#include "anki/gl/TimeQuery.h"
#include "anki/util/Assert.h"
#include "anki/gl/GlException.h"


namespace anki
{


//==============================================================================
TimeQuery::TimeQuery()
{
	glGenQueries(2, &glIds[0]);
	state = S_CREATED;
}


//==============================================================================
TimeQuery::~TimeQuery()
{
	glDeleteQueries(2, &glIds[0]);
}


//==============================================================================
void TimeQuery::begin()
{
	ANKI_ASSERT(state == S_CREATED || state == S_ENDED);

	glQueryCounter(glIds[0], GL_TIMESTAMP);

	state = S_STARTED;
}


//==============================================================================
double TimeQuery::end()
{
	ANKI_ASSERT(state == S_STARTED);

	glQueryCounter(glIds[1], GL_TIMESTAMP);

	// Wait
	GLint done = 0;
	while(!done)
	{
		/// XXX BAD BAD BAD BAD!!!!!
		glGetQueryObjectiv(glIds[1], GL_QUERY_RESULT_AVAILABLE, &done);
	}

	// Get elapsed time
	GLuint64 timerStart, timerEnd;

	glGetQueryObjectui64v(glIds[0], GL_QUERY_RESULT, &timerStart);
	glGetQueryObjectui64v(glIds[1], GL_QUERY_RESULT, &timerEnd);

	state = S_ENDED;

	return (timerEnd - timerStart) / 1000000000.0;
}


} // end namespace