Original 1984 Crystal Castles BINary image now available....

[+Allan]

I need to get back on the 5200 version at some point.

 

Yes, Please!

 

I think I'll just leave trakball support out.

 

 

Allan

[Tempest]

Off the top of my head (this is from months ago, so please pardon if I miss something...) --

 

 

XE version changes playfield colors like the arcade game, the 16K one doesn't change colors at all.

XE version has 'better' PM graphics (less x4 player width) vs. 16K one

XE version has properly masked drawing for the hat and bees vs. 16K one

XE version has god-awful flashing "invincible" Bently, 16K one is much more like arcade game

XE version has attract mode (demo) vs. 16K one

XE version is around 30-40% slower than the 16K one (or the arcade game) - not sure if that's a result of the extra graphics masking or just an intentional move to dumb it down.

Neither has high-score support IIRC.

 

 

Other thing I noticed this morning is that the XE version has a proper "Ghost" effect when Bently goes inside structures and behind things. The 16K version just shows the same old Bently graphic which makes it hard to tell if you're behind things.

 

Tempest

[Clay Cowgill]

I fought with the 5200 Trakball for a LONG time trying to get something "good enough" for Crystal Castles.

 

The problem is that the 5200 TB emulates a joystick. When it's at rest the stick is 'centered'. When you spin to the right, the virtual joystick 'tilts' to the right. If you spin faster the 'joystick' moves farther.

 

On a real arcade game, a trakball is an encoder-- it tells you the direction and the number of pulses moved. It's just like a mouse on a PC. (Except it's upside down.)

 

The problem gets to be with how the Crystal Castles code works and how the trakball is read. CC, being for the Atari 8-bits, was designed for digital joystick inputs. The method that Bentley moves is rather intimately tied to the games main timing loop. There are lots of checks performed with Bentley's position as the game 'updates' his position based on input. (On a gem? On an enemy? On the path? On an elevator? etc...)

 

Since the code is always expecting Bentley to move only one 'delta' at a time this works dandy. If however you try to move Bentley *more* than one unit at a time (like if you're trying to approximate a fast trak-ball spin) the collision detectors can break-- you'll pass over gems, through enemies, etc. To make matters worse, animation frames are triggered by seeing sequential position values, skipping over any makes Bentley skip animation frames.

 

One thing that *does* work is to slow down the movement summing. Right now I have two speeds for Bentley depending on how far you move the joystick. If you need to do something tricky you can tilt the joystick less than half way and he'll walk along slowly. If you tilt the joystick farther he moves at regular (full) speed.

 

This same technique with the trakball however, sucks. The 5200 trakball is really low resolution. You can give the trakball a mighty spin and the "joystick" will seem to move pretty far-- for a fraction of a second. What it boils down to is that for 'small' movements the trakball circuitry is really spastic (twitchy outputs), so you can only rely on larger values to get out of the noise. However, in order to get at the larger values the player has to spin that trakball a LOT. It's just not much fun to play that way.

 

(In all fairness, I also think that the trakball motion in Missile Command and Centipede is totally horrible. But again I'm an arcade guy primarily so I might just be being snooty.)

 

So, in the 5200 Crystal Castles I *could* leave the trakball support in, but I think it's pretty pitiful. I'd almost rather take the flak for "why isn't there trakball support?" than "why does trakball support suck?".

 

-Clay

[Clay Cowgill]

 

That's true. In the arcade version, the sprite actually changes to just be Bentley's *boots*. (No ghosting, or outlines, etc.) Not sure which is better really. I kinda liked the 16K version's effect better for playing-- seemed easier to see where you're going.

 

-Clay

[Curt Vendel]

Clay,

 

I have some documents from Rob Zydbel on Trakball programming for the 5200, I will pull them out, scan them and email you a copy and post it onto the 5200 trakball section of the Atari Museum and give Alex & Albert a copy to post with their hardware section of the 5200 here on AA.

