How does X2:Megablast parallax with all that colors?

[DanScott]

16 colours for background and sprites (enemies)

16 colours for the main character HW sprites... his armour changes colour as it powers up, so can change the HW sprite palette for this "effect"

Overlay score panel can be done as multiplexed hardware sprites too, as the main character (IIRC) always stays central in the screen.

I think a very good conversion of Black Tiger can be done. I will look at putting something together as a test

[sandruzzo]

Originally Posted by DanScott

16 colours for background and sprites (enemies)

16 colours for the main character HW sprites... his armour changes colour as it powers up, so can change the HW sprite palette for this "effect"

Overlay score panel can be done as multiplexed hardware sprites too, as the main character (IIRC) always stays central in the screen.

I think a very good conversion of Black Tiger can be done. I will look at putting something together as a test

Keep In mind what weìre doing for rygar

[DanScott]

Yes, i know full well what you're doing for Rygar this is a different game, different style (slightly)... and a different approach for Amiga conversion

Keep going with Rygar.. it is looking good so far.. but needs a lot of work still

[saimon69]

Originally Posted by DanScott

16 colours for background and sprites (enemies)

16 colours for the main character HW sprites... his armour changes colour as it powers up, so can change the HW sprite palette for this "effect"

Overlay score panel can be done as multiplexed hardware sprites too, as the main character (IIRC) always stays central in the screen.

I think a very good conversion of Black Tiger can be done. I will look at putting something together as a test

I could help in doing the in-game music; got specialized in two channel music lately, and i can bet most of the in-game tracks can be stepped down to that so to have the remaining two fir SFX

[DanScott]

Originally Posted by saimon69

I could help in doing the in-game music; got specialized in two channel music lately, and i can bet most of the in-game tracks can be stepped down to that so to have the remaining two fir SFX

thumbs up.. the music is quite simple in Black Tiger

I have so much experience with this coin-op

and as an 17 year old, was so dissapointed with the conversion... who knew at that time, I would go on to program some well known Amiga titles

[sandruzzo]

Originally Posted by DanScott

Yes, i know full well what you're doing for Rygar this is a different game, different style (slightly)... and a different approach for Amiga conversion

Keep going with Rygar.. it is looking good so far.. but needs a lot of work still

I know rygar is different, what I meant, is that we can do a great conversion too here

Rygar is very complex as game play, japanese are very tough

[sandruzzo]

In order to speed up things, you could use 2 big interliaved planes:

1-3-5 and 2-4-6. With this layout, you can blit objects that require less colors, but you can still have the whole 6 or 5 planes for the comples ones.

[Lazycow]

@sandruzzo: Nice idea, didn't came up with that, yet. But there's a drawback: If you blit 3-plane blitter objects - e.g. for shots or explosions or something, then the background has to be empty. If the object is placed over backgrounds, the colors will be off...

So I guess it would only work in very specific setups.

[sandruzzo]

Originally Posted by Lazycow

@sandruzzo: Nice idea, didn't came up with that, yet. But there's a drawback: If you blit 3-plane blitter objects - e.g. for shots or explosions or something, then the background has to be empty. If the object is placed over backgrounds, the colors will be off...

So I guess it would only work in very specific setups.

the second blit, will take less cycles since you don't need the whole coockie-cut

[Lazycow]

what do you mean with 2nd blit?
1. blit shape with mask (do you mean this with cookie-cut?)
2. blit background over shape (restore background)
Both blits would be faster with 3 planes. But it only works if the other planes are empty. (or do I miss something?)

[sandruzzo]

Originally Posted by Lazycow

what do you mean with 2nd blit?
1. blit shape with mask (do you mean this with cookie-cut?)
2. blit background over shape (restore background)
Both blits would be faster with 3 planes. But it only works if the other planes are empty. (or do I miss something?)

1. blit shape with mask (do you mean this with cookie-cut?) first tree plane
2. make an hole into background (faster than cookie-cut) last tree plane
3...other operations

[Lazycow]

Originally Posted by sandruzzo

2. make an hole into background (faster than cookie-cut) last tree plane

Ahh...
Ok, you would need a 2nd blit for each object, but still, that could be a little bit faster, indeed. Nice idea!

[sandruzzo]

Originally Posted by Lazycow

Ahh...
Ok, you would need a 2nd blit for each object, but still, that could be a little bit faster, indeed. Nice idea!

