MegaDOOM (Sega Mega Drive/Genesis) - [Demo by James Howard] - HD Graphics & Stereo Sound 

Amen I completely agree 👍, 32X was a dud , my SNES Doom was more impressive to me than the disappointing 32X , I sold away my 32X shortly after purchasing Doom 32X 😂🎉 Virtua Fighter was only good title on 32X , , felt scammed by SEGA ,so glad I got rid of it , , ,

no. 32x is good@@wyldelf2685

⁠@@wyldelf2685Star Wars Arcade was a fun title, Doom gave me immense joy because my family was too poor to have a computer. I got a lot of enjoyment out of it.

@@mikeg2491 yes we never had home computer growing up either , , you need to enjoy a few hours playing SNES DOOM , , ,then a few hours Playing Panasonic 3DO Doom , , and finally Sony PlayStation Doom/final Doom , , ,these have same level structure and enemies , ,it will give you proper overall perspective on Doom , ,😸👍👍

​@@wyldelf2685the SNES version was pretty impressive. Not only did it have nice graphics for the hardware the music and sound was great. The 32x version was kinda junky.

I think the challenge and the fun it's to make it run without any additional hardware. The programmer said it was a lot of room to improve it so yeah.

​@@danmakumanAn entirely understandable point of view. Nonetheless, the SVP chip is legitimate Genesis hardware, and a programming challenge in and of itself. Squeezing performance efficiency out of the SVP is an as yet unpicked fruit for retro coders.

Wasn't there originally supposed to be SVP Virtua Fighter, Virtua Cop and Daytona ?

or the x32 slot on it too

problem is the price and availability of the mega pro everdrive im still waiting for a chinese clone though i have shelled out on one 210 quid

skilled programmers on megadrive write code in asm because it is faster than c

@@pam8352 No skilled modern Formula 1 drivers because Formula 1 cars are better than older ones? Laborers aren't skilled if they use power tools instead of manual labour? No skilled gamers on modern consoles because they have better controllers than past ones? Using better tools like SGDK doesn't make you less skilled, it allows you to do more with the skills you have. Don't be ignorant.

Adding to the list of consoles that can play DOOM.

Lol

​@@pam8352 depends.

shares techniques

You can read a novel in between each frame too! Multi-tasking is great

it’s very impressive I have the cartridge, I’d like a basic map editor for it like zero tolerance has its shame such a good engine they made can’t be put to use for new ideas

Less a port, more like castle wolfenstein style shooter with a duke 3d skin, it could only do walls on a grid, it wasn't anywhere near as advanced as the doom engine.

Sega 32X version is worse then SNES one

@@dmitryyershoff7938 Yes and no. It had worse music, but better frame rate, graphics, enemy AI, and the ability to circle strafe.

@@Mechaghostman2 It also had missing enemies, additional missing geometry in the levels, does not have diminishing lighting that fades closer to darkness into the distance, the guns don't light up the environments when they fire, and a couple of other things as I recall.

​@@inceptionaland a good amount of missing levels

@@greensun1334 Because it was built from the Jaguar Version, which was also a cartridge based Console.

Put simply it’s far more complex to code snes games like this unless your some programmer like John carmack it’s the custom hardware and software it uses as usual Nintendo being dogmatic and exclusive

Also you can run full dos pc doom through a megadrive using that special everdrive pro cartridge which does the work but that option is still very clever the fx chip can’t do that obviously so I guess the sega won out for thinking ahead and being more versatile

​@@BFFoundation-ke2pi The 68000 is more powerful than the 65C816 and can be overlooked to 10.7MHz. The DMA "blast processing" is also about 2x the bandwidth.

as it was with wolf3d. That port is just perfect.

I share your sentiments!

@KRAFTWERK2K6 The bandwidth here isn't really the shortcoming. What kills us on the frame rate on this project? It's how difficult it is to calculate the start and end points for the lines. I've gone over this code.A dozen times, and there are a few performers hack left to be performed on this engine.

There are roms called md+ that use cd music no need for sega cd no more

Don't need sega cd there are md+ cd roms

The 12.5MHz CPU on the Sega CD could really make this project work. The Sega CD could also handle all of the sound, music, and scaling of monsters and rockets.

Look for the Doom 32X Resurrection port.

DOOM Resurrection uses the 32X, but progress is stalled. I believe that the Sega CD can be used to handle all of the audio.

And no deadlines whatsoever

​@Matzu-Music Those guys were able to work full time on their projects and had backing by their own company, and uh SEGA. We're really on our own.

