pouët.net

oerg866 information 82 glöps

• general:
• level: user
• personal:
• first name: eric
• last name: you dont want to know
• cdcs:
• cdc #1: Eon by The Black Lotus [web]

• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• Hey Oswald,
  
  
  Quote:

  Cool presentation indeed, but as a coder I must say,it doesnt really looks like its stretching the hardware.

  
  
  Except this is not the Amiga where you get half a dozen custom chips and easy graphic modes that take all the load off you!
  
  
  Quote:

  This console can display 80 sprites by spec, so the "bob" parts doesnt seem to do much than using whats already there.

  
  
  80 sprites by spec. Yeah, I wish. Strict limit per scan line + 80 if they're 8x8 and scattered all over the screen. Just because the hardware has memory for 80 sprite definitions doesn't mean it can display them all.
  
  
  Quote:

  Twisters, must be easy to change the gfx pointer per line, & 64kb & 64 colors for twister gfx should allow for something nicer. nice touch with doing 2 tho.

  
  
  There is no "GFX pointer". What's a GFX pointer? Yes must be easy. Must also be easy to render the shadows by changing some "GFX pointer".
  
  Yes, 64kb. Which holds 16KB of nametable definitions, the horizontal scroll parameters (240*2 words), the sprite definitions (80*8 bytes).
  
  Yes, 64 colors. Actually only 61, since you only have one BG color, not three, for 4 palettes. Actually limited to one palette per 8x8 block. And you have four. Good luck rewriting these every line.....
  
  
  Quote:

  rotating wheel, now this is interesting, looks like the HW helps to rotate some amount then change of gfx. probably best part technically.

  
  
  Yes. Looks like the HW helps to rotate some amount. Except this isn't the SNES, and there is no rotation HW at all.
  
  
  Quote:

  chessboard: cool looking screen, HW seems to be used like to its 30% potential.

  
  
  Yeah, probably only like 30%. And that text must be prerendered, too. (Hint: sarcasm)
  
  
  Quote:

  filled cube: very low accuracy rotation for a cpu with 32 bit and multiplication for free. and why is the damn thing so small?

  
  Multiplication is free.. um... no it's not. I would hardly call an instruction that eats 70 cycles "free".
  
  And remember the display is built using a nametable that defines what 8x8 chars that reside in VRAM are displayed where. This is not an amiga. We can't just render stuff at will without adding a huge amount of wasted cycles to find out where to write things.
  
  And remember, VRAM isn't mapped to address space. You either DMA (which halts the CPU... thanks SEGA) or bang data through a port. Either way it's slow as hell.
  
  
  Quote:

  oh and the interference, built in playfield + that brightness HW mode "magic".

  
  
  Nope, completely wrong. It's a separate playfield + two layers of sprites. No "fancy brightness mode" (which is called shadow & highlight by the way and can't be applied here).
  
  Did I mention that you need to interleave your sound code with timer checks wherever you are to check if you need to push a sample? While managing 9 other sound channels? I'm sure that's also done by modyfing "some pointers" :)
  
  Seriously if you don't know how hard it is to get anything going on a tile-based graphics system (no fancy bitmap modes like on amiga), please don't write dumb things like these :)
  
  And while we never said this is the most technically advanced demo on megadrive, I'm ready to stuff my mouth if you write an MD demo that trashes this one technically. Free beer included!
  
  But I'm sure it must be nicer to read docs and say "well this can do better" without having to prove it...
  
  But after all, it's just
  
  "modifying a gfx pointer" :)
  
  Have a nice day!
• isokadded on the 2013-08-26 11:55:42
• diskmag Commodore 64 Scene World #21 by People Of Liberty [web] & Scene World Magazine [web]
• yay :)
• rulezadded on the 2013-08-24 13:08:30
• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• Quote:

  How about that rotating wheel? I don't remember megadrive had such a rotation chip

  
  
  It doesn't :-)
• isokadded on the 2013-08-22 09:40:28
• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• Nooo! Gens is a terrible emulator, especially when it comes to sound ;)
  
  Here use this one: http://oerg866.mdscene.net/.stuff/retroarch_titan.zip
  
  run titan.bat
  
  It's the best emulator for this demo ATM.... (retroarch + genesis plus GX)
• isokadded on the 2013-08-21 09:37:36
• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• Yes it's a side effect. every time you update color memory it outputs a pixel to the screen of the color you just wrote to it. Sucks, but what can you do :) Also if you don't have an i7 you can use an emualtor called Regen (http://aamirm.hacking-cult.org) which we used too and only one part is broken :)
• isokadded on the 2013-08-18 22:23:08
• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• Akira: Sorry, PAL only :)
• isokadded on the 2013-08-18 22:10:26
• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• OK just checked, Fusion doesn't emulate it well at all ):
• isokadded on the 2013-08-18 22:03:36
• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• the exodus emulator can emulate it pretty well, however its aim is to be cycle exact and have 100% exact timing of all components (not very true yet but it's a good start)... you need a really beefy i7 to run most parts in full speed, sorry... www.exodusemulator.com but i've heard that it runs well in KEGA Fusion too (www.eidolons-inn.net)
• isokadded on the 2013-08-18 21:41:54
• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• Yes and most of the optimisations and fixes we wrote for the music in this demo will be put in the official public source code of Echo as well :)
• isokadded on the 2013-08-18 21:10:54
• demo SEGA Genesis/Mega Drive Overdrive by Titan [web]
• youtube live capture (: http://www.youtube.com/watch?v=T0RfrsCV3uc
• isokadded on the 2013-08-18 04:10:57