Yes. so if we need to have small object with less colors, we can use this simple trick. We have 2 possible layout 8 colors plus 8 colors! Not bad!

[mcgeezer]

There was a thread recently on Facebook relating to Xenon 2 which discussed the opinions of how bad and good people liked the game. After delving into the code of the game a little Galahad gave me a link to this thread.

The Amiga version of the game uses the Blitter extensively to so you can't realistically call it a direct ST port as they did go to some effort on the Amiga version.

But the reason for this post is around the speed and technique used on the scrolling, the programmers decided to blit absolutely everything (even the star field according Galahad but I haven't seen this in the code).

The first 2 bitplanes in the game handle the background in the game, they then seem to blit the entire foreground. It looks like they don't make any use of the sprites.

So my question is, did they make the best use of the Amiga hardware? Could they have improved the game speed wise?

My initial thoughs were that they could have used Half Brite mode given the gradients of the palette but that doesn't seem possible from my calculations.

They didn't make any use of the hardware sprites though which would certainly improved things in places.

What else could they have done?

Geezer

[Hewitson]

From a programming perspective I'm not qualified to say what they could have done better.

As far as I'm concerned there is absolutely no excuse for the framerate. Games like Hybris and Apidya look much nicer and run far more smoothly.

[mcgeezer]

Originally Posted by Hewitson

As far as I'm concerned there is absolutely no excuse for the framerate. Games like Hybris and Apidya look much nicer and run far more smoothly.

Hybris and Apidya don’t use parallax scrolling.

But this is the whole point of exploring the xenon 2 paradox, could it have been done better with the constraints they had? (Better as in frame rate)

[Galahad/FLT]

Originally Posted by Hewitson

From a programming perspective I'm not qualified to say what they could have done better.

As far as I'm concerned there is absolutely no excuse for the framerate. Games like Hybris and Apidya look much nicer and run far more smoothly.

Both also don't have remotely as many things going onscreen either.

When Xenon 2 gets hectic, it gets VERY hectic.

[roondar]

Originally Posted by mcgeezer

Hybris and Apidya don’t use parallax scrolling.

But this is the whole point of exploring the xenon 2 paradox, could it have been done better with the constraints they had? (Better as in frame rate)

I've thought about it for a bit as I like puzzling about this kinda stuff

Setting aside the number of objects thrown around on screen (as Galahad points out, it can get very hectic which means 50Hz is going to be challenging regardless of any other consideration), the main issue is the dual layer screen. The method used here is not efficient at all and doesn't suit the Amiga's hardware well. However, it's not so easy to just replace it with a way better suited for the Amiga as the game's design choices aren't really "compatible" with the way dual layer screens are normally done on the Amiga.

Normally you'd either use Dual Playfield mode or a Sprite layer. Neither are a good fit here: Dual Playfield mode doesn't have enough foreground colours and a Sprite layer can only display 128 unique pixels per scanline (which is not enough for the graphics used on the background layer).

Now the above two compromises will definitely help increase the frame rate, but will degrade the looks.

So what's left?

Well, I've thought up one potential way to improve things compared to the current "redraw the entire FG" option. What you could do is change the game to run in 5BPL as follows:

• Put one of the two background layer bitplanes in bitplane 5
• Combine the other background layer and the 4th foreground bitplane in bitplane 4 (you can probably do this with a masking blit, I'm pretty sure you won't need full cookie-cut)
• Bitplanes 1-3 are as normal

Since the scrolling is slow in Xenon, it's probably possible to do the masking over several frames instead of needing to do it every frame, which will further help (though this needs an extra buffer to prevent issues with Bob drawing).

To further improve speed, use hardware sprites for as much as possible (an easy way would be to try to draw as many of the player bullets as possible using sprites).

I'm pretty certain that a method like above will run faster than what Xenon 2 uses at the moment. I'm not so certain it will make the game run at 50Hz though.

[Tigerskunk]

A steady 25 fps would be a huge improvement already, imo.

[mcgeezer]

Originally Posted by roondar

Normally you'd either use Dual Playfield mode or a Sprite layer. Neither are a good fit here: Dual Playfield mode doesn't have enough foreground colours and a Sprite layer can only display 128 unique pixels per scanline (which is not enough for the graphics used on the background layer).

Would you get any gains by multiplexing the background layer with sprites (similar to Risky Woods?) I know RW points to the same graphics data per sprite but due to only needing 4 colours does it not make it possible?

Pretty sure you covered this in one of your cool videos about a free-form sprite layer.