True, but we need Z80 programmers to get that 5-600,000 IPS out of that CPU, and few people know how to optimize code for it, aside from a few peephole optimizations. And I only remember a handful. Better would be to use LUTs for the hard number crunching and get some 68000 experts to go over the four critical functions.

Some official ports (such as Super Nintendo and 3DO) were even worse, but people played them.

From the author: "In the BSP renderer I rewrote several 32-bit operations as 16-bit ones to better suit the 68000 CPU but it is all in C and a bit slow. I reckon a 68k ASM wizard could have made a DOOM port for the Megadrive / Genesis back in the day just like the SNES port from randallinden."

True, but physics can be scaled down and amount of enemies can be reduced. Also, you can use a large rom cart to store precalculations of all of the math. Back in the days that would have been too expensive. He is not doing that yet.

You guys can all jump aboard the get hub project and take a look at how things are done. You can even just leave a comment or read some of the ideas that we've written.

Not the same experience. A bit more tweaks could get us up to 6-10fps, and we've discussed using the VDP more to get even higher frame rates.

The gap is even wider, as the superFX just do more per clock cycle, specially when talking about multiplication operations and drawing pixels on the right format. The superFX is equivalent to a 68000 running at 30Mhz or something.

@@dan_loup nah it can only run at the designed clock speed. but it does specialize at different tasks. Idk how old you are but it's the Pentium II could play DVD discs but no amount of horse power could early pC brute force that ability.

Portugues? Italiano? Esperamos que si.

With some programmers who know how to use the DMA, VDP features, and code for 68000, I'm pretty sure that we could beat 10fps.

DMA can draw vertical strips, and you don't have to increment by one. There's a register where you can choose a different value, and you can change that value at runtime while you're drawing the line.

​​​@@MaxAbramson3ah I lost my message but it went to the root. Yes the issue with DMA is that it copies from memory. Which means the CPU has to write the strips to memory first. I just propose to write it directly to the VDP instead. Of course VDP has slow 8 bit access and the VDP is bandwidth limited, but since the texture coordinate must be calculated and a texel fetched I don't think the 68000 will write too fast. DMA solution is interesting when you write to a framebuffer first if you have to deal with transparencies or horizontal fills. But that's not needed for a simple Doom like engine.

@@what9418 20KB frame buffer in VRAM can be written to using both the CPU and DMA. DMA bandwidth is about 4-5x that of the 68000 MOVEM.w and MOVEM.l, but has some limitations. The existing engine writes to RAM, then moves the final result to VRAM, but I believe that we can get a 50-70% speedup just going straight to VRAM. And perhaps another 2-3x speedup. Shadow-Highlight Mode could be used to draw lighting and shadows very quickly by the VDP.

@@MaxAbramson3 yeah the highlighting would definitely enable a cheap, lowres lighting solution. It would be a great project to work on.

@what9418 S/H Mode is down to the pixel. It could be artifacty, but getting anywhere near 20fps on the old Genny with no extra Sega CD hardware would be a herculean task. 10-12fps is more realistic.

4MB, IIRC. Genesis carts cam theoretically be up to 15MB.

Don't forget the SVP chip, as it is a lot simpler to implement than the Sega CD's hardware, which has a considerable amount of data bottlenecks to deal with (one of the reasons that the Sonic CD special stages have such a low framerate). The CD32X is arguably in an even worse situation.

SegaCD cpu is already used in some form in latest 32x Doom Resurrection version. Also, since this demo is written in C, i believe a proper ASM optimized version would run twice as fast with stock M68000, of course an SVP version would lead at least 20-30 fps, maybe more. Point is, almost all Sega consoles still have untapped potential to be discovered.

this would have definitely been a system Seller for the Mega CD. Especially since it used only the CPUs, which John Carmack always insisted on.

@@KRAFTWERK2K6 yeah. Plus there’s a 128K mode in the genesis allowing up to 14.8 kilobytes a frame at 60hz or a whopping 34K at 50hz (one of 50hz’s biggest advantages)

@@slashrose3287 oh yeah. Sure Genesis works well with C but when making stuff like this ASM is the way to go Edit: I actually do know 68000. I’ve been doing some tests on Amiga (see my channel) but I could get my environment set up for Genesis too.

