qglbuffer.cpp

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#include <QtOpenGL/qgl.h>
#include <QtOpenGL/private/qgl_p.h>
#include <QtOpenGL/private/qglextensions_p.h>
#include <QtCore/qatomic.h>
#include "qglbuffer.h"

QT_BEGIN_NAMESPACE

class QGLBufferPrivate
{
public:
    QGLBufferPrivate(QGLBuffer::Type t)
        : ref(1),
          type(t),
          guard(0),
          usagePattern(QGLBuffer::StaticDraw),
          actualUsagePattern(QGLBuffer::StaticDraw)
    {
    }

    QAtomicInt ref;
    QGLBuffer::Type type;
    QGLSharedResourceGuard guard;
    QGLBuffer::UsagePattern usagePattern;
    QGLBuffer::UsagePattern actualUsagePattern;
};

QGLBuffer::QGLBuffer()
    : d_ptr(new QGLBufferPrivate(QGLBuffer::VertexBuffer))
{
}

QGLBuffer::QGLBuffer(QGLBuffer::Type type)
    : d_ptr(new QGLBufferPrivate(type))
{
}

QGLBuffer::QGLBuffer(const QGLBuffer &other)
    : d_ptr(other.d_ptr)
{
    d_ptr->ref.ref();
}

#define ctx d->guard.context()

QGLBuffer::~QGLBuffer()
{
    if (!d_ptr->ref.deref()) {
        destroy();
        delete d_ptr;
    }
}

QGLBuffer &QGLBuffer::operator=(const QGLBuffer &other)
{
    if (d_ptr != other.d_ptr) {
        other.d_ptr->ref.ref();
        if (!d_ptr->ref.deref()) {
            destroy();
            delete d_ptr;
        }
        d_ptr = other.d_ptr;
    }
    return *this;
}

QGLBuffer::Type QGLBuffer::type() const
{
    Q_D(const QGLBuffer);
    return d->type;
}

QGLBuffer::UsagePattern QGLBuffer::usagePattern() const
{
    Q_D(const QGLBuffer);
    return d->usagePattern;
}

void QGLBuffer::setUsagePattern(QGLBuffer::UsagePattern value)
{
    Q_D(QGLBuffer);
#if defined(QT_OPENGL_ES_1)
    // OpenGL/ES 1.1 does not support GL_STREAM_DRAW, so use GL_STATIC_DRAW.
    // OpenGL/ES 2.0 does support GL_STREAM_DRAW.
    d->usagePattern = value;
    if (value == StreamDraw)
        d->actualUsagePattern = StaticDraw;
    else
        d->actualUsagePattern = value;
#else
    d->usagePattern = d->actualUsagePattern = value;
#endif
}

#undef ctx

bool QGLBuffer::create()
{
    Q_D(QGLBuffer);
    if (d->guard.id())
        return true;
    const QGLContext *ctx = QGLContext::currentContext();
    if (ctx) {
        if (!qt_resolve_buffer_extensions(const_cast<QGLContext *>(ctx)))
            return false;
        GLuint bufferId = 0;
        glGenBuffers(1, &bufferId);
        if (bufferId) {
            d->guard.setContext(ctx);
            d->guard.setId(bufferId);
            return true;
        }
    }
    return false;
}

#define ctx d->guard.context()

bool QGLBuffer::isCreated() const
{
    Q_D(const QGLBuffer);
    return d->guard.id() != 0;
}

void QGLBuffer::destroy()
{
    Q_D(QGLBuffer);
    GLuint bufferId = d->guard.id();
    if (bufferId) {
        // Switch to the original creating context to destroy it.
        QGLShareContextScope scope(d->guard.context());
        glDeleteBuffers(1, &bufferId);
    }
    d->guard.setId(0);
    d->guard.setContext(0);
}

bool QGLBuffer::read(int offset, void *data, int count)
{
#if !defined(QT_OPENGL_ES)
    Q_D(QGLBuffer);
    if (!glGetBufferSubData || !d->guard.id())
        return false;
    while (glGetError() != GL_NO_ERROR) ; // Clear error state.
    glGetBufferSubData(d->type, offset, count, data);
    return glGetError() == GL_NO_ERROR;
#else
    Q_UNUSED(offset);
    Q_UNUSED(data);
    Q_UNUSED(count);
    return false;
#endif
}

void QGLBuffer::write(int offset, const void *data, int count)
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::allocate(): buffer not created");
#endif
    Q_D(QGLBuffer);
    if (d->guard.id())
        glBufferSubData(d->type, offset, count, data);
}

void QGLBuffer::allocate(const void *data, int count)
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::allocate(): buffer not created");
#endif
    Q_D(QGLBuffer);
    if (d->guard.id())
        glBufferData(d->type, count, data, d->actualUsagePattern);
}

bool QGLBuffer::bind()
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::bind(): buffer not created");
#endif
    Q_D(const QGLBuffer);
    GLuint bufferId = d->guard.id();
    if (bufferId) {
        if (!QGLContext::areSharing(QGLContext::currentContext(),
                                    d->guard.context())) {
#ifndef QT_NO_DEBUG
            qWarning("QGLBuffer::bind: buffer is not valid in the current context");
#endif
            return false;
        }
        glBindBuffer(d->type, bufferId);
        return true;
    } else {
        return false;
    }
}

void QGLBuffer::release()
{
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::release(): buffer not created");
#endif
    Q_D(const QGLBuffer);
    if (d->guard.id())
        glBindBuffer(d->type, 0);
}

#undef ctx

void QGLBuffer::release(QGLBuffer::Type type)
{
    const QGLContext *ctx = QGLContext::currentContext();
    if (ctx && qt_resolve_buffer_extensions(const_cast<QGLContext *>(ctx)))
        glBindBuffer(GLenum(type), 0);
}

#define ctx d->guard.context()

GLuint QGLBuffer::bufferId() const
{
    Q_D(const QGLBuffer);
    return d->guard.id();
}

#ifndef GL_BUFFER_SIZE
#define GL_BUFFER_SIZE 0x8764
#endif

int QGLBuffer::size() const
{
    Q_D(const QGLBuffer);
    if (!d->guard.id())
        return -1;
    GLint value = -1;
    glGetBufferParameteriv(d->type, GL_BUFFER_SIZE, &value);
    return value;
}

void *QGLBuffer::map(QGLBuffer::Access access)
{
    Q_D(QGLBuffer);
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::map(): buffer not created");
#endif
    if (!d->guard.id())
        return 0;
    if (!glMapBufferARB)
        return 0;
#ifdef QT_OPENGL_ES_2
    if (access != QGLBuffer::WriteOnly)
        return 0;
#endif
    return glMapBufferARB(d->type, access);
}

bool QGLBuffer::unmap()
{
    Q_D(QGLBuffer);
#ifndef QT_NO_DEBUG
    if (!isCreated())
        qWarning("QGLBuffer::unmap(): buffer not created");
#endif
    if (!d->guard.id())
        return false;
    if (!glUnmapBufferARB)
        return false;
    return glUnmapBufferARB(d->type) == GL_TRUE;
}

QT_END_NAMESPACE