qopenglbuffer.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include <QtGui/qopengl.h>
#include <QtGui/private/qopenglcontext_p.h>
#include <QtCore/qatomic.h>
#include "qopenglbuffer.h"
#include <private/qopenglextensions_p.h>
 
#ifndef GL_CONTEXT_LOST
#define GL_CONTEXT_LOST                   0x0507
#endif
 
QT_BEGIN_NAMESPACE
 
class QOpenGLBufferPrivate
{
public:
    QOpenGLBufferPrivate(QOpenGLBuffer::Type t)
        : ref(1),
          type(t),
          guard(nullptr),
          usagePattern(QOpenGLBuffer::StaticDraw),
          actualUsagePattern(QOpenGLBuffer::StaticDraw),
          funcs(nullptr)
    {
    }
 
    QAtomicInt ref;
    QOpenGLBuffer::Type type;
    QOpenGLSharedResourceGuard *guard;
    QOpenGLBuffer::UsagePattern usagePattern;
    QOpenGLBuffer::UsagePattern actualUsagePattern;
    QOpenGLExtensions *funcs;
};
 
QOpenGLBuffer::QOpenGLBuffer()
    : d_ptr(new QOpenGLBufferPrivate(QOpenGLBuffer::VertexBuffer))
{
}
 
QOpenGLBuffer::QOpenGLBuffer(QOpenGLBuffer::Type type)
    : d_ptr(new QOpenGLBufferPrivate(type))
{
}
 
QOpenGLBuffer::QOpenGLBuffer(const QOpenGLBuffer &other)
    : d_ptr(other.d_ptr)
{
    d_ptr->ref.ref();
}
 
QOpenGLBuffer::~QOpenGLBuffer()
{
    if (d_ptr && !d_ptr->ref.deref()) {
        destroy();
        delete d_ptr;
    }
}
 
QOpenGLBuffer &QOpenGLBuffer::operator=(const QOpenGLBuffer &other)
{
    if (d_ptr != other.d_ptr) {
        other.d_ptr->ref.ref();
        if (d_ptr && !d_ptr->ref.deref()) {
            destroy();
            delete d_ptr;
        }
        d_ptr = other.d_ptr;
    }
    return *this;
}
 
QOpenGLBuffer::Type QOpenGLBuffer::type() const
{
    Q_D(const QOpenGLBuffer);
    return d->type;
}
 
QOpenGLBuffer::UsagePattern QOpenGLBuffer::usagePattern() const
{
    Q_D(const QOpenGLBuffer);
    return d->usagePattern;
}
 
void QOpenGLBuffer::setUsagePattern(QOpenGLBuffer::UsagePattern value)
{
    Q_D(QOpenGLBuffer);
    d->usagePattern = d->actualUsagePattern = value;
}
 
namespace {
    void freeBufferFunc(QOpenGLFunctions *funcs, GLuint id)
    {
        funcs->glDeleteBuffers(1, &id);
    }
}
 
bool QOpenGLBuffer::create()
{
    Q_D(QOpenGLBuffer);
    if (d->guard && d->guard->id())
        return true;
    QOpenGLContext *ctx = QOpenGLContext::currentContext();
    if (ctx) {
        delete d->funcs;
        d->funcs = new QOpenGLExtensions(ctx);
        GLuint bufferId = 0;
        d->funcs->glGenBuffers(1, &bufferId);
        if (bufferId) {
            if (d->guard)
                d->guard->free();
 
            d->guard = new QOpenGLSharedResourceGuard(ctx, bufferId, freeBufferFunc);
            return true;
        }
    }
    return false;
}
 
bool QOpenGLBuffer::isCreated() const
{
    Q_D(const QOpenGLBuffer);
    return d->guard && d->guard->id();
}
 
void QOpenGLBuffer::destroy()
{
    Q_D(QOpenGLBuffer);
    if (d->guard) {
        d->guard->free();
        d->guard = nullptr;
    }
    delete d->funcs;
    d->funcs = nullptr;
}
 
bool QOpenGLBuffer::read(int offset, void *data, int count)
{
#if !QT_CONFIG(opengles2)
    Q_D(QOpenGLBuffer);
    if (!d->funcs->hasOpenGLFeature(QOpenGLFunctions::Buffers) || !d->guard->id())
        return false;
 
