OpenVG: Fix Recursive Layers

OpenVG also needed to ping-pong between two offscreen surfaces like the
OpenGL renderer.

Change-Id: I41f671d98d361eb114be5c00ebfe62710a971aaa
Reviewed-by: Laszlo Agocs <laszlo.agocs@qt.io>

5 files changed, 56 insertions, 13 deletions

diff --git a/src/plugins/scenegraph/openvg/qopenvgoffscreensurface.cpp b/src/plugins/scenegraph/openvg/qopenvgoffscreensurface.cpp
index 3a4643ab5a..80af227fb4 100644
--- a/src/plugins/scenegraph/openvg/qopenvgoffscreensurface.cpp
+++ b/src/plugins/scenegraph/openvg/qopenvgoffscreensurface.cpp
@@ -39,6 +39,9 @@
 
 #include "qopenvgoffscreensurface.h"
 
+#include <QtGui/QImage>
+#include <QDebug>
+
 QT_BEGIN_NAMESPACE
 
 QOpenVGOffscreenSurface::QOpenVGOffscreenSurface(const QSize &size)
@@ -79,6 +82,7 @@ QOpenVGOffscreenSurface::~QOpenVGOffscreenSurface()
 {
     vgDestroyImage(m_image);
     eglDestroySurface(m_display, m_renderTarget);
+    eglDestroyContext(m_display, m_context);
 }
 
 void QOpenVGOffscreenSurface::makeCurrent()
@@ -98,7 +102,6 @@ void QOpenVGOffscreenSurface::doneCurrent()
     EGLContext currentContext = eglGetCurrentContext();
     if (m_context == currentContext) {
         eglMakeCurrent(m_display, m_previousDrawSurface, m_previousReadSurface, m_previousContext);
-        m_context = EGL_NO_CONTEXT;
         m_previousContext = EGL_NO_CONTEXT;
         m_previousReadSurface = EGL_NO_SURFACE;
         m_previousDrawSurface = EGL_NO_SURFACE;
@@ -110,4 +113,11 @@ void QOpenVGOffscreenSurface::swapBuffers()
     eglSwapBuffers(m_display, m_renderTarget);
 }
 
+QImage QOpenVGOffscreenSurface::readbackQImage()
+{
+    QImage readbackImage(m_size, QImage::Format_ARGB32_Premultiplied);
+    vgGetImageSubData(m_image, readbackImage.bits(), readbackImage.bytesPerLine(), VG_sARGB_8888_PRE, 0, 0, m_size.width(), m_size.height());
+    return readbackImage;
+}
+
 QT_END_NAMESPACE
diff --git a/src/plugins/scenegraph/openvg/qopenvgoffscreensurface.h b/src/plugins/scenegraph/openvg/qopenvgoffscreensurface.h
index 833c9669bf..746e4de1cd 100644
--- a/src/plugins/scenegraph/openvg/qopenvgoffscreensurface.h
+++ b/src/plugins/scenegraph/openvg/qopenvgoffscreensurface.h
@@ -57,6 +57,8 @@ public:
     VGImage image() { return m_image; }
     QSize size() const { return m_size; }
 
+    QImage readbackQImage();
+
 private:
     VGImage m_image;
     QSize m_size;
diff --git a/src/plugins/scenegraph/openvg/qsgopenvginternalimagenode.cpp b/src/plugins/scenegraph/openvg/qsgopenvginternalimagenode.cpp
index c9545d5e9a..3dd1f9133c 100644
--- a/src/plugins/scenegraph/openvg/qsgopenvginternalimagenode.cpp
+++ b/src/plugins/scenegraph/openvg/qsgopenvginternalimagenode.cpp
@@ -79,6 +79,9 @@ void QSGOpenVGInternalImageNode::render()
     VGImage image = static_cast<VGImage>(m_texture->textureId());
     QSize textureSize = m_texture->textureSize();
 
+    if (image == VG_INVALID_HANDLE || !textureSize.isValid())
+        return;
+
 
     // If Mirrored
     if (m_mirror) {
diff --git a/src/plugins/scenegraph/openvg/qsgopenvglayer.cpp b/src/plugins/scenegraph/openvg/qsgopenvglayer.cpp
index cafd0d4e1e..047539d431 100644
--- a/src/plugins/scenegraph/openvg/qsgopenvglayer.cpp
+++ b/src/plugins/scenegraph/openvg/qsgopenvglayer.cpp
@@ -54,6 +54,7 @@ QSGOpenVGLayer::QSGOpenVGLayer(QSGRenderContext *renderContext)
     , m_recursive(false)
     , m_dirtyTexture(true)
     , m_offscreenSurface(nullptr)
+    , m_secondaryOffscreenSurface(nullptr)
 {
     m_context = static_cast<QSGOpenVGRenderContext*>(renderContext);
 }
@@ -113,7 +114,9 @@ void QSGOpenVGLayer::setItem(QSGNode *item)
 
     if (m_live && !m_item) {
         delete m_offscreenSurface;
+        delete m_secondaryOffscreenSurface;
         m_offscreenSurface = nullptr;
+        m_secondaryOffscreenSurface = nullptr;
     }
 
     markDirtyTexture();
@@ -135,7 +138,9 @@ void QSGOpenVGLayer::setSize(const QSize &size)
 
     if (m_live && m_size.isNull()) {
         delete m_offscreenSurface;
+        delete m_secondaryOffscreenSurface;
         m_offscreenSurface = nullptr;
+        m_secondaryOffscreenSurface = nullptr;
     }
 
     markDirtyTexture();
@@ -153,8 +158,7 @@ void QSGOpenVGLayer::scheduleUpdate()
 
