mnit_fps: add current_fps

Always useful.

Signed-off-by: Jean Privat <jean@pryen.org>

diff --git a/lib/mnit/mnit_fps.nit b/lib/mnit/mnit_fps.nit
index 38f0d48..cd30e83 100644 (file)
--- a/lib/mnit/mnit_fps.nit
+++ b/lib/mnit/mnit_fps.nit
@@ -26,6 +26,10 @@ redef class App
        # Applications can modify this value even during the main-loop.
        var maximum_fps writable = 60
 
+       # Current frame-rate
+       # Updated each 5 seconds.
+       var current_fps = 0.0
+
        redef fun full_frame
        do
                super
@@ -35,10 +39,27 @@ redef class App
        # The clock for limit_fps
        private var clock = new Clock
 
+       # Number of frames since the last deadline
+       # Used tocompute `current_fps`.
+       private var frame_count = 0
+
+       # Deadline used to compute `current_fps`
+       private var frame_count_deadline = 0
+
        # Check and sleep to maitain a frame-rate bellow `maximum_fps`
+       # Also periodically uptate `current_fps`
        # Is automatically called at the end of `full_frame`.
        fun limit_fps
        do
+               var t = clock.total.sec
+               if t >= frame_count_deadline then
+                       var cfps = frame_count_deadline.to_f / 5.0
+                       self.current_fps = cfps
+                       frame_count = 0
+                       frame_count_deadline = t + 5
+               end
+               frame_count += 1
+
                var mfps = maximum_fps
                if mfps <= 0 then return
                var dt = clock.lapse