From f966ff894a341265f0d90b93110ddae9c90a742c Mon Sep 17 00:00:00 2001
From: Camilla Berglund <elmindreda@elmindreda.org>
Date: Sun, 19 May 2013 19:18:18 +0200
Subject: [PATCH] Added refresh rate calculation to tearing test.

---
 tests/tearing.c | 34 ++++++++++++++++++++++++++++------
 1 file changed, 28 insertions(+), 6 deletions(-)

diff --git a/tests/tearing.c b/tests/tearing.c
index 93584285..8d46e63b 100644
--- a/tests/tearing.c
+++ b/tests/tearing.c
@@ -35,19 +35,25 @@
 #include <math.h>
 
 static int swap_interval;
+static double frame_rate;
 
-static void set_swap_interval(GLFWwindow* window, int interval)
+static void update_window_title(GLFWwindow* window)
 {
     char title[256];
 
-    swap_interval = interval;
-    glfwSwapInterval(swap_interval);
-
-    sprintf(title, "Tearing detector (interval %i)", swap_interval);
+    sprintf(title, "Tearing detector (interval %i, %0.1f Hz)",
+            swap_interval, frame_rate);
 
     glfwSetWindowTitle(window, title);
 }
 
+static void set_swap_interval(GLFWwindow* window, int interval)
+{
+    swap_interval = interval;
+    glfwSwapInterval(swap_interval);
+    update_window_title(window);
+}
+
 static void error_callback(int error, const char* description)
 {
     fprintf(stderr, "Error: %s\n", description);
@@ -67,6 +73,8 @@ static void key_callback(GLFWwindow* window, int key, int action)
 int main(void)
 {
     float position;
+    unsigned long frame_count = 0;
+    double last_time, current_time;
     GLFWwindow* window;
 
     glfwSetErrorCallback(error_callback);
@@ -82,7 +90,10 @@ int main(void)
     }
 
     glfwMakeContextCurrent(window);
-    set_swap_interval(window, swap_interval);
+    set_swap_interval(window, 0);
+
+    last_time = glfwGetTime();
+    frame_rate = 0.0;
 
     glfwSetWindowSizeCallback(window, window_size_callback);
     glfwSetKeyCallback(window, key_callback);
@@ -100,6 +111,17 @@ int main(void)
 
         glfwSwapBuffers(window);
         glfwPollEvents();
+
+        frame_count++;
+
+        current_time = glfwGetTime();
+        if (current_time - last_time > 1.0)
+        {
+            frame_rate = frame_count / (current_time - last_time);
+            frame_count = 0;
+            last_time = current_time;
+            update_window_title(window);
+        }
     }
 
     glfwTerminate();