3D graphics on the P2?

Comments

• localroger Posts: 3,451

  2013-12-23 17:40 edited 2013-12-23 17:40

  Considering they also have C I would consider 6 months to be a long wait for them to port Doom.
• JT Cook Posts: 487

  2013-12-23 20:07 edited 2013-12-23 20:07

  I doubt it, at least not on a stock setup. I think the Propeller 2 has only 128K of ram, where Doom required 4MB.
• pedward Posts: 1,642

  2013-12-23 21:58 edited 2013-12-23 21:58

  The p2 will have 256k of 256bit wide hub ram. It will also have at least 32MB of sdram, with an effective transfer rate of 120-160MB/s or faster.
  
  There are instructions to do texture mapping and rotation. The recent balls demo does texture mapping and rotation.
• Cluso99 Posts: 18,069

  2013-12-23 23:14 edited 2013-12-23 23:14

  pedward wrote: »

  The p2 will have 256k of 256bit wide hub ram. It will also have at least 32MB of sdram, with an effective transfer rate of 120-160MB/s or faster.
  
  There are instructions to do texture mapping and rotation. The recent balls demo does texture mapping and rotation.

  256KB (8k x 256bits) of Hub Ram, but can be accessed as byte/word/long and wide (8 longs).
• Seairth Posts: 2,474

  2013-12-24 05:57 edited 2013-12-24 05:57

  pedward wrote: »

  The p2 will have 256k of 256bit wide hub ram. It will also have at least 32MB of sdram, with an effective transfer rate of 120-160MB/s or faster.
  
  There are instructions to do texture mapping and rotation. The recent balls demo does texture mapping and rotation.

  
  Slight clarification: The P2 won't have 32MB of sdram, but will have support for accessing at least that much externally. I believe the initial board that Parallax will be releasing with the P2 on it will have the external 32MB SDRAM on board as well.
• Coley Posts: 1,108

  2013-12-24 06:04 edited 2013-12-24 06:04

  JT, Speak to Baggers, he has already done a raycasting engine on P2 ;-)
• pedward Posts: 1,642

  2013-12-24 10:07 edited 2013-12-24 10:07

  Seairth wrote: »

  Slight clarification: The P2 won't have 32MB of sdram, but will have support for accessing at least that much externally. I believe the initial board that Parallax will be releasing with the P2 on it will have the external 32MB SDRAM on board as well.

  I forgot to mention it was the reference board they plan to make, which will have a 32MB SDRAM chip on it.
• localroger Posts: 3,451

  2013-12-24 14:03 edited 2013-12-24 14:03

  JT Cook wrote: »

  I doubt it, at least not on a stock setup. I think the Propeller 2 has only 128K of ram, where Doom required 4MB.

  
  As others have pointed out the P2 will natively support 32Mb external SDRAM which will be provided on the reference board/module which most of us will be using so as not to mess with the second power supply and teeny tiny package pins. Considering that DOOM ran on a 20 MHz 80386 I'd expect P2 to make quick work of it.
• rod1963 Posts: 752

  2013-12-24 22:00 edited 2013-12-24 22:00

  Never played any of the new ports of Doom, but I know Doom 1 worked better on 486's with 32mb of RAM and a decent VL or PCI video card. With 386's it was just passable.
  
  I think a Doom 1 port is doable, but I just wonder how much rework to the source code and in particular the Doom engine will have to be done, then factor in how to work in a 100MB swap file. Maybe increase the SDRAM to 128MB or 256MB, that shouldn't be too hard?
  
  Might be interesting to look at a Doom port that runs on the Raspberry PI and see how they handle swapping.
• pedward Posts: 1,642

  2013-12-24 23:09 edited 2013-12-24 23:09

  Doom runs in 4MB of ram. There isn't any need to look into swapping or the rPi, it's just a straight up compilation, load, run on Linux. The rPi port was probably about support from SDL. The WAD for a level and everything it needed all fit in 4MB. The bigger challenge with Doom was the protected mode requirement because many people never ran much protected mode software other than Windows. The Dos 4GW did all the heavy lifting for that.
  
  With 32MB of SDRAM and an SD card for a filesystem, I think there are some heavy problems solved. What you have left to worry about is implementing an SDL or similar service layer for the C code to be linked against. Then you have to decide if LMM from SDRAM will work or doing overlays in HUB ram will be the prescription.
• localroger Posts: 3,451

  2013-12-25 18:26 edited 2013-12-25 18:26

  Yeah, the basic peripherals you need are keyboard, video, and sound. Video buffered in Hub RAM will be better than any late 80's era video card (none of them had acceleration in those days, and if they had Doom wouldn't use it.) The single cog running whatever they're calling LMM nowadays from the SDRAM should outperform a 386 or 486 of that era, leaving the other 7 for peripheral emulation. The sound from a P2 should also be superior to what you could get from an x86 box of that era. All in since the whole game has been converted to C, eliminating all the x86 assembly, porting it should be fairly short work once the necessary peripherals are emulated.