Enjoying your froyo?

[tepples]

I wonder whether attempting to add a hypothetical bgen to higan might help you get an account sooner.

[93143]

Wait, didn't you say you could create an interrupt for this? What would be some bad processing wise than?

The fastest possible software-transparent interrupt takes either 48 or 53.5 dots, depending on the current register size setting:

Code: Select all

(irq)         ; 6 slow, 2 fast
pha           ; 2 or 3 slow, 1 fast
lda $4211     ; 3 slow, 1 or 2 fast
pla           ; 2 or 3 slow, 2 fast
rti           ; 5 slow, 2 fast

If you want to make it actually do anything, you'll have to add at least one rep #$30 or similar at the beginning, plus whatever you want to make it actually do, plus any extra bookkeeping necessary to keep it transparent. I figure the practical minimum for a mode switch is the BGMODE write itself plus a scroll change (my code just zeroes the scroll values), plus a change to the IRQ H-timer if you're trying to do a non-vertical split. If you're just doing a scroll change, you can skip the BGMODE load/store ops, but you're probably using nonzero values for the scroll registers. Either way, you've probably about doubled the size of the above example, and now it's eating a third of your compute time. That's for one change per scanline.

Plus, interrupt positions jitter based on the size of the instructions in the interrupted code, because the processor will finish the current instruction before servicing the IRQ, and some instructions can take a couple of tile widths to execute. If you want to line up the raster writes within a narrower range than that, you have to include additional timed code like I did, or else just never use instructions beyond a certain length in your main code. I don't think there's even enough time in a scanline to stagger-step an interrupt all the way down to a single pixel for a perfect split in the presence of normal game code; it took me the majority of a scanline to null out a much smaller variance in a test ROM...

There are honestly dozens of possibilities for this, even if you do need an extra chip.

That's true, but it's such a massive undertaking that unless you have a specific goal that can't be done any other way (or you think you can use the garbage effect artistically), you're probably better off using windowing or offset-per-tile or some such, as AWJ says.

I'm only doing it because I really want my port to reproduce the graphical look of the original as closely as possible, and I need a Super FX anyway for unrelated reasons. It's more of an exercise in stretching the SNES to its limits than an attempt to realize a creative vision...

Did you ever try the nasty-looking product placement yogurt? (Or should I say "froyo"?)

No. As I said, this is the first I've heard of it, and we don't have a branch in town.

It is kinda pleasant to see Nintendo having this much success with a new property, though... I don't remember anybody offering Pikmin-themed frozen yogurt...

I imagine that if you are using FastROM along with WRAM and you're wanting to just have a precise split down the screen or something, you could do a mixture of both 1.5 pixel and 2 pixel cycles

I tried that. It didn't work, even though I carefully aligned the first write to within a single dot.

Granted, I haven't tried it without HDMA running, so that might be what was kicking the loop around, but I only barely managed a vertical split with a grumbly edge a few pixels wide. The only perfect vertical split I ever saw only worked on some frames; other frames had a diagonal split. It's touchy. I suppose one could run a bit of alignment code every scanline to eliminate the grumbliness...

And I didn't try to run any useful code during the screen - the whole thing was a timed loop. I can imagine trying to squeeze real processing into a timed loop being a hair-pulling experience. And without that, all you've got for processing is VBlank. I don't know about you, but my VBlank is stuffed with DMA...

Oh, and there's that pesky DRAM refresh in the middle of the screen. You flat-out can't do anything at all for 10 pixels in the middle of every scanline, and on later console revisions this area moves around a bit between scanlines and (I think) between frames (possibly to reduce the visibility of the associated vertical bar artifact, which seems to be due to heavy current draw). So it's actually impossible to do a vertical mode switch in the exact centre of the screen, and a diagonal split would probably need masking to look decent even if it didn't generate any garbage (mode switching does, at least when Mode 7 is involved; scroll changes don't).

...

This isn't intended to be the final word or anything. If you figure out a good way to do it, great. Tell me about it. But from what I've found out so far, it seems apparent that CPU-based mid-scanline raster effects are somewhat less useful than they sound.

[Near]

> some of those guys seem REALLY hostile towards the SNES.