DIVU takes 158 cycles on the 68000. DIVS takes 170 cycles. Trigonometric operations can take longer. IIRC, finding points for polygons takes 2301 cycles, limiting the 68000 to 3300 vertices per second or just 1100 triangles per second (or 700 quads). However, we could use LUTs to get several times that, then use the DMA to draw the actual lines forming those, for 10,000+ flat shaded polygons per second. Using 8x8 sprites as textures, we could simply calculate the location and priority of each sprite and draw those 3D objects front to back (Reverse Painters) and still get fairly impressive 3D--almost PS1 quality. Strictly for drawing mostly vertical (and a few horizontal) lines for DOOM, Starfox DMA has shown that we can get 15-20fps on the bone stock Genesis.

Why 8x8 sprites? Div is pretty fast indeed. I'd suggest simple luts for things as 1/Z, inverse tangent, and x/y and scale inputs to fit those luts. Then you can find projection points and scales almost instantly.

@what9418 We definitely went down that rabbit hole. LUTs would probably be 8x8 with one by return, or 64KB. Other LUTs (trigonemtric lookups) would have to be 16-bit with 16-bit result. There doesn't seem to be a big enough speedup on multiplies to justify large LUTs. Even 10x10->8 bit result would consume 1MB out of a maximum of 15MB available. Would definitely appreciate help with the project on GitHub.

@what9418 BTW, DOOM draws vertical lines of texture data from RAM/ROM. Genesis has enough bandwidth to draw about 320x160 at 30fps using the DMA. However, the CPU is rated for 1.3 MIP for everything (offloading some work to the Z80), and calculating the start and stop points is too much work, so LUTs and blank floors/ceilings and other economizations are necessary to get anything near 10fps. I'm reading a book on DOOM engine right now.

Expansion pack?

Muchas gracias.

Bem? Portugues?

@@MaxAbramson3 Brasileiro

@@whopoder Eu no fala. Siento.

Update: There are basically two approaches being looked at on this project, if we've got other Genesis programmers out there: i. Further 68k a C code optimizations for folks out there who know what they're doing or have some knowledge of the Amiga, Atari ST, or other 68k DOOM projects. Possible 50-100% speedup doing these peephole optimizations. ii. Switching to 128KB mode and using the powerful DMA to draw the vertical lines directly to the frame buffer in VRAM. At 320x160 (with 32 lines reserved for the HUD), that would take up 20KB in the VRAM, leaving 20KB for storing textures, then using the very fast 16-bit VRAM Copy function to draw these vertical lines at 60fps. While that latter approach would lead to some really severe cutbacks in the final product, I believe that this high frame rate and large image space will more than make up for the artifacts and missing graphical effects. This approach would also allow us to free up a lot of 68k processing time to handle the complex mathematical calculations (especially trigonometric operations) that are preventing us right now from going really fast.

MegaDoom does for the everdrive pro BUT it involves editing the doom wad IE removing and replacing maps and sprites etc.

23MIPS, IIRC, but only and extra 128KB of RAM.

Could doom wads he run on top of that engine?

Do you have the link to the code?

Yeah, but the cool thing is getting to push the genesis to its absolute hardware limits. There's something really cool about playing that system, imagining what it's really capable of.

That would be a huge project in and of itself. But it sure would look cool if we could do it.

The Genesis has some specialized hardware and 15MB of fast cart ROM that could allow it to beat the Amiga.

There was actually a discussion on a forum. Somewhere about how you might go about making doom on the master system. There might even be a demo.

Qual es?

lol it’s quite authentic looking I think

With some more System 16 hackers, we might be able to get up to the 10-15fps range. However, doing most of the work with the DMA, VDP, and LUTs might get us a small screen at 20-30fps.

But it’s still have that blast processing goodness

for a 16-bit console it’s incredible

@@protocetid It is not. No enemies, no hit detection, no doors. When you add those the frame rate will be what...1 frame per hour.

@@SonySupporter This console cost 150 USD with 1 pack in game in 91, it's the closest price I could find to the launch of Doom. It’s likely the price went down. Doom required a 486 right? "A 486 PC cost users somewhere north of £2,000 (roughly £4,500 today)."

mega everdrive pro runs full pc doom through the mega drive but that’s a cyclone IV fpga. It also has SVP inbuilt

It’s running on base hardware, that in itself is incredible. Heck even the SNES version had to have the Super FX chip to even run it at an insanely low resolution.

We think that about 10fps is possible with this engine.

CPU was made in 1979. DOOM is meant for $2,000 PC from 1994 with 4-8MB of RAM. Genesis has 64KB of RAM.

It's a direct port of the doom engine, so it depends on what you think Doom is. I personally call it 3D with restrictions :)