Bug 76397 - [IVB/HSW] ogl-samples: gl-320-fbo-layered render error with “grid”
Summary: [IVB/HSW] ogl-samples: gl-320-fbo-layered render error with “grid”
Alias: None
Product: Mesa
Classification: Unclassified
Component: Drivers/DRI/i965 (show other bugs)
Version: unspecified
Hardware: All Linux (All)
: medium normal
Assignee: Ian Romanick
QA Contact: Intel 3D Bugs Mailing List
Depends on:
Reported: 2014-03-20 11:46 UTC by meng
Modified: 2014-04-02 09:35 UTC (History)
3 users (show)

See Also:
i915 platform:
i915 features:

render error png for gl-320-fbo-layered (13.12 KB, image/png)
2014-03-20 11:48 UTC, meng

Description meng 2014-03-20 11:46:57 UTC
System Environment:
Mesa:  (master)eaf9affa5ec9c5fd919e4207ab80b4677650ac67
Xserver:(master)xorg-server- Xf86_video_intel:	
Kernel:	(drm-intel-nightly) git-ec45c7

Bug detailed description:
It’s not a regression, firstly test ogl-samples.

 - build: https://github.com/g-truc/ogl-samples

Test-case: gl-320-fbo-layered

Expected outcome:

Actual outcome:
visible grid is white instead of black. Please see error.png attached.
Comment 1 meng 2014-03-20 11:48:21 UTC
Created attachment 96097 [details]
render error png for gl-320-fbo-layered
Comment 2 Iago Toral 2014-04-01 11:34:15 UTC
Looking at the code in the test I think the result obtained in Mesa is correct and the reference expected output is actually wrong.

When rendering to the main framebuffer, the test first clears it in *white* like this:

glBindFramebuffer(GL_FRAMEBUFFER, 0);
glClearBufferfv(GL_COLOR, 0, &glm::vec4(1.0f, 1.0f, 1.0f, 1.0f)[0]);

Then renders to it with 4 different viewports with these configurations:

Viewport 0: x=2,   y=2,   w=316, h=236
Viewport 1: x=322, y=1,   w=316, h=236
Viewport 2: x=322, y=242, w=316, h=236
Viewport 3: x=2,   y=242, w=316, h=236

So obviously, there are gaps that are not being rendered and will show in the color in which the color buffer was cleared (i.e. white).

I'll ping the developers of ogl-samples about this.
Comment 3 Iago Toral 2014-04-02 06:18:02 UTC
From the og-samples developers:

"True, it seems that I forgot to update the reference image."

I filed an issue in github so they can track and fix this at some point in ogl-samples. The bug in Mesa should be closed.

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