Atari v Commodore

[Heaven/TQA]

are we not speculating about ROFL? I personally doubt that they splittet the drawing into layers... this does not make sense from programming point of view...

 

look... if we are saying we are drawing only the front mountains when necessary and save the cycles... how would you do that?

 

I mean you definitly need to redraw the whole screen... we do not have a z-buffer or a blitter where we can see if we need to draw (so to say delta-updating)

 

we draw from back to front otherwise we run in clipping issues... so... the background needs to be drawn anyway? you can not leave it there for the next frame and draw on top? why? how would you erase the moving front mountains and restore the background?

Actually, this is sort of how the routines in ROF work. The world is broken up into a grid, and the grid points form the endpoints of the fractal lines. The game draws the fractal lines front to back in layers, into a sort-of Y-buffer. it then fills from the previous Y position from each column to this current one, only drawing the delta from the previous frame.

 

The clipper uses a similar technique Loren used for REYES, where you sub-divide the line, culling parts which are totally off-screen and continuing to divide lines that have one end-point on-screen and one off-screen. This was done in 16-bit math, until the MSB hit zero, and then shifted to 8-bit math.

 

BTW, I never thought I would be posting in this thread...

--Selgus

 

sounds interesting... btw. what is REYES?

[Heaven/TQA]

are we not speculating about ROFL? I personally doubt that they splittet the drawing into layers... this does not make sense from programming point of view...

 

look... if we are saying we are drawing only the front mountains when necessary and save the cycles... how would you do that?

 

I mean you definitly need to redraw the whole screen... we do not have a z-buffer or a blitter where we can see if we need to draw (so to say delta-updating)

 

we draw from back to front otherwise we run in clipping issues... so... the background needs to be drawn anyway? you can not leave it there for the next frame and draw on top? why? how would you erase the moving front mountains and restore the background?

Actually, this is sort of how the routines in ROF work. The world is broken up into a grid, and the grid points form the endpoints of the fractal lines. The game draws the fractal lines front to back in layers, into a sort-of Y-buffer. it then fills from the previous Y position from each column to this current one, only drawing the delta from the previous frame.

 

The clipper uses a similar technique Loren used for REYES, where you sub-divide the line, culling parts which are totally off-screen and continuing to divide lines that have one end-point on-screen and one off-screen. This was done in 16-bit math, until the MSB hit zero, and then shifted to 8-bit math.

 

BTW, I never thought I would be posting in this thread...

--Selgus

 

just reread it... sounds like voxel engine? and sure front to back and not back to front?

[saehn]

No, I don't accept that B&W pictures are more beautiful than color pictures (of same object). You are just declaring beauty is subjective-- not showing I am wrong. It's more of a cop-out since it involves little effort on the part of the people to make such a vague blurb.

 

It all comes down to this... you do understand the reality that outside, in the real world, there are actually people who seriously consider black-and-white photography to be more beautiful than color, don't you? If you deny this, you are denying reality... a disturbing trend.

 

If, however, you accept that some people prefer B/W, then you must acknowledge the subjectivity of beauty.

...

Bad logic. Just because there are differences of opinion doesn't mean beauty is subjective. Obviously, you did not read or did not understand the point you are arguing against. I gave several examples like flat earth, traffic lights, beauty and the beast, etc. There are people who think earth is flat and many that think it's round so does it become subjective. There are people who cause accidents despite traffic lights so does that mean traffic lights make the world a safer place is subjective. There is ONE reality so two different opinions on it means at least one person is mistaken or wrong. Using your logic: If you accept some people have different opinions on shape of earth, you acknowledge subjectivity of the shape of the earth; duh. As I explained, it's not necessarily beauty that makes people like "uglier" things-- it can be emotions or it can be that they are diseased. A diseased person may think sugar tastes bitter but that does NOT mean sugar is bitter. So people conditioned to work with restricted distorted pictures may get used to it, but that does not mean VGA pictures are just as beautiful as C64 pictures or B&W TVs are show just as beautiful pictures as color TVs.

 

Ha, you are obtuse. The shape of the Earth is a quantifiable, measurable concept. The effectiveness of traffic lights on safety is statistically measurable. I didn't catch your "beauty and the beast" example but I'm sure it's equally ridiculous.