That they do. Utterly bizarre to me. Both systems have their pros and cons, but I'd agree the Genesis was the superior hardware. But to me, what matters are the games. And the SNES has ~15 times the JRPGs as the Genesis.

> I wonder whether attempting to add a hypothetical bgen to higan might help you get an account sooner.

I've been contemplating it (really want to play Lunar 1&2 again on the Mega CD; would be fun to use my own emulator for that), but I really just don't have the time.

[Drew Sebastino]

That they do. Utterly bizarre to me.

Because they're utterly bizarre.

Both systems have their pros and cons, but I'd agree the Genesis was the superior hardware.

I'm just curious, and I'm not saying you're wrong because you have x100 more knowledge of both systems than I do, but what makes you think so? I'm pretty sure you don't believe in blast processing. I always thought the SNES was backwards in how it was constructed (mostly with sprites), but I never really saw it as being weaker. The best part to me though is when people complain about slowdown in slowrom games.

But to me, what matters are the games. And the SNES has ~15 times the JRPGs as the Genesis.

Is that supposed to be a good thing?

Well you know 93143, just thinking, I imagine one trick you could reasonably do is have an object or something made of a BG on the left side of the screen, and then have another object on the right side of the screen on the same BG layer. What you could then do is have them move differently by doing the mid scan line trick thing, and if there's garbage in between, can't you clip it out with a window layer? This could almost be good for parallax, like if in a fighting game or something where you can't move very far to the left or the right, you have something to the left that moves not very fast and something to the right that moves faster when you move, because the thing on the right is supposed to be closer to you. They shouldn't overlap each other because you can't move enough to the right for this to happen.

You know though, with all this talk about dots, is it like the whole screen is how fast the CPU operates in one frame? Compared to the video hardware, the CPU really doesn't seem way too fast, which isn't too surprising to me though considering that on the pictures I've seen, the video hardware as a whole (both PPUs) is twice as big as the CPU, because each PPU is about that size. I like it that way better though, as if the PPUs where better, we wouldn't be having this problem in the first place... (I'm not saying they where bad though.) I still think Nintendo should have put a bus from the cartridge to the PPUs though because most of the problems with trying to do fancy stuff like this is the CPU's fault, mostly because of the slow DMA.

No. As I said, this is the first I've heard of it, and we don't have a branch in town.

Didn't you just say that that other place was by the movie theater there?

It is kinda pleasant to see Nintendo having this much success with a new property, though... I don't remember anybody offering Pikmin-themed frozen yogurt...

That's because one of the games is (in my humble opinion) infinitely better than the other, and yes, I own Pikmin. I still haven't changed my mind about the controls though.

I don't know about you, but my VBlank is stuffed with DMA...

Mine should be with all the explosions.

This isn't intended to be the final word or anything. If you figure out a good way to do it, great. Tell me about it. But from what I've found out so far, it seems apparent that CPU-based mid-scanline raster effects are somewhat less useful than they sound.

Yeah, unfortunately. I'm just curious, but since the Genesis runs at a faster clockspeed, does anyone know how many pixels a cycle is on it? How many cycles is the fastest instruction?

[tepples]

since the Genesis runs at a faster clockspeed, does anyone know how many pixels a cycle is on it?

Genesis 68000 CPU:

• Clock rate is 15/7 of S-CPU fast clock rate
• Data bus is twice as wide as that of the S-CPU
• Accesses memory every four cycles, unlike S-CPU that accesses memory every cycle

VDP:

• 256px mode: Dot rate is same as other TMS9918 derivatives and TMS9918-inspired Nintendo PPUs, 3/2 of S-CPU fast clock rate 342 dots per line
• 320px mode: Dot rate is 5/4 of 256px mode dot rate, or 15/8 of S-CPU fast clock rate, 427.5 dots per line

In other topics, I've adopted a convention of assuming that each slow S-CPU cycle is worth three 68000 cycles and each fast cycle is worth two.

How many cycles is the fastest instruction?

Google 68000 cycles per instruction brought this, which breaks each instruction into address generation and the remainder.

