xlib: add delta_time_seconds

demo/x11/nuklear_xlib.h

@@ -68,10 +68,10 @@ NK_API void                 nk_xfont_del(Display *dpy, XFont *font);
 
 
 #ifndef NK_X11_DOUBLE_CLICK_LO
-#define NK_X11_DOUBLE_CLICK_LO 20
+#define NK_X11_DOUBLE_CLICK_LO 0.02
 #endif
 #ifndef NK_X11_DOUBLE_CLICK_HI
-#define NK_X11_DOUBLE_CLICK_HI 200
+#define NK_X11_DOUBLE_CLICK_HI 0.20
 #endif
 
 typedef struct XSurface XSurface;
@@ -112,15 +112,16 @@ static struct  {
     Cursor cursor;
     Display *dpy;
     Window root;
-    long last_button_click;
+    double last_button_click;
+    double time_of_last_frame;
 } xlib;
 
-NK_INTERN long
-nk_timestamp(void)
+NK_INTERN double
+nk_get_time(void)
 {
     struct timeval tv;
     if (gettimeofday(&tv, NULL) < 0) return 0;
-    return (long)((long)tv.tv_sec * 1000 + (long)tv.tv_usec/1000);
+    return ((double)tv.tv_sec + (double)tv.tv_usec/1000000);
 }
 
 NK_INTERN unsigned long
@@ -662,6 +663,7 @@ nk_xlib_init(XFont *xfont, Display *dpy, int screen, Window root,
 
     xlib.surf = nk_xsurf_create(screen, w, h);
     nk_init_default(&xlib.ctx, font);
+    xlib.time_of_last_frame = nk_get_time();
     return &xlib.ctx;
 }
 
@@ -793,10 +795,10 @@ nk_xlib_handle_event(Display *dpy, int screen, Window win, XEvent *evt)
         const int x = evt->xbutton.x, y = evt->xbutton.y;
         if (evt->xbutton.button == Button1) {
             if (down) { /* Double-Click Button handler */
-                long dt = nk_timestamp() - xlib.last_button_click;
+                float dt = nk_get_time() - xlib.last_button_click;
                 if (dt > NK_X11_DOUBLE_CLICK_LO && dt < NK_X11_DOUBLE_CLICK_HI)
                     nk_input_button(ctx, NK_BUTTON_DOUBLE, x, y, nk_true);
-                xlib.last_button_click = nk_timestamp();
+                xlib.last_button_click = nk_get_time();
             } else nk_input_button(ctx, NK_BUTTON_DOUBLE, x, y, nk_false);
             nk_input_button(ctx, NK_BUTTON_LEFT, x, y, down);
         } else if (evt->xbutton.button == Button2)
@@ -905,6 +907,10 @@ nk_xlib_render(Drawable screen, struct nk_color clear)
     struct nk_context *ctx = &xlib.ctx;
     XSurface *surf = xlib.surf;
 
+    double now = nk_get_time();
+    xlib.ctx.delta_time_seconds = now - xlib.time_of_last_frame;
+    xlib.time_of_last_frame = now;
+
     nk_xsurf_clear(xlib.surf, nk_color_from_byte(&clear.r));
     nk_foreach(cmd, &xlib.ctx)
     {