 

There is one reality in the sense that there is one physical universe, to the best of our investigations. However, each individual experiences it through their own subjective perspective. No one has a 100% correct view of reality. Proof only exists in mathematics, which is an abstract structure. All we have as humans to sustain our perspectives is supporting evidence (which you are not providing to bolster your claim that beauty is objective (rationally measurable)). There is very strong supporting evidence that the Earth is round and that traffic lights are effective in given situations. You have still not provided evidence for your claim.

 

I don't understand how you can't tell the difference between objective and subjective reality. Your inability to see things from any perspective but your own (indeed, to even acknowledge any perspective as correct other than your own) really makes me wonder about you. Have you ever been psychologically evaluated? It would be interesting to see the results of that. Seriously, no offense. I'm curious.

[+selgus]

sounds interesting... btw. what is REYES?

Render Everything Your Eyes See... The basis for the Renderman system and what the creators of the Lucasfilms Computer division and PIXAR folks invented.

--Selgus

[+selgus]

just reread it... sounds like voxel engine? and sure front to back and not back to front?

Front to back, so if something was behind a currently rendered landscape, it was just skipped.

--Selgus

[Heaven/TQA]

just reread it... sounds like voxel engine? and sure front to back and not back to front?

Front to back, so if something was behind a currently rendered landscape, it was just skipped.

--Selgus

 

but what is the difference to a z-buffer then?

[PeteD]

Don't you just keep a column height? The voxel code I messed around doing a while ago did, that way you draw from the top of your current "height" down, then when you get the next depth into the Z if its shorter, done, if it's taller, draw down to the previous one. Not sure how RoF works though but it sounds similar..

 

 

Pete

[Kr0tki]

But they didn't and as a result there are 2 different official games.

Yeah, we know that. You showed that on screenshots, and no one disagreed with you. Was the point of the discussion only to repeat it again?

 

I wouldn't say that. You see, a game without music isn't a fully finished game, is it ?

Ah, so the Atari IK version is simply an unfinished game - it is still missing a stage and half of its music, So how dare you come here and compare a fully working game with an unfinished prototype and say that the prototype is worse?

 

Besides, IK was made by the same programmers at different time, while Pitfall II by different programmers at the same time. So the story isn't the same.

I've never said that it is, did I?

[+selgus]

just reread it... sounds like voxel engine? and sure front to back and not back to front?

Front to back, so if something was behind a currently rendered landscape, it was just skipped.

--Selgus

 

but what is the difference to a z-buffer then?

The way the algorithm works is you have a fractal line that you draw into a Y-buffer (so heights for each screen column). Then when you have that line, you can draw it into a persistent frame buffer, and from the previous Y-buffer values, only draw the vertical line which is different from the last. For lines in the buffer that are behind your current Y-buffer, it skips.

 

The depth information is not actually stored per se, the lines are just drawn front to back.

 

Clipping was an issue, and how the fractals get generated via Gaussian random numbers, so you had to run the algorithm on the full line, culling sections, to get the repeatable fractal values for the Y-buffer.

 

Maybe I should start a new thread about this...

--Selgus

[andym00]

His original 1980 video Vol Libre has a remarkable RoF feeling to it in the opening part, not surprisingly really

 

http://vimeo.com/5810737

 

 

Edited October 20, 2009 by andym00

[Rockford]

But they didn't and as a result there are 2 different official games.

Yeah, we know that. You showed that on screenshots, and no one disagreed with you. Was the point of the discussion only to repeat it again?

 

I just replied to your "coulda, shoulda, woulda". We will never know, so only hard facts remain the same.

 

 

I wouldn't say that. You see, a game without music isn't a fully finished game, is it ?

Ah, so the Atari IK version is simply an unfinished game - it is still missing a stage and half of its music, So how dare you come here and compare a fully working game with an unfinished prototype and say that the prototype is worse?

 

No, you are wrong. Unfinished music and game is referred to this:

 

......Seems what happened was Rob Hubbard was asked to do the music for the C64 and the conversion for the Atari was written later, which delayed that release.

 

So, the final Atari version was full commercial game released at full price.

 

 

Besides, IK was made by the same programmers at different time, while Pitfall II by different programmers at the same time. So the story isn't the same.

I've never said that it is, did I?

