Bug 31506

Summary: GLSL: Unsupported opcode 81 (TEX) in vertex shader
Product: Mesa Reporter: Tamas Kemenczy <tkemenczy>
Component: Drivers/DRI/i915Assignee: Eric Anholt <eric>
Status: RESOLVED DUPLICATE QA Contact:
Severity: normal    
Priority: medium    
Version: 7.9   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Attachments: Simple glut program which produces the error

Description Tamas Kemenczy 2010-11-09 10:09:14 UTC
Created attachment 40160 [details]
Simple glut program which produces the error

When accessing a sampler with the built in texture functions in a vertex shader program, the Mesa driver prints the following:

Mesa 7.9-devel implementation error: Unsupported opcode 81 (TEX) in vertex shader
Please report at bugzilla.freedesktop.org

I have attached a minimal GLUT program which reproduces this error on my hardware. The vertex shader samples a grey 2D texture and scales the x value of the vertices of a quad, which should result in a vertical white rectangle.  What happens instead is the exception is printed and the quad remains a square.

System info:
Computer model: Lenovo Thinkpad Edge 13 (Intel)
Graphics card: Intel GMA 4500MHD
Operating system: Ubuntu Maverick Meerkat 10.10 64-bit

OpenGL/GLX version info:
server glx vendor string: SGI
server glx version string: 1.4
client glx vendor string: Mesa Project and SGI
client glx version string: 1.4
GLX version: 1.4
OpenGL vendor string: Tungsten Graphics, Inc
OpenGL renderer string: Mesa DRI Mobile IntelĀ® GM45 Express Chipset GEM 20100330 DEVELOPMENT 
OpenGL version string: 2.1 Mesa 7.9-devel
OpenGL shading language version string: 1.20


The same GLUT program runs correctly on an Intel Macbook Pro with a NVIDIA GeForce 9500M.
Comment 1 Eric Anholt 2010-11-09 11:51:41 UTC
The app in this case is buggy: No vertex shader texture units are required by the spec, so you have to check if there are any before you go using them.  We could probably throw a link error, but we don't.  Resolving as a dupe of the bug for "it would be nice to support vertex texturing", which we plan on doing in the next few months.

*** This bug has been marked as a duplicate of bug 29522 ***

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