Golfing Greats/OutRun back on Analogue Pocket

History

In the late 1980s and early 1990s, the arcade market saw a surge of “realistic sports simulations,” with SEGA’s Dynamic Golf and Atari/Midway’s Golden Tee Golf enjoying great popularity. In 1991, Konami released Golfing Greats, powered by its uniquely developed PSAC2 graphics effects chip, which brought a virtual 3D golf experience to life. Thanks to this processing power, players could view vast golf courses from multiple perspectives, delivering speed, depth, and a sense of scale that made its visuals truly impressive. The atmosphere was further enhanced by the cheers of the gallery and the chirping of wild birds. Although the board featured no FM sound source and relied solely on Konami’s original PCM playback chip, it played a vital role in heightening the sense of realism.

Technical Details

This game uses the same 3D projection chip as Run'n Gun. Konami called this chip PSAC. This chip output is very similar if not equal to what can be done with Super Nintendo famous mode 7. The internal operation may differ with SNES though. The way the PSAC operates is by scanning a 2D tile map in arbitrary ways. Normal 2D games will let you see a window inside a larger tile map. But this window X/Y axes are parallel to the tile map X/Y axes and there is a 1:1 correspondence with the lines. You basically choose where to start the scan and then you see a fixed size 1:1 copy of that tile map to the screen. However, for the PSAC there is an arbitrary zoom and arbitrary orientation applied to the window. I think anything that you see on a SNES would be possible with this PSAC chip.

Konami used a huge tilemap as the PSAC input. This tilemap does not fit inside the FPGAs because of its gigantic size and having it in the SDRAM memories adds so much latency in memory reads that the screen cannot be rendered in time. The solution has been to convert the original tilemap based on 8x8 pixel tiles to a 32x32 pixel tiles. This is done on the fly as you start the core. The new tilemap takes less memory and fits inside the MiSTer/SiDi128 FPGA. It still does not fit in the Pocket's FPGA so for the first time we have had to recur to the external SRAM memory.

All this struggle with the tilemap has taken a few weeks of work. Some people would question why we spent so much time on a game that may not be that popular. But all this is development experience we gain and new features that we add to the framework. So this will accelerate work on future games.

When the game boots up, you may still see PSAC generated backgrounds poorly rendered for a couple of seconds. This occurs because the tilemap re-encoding is still in progress. In a future release we will delay the game start a bit so the re-encoding is completely finished by the time any PSAC video is displayed.

Another difficulty with the PSAC is that depending on the scene, the small SDRAM cache used in JTCORES cannot be leveraged and the full horizontal line is not read in time. This results in a bit of noise on the right hand side of the screen on a few scenes. We need to increase the SDRAM clock to fix this. Again, this will be done on the next update.

Finally, as part of this work I found out why the sound for this game was broken on MAME and I fixed it.

Technical Quirks

The game has a way to determine what the field looks like after projecting it onto the screen by a hardware mechanism. This is used to determine where the ball falls. This is not correctly implemented on MAME. I still have not had the time to report how to fix this to the MAME team.

The original game has a layer priority problem where trees in the background will hide the field map on the left of the screen. This is a genuine bug present on the PCB.

Other Updates

• OutRun core is back for Analogue Pocket users. A long standing problem was finally understood and solved. This was also a prerequisite for both Run'n Gun and CPS3 cores

• We have published our Surprise Attack schematics on JTBIN

• The shade effect on Surprise Attack affected the white color on glass walls too, but it should not. This is fixed. As a side benefit, another shade problem on the X-Men core is now fixed too