Line of Fire Question

[Leffmann]

This thread is starting to read like a cross-examination. Luckily, nobody is actually obliged to answer to the self-appointed judge, jury, and cross-examiner.

[britelite]

Originally Posted by Leffmann

This thread is starting to read like a cross-examination. Luckily, nobody is actually obliged to answer to the self-appointed judge, jury, and cross-examiner.

Yeah, I know I'm quite the a-hole for asking someone to back up their wild claims, on a technical forum...

[zero]

Originally Posted by britelite

It's hard to say, considering the movement seems to be linear

The movement is clearly not linear. Go watch a YouTube video of the AMiga version, it clearly uses a limited number of scaled images.

[britelite]

Originally Posted by zero

The movement is clearly not linear. Go watch a YouTube video of the AMiga version, it clearly uses a limited number of scaled images.

Ahh, yes, I was maybe being a bit unclear. What I meant was that the movement of the levels seems linear from the quick look I had on youtube, as in you can't move at different speeds or backwards.

The scaling could still be "realtime", in the sense that it actually could calculate the next scaled version of a bob during, for example, 10 frames while moving the previous version every frame. That would save a lot of memory, as you wouldn't need to store all the versions in memory the whole time.

[Daedalus]

Originally Posted by Leffmann

This thread is starting to read like a cross-examination. Luckily, nobody is actually obliged to answer to the self-appointed judge, jury, and cross-examiner.

True, but I (and I'm sure others too) would love to know more about the technical details of a 25-bit-plus graphics colour format (both hardware and software) - how it works, what software of the time was used to create it, what the custom DAC was like, and why they went that route instead of a standard 24-bit part...

[LaBodilsen]

Originally Posted by zero

The movement is clearly not linear. Go watch a YouTube video of the AMiga version, it clearly uses a limited number of scaled images.

Looking at the youtube video, the scaling seems pretty linear on Y-axis, but is jumping on X-axis. so maybe a combination og pre-scaled images, and some realtime Y scaling?

Also the "between" levels maps, have some pretty smooth scaling, which do not seem pre-scaled.

[saimon69]

With those scaling routines i see feasible a port of Rambo III arcade version, that i thought superior to the crappy one we had on amiga

[Shatterhand]

Line of Fire is a kinda crap game... the ARCADE verison isn't very good IMO. The port is good enough, but the game is crap.

[saimon69]

hmm, i think i have seen this flag emblem somewhere

[mcgeezer]

The game was built on the sega x board which has a palette of 98,000 colours.

Where the 21 million colour palette comes from is a bit of a mystery.

Read more here https://segaretro.org/Sega_X_Board

Edit - just looking into this.

If you read exactly what Richard Aplin says about the colours...

"The bitmap graphics were grabbed from the arcade PCB video output by Andy Heike and Nick Vincent with the colour frame grabber, and the sprites were read, decoded and converted from the arcade machine's Eproms by me. (Not a bit of bloody help from Sega either!)"

I'm reading this as the source graphics and palette never came directly from the arcade board, instead they were staged to another output which had 25 bit colour depth capabilities and then mixed down to 16 colours.

The arcade board doesn't have 21 million colours, anyone who argues otherwise would struggle with credibility.

[dlfrsilver]

Originally Posted by britelite

This has absolutely nothing to do with what I said.

Indeed, but you wanted graphic specs, you got them

[mcgeezer]

If there's one thing I know for sure hanging around in these coders threads is that you have to be able to backup your shit when you make a claim, otherwise you'll get challenged, eaten alive and probably banned.

Just ask Trachu. I haven't seen him in ages.

[dlfrsilver]

Originally Posted by mcgeezer

If there's one thing I know for sure hanging around in these coders threads is that you have to be able to backup your shit when you make a claim, otherwise you'll get challenged, eaten alive and probably banned.

