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// Copyright 2016 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include "Common/GL/GLExtensions/GLExtensions.h"
#ifndef GL_TIME_ELAPSED
#define GL_TIME_ELAPSED 0x88BF
#endif
namespace OGL
{
/*
* This class can be used to measure the time it takes for the GPU to perform a draw call
* or compute dispatch. To use:
*
* - Create an instance of GPUTimer before issuing the draw call.
* (this can be before or after any binding that needs to be done)
*
* - (optionally) call Begin(). This is not needed for a single draw call.
*
* - Issue the draw call or compute dispatch as normal.
*
* - (optionally) call End(). This is not necessary for a single draw call.
*
* - Call GetTime{Seconds,Milliseconds,Nanoseconds} to determine how long the operation
* took to execute on the GPU.
*
* NOTE: When the timer is read back, this will force a GL flush, so the more often a timer is used,
* the larger of a performance impact it will have. Only one timer can be active at any time, due to
* using GL_TIME_ELAPSED. This is not enforced by the class, however.
*
*/
class GPUTimer final
{
public:
GPUTimer()
{
glGenQueries(1, &m_query_id);
Begin();
}
~GPUTimer()
{
End();
glDeleteQueries(1, &m_query_id);
}
void Begin()
{
if (m_started)
glEndQuery(GL_TIME_ELAPSED);
glBeginQuery(GL_TIME_ELAPSED, m_query_id);
m_started = true;
}
void End()
{
if (!m_started)
return;
glEndQuery(GL_TIME_ELAPSED);
m_started = false;
}
double GetTimeSeconds()
{
GetResult();
return static_cast<double>(m_result) / 1000000000.0;
}
double GetTimeMilliseconds()
{
GetResult();
return static_cast<double>(m_result) / 1000000.0;
}
u32 GetTimeNanoseconds()
{
GetResult();
return m_result;
}
private:
void GetResult()
{
if (m_has_result)
return;
if (m_started)
End();
glGetQueryObjectuiv(m_query_id, GL_QUERY_RESULT, &m_result);
m_has_result = true;
}
GLuint m_query_id;
GLuint m_result = 0;
bool m_started = false;
bool m_has_result = false;
};
} // namespace OGL
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