[93143]

Well you know 93143, just thinking, I imagine one trick you could reasonably do is have an object or something made of a BG on the left side of the screen, and then have another object on the right side of the screen on the same BG layer. What you could then do is have them move differently by doing the mid scan line trick thing, and if there's garbage in between, can't you clip it out with a window layer? This could almost be good for parallax, like if in a fighting game or something where you can't move very far to the left or the right, you have something to the left that moves not very fast and something to the right that moves faster when you move, because the thing on the right is supposed to be closer to you. They shouldn't overlap each other because you can't move enough to the right for this to happen.

I don't see why not. But isn't this a bit of a heavy-duty process for such a mild effect? I guess if it's indicated by the direction the game design has taken, you're out of BG layers and sprites but not CPU time, and a window mask effect by itself won't cut it...

BTW, the garbage only happens with mode changes (and possibly other changes). Scroll changes seem to be clean, as long as the layer in question is transparent during the switch so you can't see the seam. (Which I guess you could ensure by using a masking window.)

Air Strike Patrol, as stated, uses it to do a neat effect with some text while using the same BG layer for a vertical status bar. There's quite a bit of space between the sidebar and the text, it seems to only change the vertical scroll values, and the text doesn't cover very many scanlines; the effect probably uses very little CPU time compared with a full-screen raster split...

If you find an application for this that doesn't devastate the rest of the game, I see no reason not to go ahead and try it. The ASP case is a good example of a neat trick that doesn't cost very much. Just beware of the SNES Jr.; it doesn't behave the same as a normal SNES and these stunts can fail on it.

...

Hang on; wasn't this thread about a tilemap editor? In that case, it'll probably work fine with less exotic techniques like HDMA and windowing...

You know though, with all this talk about dots, is it like the whole screen is how fast the CPU operates in one frame?

Mostly. The SNES is a raster display system, so you can time it based on dots and scanlines and frames, because the PPU is drawing the picture to the screen at a steady rate while the CPU is running. Of course, the CPU still runs during VBlank, so you actually get 262 scanlines of CPU time (assuming NTSC and non-interlaced). Note, however, that the CPU pauses for 10 dots (40 master cycles) in the middle of each scanline to allow the memory controller to refresh WRAM, so each scanline only spans 1324 master cycles of compute time, instead of the 1364 master cycles it takes on the wall clock (the 256 active dots only take 1024 master cycles to draw; the rest is HBlank).

Didn't you just say that that other place was by the movie theater there?

Whoops. I didn't even check that link; I assumed you just meant it was a totally different Canadian frozen yogurt chain (though this one does have U.S. locations, as I found after checking). Turns out it too is running a Splatoon promo... what are the odds, eh?

And their website design is really suspiciously similar...

Aaron Serruya, who, with his brothers Michael and Simon, founded Yogen Früz in Toronto in 1986. [...] Now chief executive of Yogurty’s, Mr. Serruya

The [Yogurty’s] brand is owned by Markham, Ont.-based International Franchise Inc., the company that acquired Yogen Früz in 2005

Oh.

To answer your question - no, I haven't. I don't go out much lately...

[DoNotWant]

But to me, what matters are the games. And the SNES has ~15 times the JRPGs as the Genesis.

Is that supposed to be a good thing?

That's a great thing! Who doesn't enjoy a good story?

[psycopathicteen]

But to me, what matters are the games. And the SNES has ~15 times the JRPGs as the Genesis.

Is that supposed to be a good thing?

That's a great thing! Who doesn't enjoy a good story?

If I want a good story, I prefer watching a movie.

[darryl.revok]

Why such SNES hate? Personally, I always disliked the Genesis. The poor color rendition and the extremely limited tonal qualities to it's sound were a huge downfall to me. Don't get me wrong, I enjoyed some of the games on the system but I generally enjoyed them in spite of the system.

I'm curious what is the draw for Genesis love? Please don't say clock speed because clock speed isn't FUN. My iPhone has a higher clock speed and I have no desire to play games on it.

I recently start getting more into SHMUPs and I read a lot of people saying SNES sucks for SHMUPs and Genesis is the only way to go. But then I look at the highly regarded SHMUPs on that system, like Thunderforce, and I don't honestly think they look very good. I honestly think Space Megaforce looks better and plays better than the critically acclaimed MUSHA.

Granted there are only a couple great SHMUPs for the SNES, but when I look at Space Megaforce or Macross: Scrambled Valkyrie, I think this may have been a limitation on the skill of the programmers and not the system.