Just ask Trachu. I haven't seen him in ages.

the difference is that my results are my proofs. To this day, i'm the only guy able to process the sega system graphics and extract them

Lately i have processed Wonderboy from Sega. I have all the sprite elements handy with the good colors

I have also worked out my magic on Shinobi

[mcgeezer]

Originally Posted by dlfrsilver

the difference is that my results are my proofs. To this day, i'm the only guy able to process the sega system graphics and extract them

Without wanting to start an argument.

You don't have any proof. Proof requires evidence to be then established and confirmed by peers in the related subject. You haven't provided any evidence to support your proof.

Regardless of what proof you think you have. I'm willing to accept that you "think" they have that many colours and you're mistaken or don't understand.

But to say you are certain that the raw bitmap/sprite/tiles contain bits that translate to 21 million onscreen colours is incorrect and therefore, you're wrong - I'd rather you just accept it and save face.

If you are right, I will happily apologise to you and accept I am wrong.

[britelite]

Originally Posted by dlfrsilver

Indeed, but you wanted graphic specs, you got them

No, you didn't give me any specs yet.

[mcgeezer]

From the Mame driver...

//
	//  Color generation details
	//
	//  Each color is made up of 5 bits, connected through one or more resistors like so:
	//
	//  Bit 0 = 1 x 3.9K ohm
	//  Bit 1 = 1 x 2.0K ohm
	//  Bit 2 = 1 x 1.0K ohm
	//  Bit 3 = 2 x 1.0K ohm
	//  Bit 4 = 4 x 1.0K ohm
	//
	//  Another data bit is connected by a tristate buffer to the color output through a
	//  470 ohm resistor. The buffer allows the resistor to have no effect (tristate),
	//  halve brightness (pull-down) or double brightness (pull-up). The data bit source
	//  is bit 15 of each color RAM entry.
	//

It's a 16 bit colour palette, 5 bits for Red, 5 bits for Green and 5 bits for Blue and 1 tristate bit controlling brightness across all three.

I work that out at 98304 available colours on the game. 15 bits giving an allowable 32,768 (colours) * 3 (brightness) = 98,304 true colours.

That's settled.

[dlfrsilver]

Originally Posted by mcgeezer

From the Mame driver...

//
	//  Color generation details
	//
	//  Each color is made up of 5 bits, connected through one or more resistors like so:
	//
	//  Bit 0 = 1 x 3.9K ohm
	//  Bit 1 = 1 x 2.0K ohm
	//  Bit 2 = 1 x 1.0K ohm
	//  Bit 3 = 2 x 1.0K ohm
	//  Bit 4 = 4 x 1.0K ohm
	//
	//  Another data bit is connected by a tristate buffer to the color output through a
	//  470 ohm resistor. The buffer allows the resistor to have no effect (tristate),
	//  halve brightness (pull-down) or double brightness (pull-up). The data bit source
	//  is bit 15 of each color RAM entry.
	//

It's a 16 bit colour palette, 5 bits for Red, 5 bits for Green and 5 bits for Blue and 1 tristate bit controlling brightness across all three.

I work that out at 98304 available colours on the game. 15 bits giving an allowable 32,768 (colours) * 3 (brightness) = 98,304 true colours.

That's settled.

I'm fine with this You found it in the mame video driver of Line of Fire. This system is used on each sega system board. For instance, wonderboy and wonderboy in monsterland use this color system.

however for the extraction, be my guest :













Just a little taste of my reverse engineering on the arcade graphic roms.

[mcgeezer]

Originally Posted by dlfrsilver

I'm fine with this You found it in the mame video driver of Line of Fire. This system is used on each sega system board. For instance, wonderboy and wonderboy in monsterland use this color system.

So you agree it does not have 21 million colours?

[LaBodilsen]

Found this little bit of info in the Final Fight startup-sequence listed here:

http://codetapper.com/amiga/comedy/final-fight/

Oh yeah.. the real-time x/y-flipping and decompressing sprite-routine is
alright too.. but a tad slow. Ah well, the Line of Fire real-time scaling
sprite routine was slightly neat as well, and look how slow that game was!

[dlfrsilver]

Originally Posted by mcgeezer

So you agree it does not have 21 million colours?

From what the mame video stands, yes.