    while (true) { // Clear error state.
        GLenum error = d->funcs->glGetError();
        if (error == GL_NO_ERROR)
            break;
        if (error == GL_CONTEXT_LOST)
            return false;
    };
    d->funcs->glGetBufferSubData(d->type, offset, count, data);
    return d->funcs->glGetError() == GL_NO_ERROR;
#else
    Q_UNUSED(offset);
    Q_UNUSED(data);
    Q_UNUSED(count);
    return false;
#endif
}
 
void QOpenGLBuffer::write(int offset, const void *data, int count)
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QOpenGLBuffer::write(): buffer not created");
#endif
    Q_D(QOpenGLBuffer);
    if (d->guard && d->guard->id())
        d->funcs->glBufferSubData(d->type, offset, count, data);
}
 
void QOpenGLBuffer::allocate(const void *data, int count)
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QOpenGLBuffer::allocate(): buffer not created");
#endif
    Q_D(QOpenGLBuffer);
    if (d->guard && d->guard->id())
        d->funcs->glBufferData(d->type, count, data, d->actualUsagePattern);
}
 
bool QOpenGLBuffer::bind()
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QOpenGLBuffer::bind(): buffer not created");
#endif
    Q_D(const QOpenGLBuffer);
    GLuint bufferId = d->guard ? d->guard->id() : 0;
    if (bufferId) {
        if (d->guard->group() != QOpenGLContextGroup::currentContextGroup()) {
#ifndef QT_NO_DEBUG
            qWarning("QOpenGLBuffer::bind: buffer is not valid in the current context");
#endif
            return false;
        }
        d->funcs->glBindBuffer(d->type, bufferId);
        return true;
    } else {
        return false;
    }
}
 
void QOpenGLBuffer::release()
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QOpenGLBuffer::release(): buffer not created");
#endif
    Q_D(const QOpenGLBuffer);
    if (d->guard && d->guard->id())
        d->funcs->glBindBuffer(d->type, 0);
}
 
void QOpenGLBuffer::release(QOpenGLBuffer::Type type)
{
    QOpenGLContext *ctx = QOpenGLContext::currentContext();
    if (ctx)
        ctx->functions()->glBindBuffer(GLenum(type), 0);
}
 
GLuint QOpenGLBuffer::bufferId() const
{
    Q_D(const QOpenGLBuffer);
    return d->guard ? d->guard->id() : 0;
}
 
int QOpenGLBuffer::size() const
{
    Q_D(const QOpenGLBuffer);
    if (!d->guard || !d->guard->id())
        return -1;
    GLint value = -1;
    d->funcs->glGetBufferParameteriv(d->type, GL_BUFFER_SIZE, &value);
    return value;
}
 
void *QOpenGLBuffer::map(QOpenGLBuffer::Access access)
{
    Q_D(QOpenGLBuffer);
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QOpenGLBuffer::map(): buffer not created");
#endif
    if (!d->guard || !d->guard->id())
        return nullptr;
    if (d->funcs->hasOpenGLExtension(QOpenGLExtensions::MapBufferRange)) {
        QOpenGLBuffer::RangeAccessFlags rangeAccess;
        switch (access) {
        case QOpenGLBuffer::ReadOnly:
            rangeAccess = QOpenGLBuffer::RangeRead;
            break;
        case QOpenGLBuffer::WriteOnly:
            rangeAccess = QOpenGLBuffer::RangeWrite;
            break;
        case QOpenGLBuffer::ReadWrite:
            rangeAccess = QOpenGLBuffer::RangeRead | QOpenGLBuffer::RangeWrite;
            break;
        }
        return d->funcs->glMapBufferRange(d->type, 0, size(), rangeAccess);
    } else {
        return d->funcs->glMapBuffer(d->type, access);
    }
}
 
void *QOpenGLBuffer::mapRange(int offset, int count, QOpenGLBuffer::RangeAccessFlags access)
{
    Q_D(QOpenGLBuffer);
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QOpenGLBuffer::mapRange(): buffer not created");
#endif
    if (!d->guard || !d->guard->id())
        return nullptr;
    return d->funcs->glMapBufferRange(d->type, offset, count, access);
}
 
bool QOpenGLBuffer::unmap()
{
    Q_D(QOpenGLBuffer);
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QOpenGLBuffer::unmap(): buffer not created");
#endif
    if (!d->guard || !d->guard->id())
        return false;
    return d->funcs->glUnmapBuffer(d->type) == GL_TRUE;
}
 
QT_END_NAMESPACE