77 lines
1.8 KiB
C
77 lines
1.8 KiB
C
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#pragma once
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#include <wrl.h>
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// Helper class for basic timing.
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ref class BasicTimer sealed
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{
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public:
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// Initializes internal timer values.
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BasicTimer()
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{
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if (!QueryPerformanceFrequency(&m_frequency))
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{
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throw ref new Platform::FailureException();
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}
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Reset();
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}
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// Reset the timer to initial values.
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void Reset()
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{
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Update();
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m_startTime = m_currentTime;
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m_total = 0.0f;
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m_delta = 1.0f / 60.0f;
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}
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// Update the timer's internal values.
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void Update()
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{
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if (!QueryPerformanceCounter(&m_currentTime))
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{
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throw ref new Platform::FailureException();
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}
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m_total = static_cast<float>(
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static_cast<double>(m_currentTime.QuadPart - m_startTime.QuadPart) /
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static_cast<double>(m_frequency.QuadPart)
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);
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if (m_lastTime.QuadPart == m_startTime.QuadPart)
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{
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// If the timer was just reset, report a time delta equivalent to 60Hz frame time.
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m_delta = 1.0f / 60.0f;
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}
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else
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{
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m_delta = static_cast<float>(
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static_cast<double>(m_currentTime.QuadPart - m_lastTime.QuadPart) /
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static_cast<double>(m_frequency.QuadPart)
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);
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}
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m_lastTime = m_currentTime;
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}
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// Duration in seconds between the last call to Reset() and the last call to Update().
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property float Total
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{
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float get() { return m_total; }
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}
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// Duration in seconds between the previous two calls to Update().
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property float Delta
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{
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float get() { return m_delta; }
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}
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private:
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LARGE_INTEGER m_frequency;
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LARGE_INTEGER m_currentTime;
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LARGE_INTEGER m_startTime;
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LARGE_INTEGER m_lastTime;
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float m_total;
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float m_delta;
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};
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