the atari Jaguar theory

[swapd0]

With a few extra registers you could draw a trapezoid with the blitter (2 trapezoids make a triangle), drawing a square with a texture is useless for 3d games,. You can still do the rasterizing with the GPU, well I mean calculate the edge slopes not the edges coordinates.

 

With a write buffer or cache you will be using the 64bit bus of the blitter at full, now when you are doing texture mapping you write pixels one by one, using only 16 bits per write. That means 1/4 of the real bandwith.

 

Writting a list of primitives just like the OP works has nothing to do with DirectX or OpenGL, also it's the way that the PSX works, you only need to write that list of commands as fast as you can, then the blitter will render it as fast as it can.

[82-T/A]

With a few extra registers you could draw a trapezoid with the blitter (2 trapezoids make a triangle), drawing a square with a texture is useless for 3d games,. You can still do the rasterizing with the GPU, well I mean calculate the edge slopes not the edges coordinates.

 

With a write buffer or cache you will be using the 64bit bus of the blitter at full, now when you are doing texture mapping you write pixels one by one, using only 16 bits per write. That means 1/4 of the real bandwith.

 

Writting a list of primitives just like the OP works has nothing to do with DirectX or OpenGL, also it's the way that the PSX works, you only need to write that list of commands as fast as you can, then the blitter will render it as fast as it can.

 

 

I kind of know what you're saying... but I've only ever developed business applications, and never anything related to graphics. You're saying obviously that the Jaguar could do it, but it would be slow as shit.. hahah...

[swapd0]

 

 

I kind of know what you're saying... but I've only ever developed business applications, and never anything related to graphics. You're saying obviously that the Jaguar could do it, but it would be slow as shit.. hahah...

 

Much faster than having the GPU waiting for the blitter to finish to send the next triangle scanline to be drawn...

[zzip]

How about we flip the question around?

 

What is it about the Jaguar that makes people wonder "what if it just didn't get a fair shake" and "why didn't it do better?"

 

Guesses:

Atari brand nostalgia

Made in America

Lots of Tramiel promises

Confusion between Atari Corp and Atari Games

64-bit, do the math

Atari brand Nostalgia I guess. A lot of us were reared on Atari, and stayed loyal to the brand, so of course we wanted to see the hardware do well.

 

As for '64-bit do the math'. I did the math, I still can't figure out how it can legitimately claim to be 64-bit

[Flojomojo]

Atari brand Nostalgia I guess. A lot of us were reared on Atari, and stayed loyal to the brand, so of course we wanted to see the hardware do well.

 

As for '64-bit do the math'. I did the math, I still can't figure out how it can legitimately claim to be 64-bit

 

We're also used to the progression of things. (below, "better" = more memory, graphics, complexity)

 

Pong was better than nothing

Atari was better than Pong

Intellivision was better than Atari

ColecoVision was better than Intellivision

NES was better than Colecovision

Genesis was better than NES

Jaguar was ... next

[toiletunes]

John Bright first used the phrase "flogging a dead horse" in 1859.

[Osgeld]

John Bright first used the phrase "flogging a dead horse" in 1859.

 

funny enough, we are still talking about it 158 years later, I think we got trolled

[82-T/A]

Atari brand Nostalgia I guess. A lot of us were reared on Atari, and stayed loyal to the brand, so of course we wanted to see the hardware do well.

 

As for '64-bit do the math'. I did the math, I still can't figure out how it can legitimately claim to be 64-bit

 

 

YOUR DOING THE MATH WRONG!!!! haha...

[VladR]

With a few extra registers you could draw a trapezoid with the blitter (2 trapezoids make a triangle), drawing a square with a texture is useless for 3d games,. You can still do the rasterizing with the GPU, well I mean calculate the edge slopes not the edges coordinates.

Sorry, I was talking about the trapezoid, when I mentioned "angled quad". My English vocabulary is unfortunately missing that particular terminology and I didn't have time to search for proper translation.

