Given the "Stage 2 Start" appears in the reflection of the water, I'd like to think the words exist in the game world and John or Eric actually see them floating there and are too jaded to react like "Whatever, not the weirdest thing I've seen today." Please do more SEGA Genesis videos, this was great! :-)

So glad you're back posting again. You're one of my favorite channels. These videos are always so interesting and well edited.

I can never get over how cleverly the game designers exploited the specific hardware in those early games!

5:39 The way you animate the graphics (like in this part) is so stylish and looks so natural that I constantly forget you're actually isolating and animating all of those things yourself. The amount of work that goes into these videos is completely superhuman 😱

99% of this is over my head. I'm not a programmer but I just find it so interesting. Nice to see you covering the Megadrive

One of the most visually impressive games I ever played on Genesis as a kid. Vectorman blew me away too.

Glad to see a video about the SEGA Mega Drive :-) Afaik this game is abusing the SAT caching mechanism (which is not described here but that is really something obscure) for the reflection effect of the level 2, it's why the actual second SAT doesn't exactly fit what we see on the screen. That is, to my knowledge, the only game relying on this feature.

Yaaay a Sega Genesis video, thanks!! Bloodlines has so many cool effects.

I really enjoy the lack of music and the actual captions. While a lot of the stuff you talk about goes right over my head, lack of music makes your voice clear and keeps me from getting distracted. Also, I do enjoy the depth at which you explain things, even if I don't fully understand it all the time.

Whoa. The detail that the water reflection in the second stage actually shows the underside of the platforms blew my mind

After watching this channel and learning the concepts of the era via the SNES series, I decided to make a simple Genesis game. So it's a cool feeling to see this channel tackle a Genesis game, and focus on a feature (H-blank interrupts) I didn't end up using in my experiments.

Rocket Knight uses the same effect on stage 3 but its even even better looking and faster.

Very interesting video! I especially like seeing how the assembly code is written. I hope that I can include some nice effects in my own Castlevania game (although I'll need to work out how to do them in C/SGDK, or else learn some real 68k assembly!).

Very cool graphics at 7:05!

Great technical developer-friendly explanations. Could you please explain the screen effects that occur in Yoshi's Island in world 1-7 while the dizzy effect is active?

My mind was blown seeing those water effects for the first time back then

These videos are awesome for me since i'm learning SGDK to make genesis games and want to know more of the low level capabilities of the genesis.

Glad you're back. You make probably the most impressive educational videos on KZfaq

I didn't expect a Mega Drive game-related video from you :O this is awesome!!!

It's amazing that video games were ever made at all.

Your videos are extraordinary for these topics. Thank you!

The legend came back :)

Welcome to SEGA, don't forget the SNES series!. I like learning from you!

That's some awesome MC68000 stuff!

I'm happy you're covering the Genesis. I grew up with one, and while it may not be as capable as the SNES, graphically speaking, it's still a notable machine (IMO).

Hello videoman I've never seen before, talking about a game I've never played before. This is really cool, and I'm glad to have stumbled in here.

That was a good eye for detail. I always thought the reflection was just the screen flipped. I never noticed the underside reflection of the bridge. Although the underside is just the same as the topside but with the pylon on top.

Genesis denisis what Nintendenesis.

One more SEGA Genesis quirk of interest for the water reflection scene: Changing the sprite table address will not update vertical positions of sprites since those are cached in the VDP itself for faster access. That cache is only updated when VRAM writes to the current location of the sprite table are done. There are basically 3 ways of working around that: (1) likely what the game did - have 2 copies of each sprite in both sprite tables, one copy for the top and one for the reflection, and hide sprites as needed by setting their X positions to be outside of the frame. Disadvantage: those hidden sprites still take bandwidth and with too much action they might not get rendered correctly but that scene does not look like that might be an issue. (2) manually update sprite Y positions after switching tables. Not the best idea since that can take a while and create render glitches too (the VDP reads the Y position twice for each scanline and if an update happens inbetween those reads it might display "glitch pixels" instead) (3) have 2 copies of each sprite in a single sprite table and use a sprite's "link field" (not shown in this video, probably for simplicity) to directly control which sprites the VDP should consider for rendering. Avoids the bandwidth issues of and needs less VRAM than (1) so no idea why the developers did not use (3)...

I really like this series

This was very interesting, great video

RGMechEx: Just uploaded a video! Me: Time that I bingewatch this channel.

Shadow-Highlight mode is the only way here to darken the screen mid-frame, since modifying the palette on Hblank on the Genesis will add garbage pixels to that line. There seem to be no workaround for this. This CRAM (color ram) garbage pixels are always shown at the bottom border (overscan) anyways, but get shifted into view if palette is modified mid-frame. Emulators fail to add these garbage pixels, but you can see them clearly on captured video from real hardware. These are limits of the Genesis VDP.

Rocket Knight Adventures (also by Konami) uses the reflection effect as well.

This is so freaking cool.

If there's one thing I've learned from all these videos about retro game programming, it's that horizontal interrupts can do _anything._ Curing cancer? Horizontal interrupts. Ending world hunger? Horizontal interrupts. Solving the climate crisis? You guessed it--horizontal interrupts.

That Greece level is a Masterpiece.

this is great in terms of the level of detail. But it would be easier to follow if instead of raw hex addresses in the machine code dumps you just labeled what vdp register they correspond to (kind of like you do on the bottom of the screen as you step thru the code). No body really needs or wants to hear you read out hex addresses of hardware registers. Furthermore, if you could put a comment after each line of assembly code saying what it does, it would be way easier to see the overall structure. The video would be a few minutes shorter, but the same level of detail AND easier to follow. Just MHO.

Awesome!!

