39 return(-1);
40 }
41
42 /* Set transparent pixel as the pixel at (0,0) */
43 if ( sprite->format->palette ) {
44 SDL_SetColorKey(sprite, (SDL_SRCCOLORKEY|SDL_RLEACCEL),
45 *(Uint8 *)sprite->pixels);
46 }
47
48 /* Convert sprite to video format */
49 temp = SDL_DisplayFormat(sprite);
50 SDL_FreeSurface(sprite);
51 if ( temp == NULL ) {
52 fprintf(stderr, "Couldn't convert background: %s\n",
53 SDL_GetError());
54 return(-1);
55 }
56 sprite = temp;
57
58 /* We're ready to roll. :) */
59 return(0);
60 }
61
MoveSprites(SDL_Surface * screen,Uint32 background)62 void MoveSprites(SDL_Surface *screen, Uint32 background)
63 {
64 int i, nupdates;
65 SDL_Rect area, *position, *velocity;
66
67 nupdates = 0;
68 /* Erase all the sprites if necessary */
69 if ( sprites_visible ) {
70 SDL_FillRect(screen, NULL, background);
71 }
72
73 /* Move the sprite, bounce at the wall, and draw */
74 for ( i=0; i<numsprites; ++i ) {
75 position = &positions[i];
76 velocity = &velocities[i];
77 position->x += velocity->x;
78 if ( (position->x < 0) || (position->x >= (screen->w - sprite_w)) ) {
79 velocity->x = -velocity->x;
80 position->x += velocity->x;
81 }
82 position->y += velocity->y;
83 if ( (position->y < 0) || (position->y >= (screen->h - sprite_w)) ) {
84 velocity->y = -velocity->y;
85 position->y += velocity->y;
86 }
87
88 /* Blit the sprite onto the screen */
89 area = *position;
90 SDL_BlitSurface(sprite, NULL, screen, &area);
91 sprite_rects[nupdates++] = area;
92 }
93
94 if (debug_flip) {
95 if ( (screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
96 static int t = 0;
97
98 Uint32 color = SDL_MapRGB (screen->format, 255, 0, 0);
99 SDL_Rect r;
100 r.x = (sin((float)t * 2 * 3.1459) + 1.0) / 2.0 * (screen->w-20);
101 r.y = 0;
102 r.w = 20;
103 r.h = screen->h;
104
105 SDL_FillRect (screen, &r, color);
106 t+=2;
107 }
108 }
109
110 /* Update the screen! */
111 if ( (screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
112 SDL_Flip(screen);
113 } else {
114 SDL_UpdateRects(screen, nupdates, sprite_rects);
115 }
116 sprites_visible = 1;
117 }
118
119 /* This is a way of telling whether or not to use hardware surfaces */
FastestFlags(Uint32 flags,int width,int height,int bpp)120 Uint32 FastestFlags(Uint32 flags, int width, int height, int bpp)
121 {
122 const SDL_VideoInfo *info;
123
124 /* Hardware acceleration is only used in fullscreen mode */
125 flags |= SDL_FULLSCREEN;
126
127 /* Check for various video capabilities */
128 info = SDL_GetVideoInfo();
129 if ( info->blit_hw_CC && info->blit_fill ) {
130 /* We use accelerated colorkeying and color filling */
131 flags |= SDL_HWSURFACE;
132 }
133 /* If we have enough video memory, and will use accelerated
134 blits directly to it, then use page flipping.
135 */
136 if ( (flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
137 /* Direct hardware blitting without double-buffering
138 causes really bad flickering.
139 */
140 if ( info->video_mem*1024 > (height*width*bpp/8) ) {
141 flags |= SDL_DOUBLEBUF;
142 } else {
143 flags &= ~SDL_HWSURFACE;
144 }
145 }
146
147 /* Return the flags */
148 return(flags);
149 }
150
main(int argc,char * argv[])151 int main(int argc, char *argv[])
152 {
153 SDL_Surface *screen;
154 Uint8 *mem;
155 int width, height;
156 Uint8 video_bpp;
157 Uint32 videoflags;
158 Uint32 background;
159 int i, done;
160 SDL_Event event;
161 Uint32 then, now, frames;
162
163 /* Initialize SDL */
164 if ( SDL_Init(SDL_INIT_VIDEO) < 0 ) {
165 fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
166 return(1);
167 }
168
169 numsprites = NUM_SPRITES;
170 videoflags = SDL_SWSURFACE|SDL_ANYFORMAT;
171 width = 640;
172 height = 480;
173 video_bpp = 8;
174 debug_flip = 0;
175 while ( argc > 1 ) {
176 --argc;
177 if ( strcmp(argv[argc-1], "-width") == 0 ) {
178 width = atoi(argv[argc]);
179 --argc;
180 } else
181 if ( strcmp(argv[argc-1], "-height") == 0 ) {
182 height = atoi(argv[argc]);
183 --argc;
184 } else
185 if ( strcmp(argv[argc-1], "-bpp") == 0 ) {