 

More specifically, I got a Rhombus/Parallelogram textured via single Blitter call. So, it's already possible.

 

 

 

 

With a write buffer or cache you will be using the 64bit bus of the blitter at full, now when you are doing texture mapping you write pixels one by one, using only 16 bits per write. That means 1/4 of the real bandwith

Not necessarily. Just because it would be implemented in the silicon does not at all mean Blitter would be able to texture in phrase blits.

Is it technically possible ? Sure, anything is. But I doubt the amount of resources needed for implementing something like this (in a silicon) would actually be spent by Atari.

Just write it down on paper, if you want to do the texturing in horizontal scanlines, how much trigonometry is involved on top of default perspective-correct texturing. It's stagerring. I have made initial research on paper, but have very quickly discarded the idea, even for GPU.

 

It's true, that at that time, my engine could not page chunks of code, and I didn't have Blitter code running from GPU, so in future I may revisit it, and while Blitter will be blitting horizontal scanlines, GPU may be burning shovels of black coal while preparing second horizontal scanline in parallel with Blitter blitting the first scanline. Note, that in this case, the Blitter would be actually veeeery probably waiting for the GPU

 

So, even in the alternate reality, if the Blitter would be able to texture any generic triangle via a single Blitter call, it would only be in pixel mode, not phrase mode.

 

Thus, everybody would be still bitching, that it's not really full 64-bit power and you gotta roll your own renderer anyway

 

 

 

 

Writting a list of primitives just like the OP works has nothing to do with DirectX or OpenGL, also it's the way that the PSX works, you only need to write that list of commands as fast as you can, then the blitter will render it as fast as it can.

While I never worked with PSX, from what I read a decade or so ago, you still had to do all the transforms and culling on the cores in ASM by yourself. I don't recall that PSX actually rasterized the triangle soup for you in HW, but perhaps it did. Either way, PSX was designed in a different timeframe and with different visual target in mind (than Jaguar), so we can't unfortunately directly compare the two.

 

You do have the point though, that jag already supports the high-level API way, even though for 2D bitmaps only. On the other hand, the algorithmic complexity of drawing a primitive rectangular bitmap compared to full 3D engine pipeline, makes it obvious why they drew the line there

[VladR]

 

Much faster than having the GPU waiting for the blitter to finish to send the next triangle scanline to be drawn...

Correct. But, what if you, instead of throwing all that GPU performance away, use it for something else ?

 

You can be reusing the engine functionality you already have in the current 4 KB chunk. For example, I'm currently trying to rewrite it in a way that will compute the mipmaps and 3D transformations of the scaled bitmaps (for the roadside objects), all the while the Blitter is blitting current horizontal scanline.

 

Or, you could compute something else (bilinear filtering of the scanline, shadows, lighting, other effects). I can see now, I should have rather designed each effect around discreet substages, but that's the price of experience

 

 

It's not easy, it's very messy, there's a lot of additional overhead (so it's not entirely free, as one might initially think, as you gotta store the original register state somewhere - it's basically like an inner interrupt) but it's entirely possible.

[2600problems]

When I do a program for the c64 (I use Simons basic) I try to use the least amount of memory possible. why could Atari make it so that the processors have a reserved Cache of Memory (say 512k of ram) for extra memory, while using its base load for graphics and sound. in short, one processor for graphics, one for sound and when the Data is used up, switch to its reserve and go from there. the Atari 2600 did it.

 

obviously bank switching died before 1990

[phoenixdownita]

When I do a program for the c64 (I use Simons basic) I try to use the least amount of memory possible. why could Atari make it so that the processors have a reserved Cache of Memory (say 512k of ram) for extra memory, while using its base load for graphics and sound. in short, one processor for graphics, one for sound and when the Data is used up, switch to its reserve and go from there. the Atari 2600 did it.

 

obviously bank switching died before 1990

What? Care to elaborate?

