Jump to content

skywaffle's Photo


Member Since 7 May 2004
OFFLINE Last Active Today, 3:44 PM

#4229327 Demo / Playable preview - Intellivania; Castlevania on Intellivision

Posted by skywaffle on Thu Feb 28, 2019 9:53 AM

Having followed some of Deep Zone's development, and seeing the Gyruss cartridges pop up on eBay really discouraged me from doing a public release with source.



There are people on this forum that steal code and produce a cartridge of someone else's work and sell it on eBay.

#4220428 Demo / Playable preview - Intellivania; Castlevania on Intellivision

Posted by skywaffle on Fri Feb 15, 2019 11:42 AM

As much as I would love to expand on Castlevania like gameplay, and had considered it as a future project.  I have already made the entire game, (every stage and boss is there and done),  there is some polish needed in areas, and I would like to figure out how to add the various secrets (although I have some, just not the ones that require kneeling, falling, waiting, or walking against walls to access).  Everything currently weighs 81kb, which leaves little room for extras, although I had contemplated trying to add some basic optional things, like item

randomization, or expanding on loop 2, similar to the original game, but maybe going farther. 


The only real reason why I opted to make a small demo rather than release what I have is for a couple reasons.  There still is more polishing I feel I can do in some later stages, but I have also been hesitant to release this, only to see someone on eBay selling an overpriced Parker Brothers Prototype of Castlevania using the ROM..  I may be off base about that though, but was getting the impression that people's efforts in the homebrew community are getting exploited.


As far as the name goes, for the longest time the title screen was an Intellivision mock up of the NES game.   I had always initially intended this to be Castlevania on the Intellivision, from an alternate universe of course, seeing that the only official ports that were ever released were some slightly average (or worse) home computer versions.  However, not wanting to stir up any legal trouble, I felt that Intellivania worked and was a nice homage to one of my favorite game series.


On the other hand, a game like "Intellivania" could introduce unique enemies, levels, quests that would make it exclusive to the console instead of an as close port as possible of a 30+ year old game people already played. I noticed that several of the officially licensed games released lately include extra levels and other enhancements to the original versions, just to make them more than just ports, but it would depend on the IP holder to not only grant a license to use the name but also to modify or extend content of the original game. 

#4219433 Demo / Playable preview - Intellivania; Castlevania on Intellivision

Posted by skywaffle on Wed Feb 13, 2019 4:21 PM

Thank you!  Strangely I have had most of this demo more or less ready months ago (I had posted videos of the first two levels on Youtube).   Although much more time has been spent trying to add things like hidden blocks, various polish on controls (stairs mostly), sound effects, and then constant rewriting of routines, music, and other optimizations for performance and/or freeing up space.  There are bits that I still would like to improve on as time allows, but overall I had felt that everything was beginning to feel more similar to how Castlevania on the NES feels.  I even spent an evening last week just playing through the original NES game, and then through the second loop (which is a harder difficulty), to help identify where some shortcomings / balance issues might be; especially in the later areas.



I just played it via the LTO Flash and that looks and sounds great! Never in a million years, did I ever expect to be playing Castlevania on an Intellivision of all things. :lol: :D

#4218530 Demo / Playable preview - Intellivania; Castlevania on Intellivision

Posted by skywaffle on Tue Feb 12, 2019 10:33 AM

Hello, sorry for the trouble,  I went ahead and uploaded a new ROM image that allows both the lower left and right buttons to work as attack.


One suggestion, map the whip action to buttons on both sides of the controller, I hold controller in left hand, using right for disc etc
Its awkward to press left buttons but easy to press right ones.

#4217880 Demo / Playable preview - Intellivania; Castlevania on Intellivision

Posted by skywaffle on Mon Feb 11, 2019 1:34 PM

Hello everyone,

I figured while working on polishing up various things for my Castlevania project, I could at least assemble a small demo for people to play around with on emulators or the LTO Flash.   It is only the first two levels, but should give an impression of what to expect. 


There are no in game instructions,  If anyone is unfamiliar with the gameplay mechanics, there should be plenty of information online.   If anyone has questions otherwise, I will be happy to answer. 



