From d62a2f793fdf10f677a2bf8a31a6734c9788a0dd Mon Sep 17 00:00:00 2001
From: Ray <raysan5@gmail.com>
Date: Wed, 19 Feb 2020 12:20:15 +0100
Subject: [PATCH] Improved GetFPS() calculation for average

---
 src/core.c | 23 ++++++++++++++++++++++-
 src/text.c | 19 +------------------
 2 files changed, 23 insertions(+), 19 deletions(-)

diff --git a/src/core.c b/src/core.c
index 2c3141129..ecf2b2845 100644
--- a/src/core.c
+++ b/src/core.c
@@ -1611,9 +1611,30 @@ void SetTargetFPS(int fps)
 }
 
 // Returns current FPS
+// NOTE: We calculate an average framerate
 int GetFPS(void)
 {
-    return (int)roundf(1.0f/GetFrameTime());
+    #define FPS_CAPTURE_FRAMES_COUNT    30      // 30 captures
+    #define FPS_AVERAGE_TIME_SECONDS   0.5f     // 500 millisecondes
+    #define FPS_STEP (FPS_AVERAGE_TIME_SECONDS/FPS_CAPTURE_FRAMES_COUNT)
+
+    static int index = 0;
+    static float history[FPS_CAPTURE_FRAMES_COUNT] = { 0 };
+    static float average = 0, last = 0;
+    float fpsFrame = GetFrameTime();
+    
+    if (fpsFrame == 0) return 0;
+
+    if ((GetTime() - last) > FPS_STEP)
+    {
+        last = GetTime();
+        index = (index + 1)%FPS_CAPTURE_FRAMES_COUNT;
+        average -= history[index];
+        history[index] = fpsFrame/FPS_CAPTURE_FRAMES_COUNT;
+        average += history[index];
+    }
+    
+    return (int)roundf(1.0f/average);
 }
 
 // Returns time in seconds for last frame drawn
diff --git a/src/text.c b/src/text.c
index 074fcdb2b..d2562179b 100644
--- a/src/text.c
+++ b/src/text.c
@@ -768,24 +768,7 @@ void UnloadFont(Font font)
 // NOTE: Uses default font
 void DrawFPS(int posX, int posY)
 {
-    // NOTE: We are rendering fps every certain time for better viewing on high framerates
-
-    static int fps = 0;
-    static int counter = 0;
-    static int refreshRate = 20;
-
-    if (counter < refreshRate) counter++;
-    else
-    {
-        fps = GetFPS();
-        refreshRate = fps;
-        counter = 0;
-    }
-
-    // TODO: Find a better way to calculate FPS, maybe calculate the mean of multiple measures?
-
-    // NOTE: We have rounding errors every frame, so it oscillates a lot
-    DrawText(TextFormat("%2i FPS", fps), posX, posY, 20, LIME);
+    DrawText(TextFormat("%2i FPS", GetFPS()), posX, posY, 20, LIME);
 }
 
 // Draw text (using default font)