Add optional flags and rect to QSGRenderNode

Having rendernodes triggering fullscreen updates with the software backend
is not ideal. Therefore, introduce the option of reporting that the rendernode
is well-behaving, meaning it only writes inside the reported bounding rectangle.

Similarly, the OpenGL batch renderer can keep using the depth buffer when the
rendernode is known to behave like the renderer expects.

Change-Id: I6acc434432c2504776f26e8917b5434b44be293d
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

6 files changed, 37 insertions, 1 deletions

diff --git a/examples/quick/scenegraph/rendernode/d3d12renderer.cpp b/examples/quick/scenegraph/rendernode/d3d12renderer.cpp
index f475ec838b..d35f82a76a 100644
--- a/examples/quick/scenegraph/rendernode/d3d12renderer.cpp
+++ b/examples/quick/scenegraph/rendernode/d3d12renderer.cpp
@@ -270,4 +270,14 @@ void D3D12RenderNode::render(const RenderState *state)
 // No need to reimplement changedStates() because no relevant commands are
 // added to the command list in render().
 
+QSGRenderNode::RenderingFlags D3D12RenderNode::flags() const
+{
+    return BoundedRectRendering | DepthAwareRendering;
+}
+
+QRectF D3D12RenderNode::rect() const
+{
+    return QRect(0, 0, m_item->width(), m_item->height());
+}
+
 #endif // HAS_D3D12
diff --git a/examples/quick/scenegraph/rendernode/d3d12renderer.h b/examples/quick/scenegraph/rendernode/d3d12renderer.h
index a81db0f398..f13a1d451c 100644
--- a/examples/quick/scenegraph/rendernode/d3d12renderer.h
+++ b/examples/quick/scenegraph/rendernode/d3d12renderer.h
@@ -60,6 +60,8 @@ public:
 
     void render(const RenderState *state) override;
     void releaseResources() override;
+    RenderingFlags flags() const override;
+    QRectF rect() const override;
 
 private:
     void init();
diff --git a/examples/quick/scenegraph/rendernode/openglrenderer.cpp b/examples/quick/scenegraph/rendernode/openglrenderer.cpp
index 33c59198b8..3de864b7b9 100644
--- a/examples/quick/scenegraph/rendernode/openglrenderer.cpp
+++ b/examples/quick/scenegraph/rendernode/openglrenderer.cpp
@@ -151,4 +151,14 @@ QSGRenderNode::StateFlags OpenGLRenderNode::changedStates() const
     return BlendState;
 }
 
+QSGRenderNode::RenderingFlags OpenGLRenderNode::flags() const
+{
+    return BoundedRectRendering | DepthAwareRendering;
+}
+
+QRectF OpenGLRenderNode::rect() const
+{
+    return QRect(0, 0, m_item->width(), m_item->height());
+}
+
 #endif // QT_NO_OPENGL
diff --git a/examples/quick/scenegraph/rendernode/openglrenderer.h b/examples/quick/scenegraph/rendernode/openglrenderer.h
index 28d528e617..1ee6350218 100644
--- a/examples/quick/scenegraph/rendernode/openglrenderer.h
+++ b/examples/quick/scenegraph/rendernode/openglrenderer.h
@@ -58,6 +58,8 @@ public:
     void render(const RenderState *state) override;
     void releaseResources() override;
     StateFlags changedStates() const override;
+    RenderingFlags flags() const override;
+    QRectF rect() const override;
 
 private:
     void init();
diff --git a/examples/quick/scenegraph/rendernode/softwarerenderer.cpp b/examples/quick/scenegraph/rendernode/softwarerenderer.cpp
index 2f11c56f29..06e406874a 100644
--- a/examples/quick/scenegraph/rendernode/softwarerenderer.cpp
+++ b/examples/quick/scenegraph/rendernode/softwarerenderer.cpp
@@ -68,7 +68,7 @@ void SoftwareRenderNode::render(const RenderState *renderState)
     p->setOpacity(inheritedOpacity());
     const QRegion *clipRegion = renderState->clipRegion();
     if (clipRegion && !clipRegion->isEmpty())
-        p->setClipRegion(*clipRegion);
+        p->setClipRegion(*clipRegion, Qt::IntersectClip);
 
     const QPointF p0(m_item->width() - 1, m_item->height() - 1);
     const QPointF p1(0, 0);
@@ -89,3 +89,13 @@ QSGRenderNode::StateFlags SoftwareRenderNode::changedStates() const
 {
     return 0;
 }
+
+QSGRenderNode::RenderingFlags SoftwareRenderNode::flags() const
+{
+    return BoundedRectRendering;
+}
+
+QRectF SoftwareRenderNode::rect() const
+{
+    return QRect(0, 0, m_item->width(), m_item->height());
+}
diff --git a/examples/quick/scenegraph/rendernode/softwarerenderer.h b/examples/quick/scenegraph/rendernode/softwarerenderer.h
index 60036f96a1..5b2a475ed8 100644
--- a/examples/quick/scenegraph/rendernode/softwarerenderer.h
+++ b/examples/quick/scenegraph/rendernode/softwarerenderer.h
@@ -54,6 +54,8 @@ public:
     void render(const RenderState *state) override;
     void releaseResources() override;
     StateFlags changedStates() const override;
+    RenderingFlags flags() const override;
+    QRectF rect() const override;
 
 private:
     QQuickItem *m_item;