OpenVG Scenegraph Adaptation

This is an OpenVG backend for the Qt Quick 2 scenegraph.

Should be feature complete now, but there are still some issues that
could be improved in future commits:

If Rectangle nodes are rendered with a non-affine transform, they will
be rendered incorrectly.  This is because paths expect affine
transformations.

The Glyph cache is a bit cheeky in that it's caching paths, but doing
so per font size.  It shoudln't need to, but right now I've not though
up a good way of getting the transform/scale needed when rendering yet.

Change-Id: Ie3c4f2df35d14279b0f9f55e0e10a873328c025b
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

1 files changed, 360 insertions, 0 deletions

diff --git a/src/plugins/scenegraph/openvg/qsgopenvglayer.cpp b/src/plugins/scenegraph/openvg/qsgopenvglayer.cpp
new file mode 100644
index 0000000000..03a82ca4ee
--- /dev/null
+++ b/src/plugins/scenegraph/openvg/qsgopenvglayer.cpp
@@ -0,0 +1,360 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQuick module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qsgopenvglayer.h"
+#include "qsgopenvgrenderer_p.h"
+#include "qsgopenvgcontext_p.h"
+
+QT_BEGIN_NAMESPACE
+
+QSGOpenVGLayer::QSGOpenVGLayer(QSGRenderContext *renderContext)
+    : m_item(nullptr)
+    , m_renderer(nullptr)
+    , m_device_pixel_ratio(1)
+    , m_mirrorHorizontal(false)
+    , m_mirrorVertical(false)
+    , m_live(true)
+    , m_grab(true)
+    , m_recursive(false)
+    , m_dirtyTexture(true)
+    , m_image(0)
+    , m_renderTarget(0)
+    , m_layerContext(0)
+{
+    m_context = static_cast<QSGOpenVGRenderContext*>(renderContext);
+    m_vgContext = m_context->vgContext();
+}
+
+QSGOpenVGLayer::~QSGOpenVGLayer()
+{
+    invalidated();
+}
+
+int QSGOpenVGLayer::textureId() const
+{
+    return static_cast<int>(m_image);
+}
+
+QSize QSGOpenVGLayer::textureSize() const
+{
+    if (m_image != 0) {
+        VGint imageWidth = vgGetParameteri(m_image, VG_IMAGE_WIDTH);
+        VGint imageHeight = vgGetParameteri(m_image, VG_IMAGE_HEIGHT);
+        return QSize(imageWidth, imageHeight);
+    }
+
+    return QSize();
+}
+
+bool QSGOpenVGLayer::hasAlphaChannel() const
+{
+    VGImageFormat format = static_cast<VGImageFormat>(vgGetParameteri(m_image, VG_IMAGE_FORMAT));
+
+    switch (format) {
+    case VG_sRGBA_8888:
+    case VG_sRGBA_8888_PRE:
+    case VG_sRGBA_5551:
+    case VG_sRGBA_4444:
+    case VG_lRGBA_8888:
+    case VG_lRGBA_8888_PRE:
+    case VG_A_8:
+    case VG_A_1:
+    case VG_A_4:
+    case VG_sARGB_8888:
+    case VG_sARGB_8888_PRE:
+    case VG_sARGB_1555:
+    case VG_sARGB_4444:
+    case VG_lARGB_8888:
+    case VG_lARGB_8888_PRE:
+    case VG_sBGRA_8888:
+    case VG_sBGRA_8888_PRE:
+    case VG_sBGRA_5551:
+    case VG_sBGRA_4444:
+    case VG_lBGRA_8888:
+    case VG_lBGRA_8888_PRE:
+    case VG_sABGR_8888:
+    case VG_sABGR_8888_PRE:
+    case VG_sABGR_1555:
+    case VG_sABGR_4444:
+    case VG_lABGR_8888:
+    case VG_lABGR_8888_PRE:
+        return true;
+        break;
+    default:
+        break;
+    }
+    return false;
+}
+
+bool QSGOpenVGLayer::hasMipmaps() const
+{
+    return false;
