After reviewing Bill Budge's Apple II demo, was questioning the lion kingdom's choices in life.  It was just a mane hair faster than glxgears.  The Apple II only did 280x192.  Obviously, he could bake all the 2D coordinates while glxgears had to recalculate all of them to be interactive.  He accessed all 280 columns while lions had to limit it to 256 to get it as fast as it was.  The slowest step for lions was the line drawing routine.  The only other thing which might have sped that up is just blitting predrawn bitmaps into the changing regions of the screen.  The giveaway was how only small parts of the screen were animated.  That would have been the ultimate speedup but not been true 3D rendering in realtime.

Glxgears could go faster if it prerendered all the bitmaps, every time the user moved it.  The memory usage would be problematic.  It could encode each line as a series of precalculated OR operations. 

The budge graphics library is available in source form.  It might be smarter to port it to C64 than invest any more in the lion demo or it could be that orthographic projection with a few more table lookups is the answer.  The manetainer said it really does all the line drawing & transformations in realtime.

https://6502disassembly.com/a2-budge3d/

Pondered going to VCF-west & trying to get someone to run glxgears on a real C64 but the cost would be $40 to get in + over $20 in driving + unknown parking.  In lieu of the Budge revelation, it would totally not be worth it.  There was nothing else in the VCF part worth viewing.  The mane thing in the museum would be the wiring inside the cray.  The lion kingdom might have more demos beyond glxgears, someday.  Seeing things run on period hardware is still a borderline goal.

Another problem with running demos from an SD card is the SD2IEC drive would be much faster than historic reality, ignoring all the seeks.  It really needs a pi1541 or real drive to be worth running some other demos.  At minimum, the lion kingdom would bring a pi1541 to a convention & try it.