OpenGL errors rendering transparency on mesa

Development
1

Hi, I’ve posted a question 2 weeks ago in the Support category but did not get a response that got me much further, so I’m trying on Development. I am trying to render transparency with VTK 9.0.1 on Mesa 18.3.4 (also observed on 20.1.8) with a very simple python script (see earlier post) but any transparent object is not rendered at all, and heaps of OpenGL related errors are reported by VTK. I don’t know how to interpret those errors or how to proceed.

Today I enabled debugging in Mesa with MESA_DEBUG=1 which appears to confirm that it get erroneous input from VTK (see mesa-18.3.4-trace.out (8.7 KB))

I would appreciate any help debugging these errors as it is blocking our migration from vtk8.1.1 to vtk9.

Thank you very much.

Andreas

2

I’ve been debugging my VTK9.0.1 and found that the vtkOpenGLState fails to initialize the TextureInternalFormats for VTK_FLOAT.

image

Seeing that 8.1.1 has similar code something else must have changed in between I suppose.

I tried setting the MESA_GL_VERSION_OVERRIDE but then I get

vtkOpenGLState.cxx:505 WARN| Error glBindFramebuffer1 OpenGL errors detected
0 : (1286) Invalid framebuffer operation

and nothing gets rendered anymore.

Googling around a bit I found an article that suggests that mesa should have the GL_ARB_texture_float extension enabled.

3

I get something similar; I can confirm that I only get the following error output if I enable transparency - if both actors are fully opaque then Mesa doesn’t report any errors:

$ MESA_DEBUG=1 python main.py
Mesa: User error: GL_INVALID_VALUE in glTexImage2D(internalFormat=GL_NONE)
Mesa: 1 similar GL_INVALID_VALUE errors
Mesa: User error: GL_INVALID_FRAMEBUFFER_OPERATION in glClear(incomplete framebuffer)
Mesa: User error: GL_INVALID_FRAMEBUFFER_OPERATION in glBlitFramebuffer(incomplete draw/read buffers)
Mesa: User error: GL_INVALID_FRAMEBUFFER_OPERATION in glDrawRangeElements(incomplete framebuffer)
Mesa: User error: GL_INVALID_FRAMEBUFFER_OPERATION in glClear(incomplete framebuffer)
Mesa: User error: GL_INVALID_FRAMEBUFFER_OPERATION in glBlitFramebuffer(incomplete draw/read buffers)
Mesa: User error: GL_INVALID_FRAMEBUFFER_OPERATION in glDrawRangeElements(incomplete framebuffer)
4

I suspect your mesa doesn’t have the proper GL extension too. Try:

glxinfo | grep GL_ARB_texture_float

Mesa 18.3.4 should have it enabled but the version on our CentOS 7 doesn’t have it either.

5

It’s true; I only have these that I assume are OpenGL ES-related:

$ glxinfo | grep -i texture_float
    GL_OES_texture_float_linear, GL_OES_texture_half_float_linear