+}
+
+void QSGOpenVGLayer::bind()
+{
+}
+
+bool QSGOpenVGLayer::updateTexture()
+{
+    bool doGrab = (m_live || m_grab) && m_dirtyTexture;
+    if (doGrab)
+        grab();
+    if (m_grab)
+        emit scheduledUpdateCompleted();
+    m_grab = false;
+    return doGrab;
+}
+
+void QSGOpenVGLayer::setItem(QSGNode *item)
+{
+    if (item == m_item)
+        return;
+    m_item = item;
+
+    if (m_live && !m_item) {
+        vgDestroyImage(m_image);
+        m_image = 0;
+    }
+
+    markDirtyTexture();
+}
+
+void QSGOpenVGLayer::setRect(const QRectF &rect)
+{
+    if (rect == m_rect)
+        return;
+    m_rect = rect;
+    markDirtyTexture();
+}
+
+void QSGOpenVGLayer::setSize(const QSize &size)
+{
+    if (size == m_size)
+        return;
+    m_size = size;
+
+    if (m_live && m_size.isNull()) {
+        vgDestroyImage(m_image);
+        m_image = 0;
+    }
+
+    markDirtyTexture();
+}
+
+void QSGOpenVGLayer::scheduleUpdate()
+{
+    if (m_grab)
+        return;
+    m_grab = true;
+    if (m_dirtyTexture) {
+        emit updateRequested();
+    }
+}
+
+QImage QSGOpenVGLayer::toImage() const
+{
+    // XXX
+    return QImage();
+}
+
+void QSGOpenVGLayer::setLive(bool live)
+{
+    if (live == m_live)
+        return;
+    m_live = live;
+
+    if (m_live && (!m_item || m_size.isNull())) {
+        vgDestroyImage(m_image);
+        m_image = 0;
+    }
+
+    markDirtyTexture();
+}
+
+void QSGOpenVGLayer::setRecursive(bool recursive)
+{
+    m_recursive = recursive;
+}
+
+void QSGOpenVGLayer::setFormat(uint format)
+{
+    Q_UNUSED(format)
+}
+
+void QSGOpenVGLayer::setHasMipmaps(bool mipmap)
+{
+    Q_UNUSED(mipmap)
+}
+
+void QSGOpenVGLayer::setDevicePixelRatio(qreal ratio)
+{
+    m_device_pixel_ratio = ratio;
+}
+
+void QSGOpenVGLayer::setMirrorHorizontal(bool mirror)
+{
+    if (m_mirrorHorizontal == mirror)
+        return;
+    m_mirrorHorizontal = mirror;
+    markDirtyTexture();
+}
+
+void QSGOpenVGLayer::setMirrorVertical(bool mirror)
+{
+    if (m_mirrorVertical == mirror)
+        return;
+    m_mirrorVertical = mirror;
+    markDirtyTexture();
+}
+
+void QSGOpenVGLayer::markDirtyTexture()
+{
+    m_dirtyTexture = true;
+    if (m_live || m_grab) {
+        emit updateRequested();
+    }
+}
+
+void QSGOpenVGLayer::invalidated()
+{
+    delete m_renderer;
+    m_renderer = 0;
+}
+
+void QSGOpenVGLayer::grab()
+{
+    if (!m_item || m_size.isNull()) {
+        vgDestroyImage(m_image);
+        m_image = 0;
+        m_dirtyTexture = false;
+        return;
+    }
+    QSGNode *root = m_item;
+    while (root->firstChild() && root->type() != QSGNode::RootNodeType)
+        root = root->firstChild();
+    if (root->type() != QSGNode::RootNodeType)
+        return;
+
+    if (!m_renderer) {
+        m_renderer = new QSGOpenVGRenderer(m_context);
+        connect(m_renderer, SIGNAL(sceneGraphChanged()), this, SLOT(markDirtyTexture()));
+    }
+    m_renderer->setDevicePixelRatio(m_device_pixel_ratio);
+    m_renderer->setRootNode(static_cast<QSGRootNode *>(root));
+
+    if (m_image == 0 || m_imageSize != m_size ) {
+        if (m_image != 0)
+            vgDestroyImage(m_image);
