Add the QGLBuffer class to Qt 4.7 for VBO's

Reviewed-by: Sarah Smith

1 files changed, 454 insertions, 0 deletions

diff --git a/src/opengl/qglbuffer.cpp b/src/opengl/qglbuffer.cpp
new file mode 100644
index 0000000..2018086
--- /dev/null
+++ b/src/opengl/qglbuffer.cpp
@@ -0,0 +1,454 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtOpenGL module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtOpenGL/qgl.h>
+#include <QtOpenGL/private/qgl_p.h>
+#include <QtOpenGL/private/qglextensions_p.h>
+#include "qglbuffer.h"
+
+QT_BEGIN_NAMESPACE
+
+/*!
+    \class QGLBuffer
+    \brief The QGLBuffer class provides functions for creating and managing GL buffer objects.
+    \since 4.7
+    \ingroup painting-3D
+
+    Buffer objects are created in the GL server so that the
+    client application can avoid uploading vertices, indices,
+    texture image data, etc every time they are needed.
+*/
+
+/*!
+    \enum QGLBuffer::Type
+    This enum defines the type of GL buffer object to create with QGLBuffer.
+
+    \value VertexBuffer Vertex buffer object for use when specifying
+           vertex arrays.
+    \value IndexBuffer Index buffer object for use with \c{glDrawElements()}.
+    \value PixelPackBuffer Pixel pack buffer object for reading pixel
+           data from the GL server (for example, with \c{glReadPixels()}).
+           Not supported under OpenGL/ES.
+    \value PixelUnpackBuffer Pixel unpack buffer object for writing pixel
+           data to the GL server (for example, with \c{glTexImage2D()}).
+           Not supported under OpenGL/ES.
+*/
+
+/*!
+    \enum QGLBuffer::UsagePattern
+    This enum defines the usage pattern of a QGLBuffer object.
+
+    \value StreamDraw The data will be set once and used a few times
+           for drawing operations.  Under OpenGL/ES 1.1 this is identical
+           to StaticDraw.
+    \value StreamRead The data will be set once and used a few times
+           for reading data back from the GL server.  Not supported
+           under OpenGL/ES.
+    \value StreamCopy The data will be set once and used a few times
+           for reading data back from the GL server for use in further
+           drawing operations.  Not supported under OpenGL/ES.
+    \value StaticDraw The data will be set once and used many times
+           for drawing operations.
+    \value StaticRead The data will be set once and used many times
+           for reading data back from the GL server.  Not supported
+           under OpenGL/ES.
+    \value StaticCopy The data will be set once and used many times
+           for reading data back from the GL server for use in further
+           drawing operations.  Not supported under OpenGL/ES.
+    \value DynamicDraw The data will be modified repeatedly and used
+           many times for drawing operations.
+    \value DynamicRead The data will be modified repeatedly and used
+           many times for reading data back from the GL server.
+           Not supported under OpenGL/ES.
+    \value DynamicCopy The data will be modified repeatedly and used
+           many times for reading data back from the GL server for
+           use in further drawing operations.  Not supported under OpenGL/ES.
+*/
+
+/*!
+    \enum QGLBuffer::Access
+    This enum defines the access mode for QGLBuffer::map().
+
+    \value ReadOnly The buffer will be mapped for reading only.
+    \value WriteOnly The buffer will be mapped for writing only.
+    \value ReadWrite The buffer will be mapped for reading and writing.
+*/
+
+class QGLBufferPrivate
+{
+public:
+    QGLBufferPrivate(QGLBuffer::Type t)
+        : type(t),
+          guard(0),
+          usagePattern(QGLBuffer::StaticDraw),
+          actualUsagePattern(QGLBuffer::StaticDraw)
+    {
+    }
+
+    QGLBuffer::Type type;
+    QGLSharedResourceGuard guard;
+    QGLBuffer::UsagePattern usagePattern;
+    QGLBuffer::UsagePattern actualUsagePattern;
+};
+
+/*!
+    Constructs a new buffer object of \a type.
+
+    Note: this constructor just creates the QGLBuffer instance.  The actual
+    buffer object in the GL server is not created until create() is called.
+
+    \sa create()
+*/
+QGLBuffer::QGLBuffer(QGLBuffer::Type type)
+    : d_ptr(new QGLBufferPrivate(type))
+{
+}
+
+#define ctx d->guard.context()
+
+/*!
+    Destroys this buffer object, including the storage being
+    used in the GL server.
+*/
+QGLBuffer::~QGLBuffer()
+{
+    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);
+    }
+}
+
+/*!
+    Returns the type of buffer represented by this object.
+*/
+QGLBuffer::Type QGLBuffer::type() const
+{
+    Q_D(const QGLBuffer);
+    return d->type;
+}
+
+/*!
+    Returns the usage pattern for this buffer object.
+    The default value is StaticDraw.
+
+    \sa setUsagePattern()
+*/
+QGLBuffer::UsagePattern QGLBuffer::usagePattern() const
+{
+    Q_D(const QGLBuffer);
+    return d->usagePattern;
+}
+
+/*!
+    Sets the usage pattern for this buffer object to \a value.
+    This function must be called before allocate() or write().
+
+    \sa usagePattern(), allocate(), write()
+*/
+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
+
+/*!
+    Creates the buffer object in the GL server.  Returns true if
+    the object was created; false otherwise.
+
+    This function must be called with a current QGLContext.
+    The buffer will be bound to and can only be used in