 QImage QSGOpenVGLayer::toImage() const
 {
-    // XXX
-    return QImage();
+    return m_offscreenSurface->readbackQImage();
 }
 
 void QSGOpenVGLayer::setLive(bool live)
@@ -165,7 +169,9 @@ void QSGOpenVGLayer::setLive(bool live)
 
     if (m_live && (!m_item || m_size.isNull())) {
         delete m_offscreenSurface;
+        delete m_secondaryOffscreenSurface;
         m_offscreenSurface = nullptr;
+        m_secondaryOffscreenSurface = nullptr;
     }
 
     markDirtyTexture();
@@ -218,16 +224,20 @@ void QSGOpenVGLayer::markDirtyTexture()
 void QSGOpenVGLayer::invalidated()
 {
     delete m_offscreenSurface;
+    delete m_secondaryOffscreenSurface;
     delete m_renderer;
     m_renderer = nullptr;
     m_offscreenSurface = nullptr;
+    m_secondaryOffscreenSurface = nullptr;
 }
 
 void QSGOpenVGLayer::grab()
 {
     if (!m_item || m_size.isNull()) {
         delete m_offscreenSurface;
+        delete m_secondaryOffscreenSurface;
         m_offscreenSurface = nullptr;
+        m_secondaryOffscreenSurface = nullptr;
         m_dirtyTexture = false;
         return;
     }
@@ -244,14 +254,23 @@ void QSGOpenVGLayer::grab()
     m_renderer->setDevicePixelRatio(m_device_pixel_ratio);
     m_renderer->setRootNode(static_cast<QSGRootNode *>(root));
 
-
+    bool deleteOffscreenSurfaceLater = false;
     if (m_offscreenSurface == nullptr || m_offscreenSurface->size() != m_size ) {
-        if (m_offscreenSurface != nullptr)
+        if (m_recursive) {
+            deleteOffscreenSurfaceLater = true;
+            delete m_secondaryOffscreenSurface;
+            m_secondaryOffscreenSurface = new QOpenVGOffscreenSurface(m_size);
+        } else {
             delete m_offscreenSurface;
-
-        m_offscreenSurface = new QOpenVGOffscreenSurface(m_size);
+            delete m_secondaryOffscreenSurface;
+            m_offscreenSurface = new QOpenVGOffscreenSurface(m_size);
+            m_secondaryOffscreenSurface = nullptr;
+        }
     }
 
+    if (m_recursive && !m_secondaryOffscreenSurface)
+        m_secondaryOffscreenSurface = new QOpenVGOffscreenSurface(m_size);
+
     // Render texture.
     root->markDirty(QSGNode::DirtyForceUpdate); // Force matrix, clip and opacity update.
     m_renderer->nodeChanged(root, QSGNode::DirtyForceUpdate); // Force render list update.
@@ -267,17 +286,25 @@ void QSGOpenVGLayer::grab()
     m_renderer->setProjectionMatrixToRect(mirrored);
     m_renderer->setClearColor(Qt::transparent);
 
-    m_offscreenSurface->makeCurrent();
 
-    // 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();
+    if (m_recursive)
+        m_secondaryOffscreenSurface->makeCurrent();
+    else
+        m_offscreenSurface->makeCurrent();
 
     m_renderer->renderScene();
 
     // Make the previous surface and context active again
-    m_offscreenSurface->doneCurrent();
+    if (m_recursive) {
+        if (deleteOffscreenSurfaceLater) {
+            delete m_offscreenSurface;
+            m_offscreenSurface = new QOpenVGOffscreenSurface(m_size);
+        }
+        m_secondaryOffscreenSurface->doneCurrent();
+        qSwap(m_offscreenSurface, m_secondaryOffscreenSurface);
+    } else {
+        m_offscreenSurface->doneCurrent();
+    }
 
     root->markDirty(QSGNode::DirtyForceUpdate); // Force matrix, clip, opacity and render list update.
 
diff --git a/src/plugins/scenegraph/openvg/qsgopenvglayer.h b/src/plugins/scenegraph/openvg/qsgopenvglayer.h
index 760a22f0bc..2af0bfb40f 100644
--- a/src/plugins/scenegraph/openvg/qsgopenvglayer.h
+++ b/src/plugins/scenegraph/openvg/qsgopenvglayer.h
@@ -105,6 +105,7 @@ private:
     bool m_dirtyTexture;
 
     QOpenVGOffscreenSurface *m_offscreenSurface;
+    QOpenVGOffscreenSurface *m_secondaryOffscreenSurface;
 };
 
 QT_END_NAMESPACE