git.itanic.dy.fi Git - sdl-planets/blob - main.c

   1 #include <SDL.h>
   2 #include <unistd.h>
   3 #include <stdio.h>
   4 #include <time.h>
   5
   6 #include "random.h"
   7 #include "planet.h"
   8
   9 #define MAX_FPS 60
  10
  11 static void fade_buf(SDL_Surface *screen, double fade)
  12 {
  13         int i;
  14         unsigned int *buf = screen->pixels;
  15         unsigned char *b;
  16         unsigned char amount;
  17         static double threshold;
  18         threshold += fade;
  19
  20         if (threshold > 1) {
  21                 amount = threshold;
  22                 threshold -= amount;
  23         } else {
  24                 return;
  25         }
  26
  27         for (i = 0; i < screen->pitch * screen->h / sizeof(*buf); i++) {
  28                 if (!buf[i])
  29                         continue;
  30                 b = (unsigned char *)&buf[i];
  31                 *b = *b >= amount ? (*b - amount) : *b;
  32                 b++;
  33                 *b = *b >= amount ? (*b - amount) : *b;
  34                 b++;
  35                 *b = *b >= amount ? (*b - amount) : *b;
  36         }
  37 }
  38
  39 static void clear_buf(SDL_Surface *screen)
  40 {
  41         int i;
  42         unsigned int *buf = screen->pixels;
  43
  44         for (i = 0; i < screen->pitch * screen->h / 4; i++)
  45                 buf[i] = 0;
  46 }
  47
  48 /* Return time in microseconds */
  49
  50 static unsigned long gettime(void)
  51 {
  52         struct timespec tp;
  53         unsigned long ret;
  54         static unsigned long start;
  55
  56         clock_gettime(CLOCK_MONOTONIC, &tp);
  57
  58         ret = tp.tv_sec * 1000 * 1000;
  59         ret += tp.tv_nsec / 1000;
  60
  61         if (!start)
  62                 start = ret;
  63
  64         return ret - start;
  65 }
  66
  67 struct sim_status {
  68         SDL_Surface *screen;
  69         struct camera *cam;
  70         double time_scale;
  71         int tracers_enabled;
  72 };
  73
  74 static int poll_events(struct sim_status *status, double time)
  75 {
  76         static double time_scale_rate = 1;
  77         SDL_Event event;
  78         struct camera *cam = status->cam;
  79
  80         status->time_scale *= pow(time_scale_rate, time);
  81
  82         while (SDL_PollEvent(&event)) {
  83                 switch (event.type) {
  84                 case SDL_KEYDOWN:
  85                         switch (event.key.keysym.sym) {
  86                         case SDLK_ESCAPE:
  87                                 goto quit;
  88                         case SDLK_LEFT:
  89                                 cam->speed.x = -CAM_SPEED;
  90                                 break;
  91                         case SDLK_RIGHT:
  92                                 cam->speed.x = CAM_SPEED;
  93                                 break;
  94                         case SDLK_UP:
  95                                 cam->speed.y = -CAM_SPEED;
  96                                 break;
  97                         case SDLK_DOWN:
  98                                 cam->speed.y = CAM_SPEED;
  99                                 break;
 100                         case SDLK_PLUS:
 101                         case SDLK_q:
 102                                 cam->zoom_rate = CAM_ZOOM_RATE;
 103                                 break;
 104                         case SDLK_MINUS:
 105                         case SDLK_w:
 106                                 cam->zoom_rate = 1 / CAM_ZOOM_RATE;
 107                                 break;
 108                         case SDLK_s:
 109                                 time_scale_rate = 1.5;
 110                                 break;
 111                         case SDLK_a:
 112                                 time_scale_rate = 1 / 1.5;
 113                                 break;
 114                         case SDLK_1:
 115                                 status->time_scale = 1;
 116                                 break;
 117                         case SDLK_2:
 118                                 status->time_scale = 10;
 119                                 break;
 120                         case SDLK_3:
 121                                 status->time_scale = 20;
 122                                 break;
 123                         case SDLK_4:
 124                                 status->time_scale = 30;
 125                                 break;
 126                         case SDLK_t:
 127                                 status->tracers_enabled =
 128                                         !status->tracers_enabled;
 129                         default:
 130                                 break;
 131                         }
 132                         break;
 133                 case SDL_KEYUP:
 134                         switch (event.key.keysym.sym) {
 135                         case SDLK_LEFT:
 136                                 cam->speed.x = 0;
 137                                 break;
 138                         case SDLK_RIGHT:
 139                                 cam->speed.x = 0;
 140                                 break;
 141                         case SDLK_UP:
 142                                 cam->speed.y = 0;
 143                                 break;
 144                         case SDLK_DOWN:
 145                                 cam->speed.y = 0;
 146                                 break;
 147                         case SDLK_PLUS:
 148                         case SDLK_q:
 149                                 cam->zoom_rate = 1;
 150                                 break;
 151                         case SDLK_MINUS:
 152                         case SDLK_w:
 153                                 cam->zoom_rate = 1;
 154                                 break;
 155                         case SDLK_s:
 156                                 time_scale_rate = 1;
 157                                 break;
 158                         case SDLK_a:
 159                                 time_scale_rate = 1;
 160                                 break;
 161                         default:
 162                                 break;
 163                         }