186 video_bpp = atoi(argv[argc]);
187 videoflags &= ~SDL_ANYFORMAT;
188 --argc;
189 } else
190 if ( strcmp(argv[argc], "-fast") == 0 ) {
191 videoflags = FastestFlags(videoflags, width, height, video_bpp);
192 } else
193 if ( strcmp(argv[argc], "-hw") == 0 ) {
194 videoflags ^= SDL_HWSURFACE;
195 } else
196 if ( strcmp(argv[argc], "-flip") == 0 ) {
197 videoflags ^= SDL_DOUBLEBUF;
198 } else
199 if ( strcmp(argv[argc], "-debugflip") == 0 ) {
200 debug_flip ^= 1;
201 } else
202 if ( strcmp(argv[argc], "-fullscreen") == 0 ) {
203 videoflags ^= SDL_FULLSCREEN;
204 } else
205 if ( isdigit(argv[argc][0]) ) {
206 numsprites = atoi(argv[argc]);
207 } else {
208 fprintf(stderr,
209 "Usage: %s [-bpp N] [-hw] [-flip] [-fast] [-fullscreen] [numsprites]\n",
210 argv[0]);
211 quit(1);
212 }
213 }
214
215 /* Set video mode */
216 screen = SDL_SetVideoMode(width, height, video_bpp, videoflags);
217 if ( ! screen ) {
218 fprintf(stderr, "Couldn't set %dx%d video mode: %s\n",
219 width, height, SDL_GetError());
220 quit(2);
221 }
222
223 /* Load the sprite */
224 if ( LoadSprite("icon.bmp") < 0 ) {
225 quit(1);
226 }
227
228 /* Allocate memory for the sprite info */
229 mem = (Uint8 *)malloc(4*sizeof(SDL_Rect)*numsprites);
230 if ( mem == NULL ) {
231 SDL_FreeSurface(sprite);
232 fprintf(stderr, "Out of memory!\n");
233 quit(2);
234 }
235 sprite_rects = (SDL_Rect *)mem;
236 positions = sprite_rects;
237 sprite_rects += numsprites;
238 velocities = sprite_rects;
239 sprite_rects += numsprites;
240 sprite_w = sprite->w;
241 sprite_h = sprite->h;
242 srand(time(NULL));
243 for ( i=0; i<numsprites; ++i ) {
244 positions[i].x = rand()%(screen->w - sprite_w);
245 positions[i].y = rand()%(screen->h - sprite_h);
246 positions[i].w = sprite->w;
247 positions[i].h = sprite->h;
248 velocities[i].x = 0;
249 velocities[i].y = 0;
250 while ( ! velocities[i].x && ! velocities[i].y ) {
251 velocities[i].x = (rand()%(MAX_SPEED*2+1))-MAX_SPEED;
252 velocities[i].y = (rand()%(MAX_SPEED*2+1))-MAX_SPEED;
253 }
254 }
255 background = SDL_MapRGB(screen->format, 0x00, 0x00, 0x00);
256
257 /* Print out information about our surfaces */
258 printf("Screen is at %d bits per pixel\n",screen->format->BitsPerPixel);
259 if ( (screen->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
260 printf("Screen is in video memory\n");
261 } else {
262 printf("Screen is in system memory\n");
263 }
264 if ( (screen->flags & SDL_DOUBLEBUF) == SDL_DOUBLEBUF ) {
265 printf("Screen has double-buffering enabled\n");
266 }
267 if ( (sprite->flags & SDL_HWSURFACE) == SDL_HWSURFACE ) {
268 printf("Sprite is in video memory\n");
269 } else {
270 printf("Sprite is in system memory\n");
271 }
272 /* Run a sample blit to trigger blit acceleration */
273 { SDL_Rect dst;
274 dst.x = 0;
275 dst.y = 0;
276 dst.w = sprite->w;
277 dst.h = sprite->h;
278 SDL_BlitSurface(sprite, NULL, screen, &dst);
279 SDL_FillRect(screen, &dst, background);
280 }
281 if ( (sprite->flags & SDL_HWACCEL) == SDL_HWACCEL ) {
282 printf("Sprite blit uses hardware acceleration\n");
283 }
284 if ( (sprite->flags & SDL_RLEACCEL) == SDL_RLEACCEL ) {
285 printf("Sprite blit uses RLE acceleration\n");
286 }
287
288 /* Loop, blitting sprites and waiting for a keystroke */
289 frames = 0;
290 then = SDL_GetTicks();
291 done = 0;
292 sprites_visible = 0;
293 while ( !done ) {
294 /* Check for events */
295 ++frames;
296 while ( SDL_PollEvent(&event) ) {
297 switch (event.type) {
298 case SDL_MOUSEBUTTONDOWN:
299 SDL_WarpMouse(screen->w/2, screen->h/2);
300 break;
301 case SDL_KEYDOWN:
302 /* Any keypress quits the app... */
303 case SDL_QUIT:
304 done = 1;
305 break;
306 default:
307 break;
308 }
309 }
310 MoveSprites(screen, background);
311 }
312 SDL_FreeSurface(sprite);
313 free(mem);
314
315 /* Print out some timing information */
316 now = SDL_GetTicks();
317 if ( now > then ) {
318 printf("%2.2f frames per second\n",
319 ((double)frames*1000)/(now-then));
320 }
321 SDL_Quit();
322 return(0);
323 }
324