demo: fix demo_getc() to use MAXSLEEP (12.5ms)

src/demo/demo.h

@@ -89,6 +89,7 @@ demo_getc_blocking(struct notcurses* nc, ncinput* ni){
 
 /*-------------------------------time helpers----------------------------*/
 #define GIG 1000000000ul
+#define MAXSLEEP (GIG / 80) // nanoseconds
 
 static inline uint64_t
 timespec_to_ns(const struct timespec* ts){

src/demo/hud.c

@@ -26,6 +26,8 @@ static int plot_grab_y = -1;
 // position of the plot *when grab started*
 static int plot_pos_y;
 
+#define FPSHZ 10
+
 // how many columns for runtime?
 #define HUD_ROWS (3 + 2) // 2 for borders
 static const int HUD_COLS = 23 + 2; // 2 for borders
@@ -513,7 +515,7 @@ demo_nanosleep_abstime_ns(struct notcurses* nc, uint64_t deadline){
   clock_gettime(CLOCK_MONOTONIC, &now);
   while(deadline > timespec_to_ns(&now)){
     fsleep.tv_sec = 0;
-    fsleep.tv_nsec = GIG / 100;
+    fsleep.tv_nsec = MAXSLEEP;
     if(deadline - timespec_to_ns(&now) < GIG / 100){
       fsleep.tv_nsec = deadline - timespec_to_ns(&now);
     }
@@ -563,7 +565,7 @@ int demo_render(struct notcurses* nc){
     if(!plot_hidden){
       ncplane_move_top(ncuplot_plane(plot));
     }
-    uint64_t ns = (timespec_to_ns(&ts) - plottimestart) / (GIG / 10);
+    uint64_t ns = (timespec_to_ns(&ts) - plottimestart) / (GIG / FPSHZ);
     ncuplot_add_sample(plot, ns, 1);
   }
   if(menu){

src/demo/input.c

@@ -47,20 +47,22 @@ handle_mouse(const ncinput* ni){
 // absolute deadline, so convert it up.
 char32_t demo_getc(struct notcurses* nc, const struct timespec* ts, ncinput* ni){
   struct timespec now;
+  clock_gettime(CLOCK_REALTIME, &now);
   uint64_t ns;
-  struct timespec abstime;
   // yes, i'd like CLOCK_MONOTONIC too, but pthread_cond_timedwait() is based off
   // of crappy CLOCK_REALTIME :/
   // abstime shouldn't be further out than our maximum sleep time -- this can
   // lead to 0 frames output during the wait (happening now with zoo FIXME)
   if(ts){
-    clock_gettime(CLOCK_REALTIME, &now);
-    ns = timespec_to_ns(&now) + timespec_to_ns(ts);
-    ns_to_timespec(ns, &abstime);
+    ns = timespec_to_ns(ts);
   }else{
-    abstime.tv_sec = ~0;
-    abstime.tv_nsec = ~0;
+    ns = MAXSLEEP;
+  }
+  if(ns > MAXSLEEP){
+    ns = MAXSLEEP;
   }
+  struct timespec abstime;
+  ns_to_timespec(ns + timespec_to_ns(&now), &abstime);
   bool handoff = false; // does the input go back to the user?
   char32_t id;
   do{