He's alive!

I had just assumed this was done by changing the palette and offsetting the sprite positions manually, but this would be faster of course.

I'm impressed that they made separate tiles and map data for the reflections.

You could summarize this entire series with “moving stuff during horizontal interrupts”

I'm learning how to code the Genesis and this was quite informative. In the first piece of code you showed, I noticed that no registers were used and it was all either memory-to-memory or immediates to memory - this was likely deliberate to avoid the cost of putting all the registers onto the stack and popping them off before the RTE. Funnily enough this is something that a lot of modern CPUs can't do - your smartphone CANNOT directly move memory to memory without using registers.

The light beam effect uses Hilight/Shade mode on the genesis allowing up to 183 colors from a total of 3,375. Edit: and the darkening thing does the same. Ps, the Genesis doesn’t need interrupts to shift the screen horizontally , it can have a table in VRAM for this.

amazing

So not a palette swap but done via shadow mode in register, and playing with horizontal interrupts. The flips of horizontal and vertical flags, vertical offsets, and a separate Sprite attribute table to jumpy to, I didn't get at all. That's pretty cool!

underrated

I know it's a relatively simple effect visually, but I've always liked they way they rendered robots/enemies in Gunstar Heroes: The Bravo Man, Valvation, and many others were just pieces, or even pieces of pieces, on the sprite sheets, but they were rendered cohesively and even had quite a bit of personality. (My theory is Treasure saw that the Genesis had an odd call system for large sprites, and just used it for... everything they could get their hands on. You could see them dabble with this in Dynamite Headdy, but not quite commit yet. And you know this could go horribly wrong if you've ever watched or played Earnest Evans.) Seven Force is particularly impressive because of it's many forms made from a few parts plus some uniques, and Core Guard System (Dragon/Hammer/Runner) is impressive because it's doing all this, plus being rendered in front of a vertically rotating BG that changes speeds not only each form, but as the boss moves within the phase. Tho not the system of my childhood, your videos on the SNES and it's games really makes me appreciate the games I was limited to as a kid. This channel is amazing! :3

The Split screen in 6-2 feels like an emulation error.

Gotta love inline ASM!

Thank you! This is one of the best videos I've watched regarding Mega Drive/Genesis development. Where did you get the assembly source code for this?

Konami was a beasts of visual effects back then with sega and snes

En Comix Zone tienes efectos muy interesantes, muy buen vídeo 📹 y contenido.

I'd be interested in a general overview of how Genesis graphics work and what all modes and effects it can do.

I love the 68000

Jurassic Park: Rampage Edition - T-REX Chase Scene

What about the sprite flipping effects that are also used in the last stage?I actually saw that those where not emulated well on the old Genecyst DOS emulator.

11 flunked their sats

Always wondered if this was a mode 7 hardware like trick

Think you could do a video on Genesis DMA?

So those 6-2 screen segments may actually be misdrawn due to the code not accounting for a timer delaying when the scanline counts are actually applied? I'd love to see what was intended and if it would make playing 6-2 easier.

when you were going to talk about how the sprites dont clip into each i thought youd say they were masked away.. instead found out the sprite table is even less static than i thought

WHAT ABOUT THE RASTA EFFECT MON?

I wonder if it would be possible to enhance the reflection by also offsetting lines horizontally and doubling or skipping lines to shorten or stretch the reflection and make it a little more realistic. Doing all of that at once alone nevermind with additional highlight and shadow is probably asking too much of the Genesis.

do the water effects in Rocket Knight Adventures use the same routine? as both are Konami games

Would the sprite shenanigans work the same way on an SNES? I've never seen anyone change the OAM in an H-blank before.

I noticed something! Because the Genesis's screen isn't a perfect 4:3, the screen in this vid (and all of its sprites) are ever-so-slightly squished. This is most noticeable in one level you showed in the intro, with the gears that are more oval than circle.

My guess was that they changed the Y scroll on every scanline below the water.

I think I would just put a copy of the sprites rotated and underneath the characters and use masking and opacity stuff to make it look like water reflection

7:09 What's that weird 68000 assembler syntax? For sure, not Motorola's one. It lacks the # sign for constants and introduces ( ) for indirection 😵

Why is the gameplay footage presented in 8:7? Megadrive is 320x224 NTSC.

Great video! I didn't know this game even existed on the Genesis, much less used such interesting effects. I'm curious: I'm sure the same background effects are easily achievable on the SNES using HDMA, but can the sprite splitting be done there as well? I'm trying to remember if there's some reason why manipulating the OAM mid-frame was either impossible or inadvisable.

next crash bandicoot 1 2 3 how level loadings and animations work and etc...

yo the spc700 plz

Yikes, what's up with that Bloodlines aspect ratio? It's so squished horizontally 💀

Edit: You're using the Castlevania sprites. Disregard. -Are you able to modify the monospace font you use for addresses and code? The O and 0 look a bit too similar; perhaps someone could add a stroke or slash to differentiate them at a glance.- -Of course, programmers would know that O is not a valid hexadecimal value, but still.-

I think they were using Ray Tracing on the Genesis.

Episode five?

Why are the line of codes using dollar sign

Rastafarian effects

Im confused by this „Horizontal” interrupts naming for raster/scanline, when clearly they are Vertical, although making horizontal splits or bands (?!) …

The water reflection is kinda nice but that slicing screen effect is the ugliest thing ever. I thought the game was broken when I saw that back then.

Hmm, so this could run on the SNES, couldn't it?

Ray tracing in sega genesis!

🙃 𝓟Ř𝔬𝓂𝔬𝐒ϻ

No explenations about the lightning shadows and rotating gears and 3D rotating. Tower,that means a big thumbs down 👎