Enhance renderpass-related notes in QSGRendererInterface docs

Change-Id: I4285b9cbbc167350dff27906fd4d8ac1474495d4
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
(cherry picked from commit eee26818f198f7d65d44179bb7c38932ec7f0928)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 13 insertions, 5 deletions

diff --git a/src/quick/scenegraph/coreapi/qsgrendererinterface.cpp b/src/quick/scenegraph/coreapi/qsgrendererinterface.cpp
index 7debb0ccf9..5245b6d950 100644
--- a/src/quick/scenegraph/coreapi/qsgrendererinterface.cpp
+++ b/src/quick/scenegraph/coreapi/qsgrendererinterface.cpp
@@ -93,7 +93,11 @@ QT_BEGIN_NAMESPACE
     \value RhiRedirectRenderTarget The resource is a pointer to a
     QRhiTextureRenderTarget instance that is associated with the window and its
     QQuickRenderControl. The value is null when the window is not associated
-    with a QQuickRenderControl. This value was introduced in Qt 6.0.
+    with a QQuickRenderControl. Note that the value always reflects the main
+    texture render target and it does not depend on the Qt Quick scene, meaning
+    it does not take any additional texture-targeting render passes generated
+    by ShaderEffect or QQuickItem layers into account. This value was
+    introduced in Qt 6.0.
 
     \value PhysicalDeviceResource The resource is a pointer to the pysical
     device object used by the scenegraph, when applicable. For example, a
@@ -119,10 +123,14 @@ QT_BEGIN_NAMESPACE
     QVulkanInstance used by the scenegraph, when applicable. This value was
     introduced in Qt 5.14.
 
-    \value RenderPassResource The resource is a pointer to the render pass used
-    by the scenegraph, describing the color and depth/stecil attachments and
-    how they are used. For example, a \c{VkRenderPass *}. This value was
-    introduced in Qt 5.14.
+    \value RenderPassResource The resource is a pointer to the main render pass
+    used by the scenegraph, describing the color and depth/stecil attachments
+    and how they are used. For example, a \c{VkRenderPass *}. Note that the
+    value always reflects the main render target (either the on-screen window
+    or the texture QQuickRenderControl redirects to) and it does not depend on
+    the Qt Quick scene, meaning it does not take any additional
+    texture-targeting render passes generated by ShaderEffect or QQuickItem
+    layers into account. This value was introduced in Qt 5.14.
 
     \value RedirectPaintDevice The resource is a pointer to QPaintDevice instance
     that is associated with the window and its QQuickRenderControl. The value is