Share depth-stencil buffers between ShaderEffectSources of same size.

Change-Id: If325a38175249c3a3ffe5043d42ba35dbf90ce0c
Reviewed-by: Gunnar Sletta <gunnar.sletta@nokia.com>

2 files changed, 319 insertions, 0 deletions

diff --git a/src/quick/scenegraph/util/qsgdepthstencilbuffer.cpp b/src/quick/scenegraph/util/qsgdepthstencilbuffer.cpp
new file mode 100644
index 0000000000..bca57a3b6b
--- /dev/null
+++ b/src/quick/scenegraph/util/qsgdepthstencilbuffer.cpp
@@ -0,0 +1,177 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qsgdepthstencilbuffer_p.h"
+
+QT_BEGIN_NAMESPACE
+
+QSGDepthStencilBuffer::QSGDepthStencilBuffer(QOpenGLContext *context, const Format &format)
+    : m_functions(context)
+    , m_manager(0)
+    , m_format(format)
+    , m_depthBuffer(0)
+    , m_stencilBuffer(0)
+{
+    // 'm_manager' is set by QSGDepthStencilBufferManager::insertBuffer().
+}
+
+QSGDepthStencilBuffer::~QSGDepthStencilBuffer()
+{
+    if (m_manager)
+        m_manager->m_buffers.remove(m_format);
+}
+
+void QSGDepthStencilBuffer::attach()
+{
+    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
+                                          GL_RENDERBUFFER, m_depthBuffer);
+    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
+                                          GL_RENDERBUFFER, m_stencilBuffer);
+}
+
+void QSGDepthStencilBuffer::detach()
+{
+    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT,
+                                          GL_RENDERBUFFER, 0);
+    m_functions.glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT,
+                                          GL_RENDERBUFFER, 0);
+}
+
+
+QSGDefaultDepthStencilBuffer::QSGDefaultDepthStencilBuffer(QOpenGLContext *context, const Format &format)
+    : QSGDepthStencilBuffer(context, format)
+{
+    const GLsizei width = format.size.width();
+    const GLsizei height = format.size.height();
+
+    if (format.attachments == (DepthAttachment | StencilAttachment)
+            && m_functions.hasOpenGLExtension(QOpenGLExtensions::PackedDepthStencil))
+    {
+        m_functions.glGenRenderbuffers(1, &m_depthBuffer);
+        m_functions.glBindRenderbuffer(GL_RENDERBUFFER, m_depthBuffer);
+        if (format.samples && m_functions.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)) {
+            m_functions.glRenderbufferStorageMultisample(GL_RENDERBUFFER, format.samples,
+                GL_DEPTH24_STENCIL8, width, height);
+        } else {
+            m_functions.glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, width, height);
+        }
+        m_stencilBuffer = m_depthBuffer;
+    }
+    if (!m_depthBuffer && (format.attachments & DepthAttachment)) {
+        m_functions.glGenRenderbuffers(1, &m_depthBuffer);
+        m_functions.glBindRenderbuffer(GL_RENDERBUFFER, m_depthBuffer);
+#ifdef QT_OPENGL_ES
+        const GLenum internalFormat = m_functions.hasOpenGLExtension(QOpenGLExtensions::Depth24)
+                ? GL_DEPTH_COMPONENT24 : GL_DEPTH_COMPONENT16;
+#else
+        const GLenum internalFormat = GL_DEPTH_COMPONENT;
+#endif
+        if (format.samples && m_functions.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)) {
+            m_functions.glRenderbufferStorageMultisample(GL_RENDERBUFFER, format.samples,
+                internalFormat, width, height);
+        } else {
+            m_functions.glRenderbufferStorage(GL_RENDERBUFFER, internalFormat, width, height);
+        }
+    }
+    if (!m_stencilBuffer && (format.attachments & StencilAttachment)) {
+        m_functions.glGenRenderbuffers(1, &m_stencilBuffer);
+        m_functions.glBindRenderbuffer(GL_RENDERBUFFER, m_stencilBuffer);
+#ifdef QT_OPENGL_ES
+        const GLenum internalFormat = GL_STENCIL_INDEX8;
+#else
+        const GLenum internalFormat = GL_STENCIL_INDEX;
+#endif
+        if (format.samples && m_functions.hasOpenGLExtension(QOpenGLExtensions::FramebufferMultisample)) {
+            m_functions.glRenderbufferStorageMultisample(GL_RENDERBUFFER, format.samples,
+                internalFormat, width, height);
+        } else {
+            m_functions.glRenderbufferStorage(GL_RENDERBUFFER, internalFormat, width, height);
+        }
+    }
+}
+
+QSGDefaultDepthStencilBuffer::~QSGDefaultDepthStencilBuffer()
+{
+    free();
+}
+
+void QSGDefaultDepthStencilBuffer::free()
+{
+    if (m_depthBuffer)
+        m_functions.glDeleteRenderbuffers(1, &m_depthBuffer);
+    if (m_stencilBuffer && m_stencilBuffer != m_depthBuffer)
+        m_functions.glDeleteRenderbuffers(1, &m_stencilBuffer);
+    m_depthBuffer = m_stencilBuffer = 0;
+}
+
+
+QSGDepthStencilBufferManager::~QSGDepthStencilBufferManager()
+{
