1 files changed, 76 insertions, 0 deletions
diff --git a/Tests/VSWinStorePhone/Direct3DApp1/BasicTimer.h b/Tests/VSWinStorePhone/Direct3DApp1/BasicTimer.h
new file mode 100644
index 0000000..b58c77d
--- /dev/null
+++ b/Tests/VSWinStorePhone/Direct3DApp1/BasicTimer.h
@@ -0,0 +1,76 @@
+#pragma once
+
+#include <wrl.h>
+
+// Helper class for basic timing.
+ref class BasicTimer sealed
+{
+public:
+  // Initializes internal timer values.
+  BasicTimer()
+  {
+    if (!QueryPerformanceFrequency(&m_frequency))
+    {
+      throw ref new Platform::FailureException();
+    }
+    Reset();
+  }
+
+  // Reset the timer to initial values.
+  void Reset()
+  {
+    Update();
+    m_startTime = m_currentTime;
+    m_total = 0.0f;
+    m_delta = 1.0f / 60.0f;
+  }
+
+  // Update the timer's internal values.
+  void Update()
+  {
+    if (!QueryPerformanceCounter(&m_currentTime))
+    {
+      throw ref new Platform::FailureException();
+    }
+
+    m_total = static_cast<float>(
+      static_cast<double>(m_currentTime.QuadPart - m_startTime.QuadPart) /
+      static_cast<double>(m_frequency.QuadPart)
+      );
+
+    if (m_lastTime.QuadPart == m_startTime.QuadPart)
+    {
+      // If the timer was just reset, report a time delta equivalent to 60Hz frame time.
+      m_delta = 1.0f / 60.0f;
+    }
+    else
+    {
+      m_delta = static_cast<float>(
+        static_cast<double>(m_currentTime.QuadPart - m_lastTime.QuadPart) /
+        static_cast<double>(m_frequency.QuadPart)
+        );
+    }
+
+    m_lastTime = m_currentTime;
+  }
+
+  // Duration in seconds between the last call to Reset() and the last call to Update().
+  property float Total
+  {
+    float get() { return m_total; }
+  }
+
+  // Duration in seconds between the previous two calls to Update().
+  property float Delta
+  {
+    float get() { return m_delta; }
+  }
+
+private:
+  LARGE_INTEGER m_frequency;
+  LARGE_INTEGER m_currentTime;
+  LARGE_INTEGER m_startTime;
+  LARGE_INTEGER m_lastTime;
+  float m_total;
+  float m_delta;
+};