LLVMpipe Software OpenGL Implementation Picks Up More GL4 Extensions

It's 2019 and OpenGL 4.6 remains the latest version of this once predominant graphics API yet Mesa's Gallium3D LLVMpipe software rasterizer is still only exposing OpenGL 3.3.

LLVMpipe while the default fallback on many Linux desktops in the case of no hardware OpenGL support doesn't receive too much attention these days. At least this weekend Red Hat's David Airlie did contribute a handful of improvements to LLVMpipe for Mesa 19.2.

Newly-enabled extensions for LLVMpipe include ARB_shader_atomic_counters, ARB_shader_storage_buffer_object, ARB_shader_atomic_counter_ops, ARB_shader_atomic_counters, and ARB_shader_storage_buffer_object. It's nice seeing those storage buffer and shader atomic extensions now enabled for this fallback/software GL driver, but still not enough for LLVMpipe to officially advertise any GL4 version.

Blocking LLVMpipe from OpenGL 4.0 remains ARB_gpu_shader5, ARB_sample_shading, and ARB_tessellation_shader support. After that there are a handful of extensions needed before LLVMpipe could theoretically be at OpenGL 4.5 as the next major milestone.

Even with today's increasingly powerful CPUs, LLVMpipe still isn't enough for even really running most vintage games, but can be useful as a fall-back for desktop compositors. Though most desktops don't use much in the way of GL4 functionality, another use-case for LLVMpipe is to be a vendor-neutral OpenGL driver for testing of behavior to which OpenGL 4.x support could come in handy. But for now in Mesa 19.2 it remains at OpenGL 3.3 but at least more GL4 extensions are chipping away.