No, but I did and I wanted to place emphasis on it, since it's the essence (as I had mentioned previously)

[Heaven/TQA]

just reread it... sounds like voxel engine? and sure front to back and not back to front?

Front to back, so if something was behind a currently rendered landscape, it was just skipped.

--Selgus

 

but what is the difference to a z-buffer then?

The way the algorithm works is you have a fractal line that you draw into a Y-buffer (so heights for each screen column). Then when you have that line, you can draw it into a persistent frame buffer, and from the previous Y-buffer values, only draw the vertical line which is different from the last. For lines in the buffer that are behind your current Y-buffer, it skips.

 

The depth information is not actually stored per se, the lines are just drawn front to back.

 

Clipping was an issue, and how the fractals get generated via Gaussian random numbers, so you had to run the algorithm on the full line, culling sections, to get the repeatable fractal values for the Y-buffer.

 

Maybe I should start a new thread about this...

--Selgus

 

yes... because I would be interested as I have searched the web for more information esp. on the ROFL code... in nearly non 8bit atari demo or c64 you see something similar like ROFL or Eidolon which is a reverse version...

 

on the newsgroups you find some basic information but not actually depending on the ROFL algorithm... I went into Eidolon and had some insights how the screen is drawn, where the shapes of the monsters are etc... but not into the maths.

[Kr0tki]

I just replied to your "coulda, shoulda, woulda". We will never know, so only hard facts remain the same.

And what relation has your answer to my "coulda shoulda" discussion with TMR? You want to tell TMR that C64 counldn't do a 2-level Pitfall II only because they didn't do it back in 1984?

 

Ah, so the Atari IK version is simply an unfinished game - it is still missing a stage and half of its music, So how dare you come here and compare a fully working game with an unfinished prototype and say that the prototype is worse?

No, you are wrong. Unfinished music and game is referred to this (...)

You don't see a joke when it hits you in the face, do you? You could as well say

You said that joke about a giraffe that walks into a bar? Well you're WRONG, a giraffe is to tall to walk to a bar!

Priceless.

 

No, but I did and I wanted to place emphasis on it, since it's the essence (as I had mentioned previously)

The essence of what? You came and showed that Atari IK is a bit worse than C64 one, then others say it could be made better, and you come back to say that "the essence is it's still worse". What's the point? Try moving the discussion further.

[atariksi]

No, I don't accept that B&W pictures are more beautiful than color pictures (of same object). You are just declaring beauty is subjective-- not showing I am wrong. It's more of a cop-out since it involves little effort on the part of the people to make such a vague blurb.

 

It all comes down to this... you do understand the reality that outside, in the real world, there are actually people who seriously consider black-and-white photography to be more beautiful than color, don't you? If you deny this, you are denying reality... a disturbing trend.

 

If, however, you accept that some people prefer B/W, then you must acknowledge the subjectivity of beauty.

...

Bad logic. Just because there are differences of opinion doesn't mean beauty is subjective. Obviously, you did not read or did not understand the point you are arguing against. I gave several examples like flat earth, traffic lights, beauty and the beast, etc. There are people who think earth is flat and many that think it's round so does it become subjective. There are people who cause accidents despite traffic lights so does that mean traffic lights make the world a safer place is subjective. There is ONE reality so two different opinions on it means at least one person is mistaken or wrong. Using your logic: If you accept some people have different opinions on shape of earth, you acknowledge subjectivity of the shape of the earth; duh. As I explained, it's not necessarily beauty that makes people like "uglier" things-- it can be emotions or it can be that they are diseased. A diseased person may think sugar tastes bitter but that does NOT mean sugar is bitter. So people conditioned to work with restricted distorted pictures may get used to it, but that does not mean VGA pictures are just as beautiful as C64 pictures or B&W TVs are show just as beautiful pictures as color TVs.

 

Ha, you are obtuse. The shape of the Earth is a quantifiable, measurable concept. The effectiveness of traffic lights on safety is statistically measurable. I didn't catch your "beauty and the beast" example but I'm sure it's equally ridiculous.

..

