When I saw video from an arcade PCB I guessed that the shimmer was something do with what I called "spooky" sprites which is something I encountered when I made some tests for sprite positioning and scaling. I ignored it at the time because I hadn't seen any games use it.

The latest version of the Taito F2 core fixes the shadows in PuLiRuLa so they "shimmer" like you see in the video. The shadows are just the character sprites drawn with a black color palette and scaled down vertically. So what makes them shimmer?

I've sold out of PicoROMs. I made 150 and sold 130. I'm surprised I managed to sell so many because I think it's pretty niche. I've no idea what people are using them for, so if you bought some and you are using them, please let me know!

The TC0360PRI is used in the Taito F2 and several other boards. I prioritizes/mixes up to 3 12-bit color inputs. It has a few different "blend" modes for combining the inputs and some flags for those modes. I built a little test screen so I could test all the different parameters on real hardware.

What does it sound like? Amazing. All the beep, bloops and csssschks you could hope for. I captured this audio through the supergun and ran the same test on the core on the DE-10 and captured it's output using a HDMI capture device, then compared them using MDFourier.

Having your own code running on hardware and the simulator allows narrow it down to the bare essentials. Really useful when you just want to see that first image on screen to keep yourself motivated.

I damaged a Final Blow board almost two years ago and that's what motivated me to develop the PicoROM. I used it through out development to build small isolated test cases that I could run on real hardware and in the simulator and compare the results.

Robert Peip uses save states extensively so I knew they would be useful, but I never appreciated just how useful. Simulation is slow, about 1fps, so being able to jump to a particular point in time is a huge time saving. Being able to save a state on the DE-10 and load it in the sim is massive!

I took inspiration from @mrjimmystones.bsky.social and built my own verilator-based simulator. This allows for significantly faster compile times, 10 seconds vs 13 minutes. It makes it possible to trace the entire state of the system at any time.

A month ago I started working on an FPGA core for Taito's Final Blow, the first game on their F2 arcade system. Yesterday I had it running on the #MiSTerFPGA with all major systems in place. Lots of bugs left to fix, but the hardest parts are done.