Improve View3D docs about performance benefits

Change-Id: I18a8470fd54272d5f8f08f0658edce42d9798055
Reviewed-by: Christian Stromme <christian.stromme@qt.io>

1 files changed, 12 insertions, 3 deletions

diff --git a/src/imports/studio3d/q3dsstudio3dview.cpp b/src/imports/studio3d/q3dsstudio3dview.cpp
index 14b8434..855f75e 100644
--- a/src/imports/studio3d/q3dsstudio3dview.cpp
+++ b/src/imports/studio3d/q3dsstudio3dview.cpp
@@ -57,12 +57,21 @@ QT_BEGIN_NAMESPACE
     composition is done by the means of Qt Quick, by positioning, sizing and
     blending the View3D items.
 
+    \note View3D can improve performance significantly (the gain depends on the
+    size of the item) for Qt 3D Studio presentations with a single layer in the
+    scene. This is because the unnecessary - but with \l Studio3D implicit -
+    composition step (rendering the layer into a texture and then blending it
+    with the output from other layers) is avoided. This can be especially
+    important on devices with mobile/embedded GPUs that have more limited
+    fragment processing power.
+
     \note Views are also useful to avoid the resource and performance
     implications of having multiple \l Studio3D items in a scene: Instead of
     multiple \l Studio3D items (and thus running multiple instances of 3D
-    engines in parallel), have only one presentation, represented by a \l
-    Studio3D item, and display and compose the contents of the layers via
-    separate View3D items.
+    engines in parallel), have only one presentation, represented by a
+    \l Studio3D item, and display and compose the contents of the layers via
+    separate View3D items. This way there is only one 3D engine running under
+    the hood, taking care of the contents of all the View3D items.
 
     \section2 Example usage