+    that context (or any other context that is shared with it).
+
+    This function will return false if the GL implementation
+    does not support buffers, or there is no current QGLContext.
+
+    \sa isCreated(), allocate(), write()
+*/
+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()
+
+/*!
+    Returns true if this buffer has been created; false otherwise.
+
+    \sa create()
+*/
+bool QGLBuffer::isCreated() const
+{
+    Q_D(const QGLBuffer);
+    return d->guard.id() != 0;
+}
+
+/*!
+    Reads the \a size bytes in this buffer starting at \a offset
+    into \a data.  Returns true on success; false if reading from
+    the buffer is not supported.  Buffer reading is not supported
+    under OpenGL/ES.
+
+    It is assumed that this buffer has been bound to the current context.
+
+    \sa write(), bind()
+*/
+bool QGLBuffer::read(int offset, void *data, int size)
+{
+#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, size, data);
+    return glGetError() == GL_NO_ERROR;
+#else
+    Q_UNUSED(offset);
+    Q_UNUSED(data);
+    Q_UNUSED(size);
+    return false;
+#endif
+}
+
+/*!
+    Replaces the \a size bytes of this buffer starting at \a offset
+    with the contents of \a data.  Any other bytes in the buffer
+    will be left unmodified.
+
+    It is assumed that create() has been called on this buffer and that
+    it has been bound to the current context.
+
+    \sa create(), read(), allocate()
+*/
+void QGLBuffer::write(int offset, const void *data, int size)
+{
+    Q_D(QGLBuffer);
+    if (d->guard.id())
+        glBufferSubData(d->type, offset, size, data);
+}
+
+/*!
+    Allocates \a size bytes of space to the buffer, initialized to
+    the contents of \a data.  Any previous contents will be removed.
+
+    It is assumed that create() has been called on this buffer and that
+    it has been bound to the current context.
+
+    \sa create(), read(), write()
+*/
+void QGLBuffer::allocate(const void *data, int size)
+{
+    Q_D(QGLBuffer);
+    if (d->guard.id())
+        glBufferData(d->type, size, data, d->actualUsagePattern);
+}
+
+/*!
+    \fn void QGLBuffer::allocate(int size)
+    \overload
+
+    Allocates \a size bytes of space to the buffer.  Any previous
+    contents will be removed.
+
+    It is assumed that create() has been called on this buffer and that
+    it has been bound to the current context.
+
+    \sa create(), write()
+*/
+
+/*!
+    Binds the buffer associated with this object to the current
+    GL context.  Returns false if binding was not possible, usually because
+    type() is not supported on this GL implementation.
+
+    The buffer must be bound to the same QGLContext current when create()
+    was called, or to another QGLContext that is sharing with it.
+    Otherwise, false will be returned from this function.
+
+    \sa release(), create()
+*/
+bool QGLBuffer::bind() const
+{
+    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;
+    }
+}
+
+/*!
+    Releases the buffer associated with this object from the
+    current GL context.
+
+    This function must be called with the same QGLContext current
+    as when bind() was called on the buffer.
+
+    \sa bind()
+*/
+void QGLBuffer::release() const
+{
+    Q_D(const QGLBuffer);
+    if (d->guard.id())
+        glBindBuffer(d->type, 0);
+}
+
+/*!
+    Returns the GL identifier associated with this buffer; zero if
+    the buffer has not been created.
+
+    \sa isCreated()
+*/
+uint QGLBuffer::bufferId() const
+{
+    Q_D(const QGLBuffer);
+    return d->guard.id();
+}
+
+#ifndef GL_BUFFER_SIZE
+#define GL_BUFFER_SIZE 0x8764
+#endif
+
+/*!
+    Returns the size of the data in this buffer, for reading operations.
+    Returns -1 if fetching the buffer size is not supported, or the
+    buffer has not been created.
+
+    It is assumed that this buffer has been bound to the current context.
+
+    \sa isCreated(), bind()
+*/
+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;
+}
+
+/*!
+    Maps the contents of this buffer into the application's memory
+    space and returns a pointer to it.  Returns null if memory
+    mapping is not possible.  The \a access parameter indicates the
+    type of access to be performed.
+
+    It is assumed that create() has been called on this buffer and that
+    it has been bound to the current context.
+
+    This function is only supported under OpenGL/ES if the
+    \c{GL_OES_mapbuffer} extension is present.
+
+    \sa unmap(), create(), bind()
+*/
+void *QGLBuffer::map(QGLBuffer::Access access)
+{
+    Q_D(QGLBuffer);
+    if (!d->guard.id())
+        return 0;
+    if (!glMapBufferARB)
+        return 0;
+    return glMapBufferARB(d->type, access);
+}
+
+/*!
+    Unmaps the buffer after it was mapped into the application's
+    memory space with a previous call to map().  Returns true if
+    the unmap succeeded; false otherwise.
+
+    It is assumed that this buffer has been bound to the current context,
+    and that it was previously mapped with map().
+
+    This function is only supported under OpenGL/ES if the
+    \c{GL_OES_mapbuffer} extension is present.
+
+    \sa map()
+*/
+bool QGLBuffer::unmap()
+{
+    Q_D(QGLBuffer);
+    if (!d->guard.id())
+        return false;
+    if (!glUnmapBufferARB)
+        return false;
+    return glUnmapBufferARB(d->type) == GL_TRUE;
+}
+
+QT_END_NAMESPACE