On Thu, 20 Nov 2025 11:37:53 GMT, Ambarish Rapte <[email protected]> wrote:
> **Issue:**
> With metal pipeline, frame tearing is observed when scrolling the content.
> Perform small fling gesture scrolls for observing the issue, the issue
> occurs/observed easily when scroll is coming to and end.
>
> **Cause:**
> vsync is not enabled for metal pipeline.
>
> **Fix:**
> 1. Enable vsync for metal pipeline. The vsync shall be enabled by default. It
> can be disabled with `-Djavafx.animation.fullspeed=true`.
> 2. Synchronize the access to offline render target texture.
> 2.1 The `GlassMTLFrameBufferObject._texture` object is created and destroyed
> by **QuantumRenderer** thread, and
> 2.2 `GlassMTLFrameBufferObject._texture` is also accessed on **Appkit**
> thread through function `GlassLayerMTL.blitToScreen()`
> 2.3 NSLock is created to synchronize the acess
> 2.4 Without this synchronization, a crash could occur in scenario when JavaFX
> app window is moved between screens that differ in refresh rate.
>
> **Verification:**
> 1. Test that no frame tearing is observed, when scrolling(easy to test with
> small fling scrolls)
> 2. Test no issue observed when moving window among screens.
> 3. General sanity testing of UI.
>
> **Test:**
> A unit or system test is not possible for this scenario.
modules/javafx.graphics/src/main/native-glass/mac/GlassLayerMTL.m line 155:
> 153: // {
> 154: // The texture is locked, either being created/destroyed or
> being encoded into BlitEncoder
> 155: // hence the frame could be dropped.
Just a curiosity question, but would we have a possibility to wait for the
texture to become available to us instead of dropping the frame?
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PR Review Comment: https://git.openjdk.org/jfx/pull/1978#discussion_r2556015087
