////  Created by Bradley Austin Davis on 2016/05/15//  Copyright 2013-2016 High Fidelity, Inc.////  Distributed under the Apache License, Version 2.0.//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html//#include "GL41Backend.h"#include <gpu/gl/GLBuffer.h> namespace gpu {    namespace gl41 {        class GL41Buffer : public gpu::gl::GLBuffer {            using Parent = gpu::gl::GLBuffer;            static GLuint allocate() {                GLuint result;                glGenBuffers(1, &result);                return result;            }             ~GL41Buffer() {                 if (_texBuffer) {                    auto backend = _backend.lock();                    if (backend) {                        backend->releaseTexture(_texBuffer, 0);                    }                }            }         public:            GL41Buffer(const std::weak_ptr<gl::GLBackend>& backend, const Buffer& buffer, GL41Buffer* original) : Parent(backend, buffer, allocate()) {                glBindBuffer(GL_COPY_WRITE_BUFFER, _buffer);                glBufferData(GL_COPY_WRITE_BUFFER, _size, nullptr, GL_DYNAMIC_DRAW);                glBindBuffer(GL_COPY_WRITE_BUFFER, 0);                 if (original && original->_size) {                    glBindBuffer(GL_COPY_WRITE_BUFFER, _buffer);                    glBindBuffer(GL_COPY_READ_BUFFER, original->_buffer);                    glCopyBufferSubData(GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, 0, 0, original->_size);                    glBindBuffer(GL_COPY_WRITE_BUFFER, 0);                    glBindBuffer(GL_COPY_READ_BUFFER, 0);                    (void)CHECK_GL_ERROR();                }                Backend::setGPUObject(buffer, this);            }             void transfer() override {                glBindBuffer(GL_COPY_WRITE_BUFFER, _buffer);                (void)CHECK_GL_ERROR();                Size offset;                Size size;                Size currentPage { 0 };                auto data = _gpuObject._renderSysmem.readData();                while (_gpuObject._renderPages.getNextTransferBlock(offset, size, currentPage)) {                    glBufferSubData(GL_COPY_WRITE_BUFFER, offset, size, data + offset);                    (void)CHECK_GL_ERROR();                }                glBindBuffer(GL_COPY_WRITE_BUFFER, 0);                (void)CHECK_GL_ERROR();                _gpuObject._renderPages._flags &= ~PageManager::DIRTY;            }             // REsource BUffer are implemented with TextureBuffer             GLuint _texBuffer { 0 };            GLuint getTexBufferId() {                if (!_texBuffer) {                    glGenTextures(1, &_texBuffer);                    glActiveTexture(GL_TEXTURE0 + GL41Backend::RESOURCE_BUFFER_TEXBUF_TEX_UNIT);                    glBindTexture(GL_TEXTURE_BUFFER, _texBuffer);                    glTexBuffer(GL_TEXTURE_BUFFER, GL_RGBA32F, _buffer);                    glBindTexture(GL_TEXTURE_BUFFER, 0);                    (void)CHECK_GL_ERROR();                }                return _texBuffer;            }        };    }} using namespace gpu;using namespace gpu::gl;using namespace gpu::gl41;  GLuint GL41Backend::getBufferID(const Buffer& buffer) {    return GL41Buffer::getId<GL41Buffer>(*this, buffer);} GLuint GL41Backend::getBufferIDUnsynced(const Buffer& buffer) {    return GL41Buffer::getIdUnsynced<GL41Buffer>(*this, buffer);} GLuint GL41Backend::getResourceBufferID(const Buffer& buffer) {    auto* object = GL41Buffer::sync<GL41Buffer>(*this, buffer);    if (object) {        return object->getTexBufferId();    } else {        return 0;    }} GLBuffer* GL41Backend::syncGPUObject(const Buffer& buffer) {    return GL41Buffer::sync<GL41Buffer>(*this, buffer);} bool GL41Backend::bindResourceBuffer(uint32_t slot, const BufferPointer& buffer) {    GLuint texBuffer = GL41Backend::getResourceBufferID((*buffer));    if (texBuffer) {        glActiveTexture(GL_TEXTURE0 + GL41Backend::RESOURCE_BUFFER_SLOT0_TEX_UNIT + slot);         glBindTexture(GL_TEXTURE_BUFFER, texBuffer);         (void)CHECK_GL_ERROR();         assign(_resource._buffers[slot], buffer);         return true;    }     return false;} void GL41Backend::releaseResourceBuffer(uint32_t slot) {    auto& bufferReference = _resource._buffers[slot];    auto buffer = acquire(bufferReference);    if (buffer) {        glActiveTexture(GL_TEXTURE0 + GL41Backend::RESOURCE_BUFFER_SLOT0_TEX_UNIT + slot);         glBindTexture(GL_TEXTURE_BUFFER, 0);        reset(bufferReference);    }}