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