 

 

 

Curt

[+Allan]

I fought with the 5200 Trakball for a LONG time trying to get something "good enough" for Crystal Castles.

 

The problem is that the 5200 TB emulates a joystick. When it's at rest the stick is 'centered'. When you spin to the right, the virtual joystick 'tilts' to the right. If you spin faster the 'joystick' moves farther.

 

On a real arcade game, a trakball is an encoder-- it tells you the direction and the number of pulses moved. It's just like a mouse on a PC. (Except it's upside down.)

 

The problem gets to be with how the Crystal Castles code works and how the trakball is read. CC, being for the Atari 8-bits, was designed for digital joystick inputs. The method that Bentley moves is rather intimately tied to the games main timing loop. There are lots of checks performed with Bentley's position as the game 'updates' his position based on input. (On a gem? On an enemy? On the path? On an elevator? etc...)

 

Since the code is always expecting Bentley to move only one 'delta' at a time this works dandy. If however you try to move Bentley *more* than one unit at a time (like if you're trying to approximate a fast trak-ball spin) the collision detectors can break-- you'll pass over gems, through enemies, etc. To make matters worse, animation frames are triggered by seeing sequential position values, skipping over any makes Bentley skip animation frames.

 

One thing that *does* work is to slow down the movement summing. Right now I have two speeds for Bentley depending on how far you move the joystick. If you need to do something tricky you can tilt the joystick less than half way and he'll walk along slowly. If you tilt the joystick farther he moves at regular (full) speed.

 

This same technique with the trakball however, sucks. The 5200 trakball is really low resolution. You can give the trakball a mighty spin and the "joystick" will seem to move pretty far-- for a fraction of a second. What it boils down to is that for 'small' movements the trakball circuitry is really spastic (twitchy outputs), so you can only rely on larger values to get out of the noise. However, in order to get at the larger values the player has to spin that trakball a LOT. It's just not much fun to play that way.

 

(In all fairness, I also think that the trakball motion in Missile Command and Centipede is totally horrible. But again I'm an arcade guy primarily so I might just be being snooty.)

 

So, in the 5200 Crystal Castles I *could* leave the trakball support in, but I think it's pretty pitiful. I'd almost rather take the flak for "why isn't there trakball support?" than "why does trakball support suck?".

 

-Clay

 

Personally I love the trackball on Missile Command, Centipede, and especially Millipede. I can get much better scores using the Track Ball. But if any joystick came close to being like a Trackball, it's the 5200 stick. Although it would be a disappointment if there was no trackball control on CC, it would be worse if you kept stuggling with the TB control and delayed finishing it.

 

Looking forward to CC with or without TB control.

 

Allan

[Dutchman2000]

Clay-

 

The input routine might need to be completely rewritten to support the 5200 analog sticks and trak-ball. Different speeds are obtainable with these sticks, as 5200 tempest proves. You will spin faster around the tubes when you move the stick faster.

 

I might be able to help you do that.

[Curt Vendel]

Clay-

 

The input routine might need to be completely rewritten to support the 5200 analog sticks and trak-ball. Different speeds are obtainable with these sticks, as 5200 tempest proves. You will spin faster around the tubes when you move the stick faster.

 

I might be able to help you do that.

 

GEEK!!!

 

[Dutchman2000]

Thanks Curt, I didn't know you cared!

[classics]

For those of you who would like to load this from disk or want it in Atari exe format you can download it here.

 

It just the same rom image with an Atari binary load header attached.

 

http://www.atarimax.com/crystal.zip

[+Allan]

Clay,

 

 I have some documents from Rob Zydbel on Trakball programming for the 5200, I will pull them out, scan them and email you a copy and post it onto the 5200 trakball section of the Atari Museum and give Alex & Albert a copy to post with their hardware section of the 5200 here on AA.

 

 

 

Curt

 

Hi Curt,

 

Did you ever get a chance to scan and post these? Very curious!

 

Allan

[Curt Vendel]

Hi Allan,

 

I'll post them sometime Wed/Thurs....

 

 

Curt