dolphin/Source/Core/VideoBackends/OGL/BoundingBox.cpp

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// Copyright 2014 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.
2016-05-26 17:42:07 +00:00
#include <cstring>
#include "Common/GL/GLUtil.h"
#include "VideoBackends/OGL/BoundingBox.h"
#include "VideoCommon/DriverDetails.h"
#include "VideoCommon/VideoConfig.h"
static GLuint s_bbox_buffer_id;
namespace OGL
{
void BoundingBox::Init()
{
if (g_ActiveConfig.backend_info.bSupportsBBox)
{
int initial_values[4] = {0, 0, 0, 0};
glGenBuffers(1, &s_bbox_buffer_id);
glBindBuffer(GL_SHADER_STORAGE_BUFFER, s_bbox_buffer_id);
glBufferData(GL_SHADER_STORAGE_BUFFER, 4 * sizeof(s32), initial_values, GL_DYNAMIC_DRAW);
glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 3, s_bbox_buffer_id);
}
}
void BoundingBox::Shutdown()
{
if (g_ActiveConfig.backend_info.bSupportsBBox)
glDeleteBuffers(1, &s_bbox_buffer_id);
}
void BoundingBox::Set(int index, int value)
{
glBindBuffer(GL_SHADER_STORAGE_BUFFER, s_bbox_buffer_id);
glBufferSubData(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int), &value);
glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
}
int BoundingBox::Get(int index)
{
int data = 0;
glBindBuffer(GL_SHADER_STORAGE_BUFFER, s_bbox_buffer_id);
if (!DriverDetails::HasBug(DriverDetails::BUG_SLOWGETBUFFERSUBDATA))
{
// Using glMapBufferRange to read back the contents of the SSBO is extremely slow
// on nVidia drivers. This is more noticeable at higher internal resolutions.
// Using glGetBufferSubData instead does not seem to exhibit this slowdown.
glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int), &data);
}
else
{
// Using glMapBufferRange is faster on AMD cards by a measurable margin.
void* ptr = glMapBufferRange(GL_SHADER_STORAGE_BUFFER, index * sizeof(int), sizeof(int),
GL_MAP_READ_BIT);
if (ptr)
{
memcpy(&data, ptr, sizeof(int));
glUnmapBuffer(GL_SHADER_STORAGE_BUFFER);
}
}
glBindBuffer(GL_SHADER_STORAGE_BUFFER, 0);
return data;
}
};