Hydra Book & Propeller

Oldbitcollector (Jeff)

I just got my "Game programming for the Hydra" book this afternoon. I'm curious how many of the examples are runnable on the Propeller. (Perhaps with some adjustments?) I'm attempting to get my 12 year old interested in the idea of creating his own games, but I don't really want to make the investment into the Hydra until I see if it actually "takes" -- We've spent plenty of money on other things just to loose interest. (Although Dad would play with it. [noparse]:)[/noparse] )

Perhaps if the propeller just isn't up to the task, does anyone know of a good environment for the PC which might spark his interest in that direction that we could try?

Oldbit

Paul Baker

You have all the material you need to run a fair portion of the Hydra material, the book does a good job explaining the external circuitry. There are no "magic chips" on the Hydra like there is on the SX based consoles Andre' has made. The only thing you may be bumping up against is the extra EEPROM space that comes standard with the Hydra (and the experimenter card slot) for extra asset management required by some of the more complex games.

The Hydra does an excellent job is rolling everything up into what you need to start designing your own games, doing it yourself would require a bit more cobbling of things together to get an approximation of the Hydra (the SNES controllers are a good example).

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

Post Edited (Paul Baker (Parallax)) : 4/10/2007 11:01:02 PM GMT

Mike Green

Keep in mind that the I/O pin numbers are different for the keyboard and display drivers and the keyboard driver is different. There is a "combo" keyboard driver in the Object Exchange that takes care of this.

Also, there are no game controllers on the Demo Board or Protoboard.

AndreL

Basically, all of the demos will work that not do rely on the game controller only. As it has been mentioned though to get them to work its simply a matter of switching the pingroup during the call to the mouse/keyboard driver and the pingroup of the VGA and or NTSC depending on which other propeller board you have. But, bottom line is that its a matter of seconds once you know what to change.

I purposely did NOT use over the 32K limit on the other propeller boards for the book. The idea was to make the demos work on all the propeller boards.

Andre'

Paul Baker

Thanks for clarifying the last point Andre', I was unaware that you made all of them fit on 32K.

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Paul Baker
Propeller Applications Engineer

Parallax, Inc.

AndreL

Yes, its was hard to control myself, but compatibility was more important, so more people could use it. Of course, this made programming 100x harder, compression of assets and all kinds of memory tricks had to be used to get the programs to fit. Considering that, I would say that with a gun to my head (literally, thinking something like the scene in Swordfish where he has 60 seconds to hack into the FBI or whatever), I could probably fit 2-3x more in the same space if I had to. So 32K definitely was more than enough to program all the demos, but without too much work. With 128K, you can get sloppy and relax a bit.

Then again with that scene, I would have done it for free [noparse]:)[/noparse]

Andre'

Mike Green

Because of the different PS/2 wiring scheme between the Hydra and the other Propeller boards, you can't just change the pingroup for the keyboard and the mouse and have the drivers work. I put together a combination driver for the keyboard (in the Object Exchange) that works for both with only a pin number change, but there's no equivalent yet for the mouse. You have to use the proper mouse driver (Hydra vs. Demo Board/Protoboard). It's not a big deal, but it has to be done.

AndreL

That's if the board doesn't use the 4 pin keyboard/mouse drivers. The older demo does, so if he has an older demo board then he would use the ISO driver like the hydra, else the 2-wire driver. So the point is, yes, the keyboard and mouse drivers have to match the hardware, the hydra uses the 4-pin iso version of the drivers. That's a simple enough switch, just a filename and it will work since the other drivers are a little smaller I think as well.

Andre'

Oldbitcollector (Jeff)

I'm using the Protoboard. (just ordered my second one with the book) I'm extremely pleased to see that the Hydra demo's were designed to fit within the memory boundaries. That being the case, it sounds like the keyboard driver is a file switch out, perhaps the mouse won't be too difficult to handle. Just when I was beginning to think I'd seen the most the propeller could handle. (Not even close)

I've noticed that the book breaks down the individual sections, but I'm lost as to how the many inputs were obtained. Perhaps that is the additional chip I see on the Hydra's board in the pics?

So if I understand correctly the Hydra is simply a ready-to-use propeller with all of the "toys" ready to connect. I guess what has thrown me off is the fact that I don't see many developed items posted for the propeller based on the content of this book. If I'm right, then I must really have finally gotten in on the ground floor. (Hmmm Fresh Technology! I love it!)

After spending an hour skimming chapters tonight it looks like I've got a year of content to digest. I'm floored that this is all in one little chip.

Oldbitcollector

AndreL

The hydra just has more IO than the demo boards, plus it has the expansion port to add cards to, so it can be used to expand it like the SRAM card I am about to release. Other than that, the hydra is a propeller more or less. The extra chip you see is a buffer for the VGA signals so if you have monitor plugged in and you are NOT doing VGA you can use the same IO pins without disturbing/driving the VGA, so it allows you to multiplex the VGA with the extra IO and not loose 8 io pins.

Andre'

Oldbitcollector (Jeff)

I sat down and read about half the Hydra book today...
While I was reading, I was pondering prop's new ability to read/write to SD.

To coin a phrase from one of my favorite authors....

"OMG, It's full of stars!"


I think I've already gleaned enough information to at least begin writing some of my own objects immediately... It'lll take me a several more passes to grasp the graphics stuff.
Wow..

Oldbitcollector

AndreL

I have quoted 2001 in a couple of my books as well [noparse]:)[/noparse] Anyway, the graphics stuff is the good stuff, it will take a few times, but the early demos are nice since they start with plot pixel and work their way up.

Andre'

Bamse

I just finished the book and I'm about to start trying the out examples (yes, I'm a slow reader).

The book explains everything so well that I feel like it's going to be harder to learn Spin than using the HEL driver.

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Living on the planet Earth might be expensive but it includes a free trip around the sun every year...

Experience level:
[noparse][[/noparse] ] Let's connect the motor to pin 1, it's a 6V motor so it should be fine.
[noparse][[/noparse] ] OK, I got my resistors hooked up with the LEDs.
[noparse][[/noparse]X] I got the Motor hooked up with the H-bridge and the 555 is supplying the PWM.
[noparse][[/noparse] ] Now, if I can only program the BOE-BOT to interface with he Flux Capacitor.
[noparse][[/noparse] ] I dream in SX28 assembler...

/Bamse

AndreL

The HEL driver is really easy to use. Moding it is pretty easy as well, so its a good starting point to play with an integrated graphics and tv driver that does everything and sprites.

Andre'
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Oldbitcollector (Jeff)

Can the HEL driver be readily converted over for use with the Propeller board?

Oldbit

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"Two things are infinite: the universe and human stupidity; and I'm not sure about the universe." -Albert Einstein

AndreL

It works already I believe, the pingroup used for video is the same, else its just a single line of code you need to change.

Andre'