[Stef]

Because they're utterly bizarre.

As some guys can be here belong the Megadrive...

Both systems have their pros and cons, but I'd agree the Genesis was the superior hardware.

I'm just curious, and I'm not saying you're wrong because you have x100 more knowledge of both systems than I do, but what makes you think so? I'm pretty sure you don't believe in blast processing. I always thought the SNES was backwards in how it was constructed (mostly with sprites), but I never really saw it as being weaker.

Did you at least know the Megadrive hardware ?
Byuu has probably good reasons to think that and you know i'm sharing this feeling.
Byuu wrote the most famous SNES emulator along others great things so i guess you can trust him on that point. I believe than any people with strong hardware knowledges and specifically about both systems would tell you the Megadrive was the superior hardware. The SNES of course has the edge on some aspects (much more colors, more hardware GFX effects, orchestral sound) but for a system 2 years newer that is the least to expect... However compared to the MD it has so much pitfalls and that's when you develop on both systems you understand you can definitely do more with the Megadrive. The SNES hardware is just so unbalanced and painful to develop with where the Megadrive is straightforward and cleverly designed, that is the point.

The 68000 is for me definitely a big advantage over the SNES but that is not the only one... column scrolling (doable with the offset per tile but again painful), packed tile data format, powerful and flexible sprite capabilities, flexible sound hardware.
The SNES has the nice HDMA thing which is definitely a great addition but imo almost everything else is not really worthy.
The Megadrive also has its weakness as the (very) limited number of color palette but that is almost the only real weakness of this system, i even bet that with 8 palettes instead of 4 the Megadrive story could have been different.

[Stef]

Why such SNES hate? Personally, I always disliked the Genesis.

Why such Genesis hate ??

The poor color rendition and the extremely limited tonal qualities to it's sound were a huge downfall to me. Don't get me wrong, I enjoyed some of the games on the system but I generally enjoyed them in spite of the system.

I'm curious what is the draw for Genesis love? Please don't say clock speed because clock speed isn't FUN. My iPhone has a higher clock speed and I have no desire to play games on it.

Personally i owned both systems back in time and i loved both... I would say i even played more the SNES than the Megadrive but definitely both systems were great to play with. Today as i'm developing on these systems (well actually the Megadrive but at least i tried on SNES) my mind is biased and i'm more judging them about their hardware design and capabilities. I am even dismayed that the SNES was always considered as the superior hardware by magazine when i was younger as definitely it was not really the case, marketing work...

I recently start getting more into SHMUPs and I read a lot of people saying SNES sucks for SHMUPs and Genesis is the only way to go. But then I look at the highly regarded SHMUPs on that system, like Thunderforce, and I don't honestly think they look very good. I honestly think Space Megaforce looks better and plays better than the critically acclaimed MUSHA.

Granted there are only a couple great SHMUPs for the SNES, but when I look at Space Megaforce or Macross: Scrambled Valkyrie, I think this may have been a limitation on the skill of the programmers and not the system.

That is just matter of taste but definitely the Megadrive has a better library when it comes to SHMUPS... I recommend you Gynoug which is my preferred on the Megadrive :p Snes has some great titles (R-Type 3, Pop twin bee, Phalanx) but less than the Megadrive in that department.

[tepples]

And their website design is really suspiciously similar...

Aaron Serruya, who, with his brothers Michael and Simon, founded Yogen Früz in Toronto in 1986. [...] Now chief executive of Yogurty’s, Mr. Serruya

The [Yogurty’s] brand is owned by Markham, Ont.-based International Franchise Inc., the company that acquired Yogen Früz in 2005

Oh.

To answer your question - no, I haven't. I don't go out much lately...

Can someone provide a sharp scan of the "yogurtys.com" text on a Yogurty's cup? I'd like to see what font it uses, and the cups in the photo for the Splatoon ad campaign aren't sharp enough for WhatTheFont/WhatFontIs.

[psycopathicteen]

How is collumn scrolling "painful" on the SNES? You just upload the scroll values of each column to the second row in BG3's tilemap with bit-13 set.

[Near]

>> Both systems have their pros and cons, but I'd agree the Genesis was the superior hardware.
> I'm just curious, and I'm not saying you're wrong because you have x100 more knowledge of both systems than I do, but what makes you think so?

