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
15SDL_Surface *sprite;
16int numsprites;
17SDL_Rect *sprite_rects;
18SDL_Rect *positions;
19SDL_Rect *velocities;
20int sprites_visible;
21int debug_flip;
22Uint16 sprite_w, sprite_h;
23
24/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
25static void quit(int rc)
26{
27	SDL_Quit();
28	exit(rc);
29}
30
31int 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
62void 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 */
120Uint32 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
151int 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