Garbage output in Viewport with OpenSubdiv device set to GLSL Compute #45909

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Anshu Arya · 2015-08-26T08:46:16+02:00

Anshu Arya commented

2015-08-26 08:46:16 +02:00

Using OpenSubdiv on an AMD A10-6800K and A10-7850K on Win8.1 or Win10 with OpenSubdiv and compute device GLSL Compute results in garbage output for Dragon blend example. Also results in random artifacts with other scenes. Other compute devices for OpenSubdiv do not show errors.

Example output of "GLSL Transform Feedback" device:

Example output of "GLSL Compute" device:

SystemInfo for A10-6800K: systeminfo.txt

Using OpenSubdiv on an AMD A10-6800K and A10-7850K on Win8.1 or Win10 with OpenSubdiv and compute device GLSL Compute results in garbage output for Dragon blend example. Also results in random artifacts with other scenes. Other compute devices for OpenSubdiv do not show errors. Example output of "GLSL Transform Feedback" device: ![GLSLTransformFeedback.png](https://archive.blender.org/developer/F228065/GLSLTransformFeedback.png) Example output of "GLSL Compute" device: ![GLSLCompute.png](https://archive.blender.org/developer/F228063/GLSLCompute.png) SystemInfo for A10-6800K: [systeminfo.txt](https://archive.blender.org/developer/F228067/systeminfo.txt)

Anshu Arya commented

2015-08-26 08:46:16 +02:00

Changed status to: 'Open'

Sergey Sharybin was assigned by Anshu Arya

2015-08-26 08:46:16 +02:00

Anshu Arya commented

2015-08-26 08:46:16 +02:00

Added subscriber: @anshuarya

blender-admin commented

2015-08-26 12:10:24 +02:00

This issue was referenced by 6ca12d157f

This issue was referenced by 6ca12d157fbfdf1a71a06a87fb5f258ae98ebe02

Sergey Sharybin commented

2015-08-26 12:14:41 +02:00

Changed status from 'Open' to: 'Resolved'

Sergey Sharybin closed this issue

2015-08-26 12:14:41 +02:00

Anshu Arya commented

2015-09-15 20:13:13 +02:00

Forwarding info from Qun Lin:
"It is an application issue. Application forgot to specify the block layout for all shader storage blocks in compute shader.
They assume the default layout is std430. But according to spec, the default layout is shared, which layout is dependent on driver’s implementation, and app should query each member’s offset if they want to use shared layout.
To fix this issue, application only needs to add following line at the beginning of the shader source code:
layout(std430) buffer;
Attached is modified compute shader, in case you need it. With these modified shaders, corruption disappears."

Links to compute shader code referenced above:
https://dl.dropboxusercontent.com/u/3047603/computeshader1.txt
https://dl.dropboxusercontent.com/u/3047603/computeshader2.txt

Forwarding info from Qun Lin: "It is an application issue. Application forgot to specify the block layout for all shader storage blocks in compute shader. They assume the default layout is std430. But according to spec, the default layout is shared, which layout is dependent on driver’s implementation, and app should query each member’s offset if they want to use shared layout. To fix this issue, application only needs to add following line at the beginning of the shader source code: layout(std430) buffer; Attached is modified compute shader, in case you need it. With these modified shaders, corruption disappears." Links to compute shader code referenced above: https://dl.dropboxusercontent.com/u/3047603/computeshader1.txt https://dl.dropboxusercontent.com/u/3047603/computeshader2.txt

Anshu Arya commented

2015-09-24 20:54:17 +02:00

This has been solved by: https://github.com/PixarAnimationStudios/OpenSubdiv/pull/742

When Blender pulls in OpenSubdiv v3.0.3, corruption should be gone.

This has been solved by: https://github.com/PixarAnimationStudios/OpenSubdiv/pull/742 When Blender pulls in OpenSubdiv v3.0.3, corruption should be gone.

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Reference: blender/blender#45909

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Garbage output in Viewport with OpenSubdiv device set to GLSL Compute #45909