The CPU. As a developer wanting to make a game to run on a game console, being able to write in C is such an incredible advantage. The Genesis has a real CPU with 16 registers.

There have been attempts to make C compilers for 65xx processors, but they produce code that's unusably slow and horribly inefficient. C is just entirely incompatible with the notion of "one actual register, two index registers" (and even with the one actual math register; you can't natively multiply, divide, shift/rotate by more than one bit at a time, etc)

As a game developer, I'd take the video and sound hit (both of which also come at added complexity compared to the Genesis.) I would absolutely dread the idea of writing a full-fledged RPG engine in SNES assembler. And those damned M/X flags on P ... I hate them so very, very much.

Conversely, as an emulator developer / ROM hacker, I much prefer analyzing others' SNES ASM, because it's so much simpler, and you don't have to work your way through obscene "shell game" behavior that C compilers generate with variables in registers.

> Is that supposed to be a good thing?

For someone who likes JRPG/JSLGs like me, yes.

Genesis has a few, and I love those games. Shining Force 1&2, Phantasy Star IV (III was total shit), and if you go to the Mega CD ... Lunar 1&2.

But the SNES ... oh man. Lufia 1&2, BoF 1&2, Final Fantasy 4-6, Dragon Quest 1,2,3,5,6, Bahamut Lagoon, Tales of Phantasia, Chrono Trigger, Star Ocean, Tengai Makyou Zero, Der Langrisser, Dai Kaijuu Monogatari 1&2, Arabian Nights, Power of the Hired, Soul Blader, Terranigma, Illusion of Gaia, Chaos Seed, Ys 3-5, Seiken Densetsu 2&3, Aretha 1&2, Bakumatsu Oni, Kourinden Oni, Emerald Dragon, Romancing SaGa 1-3, Farland Story 1&2, Tactics Ogre, Bushi Seiryuuden, Last Bible III, ... and those are just my personal favorites. There's like five times more than that.

If the game libraries were reversed, I'd have been Nemesis, but in 2004.

I'd easily take an SNES over a PS4. So to me, arguing about which hardware was superior is just a waste of time. I don't play hardware, I play games.

> Granted there are only a couple great SHMUPs for the SNES, but when I look at Space Megaforce or Macross: Scrambled Valkyrie, I think this may have been a limitation on the skill of the programmers and not the system.

Frankly, you're wasting your time playing shmups on any old console.

Why dick around with MUSHA vs Space Megaforce when you could be playing Dodonpachi with your monitor tilted into portrait mode instead?

SHMUPS aren't RPGs. There's no compelling story to trump the graphical limitations.

https://youtu.be/iJwhq2pkhhc?t=2800 => "WHERE IS YOUR SPRITE LIMIT GOD NOW?!"

[Drew Sebastino]

As some guys can be here belong the Megadrive...

I get the first part of what you said, but not "belong the Megadrive".

Did you at least know the Megadrive hardware ?

Not too much, and I never said that whatever reason he would say would be wrong. This is basically what I know:

Has a 256x224 screen mode, and a 320x224 screen mode.
In 256 pixel mode, there are 256 sprite pixels per line.
In 320 pixel mode, there are 320 sprite pixels per line.
In 256 pixel mode, there are 64 sprites.
In 320 pixel mode, there are 80 sprites.

(why in the world would you even choose 256 pixel mode then?)