You can't undertstand your own logic and you are insulting me again. Every reply you try to throw insults at me as if that's going to help your absurd conclusions. First I corrected you because you weren't even addressing the point. Now you can't follow your own logic. Differences of opinion DO NOT make things subjective. There are people who think earth is flat and is in their experience. Have you measured the earth to be circular? I doubt it given you can't even follow your own absurd logic to its absurd conclusions. There are people who think traffic lights aren't worth having. On the contrary, billions of people have color TVs because it gives a MORE beautiful picture than B&W. VGA pictures look more beautiful than CGA/C64. You can measure and study quantization of analog to digital and see which is more beautiful.

 

There is one reality in the sense that there is one physical universe, to the best of our investigations. However, each individual experiences it through their own subjective perspective. No one has a 100% correct view of reality.

...

UTTER RUBBISH. Just your speculation. YOU DO NOT HAVE A CORRECT VIEW OF REALITY. Do not speculate NO ONE does. Have you gone to every person on earth and drew this conclusion. You haven't. Anyone who doesn't see 256 colors when there are 256 is diseased. Anyone who thinks beauty is subjective because of other reasons unrelated to beauty does not know logic.

 

Proof only exists in mathematics, which is an abstract structure.

...

More rubbish. What a hypocrite. Keeps declaring things without any evidence and then blames me for not providing any evidence when the evidence is in FRONT OF YOUR NOSE.

 

All we have as humans to sustain our perspectives is supporting evidence (which you are not providing to bolster your claim that beauty is objective (rationally measurable)). There is very strong supporting evidence that the Earth is round and that traffic lights are effective in given situations. You have still not provided evidence for your claim.

...

I also gave many other examples-- beauty pageant, digitized sound cards, etc.. How many times do I have to correct your views. There are difference of opinions on things that are objective. You are desperately trying to find fault with things YOU DO NOT UNDERSTAND.

 

I don't understand how you can't tell the difference between objective and subjective reality.

...

I can, it's you who can't. The world is more beautiful with more colors and more shades. That's experimentable, quantifiable, etc.

 

Your inability to see things from any perspective but your own (indeed, to even acknowledge any perspective as correct other than your own) really makes me wonder about you. Have you ever been psychologically evaluated? It would be interesting to see the results of that. Seriously, no offense. I'm curious.

 

You are mentally deranged if you think b&w TVs give more beautiful picture than color TV, VGA gives uglier picture than C64 pictures, etc. etc. You need to see a psychologist. My perspecrtive is 2+2=4. If someone else says 2+2=3.9, he should see a psychologist. Give up your foolish ideas and prove something. Stop just making false accustaions-- I haven't provided any proof. So far I have had to remind you what I stated already-- that's a sign of mental derangement-- to argue something without even reading or understanding it. Why don't you just admit at least that you don't even understand what you are trying to argue against. Go back and read everything in context and then compose a rational reply. Your very first reply indicates your bias.

[emkay]

Well, you found at least one. But, have a closer look at the viewing distance(depth) and that the C64 version is full of this "front moving" "back does not".

If you flied in the Atari version straight without turning, with speed set to 1/8 (this C64 film is full of such flying), you'd notice the same feature. Only it would be less noticeable due to higher framerate.

 

Next time try actually running the game before you start bragging about it.

 

 

A) It's simply not true, what you are writing. The A8 version is often correcting the shape of a hill, in the background and in the foreground, where the shape does not change in the C64 version.

 

B) Another interesting fact (thanks to TMR for the tip),If switching Vice to 200% speed, the rotations still stand coarse. Not as fine as the A8 version.

[Kr0tki]

A) It's simply not true, what you are writing. The A8 version is often correcting the shape of a hill, in the background and in the foreground, where the shape does not change in the C64 version.

If instead of using the word "often" you said "always" then you would have a point; otherwise you can't say I wasn't writing truth. In reality your "often" is sometimes as much as "1 in 4 frames".

[emkay]

A) It's simply not true, what you are writing. The A8 version is often correcting the shape of a hill, in the background and in the foreground, where the shape does not change in the C64 version.

If instead of using the word "often" you said "always" then you would have a point; otherwise you can't say I wasn't writing truth. In reality your "often" is sometimes as much as "1 in 4 frames".

 

Simple maths:

 

Doing something -one time- is infinetly more than doing it never

 

 

The A8 version only does no changes in the screenupdates if the range is the farthest.