Are you hinting at dynamically reserved memory or actual dedicated memory for each chip?

[2600problems]

dedicated for each chip

[2600problems]

in other words, have one set of chips with dedicated memory (say 14MB) so that when the system needs extra ram it can pull from the chips. its not much but it could be useful.

[phoenixdownita]

I thought one of the design tenet of the Jag was the unified 64bit access bus that hid "everything".

 

Likely they miscalculated the requirements in terms of bandwidth for the kind of games that were to become popular in that period. Once you want to support sw rendering (aka 3D or 3D-ish as opposed to tile/sprite based games) and have textures there's a lot of accesses that are needed for each and every frame.

 

Multibus systems with dedicated memories were all the rage in the arcades, and in some (but not all) of the consoles of its time, I believe most of Atari designs wrt home consoles/computer were shared bus (no actual dedicated memory/bus), not that it matters giving the project was acquired but kind of fitting anyway. I am not sure about the Atari Arcade machines, I'd be surprised if they were shared bus/mem as all competitors afaik had dedicated subsystems with dedicated bus & mems.

[+madman]

There are so many things wrong w/what you are saying, 2600problems. The first of which is I believe you are confusing ROM and RAM.

[2600problems]

what exactly am I getting wrong? that you could add a separate 512k to ram?

[high voltage]

I think the 90s 64 bit consoles didn't do well at all.

N64 = fuzzy graphics, worse looking than PS games, not many good games on N64 when compared to PS, Superman (nuff said)...Funnily enough, it's my favourite Nintendo console, maybe I'm a sucker for bad consoles.

Edited June 12, 2017 by high voltage

[WIZZARD77]

N64 had Mario Banjo and Donkey Kong. PS had Bubsy 3D nuff said.

[phoenixdownita]

I think the 90s 64 bit consoles didn't do well at all.

N64 = fuzzy graphics, worse looking than PS games, not many good games on N64 when compared to PS, Superman (nuff said)...Funnily enough, it's my favourite Nintendo console, maybe I'm a sucker for bad consoles.

N64=fuzzy .... turns out that was a design choice. Questionable but still a choice. The recent discoveries on how to turn off the "smearing" in N64 games via AR codes (or SW patching if you prefer) shows the HW was plenty capable of unblurred rendering.

In that mode it also shows how the textures were "speckled" that I speculate was used to simulate a higher color count (via blur/smear/anti-aliasing) while using very little underneath.

 

I agree that blurring at 320x200 or whereabouts was a bad decision in hindsight, not sure why they didn't allow devs to go unblurred much earlier (there were games that did that if memory serves it was towards the end of the lifecycle of the N64 ... but I may remember wrong)

[2600problems]

worst console of the 90's was the Phillips cd-I no doubt

[Ayreon]

But it wasn't really intended as a console. Commodore CDTV, Tandy VIS and to a certain extend Pioneer's LaserActive were in the same boat and I think less popular than the CD-I.

[rocky1138]

I believe one of the most important things about a console is the controller design. I don't understand how Nintendo had 6 buttons with the SNES, and later Genesis comes out with 6 button controller to compete with that, and then the Jaguar when it comes out way after has a 3 button controller at launch(and no, the keypad buttons don't count). To me that was just plain stupid putting a system out to compete with those 2 systems and even next gen later but take a step back from them on controller design. As far as graphics, speed, etc. I have no clue because I never bought one to play due to the controller design. Bought a Genesis instead.

 

I completely agree. I often think that it would have also been awesome to have 4 controller ports standard as later consoles went this method. It would have been groundbreaking.

[racerx]

I think the 90s 64 bit consoles didn't do well at all.

N64 = fuzzy graphics, worse looking than PS games...

Play Tomb Raider and Mario 64 back to back. N64 games, especially early on, certainly had their problems texture- and storage-wise, but a lot of PlayStation games are unplayable pixelated messes.

[2600problems]

what is a good tool for jag development... that doesn't use c scripting