+    for (Hash::const_iterator it = m_buffers.constBegin(); it != m_buffers.constEnd(); ++it) {
+        QSGDepthStencilBuffer *buffer = it.value().data();
+        buffer->free();
+        buffer->m_manager = 0;
+    }
+}
+
+QSharedPointer<QSGDepthStencilBuffer> QSGDepthStencilBufferManager::bufferForFormat(const QSGDepthStencilBuffer::Format &fmt)
+{
+    Hash::const_iterator it = m_buffers.constFind(fmt);
+    if (it != m_buffers.constEnd())
+        return it.value().toStrongRef();
+    return QSharedPointer<QSGDepthStencilBuffer>();
+}
+
+void QSGDepthStencilBufferManager::insertBuffer(const QSharedPointer<QSGDepthStencilBuffer> &buffer)
+{
+    Q_ASSERT(buffer->m_manager == 0);
+    Q_ASSERT(!m_buffers.contains(buffer->m_format));
+    buffer->m_manager = this;
+    m_buffers.insert(buffer->m_format, buffer.toWeakRef());
+}
+
+uint qHash(const QSGDepthStencilBuffer::Format &format)
+{
+    return qHash(qMakePair(format.size.width(), format.size.height()))
+            ^ (uint(format.samples) << 12) ^ (uint(format.attachments) << 28);
+}
+
+QT_END_NAMESPACE
diff --git a/src/quick/scenegraph/util/qsgdepthstencilbuffer_p.h b/src/quick/scenegraph/util/qsgdepthstencilbuffer_p.h
new file mode 100644
index 0000000000..0d8847feb4
--- /dev/null
+++ b/src/quick/scenegraph/util/qsgdepthstencilbuffer_p.h
@@ -0,0 +1,142 @@
+/****************************************************************************
+**
+** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** 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.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU General
+** Public License version 3.0 as published by the Free Software Foundation
+** and appearing in the file LICENSE.GPL included in the packaging of this
+** file. Please review the following information to ensure the GNU General
+** Public License version 3.0 requirements will be met:
+** http://www.gnu.org/copyleft/gpl.html.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QSGDEPTHSTENCILBUFFER_P_H
+#define QSGDEPTHSTENCILBUFFER_P_H
+
+#include <QtCore/qsize.h>
+#include <QtGui/private/qopenglcontext_p.h>
+#include <QtGui/private/qopenglextensions_p.h>
+#include <QtCore/qsharedpointer.h>
+#include <QtCore/qhash.h>
+
+QT_BEGIN_HEADER
+
+QT_BEGIN_NAMESPACE
+
+class QSGDepthStencilBufferManager;
+
+class QSGDepthStencilBuffer
+{
+public:
+    enum Attachment
+    {
+        NoAttachment = 0x00,
+        DepthAttachment = 0x01,
+        StencilAttachment = 0x02
+    };
+    Q_DECLARE_FLAGS(Attachments, Attachment)
+
+    struct Format
+    {
+        QSize size;
+        int samples;
+        QSGDepthStencilBuffer::Attachments attachments;
+        bool operator == (const Format &other) const;
+    };
+
+    QSGDepthStencilBuffer(QOpenGLContext *context, const Format &format);
+    virtual ~QSGDepthStencilBuffer();
+
+    // Attaches this depth stencil buffer to the currently bound FBO.
+    void attach();
+    // Detaches this depth stencil buffer from the currently bound FBO.
+    void detach();
+
+    QSize size() const { return m_format.size; }
+    int samples() const { return m_format.samples; }
+    Attachments attachments() const { return m_format.attachments; }
+
+protected:
+    virtual void free() = 0;
+
+    QOpenGLExtensions m_functions;
+    QSGDepthStencilBufferManager *m_manager;
+    Format m_format;
+    GLuint m_depthBuffer;
+    GLuint m_stencilBuffer;
+
+    friend class QSGDepthStencilBufferManager;
+};
+
+Q_DECLARE_OPERATORS_FOR_FLAGS(QSGDepthStencilBuffer::Attachments)
+
+inline bool QSGDepthStencilBuffer::Format::operator == (const Format &other) const
+{
+    return size == other.size && samples == other.samples && attachments == other.attachments;
+}
+
+
+class QSGDefaultDepthStencilBuffer : public QSGDepthStencilBuffer
+{
+public:
+    QSGDefaultDepthStencilBuffer(QOpenGLContext *context, const Format &format);
+    virtual ~QSGDefaultDepthStencilBuffer();
+
+protected:
+    virtual void free();
+};
+
+
+class QSGDepthStencilBufferManager
+{
+public:
+    QSGDepthStencilBufferManager(QOpenGLContext *ctx) : m_context(ctx) { }
+    ~QSGDepthStencilBufferManager();
+    QOpenGLContext *context() const { return m_context; }
+    QSharedPointer<QSGDepthStencilBuffer> bufferForFormat(const QSGDepthStencilBuffer::Format &fmt);
+    void insertBuffer(const QSharedPointer<QSGDepthStencilBuffer> &buffer);
+
+private:
+    typedef QHash<QSGDepthStencilBuffer::Format, QWeakPointer<QSGDepthStencilBuffer> > Hash;
+    QOpenGLContext *m_context;
+    Hash m_buffers;
+
+    friend class QSGDepthStencilBuffer;
+};
+
+extern uint qHash(const QSGDepthStencilBuffer::Format &format);
+
+QT_END_NAMESPACE
+
+QT_END_HEADER
+
+#endif