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