main loop: Limit to max 60FPS

[sdl-planets] / main.c

diff --git a/main.c b/main.c
index 84b180e6e2b535ec4d7eb313dc2889f8bca03286..c8d00a369188255fb04454be1b901a4bacabd971 100644 (file)
--- a/main.c
+++ b/main.c
@@ -6,6 +6,8 @@
 #include "random.h"
 #include "planet.h"
 
+#define MAX_FPS 60
+
 static void fade_buf(SDL_Surface *screen, double amount)
 {
        int i;
@@ -143,9 +145,10 @@ static void loop(SDL_Surface *screen, int num_of_planets, double total_mass,
        struct camera camera;
        int planets;
        int framecount = 0, last_fps_time = 0;
-       int last_framecount = 0;
-       unsigned long long old_ticks, ticks;
-       double time = 0, last_fps = 0, time_scale = 1;
+       int last_framecount = 0, last_step_count = 0;
+       unsigned long old_ticks, ticks = 0, last_frame_tick = 0;
+       unsigned long step_count = 0;
+       double time = 0, last_fps = 0, time_scale = 1, last_sps = 0;
 
        init_camera(&camera);
 
@@ -173,8 +176,27 @@ static void loop(SDL_Surface *screen, int num_of_planets, double total_mass,
                        move_planet(pl1, time * time_scale);
                }
 
-               SDL_LockSurface(screen);
+               move_camera(&camera, time);
+
+               if (poll_events(&screen, &camera, &time_scale, time))
+                       return;
 
+               old_ticks = ticks;
+               ticks = gettime();
+               time = (ticks - old_ticks) / (1000.0 * 1000.0) ;
+               time = MIN(time, 0.02);
+               step_count++;
+
+               /*
+                * Do not draw to the screen more often than MAS_FPS
+                * per second
+                */
+               if (last_frame_tick + (1000 * 1000) / MAX_FPS > ticks)
+                       continue;
+
+               last_frame_tick = ticks;
+
+               SDL_LockSurface(screen);
                clear_buf(screen);
 
                list_for_each_entry(pl1, &planet->list, list) {
@@ -186,27 +208,28 @@ static void loop(SDL_Surface *screen, int num_of_planets, double total_mass,
 
                SDL_Flip(screen);
 
-               move_camera(&camera, time);
-
-               if (poll_events(&screen, &camera, &time_scale, time))
-                       return;
-
-               old_ticks = ticks;
-               ticks = gettime();
-               time = (ticks - old_ticks) / 1000.0;
-               time = MIN(time, 0.02);
-
-               if (last_fps_time + 500 < ticks) {
+               if (last_fps_time + (500 * 1000) < ticks) {
                        last_framecount = framecount - last_framecount;
-                       last_fps = last_framecount * 1000 /
+                       last_fps = last_framecount * 1000 * 1000 /
                                (float)(ticks - last_fps_time);
                        last_framecount = framecount;
+
+                       last_step_count = step_count - last_step_count;
+                       last_sps = last_step_count * 1000 * 1000 /
+                               (float)(ticks - last_fps_time);
+                       last_step_count = step_count;
+
                        last_fps_time = ticks;
                }
-               printf("  \rFrames/s: %.2f, Frame: %d, planets: %d"
-                      ", scale %.2f, zoom %.2f",
-                      last_fps, framecount++, planets, time_scale,
-                      camera.zoom);
+
+
+               printf("  \rFrames/s: %.2f, planets: %d"
+                      ", scale %.2f, zoom %.2f, steps/s: %.2f, %ld",
+                      last_fps, planets, time_scale,
+                      camera.zoom, last_sps, step_count);
+
+
+               framecount++;
        }
 }