Blank preview on MK4S when gCode downloaded from Linux RPi5

[dwprod38]

I've noticed a blank preview on MK4S screen panel when gCode sent from PrusaSlicer (version 2.9.4) installed on Linux RPi5 and preview on MK4S screen panel when gCode sent from PrusaSlicer (version 2.9.4) installed on Win or Mac.

Something in compiled source code to ARM Linux for RPi5 create a thumbnail generation corruption in gCode file...

• Hardware: Raspberry Pi 5 8GB
• OS Raspbian BookWorms
• PrusaSlicer-2.9.4 ARM AppImage

Despite blank preview picture, the printing works fine.

Cheers

[davidk]

This might be due to OpenGL ES not being expected since the embedded QOI previews are generated from snapshots of the build plate.

OpenGL ES is broken (but necessary for the Pi) - a workaround would be to build without -DSLIC3R_OPENGL_ES=1 and run the AppImage with LIBGL_ALWAYS_SOFTWARE=1 to force software rendering (otherwise OpenGL 3.2 is used, which isn't available and results in a blank build platform preview on a Pi).

[dwprod38]

Hello @davidk

I've checked OpenGl V3.1 works fine on RPi5 as shown below...

I've tried to build from source with suppressed line "-DSLIC3R_OPENGL_ES=1" but fail a the end as shown below:

I don't understand by "run the AppImage with LIBGL_ALWAYS_SOFTWARE=1 to force software rendering" : how include "LIBGL_ALWAYS_SOFTWARE=1" in command line to launch AppImage ? (didn't works as shown below)

Regards

[davidk]

A modified build with -DSLIC3R_OPENGL_ES=1 removed is available here: https://github.com/davidk/PrusaSlicer-ARM.AppImage/actions/runs/20904217857

To run after downloading, unzip the file and execute the following:

$ export LIBGL_ALWAYS_SOFTWARE=1
$ ./PrusaSlicer-2.9.4-aarch64-full.AppImage

This will be slower as it is not using hardware acceleration.. Running without LIBGL_ALWAYS_SOFTWARE results in a blank build platform as OpenGL 3.2 is required. It may be possible to do instead MESA_GL_VERSION_OVERRIDE=3.2 but I have not tested this end to end

[dwprod38]

A modified build with -DSLIC3R_OPENGL_ES=1 removed is available here: https://github.com/davidk/PrusaSlicer-ARM.AppImage/actions/runs/20904217857

To run after downloading, unzip the file and execute the following:

$ export LIBGL_ALWAYS_SOFTWARE=1
$ ./PrusaSlicer-2.9.4-aarch64-full.AppImage

This will be slower as it is not using hardware acceleration.. Running without LIBGL_ALWAYS_SOFTWARE results in a blank build platform as OpenGL 3.2 is required. It may be possible to do instead MESA_GL_VERSION_OVERRIDE=3.2 but I have not tested this end to end

Good job David : the exported gcode file with RPi5 works like a charm. The thumbnail picture is correctly displayed in PrusaConnect and on MK4S screen !

Regards