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New game project: Jetpac


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Looking good! I'm finding that it's sometime difficult to pick up fuel or rocket parts. I walk over the object multiple times and it doesn't seem to register. Then, all of a sudden it does register. Any ideas?

 

Willsy, that used to be a problem when COINC was buggy. You fixed that with TF version 1.2.2. I have no issues with grabbing objects and rocket parts when walking on my end. Are you sure you are using the last version of TF?

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Willsy, that used to be a problem when COINC was buggy. You fixed that with TF version 1.2.2. I have no issues with grabbing objects and rocket parts when walking on my end. Are you sure you are using the last version of TF?

Ah! I was using 1.2.1:4 on my office machine. I'll upgrade it :-)

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This has been a good week for time and getting things done, so I will start on the sound Sunday around packing stuff for the Faire. I am hoping to get most of it done as I will not be able to do more hobby work again until Thursday.

 

Sounds great! Looking forward to seeing the results! Thanks again for tackling this :)

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  • 3 weeks later...

Ultimate's first release was Jetpac in May 1983 for the 16K Spectrum, followed by BBC Micro and Commodore VIC-20 versions. It was a huge commercial success; the Spectrum version alone sold more than 300,000 copies to a market of only one million Spectrum owners at the time, and providing the fledgling company with a turnover in excess of £1 million.

Has a reference (7) to a glossy 6 page (starting at page 50) article. Avail. ;)

The article has this in the beginning

 

Though Jetpac never set a toe inside an arcade, for many its appeal and brilliance largely came from the fact that it looked and played like an arcade game. Its visuals were big, bright, and well detailed, its animation slick and smooth, even the laser weapon fired by its hero conjured up memories of blasting away aliens in Defender.

and later

 

"The thing that stood out to me the most was the laser firing effect. 'That's just like Defender', I thought!"

I think Forth may have a hard time keeping up with the laser, but I hope you'll try and implement it as seen in the original (from 0:55 in the video below). If not allowing the apparent 4 shots on screen at once, then at least try and go for 1 shot on screen with the same animation.

 

;)

 

Edited by sometimes99er
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You can check the current implementation of laser fire with version 0.2 at the top of the thread. The problem lies not so much in the speed of Turbo Forth but in the fact that I do no have access to bitmap mode in TF. The laser fire is clearly bitmap based in the original... What I have implemented is a series of sprites in a row, and although some of them will necessarily not show up once more than 4 are on a single row, with repeated fire it actually gives the illusion of flickering which works :) Nonetheless, I am still not 100% happy with the laser as of yet, but it will have to do for the time being until the rest of the game elements are in place. Currently working on the Monsters animations and motions as this is the last major element for the game. Making good progress here.

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You can check the current implementation of laser fire with version 0.2 at the top of the thread. The problem lies not so much in the speed of Turbo Forth but in the fact that I do no have access to bitmap mode in TF. The laser fire is clearly bitmap based in the original... What I have implemented is a series of sprites in a row, and although some of them will necessarily not show up once more than 4 are on a single row, with repeated fire it actually gives the illusion of flickering which works :) Nonetheless, I am still not 100% happy with the laser as of yet, but it will have to do for the time being until the rest of the game elements are in place. Currently working on the Monsters animations and motions as this is the last major element for the game. Making good progress here.

Yes, I saw that one. I think you're running/going to run short on sprites, and have some disappear or not even show up in their individual lifespan. Do you consider a sprite flicker routine ?

 

Tursi once did a plot routine in plain Basic and drew a high resolution picture of Albert from MAD. This method involves dedicating characters to the screen as if they are part of a real bitmap. Faking bitmap.

 

So, if you stay with 1 color for lasers, you could do all 4 lasers. But you may have to reserve 4 x 32 = 128 characters for that. If you downsize to only 1 laser at a time, then you need 32 characters, or in this case, you can reuse characters and only need 7 characters, and the trick to this is not especially complex.

 

I can try and demonstrate later if you want. All fine if you don't.

 

;)

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Yes, I saw that one. I think you're running/going to run short on sprites, and have some disappear or not even show up in their individual lifespan. Do you consider a sprite flicker routine ?

 

Tursi once did a plot routine in plain Basic and drew a high resolution picture of Albert from MAD. This method involves dedicating characters to the screen as if they are part of a real bitmap. Faking bitmap.

 

So, if you stay with 1 color for lasers, you could do all 4 lasers. But you may have to reserve 4 x 32 = 128 characters for that. If you downsize to only 1 laser at a time, then you need 32 characters, or in this case, you can reuse characters and only need 7 characters, and the trick to this is not especially complex.

 

I can try and demonstrate later if you want. All fine if you don't.

 

;)

 

Actually I still have 10 sprites to play with even after the monsters are on screen :) I have thought of using characters instead of sprites for the fire sequence, but the main complication will be checking for interaction with both background characters and sprites, primarily from a speed standpoint. I may go back to that at some point, but not until I have the main game elements all in place. Also, because the Jetman sprite is moving 1 or 2 pixels at a time horizontally, the start of the laser may not always coincide with the laser gun muzzle, although that may not be a deal breaker. For vertical movement, I could have 8 separate definitions for the same set of characters, each one offset by one pixel line, and just changing the definition on the fly depending on the vertical position of Jetman. All this of course implies only one beam in any 8 pixel row, and that may be OK too.

I've done fake bitmap in XB when I recreated Archimede's spiral, so I'm familiar with the process. But the kind of calculations required to redefine characters on the fly are rather time consuming and not really needed as noted above :)

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  • 2 weeks later...

Here's a quick video of current state. I am not yet releasing the current version's source code as I still have a few bugs to fix. Hopefully this should happen by end of week. All the main game elements have now been implemented with the exception of sound, so it's looking pretty good :)

 

https://youtu.be/TAfivH3XMOQ

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Damn! That's awesome man. You really nailed it!

 

Level 2 seemed faster than level 1. Did you hit CPU overdrive on Classic99 or something?

 

Really impressed! :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup:

 

Thanks :) Background collision was still not implemented on level 2 :P The behavior of the monsters varies from level to level, and I'm still working on that.

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Having played the Vic20, BBC Micro and ZX Spectrum versions, I think I can say that this version compares best with the original. This was also true of SabreWulf and Jet Set Willy, it seems that the 4a is well suited to Spectrum conversions.

 

Yes. The spectrum and the TI have the exact same screen resolution: 256x192. That makes things a lot easier.

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