Use one render loop per QQuickWindow

See the task for the full reasoning behind this patch.

The threaded renderloop has been refactored to have one window per
thread. This is mostly a simplification of the current code path where
for loops over multiple windows are turned into if (window).

The QSGContext has been split into two classes, QSGRenderContext
for which there is one per OpenGLContext.

The rest of the patch is name changes and a couple of cleanups
in the hopes of simplifying this change.

Task-number: QTBUG-33993

Change-Id: I31c81f9694d7da7474a72333169be38de62613c4
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>

1 files changed, 14 insertions, 17 deletions

diff --git a/src/quick/items/qquickshadereffectsource.cpp b/src/quick/items/qquickshadereffectsource.cpp
index e86550d731..c05545c292 100644
--- a/src/quick/items/qquickshadereffectsource.cpp
+++ b/src/quick/items/qquickshadereffectsource.cpp
@@ -45,6 +45,7 @@
 #include "qquickwindow_p.h"
 #include <private/qsgadaptationlayer_p.h>
 #include <QtQuick/private/qsgrenderer_p.h>
+#include <qsgsimplerectnode.h>
 
 #include "qopenglframebufferobject.h"
 #include "qmath.h"
@@ -143,7 +144,7 @@ QQuickShaderEffectTexture::QQuickShaderEffectTexture(QQuickItem *shaderSource)
 #ifdef QSG_DEBUG_FBO_OVERLAY
     , m_debugOverlay(0)
 #endif
-    , m_context(QQuickItemPrivate::get(shaderSource)->sceneGraphContext())
+    , m_context(QQuickItemPrivate::get(shaderSource)->sceneGraphRenderContext())
     , m_mipmap(false)
     , m_live(true)
     , m_recursive(false)
@@ -326,7 +327,7 @@ void QQuickShaderEffectTexture::grab()
         || (!m_fbo->format().mipmap() && m_mipmap))
     {
         if (!m_multisamplingChecked) {
-            if (m_context->glContext()->format().samples() <= 1) {
+            if (m_context->openglContext()->format().samples() <= 1) {
                 m_multisampling = false;
             } else {
                 QList<QByteArray> extensions = QByteArray((const char *)glGetString(GL_EXTENSIONS)).split(' ');
@@ -342,7 +343,7 @@ void QQuickShaderEffectTexture::grab()
             QOpenGLFramebufferObjectFormat format;
 
             format.setInternalTextureFormat(m_format);
-            format.setSamples(m_context->glContext()->format().samples());
+            format.setSamples(m_context->openglContext()->format().samples());
             m_secondaryFbo = new QOpenGLFramebufferObject(m_size, format);
             m_depthStencilBuffer = m_context->depthStencilBufferForFbo(m_secondaryFbo);
         } else {
@@ -385,20 +386,16 @@ void QQuickShaderEffectTexture::grab()
 #ifdef QSG_DEBUG_FBO_OVERLAY
     if (qmlFboOverlay()) {
         if (!m_debugOverlay)
-            m_debugOverlay = m_context->createRectangleNode();
+            m_debugOverlay = new QSGSimpleRectNode();
         m_debugOverlay->setRect(QRectF(0, 0, m_size.width(), m_size.height()));
         m_debugOverlay->setColor(QColor(0xff, 0x00, 0x80, 0x40));
-        m_debugOverlay->setPenColor(QColor());
-        m_debugOverlay->setPenWidth(0);
-        m_debugOverlay->setRadius(0);
-        m_debugOverlay->update();
         root->appendChildNode(m_debugOverlay);
     }
 #endif
 
     m_dirtyTexture = false;
 
-    QOpenGLContext *ctx = m_context->glContext();
+    QOpenGLContext *ctx = m_context->openglContext();
     m_renderer->setDeviceRect(m_size);
     m_renderer->setViewportRect(m_size);
     QRectF mirrored(m_rect.left(), m_rect.bottom(), m_rect.width(), -m_rect.height());
@@ -591,8 +588,8 @@ void QQuickShaderEffectSource::ensureTexture()
         return;
 
     Q_ASSERT_X(QQuickItemPrivate::get(this)->window
-               && QQuickItemPrivate::get(this)->sceneGraphContext()
-               && QThread::currentThread() == QQuickItemPrivate::get(this)->sceneGraphContext()->thread(),
+               && QQuickItemPrivate::get(this)->sceneGraphRenderContext()
+               && QThread::currentThread() == QQuickItemPrivate::get(this)->sceneGraphRenderContext()->thread(),
                "QQuickShaderEffectSource::ensureTexture",
                "Cannot be used outside the rendering thread");
 
@@ -603,13 +600,13 @@ void QQuickShaderEffectSource::ensureTexture()
 
 QSGTextureProvider *QQuickShaderEffectSource::textureProvider() const
 {
+    const QQuickItemPrivate *d = QQuickItemPrivate::get(this);
+    if (!d->window || !d->sceneGraphRenderContext() || QThread::currentThread() != d->sceneGraphRenderContext()->thread()) {
+        qWarning("QQuickShaderEffectSource::textureProvider: can only be queried on the rendering thread of an exposed window");
+        return 0;
+    }
+
     if (!m_provider) {
-        // Make sure it gets thread affinity on the rendering thread so deletion works properly..
-        Q_ASSERT_X(QQuickItemPrivate::get(this)->window
-                   && QQuickItemPrivate::get(this)->sceneGraphContext()
-                   && QThread::currentThread() == QQuickItemPrivate::get(this)->sceneGraphContext()->thread(),
-                   "QQuickShaderEffectSource::textureProvider",
-                   "Cannot be used outside the rendering thread");
         const_cast<QQuickShaderEffectSource *>(this)->m_provider = new QQuickShaderEffectSourceTextureProvider();
         const_cast<QQuickShaderEffectSource *>(this)->ensureTexture();
         connect(m_texture, SIGNAL(updateRequested()), m_provider, SIGNAL(textureChanged()));