[Kr0tki]

Simple maths:

 

Doing something -one time- is infinetly more than doing it never

 

Yeah, but often that's not often enough to call it often

 

The A8 version only does no changes in the screenupdates if the range is the farthest.

So we agree. But the other version happens to do the same.

[José Pereira]

Hello all.

 

If you want you could get sources from many, many of the Gremlin Graphics games for diferent machines (it's an authorized/official Site).

This came to me, because of this Game challenge and I was trying to find a game that was done by two portuguese sisters (Marco and Rui Tito) - ALIEN RESOLUTION (Gremlin Graphics), I am trying to find if there's an CPC version, not only the ZX one (I think I saw something about this in C&VGames). And the strangest thing is that I get a message from one of them some days ago on my personal Mail. He's now with one of that enterprises that are always sending things to our Mail (no, not that kind of things!...). I send him an answer about A8 and RetroComputers nowadays, but with no answer untill now. They know something about A8, because they put some listings in portuguse newspapers on the past.

 

O.K. but here is the adresse if someone interested in:

www.gremlinworld.emuunlim.com

 

 

 

By the way, just another thing:

Anyone knows about any Site with Web pages of old Computer Games Spanish Magazines:

MicroHobby (ZX like Crash/Sinclair User)

Micro Mania (like Computer & Video Games but with many maps with real screenshots for various formats).

 

 

Bye now.

José Pereira.

[José Pereira]

Sorry, sorry, sorry.

 

 

My English, oh God.

 

They say "source", not "source code".

 

 

It's only download games.

 

Sorry again.

josé Pereira.

[TMR]

B) Another interesting fact (thanks to TMR for the tip),If switching Vice to 200% speed, the rotations still stand coarse. Not as fine as the A8 version.

 

No, because the turn speed is adjusted for the C64 otherwise the control response speed would be different and the game significantly harder to actually play. Any modified version that took advantage of extra hardware to speed the game up (REU for faster screen clearance, SuperCPU for a 65816, C128 in fast mode during the borders, C64DTV in "fast" mode or it's DMA for the screen clear) would all need the turns re-tuned to allow for that difference.

[TMR]

My English, oh God.

 

They say "source", not "source code".

 

 

It's only download games.

 

T'be honest, we probably don't really want source code... if only one side has a Z80 coder on, that could theoretically make things harder for the other if we were planning to take anything past the core logic.

 

It's not a brilliant archive of Gremlin stuff to be honest, they're missing a couple of formats and indeed games (for example, on the C64 there's no Mask 3 or Bounder on the Rebound unless they've mis-labelled their download of Bounder as it).

[Lazarus]

Well, you found at least one. But, have a closer look at the viewing distance(depth) and that the C64 version is full of this "front moving" "back does not".

If you flied in the Atari version straight without turning, with speed set to 1/8 (this C64 film is full of such flying), you'd notice the same feature. Only it would be less noticeable due to higher framerate.

 

Next time try actually running the game before you start bragging about it.

 

A) It's simply not true, what you are writing. The A8 version is often correcting the shape of a hill, in the background and in the foreground, where the shape does not change in the C64 version.

Both versions do the same math and both versions render all lines every frame. And that sometimes the far away lines don't move also happens on the A8 version, and in fact it even happens MORE OFTEN on A8 because of the higher framerate which results in less coordinate deltas between each frame.

[emkay]

All the justification of C64 guys do not help. A8 is clearly superior in every detail, when it come to 3d/ego rendering. A half blind recognizes that the A8 is doing much more on the screen AND is clearly faster.

[emkay]

B) Another interesting fact (thanks to TMR for the tip),If switching Vice to 200% speed, the rotations still stand coarse. Not as fine as the A8 version.

 

No, because the turn speed is adjusted for the C64 otherwise the control response speed would be different and the game significantly harder to actually play. Any modified version that took advantage of extra hardware to speed the game up (REU for faster screen clearance, SuperCPU for a 65816, C128 in fast mode during the borders, C64DTV in "fast" mode or it's DMA for the screen clear) would all need the turns re-tuned to allow for that difference.

 

 

Please, get serious. The emulation runs at double speed. At least the CPU speed gets doubled, but it doesn't help to get as accurate as the A8 version.

Possibly it is an emulation issue, but you mentioned to use it for a comparision.