 164                         break;
 165                 case SDL_VIDEORESIZE:
 166                         status->screen =
 167                                 SDL_SetVideoMode(event.resize.w,
 168                                                  event.resize.h,
 169                                                  32,
 170                                                  status->screen->flags);
 171                         break;
 172                 case SDL_QUIT:
 173                         goto quit;
 174                 }
 175         }
 176
 177         return 0;
 178 quit:
 179         printf("\nExiting. Good bye!\n");
 180         return 1;
 181 }
 182
 183 static void loop(SDL_Surface *screen, int num_of_planets, double total_mass,
 184                  double range)
 185 {
 186         struct sim_status status;
 187         struct planet *planet, *pl1, *pl2;
 188         struct camera camera;
 189         int planets;
 190         int framecount = 0, last_fps_time = 0;
 191         int last_framecount = 0, last_step_count = 0;
 192         unsigned long old_ticks, ticks = 0, last_frame_tick = 0;
 193         unsigned long step_count = 0;
 194         double last_fps = 0, last_sps = 0;
 195         double step_time = 0, true_time = 0;
 196
 197         init_camera(&camera);
 198
 199         status.cam = &camera;
 200         status.time_scale = 1;
 201         status.screen = screen;
 202         status.tracers_enabled = 0;
 203
 204         planet = malloc(sizeof(*planet));
 205         init_planet(planet);
 206         create_planets(planet, num_of_planets, total_mass, range);
 207
 208         ticks = SDL_GetTicks();
 209         while (1) {
 210                 planets = 0;
 211
 212                 list_for_each_entry(pl1, &planet->list, list) {
 213                         pl2 = list_to_planet(pl1->list.next);
 214                         list_for_each_entry_from(pl2, &planet->list, list) {
 215                                 struct planet *ptmp;
 216                                 if (!gravitize_planets(pl1, pl2,
 217                                                        step_time))
 218                                         continue;
 219
 220                                 ptmp = list_to_planet(pl2->list.prev);
 221                                 merge_planets(pl1, pl2);
 222                                 pl2 = ptmp;
 223                         }
 224
 225                         move_planet(pl1, step_time);
 226                 }
 227
 228                 move_camera(&camera, true_time);
 229
 230                 if (poll_events(&status, true_time))
 231                         return;
 232
 233                 old_ticks = ticks;
 234                 ticks = gettime();
 235                 true_time = (ticks - old_ticks) / (1000.0 * 1000.0) ;
 236                 step_time = true_time * status.time_scale;
 237                 step_time = MIN(step_time, 0.02);
 238                 step_count++;
 239
 240                 /*
 241                  * Do not draw to the screen more often than MAX_FPS
 242                  * per second
 243                  */
 244                 if (last_frame_tick + (1000 * 1000) / MAX_FPS > ticks)
 245                         continue;
 246
 247                 last_frame_tick = ticks;
 248
 249                 SDL_LockSurface(screen);
 250
 251                 if (status.tracers_enabled &&
 252                     !camera.speed.x && !camera.speed.y &&
 253                     camera.zoom_rate == 1) {
 254                         fade_buf(screen, 10 * true_time);
 255                 } else {
 256                         clear_buf(screen);
 257                 }
 258
 259                 list_for_each_entry(pl1, &planet->list, list) {
 260                         draw_planet(screen, pl1, &camera);
 261                         planets++;
 262                 }
 263
 264                 SDL_UnlockSurface(screen);
 265
 266                 SDL_Flip(screen);
 267
 268                 if (last_fps_time + (500 * 1000) < ticks) {
 269                         last_framecount = framecount - last_framecount;
 270                         last_fps = last_framecount * 1000 * 1000 /
 271                                 (float)(ticks - last_fps_time);
 272                         last_framecount = framecount;
 273
 274                         last_step_count = step_count - last_step_count;
 275                         last_sps = last_step_count * 1000 * 1000 /
 276                                 (float)(ticks - last_fps_time);
 277                         last_step_count = step_count;
 278
 279                         last_fps_time = ticks;
 280                 }
 281
 282
 283                 printf("  \rFrames/s: %.2f, steps/s: %.2f, planets: %d"
 284                        ", scale %.2f, zoom %.2f, step %ld",
 285                        last_fps, last_sps, planets, status.time_scale,
 286                        camera.zoom, step_count);
 287                 fflush(stdout);
 288
 289
 290                 framecount++;
 291         }
 292 }
 293
 294 int main(int argc, char *argv[])
 295 {
 296         SDL_Surface *screen;
 297         int flags = SDL_DOUBLEBUF | SDL_HWSURFACE | SDL_RESIZABLE;
 298         int planets = 100, xres = 800, yres = 600;
 299         double total_mass = 50000;
 300         double range = 500;
 301
 302         if (SDL_Init(SDL_INIT_VIDEO) != 0) {
 303                 fprintf(stderr, "Unable to initialize SDL: %s\n",
 304                         SDL_GetError());
 305
 306                 return 1;
 307         }
 308         atexit(SDL_Quit);
 309
 310         if (argc >= 2)
 311                 planets = atoi(argv[1]);
 312
 313         if (argc >= 3)
 314                 total_mass = atof(argv[2]);
 315
 316         if (argc >= 4)
 317                 range = atof(argv[3]);
 318
 319         screen = SDL_SetVideoMode(xres, yres, 32, flags);
 320         if (screen == NULL) {
 321                 fprintf(stderr, "Unable to set video mode: %s\n",
 322                         SDL_GetError());
 323                 return 2;
 324         }
 325
 326         SDL_WM_SetCaption(argv[0], NULL);
 327
 328         loop(screen, planets, total_mass, range);
 329
 330         return 0;
 331 }
 332