+
+        m_image = vgCreateImage(VG_lARGB_8888_PRE, m_size.width(), m_size.height(), VG_IMAGE_QUALITY_BETTER);
+        m_imageSize = m_size;
+
+        //Destroy old RenderTarget
+        if (m_renderTarget != 0)
+            eglDestroySurface(m_vgContext->eglDisplay(), m_renderTarget);
+
+        const EGLint configAttribs[] = {
+            EGL_CONFORMANT, EGL_OPENVG_BIT,
+            EGL_SURFACE_TYPE, EGL_PBUFFER_BIT,
+            EGL_RED_SIZE, 8,
+            EGL_GREEN_SIZE, 8,
+            EGL_BLUE_SIZE, 8,
+            EGL_ALPHA_SIZE, 8,
+            EGL_ALPHA_MASK_SIZE, 8,
+            EGL_NONE
+        };
+
+        EGLConfig pbufferConfig;
+        EGLint numConfig;
+        eglChooseConfig(m_vgContext->eglDisplay(), configAttribs, &pbufferConfig, 1, &numConfig);
+
+        if (m_layerContext == 0) {
+            // Create new context
+            m_layerContext = eglCreateContext(m_vgContext->eglDisplay(), pbufferConfig, m_vgContext->eglContext(), 0);
+        }
+
+        m_renderTarget = eglCreatePbufferFromClientBuffer(m_vgContext->eglDisplay(),
+                                                          EGL_OPENVG_IMAGE,
+                                                          (EGLClientBuffer)m_image,
+                                                          pbufferConfig,
+                                                          0);
+    }
+
+    if (m_renderTarget == EGL_NO_SURFACE) {
+        qDebug() << "invalid renderTarget!";
+        return;
+    }
+
+    // Render texture.
+    root->markDirty(QSGNode::DirtyForceUpdate); // Force matrix, clip and opacity update.
+    m_renderer->nodeChanged(root, QSGNode::DirtyForceUpdate); // Force render list update.
+
+    m_dirtyTexture = false;
+
+    m_renderer->setDeviceRect(m_size);
+    m_renderer->setViewportRect(m_size);
+    QRect mirrored(m_mirrorHorizontal ? m_rect.right() * m_device_pixel_ratio : m_rect.left() * m_device_pixel_ratio,
+                   m_mirrorVertical ? m_rect.top() * m_device_pixel_ratio : m_rect.bottom() * m_device_pixel_ratio,
+                   m_mirrorHorizontal ? -m_rect.width() * m_device_pixel_ratio : m_rect.width() * m_device_pixel_ratio,
+                   m_mirrorVertical ? m_rect.height() * m_device_pixel_ratio : -m_rect.height() * m_device_pixel_ratio);
+    m_renderer->setProjectionMatrixToRect(mirrored);
+    m_renderer->setClearColor(Qt::transparent);
+
+    eglMakeCurrent(m_vgContext->eglDisplay(), m_renderTarget, m_renderTarget, m_layerContext);
+
+    // Before Rendering setup context for adjusting to Qt Coordinates to PixelBuffer
+    // Should already be inverted by default
+    vgSeti(VG_MATRIX_MODE, VG_MATRIX_PATH_USER_TO_SURFACE);
+    vgLoadIdentity();
+
+    m_renderer->renderScene();
+
+    eglSwapBuffers(m_vgContext->eglDisplay(), m_renderTarget);
+
+    // make the default surface current again
+    m_vgContext->makeCurrent();
+
+    root->markDirty(QSGNode::DirtyForceUpdate); // Force matrix, clip, opacity and render list update.
+
+    if (m_recursive)
+        markDirtyTexture(); // Continuously update if 'live' and 'recursive'.
+}
+
+QT_END_NAMESPACE