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