598538 - Applying a rotate transform changes dimensions with GL layers on Mac

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Boris Zbarsky [:bzbarsky]]

Attachment: Testcase

BUILD: Current tip build (or today's nightly, pick your poison)

STEPS TO REPRODUCE:
1)  Start the browser with MOZ_ACCELERATED=1
2)  Load the attached testcase
3)  Hover over the green square

EXPECTED RESULTS: The square rotates 720 degrees clockwise and stays a square the whole time

ACTUAL RESULTS: The square becomes decidedly nonsquare when it's not axis-aligned.

Rendering without MOZ_ACCELERATED=1 is correct

Comment 1

[Matt Woodrow (:mattwoodrow)]

Attachment: Fix

When we have transformed content, we can end up needing a temporary surface larger than the window size.

gDumpPaintList output showing a window of size 973x715 and a ContainerLayer with a visible area size of 1106x1124 - http://pastebin.mozilla.org/795640

This patch resets the viewport rect (and tells the manager to setup the view matrices) when we create a temporary FBO.

Comment 2

[Joe Drew (not getting mail)]

There's an extra fViewport in ContainerLayerOGL::RenderLayer, which isn't needed because SetupPipeline also does fViewport.

Comment 3

[Matt Woodrow (:mattwoodrow)]

Attachment: Removed extra fViewport call.

We still end up calling fViewport twice when resetting the viewport, but this seems cleaner than not using PushViewport

Comment 4

[Joe Drew (not getting mail)]

http://hg.mozilla.org/mozilla-central/rev/879acd43522e

Comment 5

[Boris Zbarsky [:bzbarsky]]

Attachment: Testcase that really shows this rocking

This plus bug 598143 being fixed makes this testcase happy (and fast!).