Has a shadow and highlight mode that can either double the brightness of the darkness of a color under it? Can't this actually increase the total color count?
Has a 9bit color depth.
All tiles are 4bpp.
All tiles are packed pixel?
Has an interlaced mode that's used in the competition 2 player in Sonic 2. (I heard it took a lot of silicon real estate in the video processor that could have been used for something like more colors)
Has the hardware in the video chip for selecting up to 384 color entries, but there's only enough space for 64 colors and I don't think anything was built to be able to select that many palettes. (Wasn't there an arcade game based off the Genesis hardware that used this?)
Every sprite can be some combination of 8, 16, 24, or 32 by 8, 16, 24, or 32 pixels large.
Each sprite and BG tile can select 4 different 16 color palettes from a shared bank.
I think I remember that sprite information is stored in vram and that it's actually safe to update it mid screen.
Each sprite entry is (I think?) 8 bytes, and sprites (thankfully) have access to all tiles in vram.
There are 2 BG that have access to all tiles.
There is a scrolling table for BG layers because there isn't anything like hdma.
There is also a 16x16 column scrolling table, and I think I remember hearing that there's only 20 entries so one of them wraps around when the screen scrolls.
Has a 7.6Mhz 68000
Has I think about around a 4Mhz Z80 for sound and the Master System?
Has one PCM channel for sound.
Has several (I don't know the specific number) FM channels for sound.
Has 64KB of main ram.
Has 64KB of video ram (but was potentially going to have 128KB).
Some have a bios that loads up "licensed by Sega" or something, but I think Sega ended up getting in trouble with Accolade?

Okay, you can tell I'm getting desperate...

The SNES hardware is just so unbalanced and painful to develop with where the Megadrive is straightforward and cleverly designed, that is the point.

I can't actually disagree with you there. :/

flexible sound hardware.

Isn't the sound hardware on the Genesis less flexible? I recall hearing a story about how in Mortal Kombat III on the Genesis, samples had to be played at half quality to try to have multiple sound effects going on, which is often the case for fighting games.

The Megadrive also has its weakness as the (very) limited number of color palette but that is almost the only real weakness of this system, i even bet that with 8 palettes instead of 4 the Megadrive story could have been different.

That was enough for me. The SNES may not have 512 colors, and the Turbo Graphics 16 may have only had 9bit color depth, but the Genesis got hit hard. I'll also take my 256 color and 16 color BGs at 256 pixels over 2 16 color BGs at 320 pixels, but that's just personal preference.

I am even dismayed that the SNES was always considered as the superior hardware by magazine when i was younger as definitely it was not really the case, marketing work...

https://www.youtube.com/watch?v=zlulSyBI2aY

Phalanx

I... guess? Of course I'm going to agree with you about R-Type 3 though. Super R-Type would be better if it weren't in slowmo, but it's still a fairly mediocre attempt. I don't like Gradius, and I think Axelay is tremendously overrated, although I only did about 1 level.

Why such Genesis hate ??

I didn't really get darryl.revok talking about SNES hate, because I don't really see any of that here.

How is collumn scrolling "painful" on the SNES? You just upload the scroll values of each column to the second row in BG3's tilemap with bit-13 set.

I didn't get it either.

The CPU. As a developer wanting to make a game to run on a game console, being able to write in C is such an incredible advantage. The Genesis has a real CPU with 16 registers.

There have been attempts to make C compilers for 65xx processors, but they produce code that's unusably slow and horribly inefficient. C is just entirely incompatible with the notion of "one actual register, two index registers" (and even with the one actual math register; you can't natively multiply, divide, shift/rotate by more than one bit at a time, etc)

More than once, this is where our opinions differ. I'd rather write in machine code than C, and I'd rather have a better PPU than a better CPU. I don't know about you, but if I don't have way too much I can do with the video hardware, I'll try and limit what I originally wanted to do, but if I'm not as limited and the CPU just can't keep up very well and there's slowdown, I'd either add an expansion chip, (not trying to imply that it's easy though) or I'd just shrug my shoulders and say oh well.

Frankly, you're wasting your time playing shmups on any old console.

Why dick around with MUSHA vs Space Megaforce when you could be playing Dodonpachi with your monitor tilted into portrait mode instead?

Why dick around with Final Fantasy 6 vs. Chrono Trigger when you could be playing Final Fantasy 3,000?

SHMUPS aren't RPGs. There's no compelling story to trump the graphical limitations.

Are graphical limitations all that matter? The game you posted in the video actually looked rather boring, just a bunch of slow bullets that seem to disappear for whatever reason. I'd much rather stick to the "outdated" R-Type.

Can someone provide a sharp scan of the "yogurtys.com" text on a Yogurty's cup? I'd like to see what font it uses, and the cups in the photo for the Splatoon ad campaign aren't sharp enough for WhatTheFont/WhatFontIs.

That would be cool. I just noticed that I sort of made a bad pun... Should I instead say that would be "fresh"?

If I want a good story, I prefer watching a movie.

This.