Attached Files

#4215232 Question regarding storing multiple values into a single 16-bit wide value

Posted by skywaffle on Thu Feb 7, 2019 5:34 PM

I am interested in the possible benefits of both.  Currently I have really poured my time into just one project.  But I can't help but wonder about other types of games.  Some may have a need for smarter management of memory.  But currently my biggest obstacle has been ROM space.   I just am wanting to avoid the need for page flipping, and honestly it seems like I won't have to now.


When I started my Castlevania project, I did not know anything about IntyBASIC, and really am not a programmer.  However, over the months, I have learned an awful lot, and despite trying to always use the manual for reference,  some benefits to commands are not always obvious from the get go.   For example, in just the past month or so I learned just how invaluable Define Varptr is.   I always wondered why it seemed as if I could not define grams dynamically, as the Screen command could do so (and did not use "Varptr").   Getting rid of tons of define commands alone freed up space, not to mention made for much easier animation routines.


OK, so it sounds like it could end up being a little bit of both:  Packing ROM lookup tables and possibly packing values in memory.  The initial need was ROM tables, but RAM variables may also need it eventually.


Storing projectile on/off status in a single 16-bit variable shouldn't be too costly.  I'd recommend having two lookup tables:  One for setting bits and one for clearing bits.  Then you could define some simple functions like this:


DEF FN SetBit(var, bit) var = NOT (NOT var AND ClrMask(bit))
DEF FN ClrBit(var, bit) var = var AND ClrMask(bit)
DEF FN TstBit(val, bit) ((val) AND SetMask(bit))

' This is the same as the power-of-2 table, so you can reuse that
' if you've already got it somewhere, rather than adding a redundant table.
SetMask:  DATA $0001, $0002, $0004, $0008
          DATA $0010, $0020, $0040, $0080
          DATA $0100, $0200, $0400, $0800
          DATA $1000, $2000, $4000, $8000

' This is the bitwise-inverse of the SetMask table.
          DATA $FFEF, $FFDF, $FFBF, $FF7F
          DATA $FEFF, $FDFF, $FBFF, $F7FF
          DATA $EFFF, $DFFF, $BFFF, $7FFF


SetBit() is written the way it is due to the fact the CPU doesn't have an OR instruction.  That particular sequence generates reasonable code it appears.

#4206058 Little Nemo

Posted by skywaffle on Fri Jan 25, 2019 5:04 PM

Thank you!   I'm glad other people have gotten some enjoyment from some of these songs ported over to the Intellivision.  I figure I would eventually upload the source for some of the other songs that I had posted on Youtube if anyone is interested.  I just keep finding myself busy with the Castlevania project, but it is finally shaping up to be a fairly playable feeling game, I just need to work on some little bugs here and there and some polish mostly.

#4205169 Little Nemo

Posted by skywaffle on Thu Jan 24, 2019 1:22 PM


Just felt like taking a break from working on Castlevania to mess around with some music and ideas of games that may work in some shape or form on the Intellivision.


I figured I would post this here for anyone that wants to have a listen.


Attached Files

#4194962 IntyBASIC Music question

Posted by skywaffle on Thu Jan 10, 2019 5:21 PM

I have only dedicated the third sound channel (sound 2) to sound effects, and tried to just get away from using the noise channel and keeping it reserved for percussion.   I had been rewriting all the music to utilize only two channels, while keeping the drums.  Honestly just using "play simple" works well enough in most cases, especially now that the drums work in conjunction.   Logic to disable channels of the music is overkill..  I already have enough CPU cycles being eaten with various game logic.  Nevertheless, I am always impressed to see what the Intellivision can do.

#4194143 IntyBASIC Music question

Posted by skywaffle on Wed Jan 9, 2019 3:26 PM

Thank you!  That fixed the issue for me!

#4193635 IntyBASIC v1.4.0 call for testers

Posted by skywaffle on Tue Jan 8, 2019 8:36 PM

I was able to compile my Castlevania project with the new IntyBASIC with no issues.  The MUSIC GOSUB commands are something I am really excited to have access to and have already begun reworking the music to take advantage of

#4140908 Castlevania for Intellivision - actual gameplay

Posted by skywaffle on Tue Oct 23, 2018 6:23 PM

While playing around with ideas of what to make while initially trying to understand IntyBASIC, Gradius was something I really wanted to see.  I am just not sure how doable it would be.  I am sure you could restrict options/multiples and cut down things to make it work though.   The biggest issue I see is working with 8x16 maximum resolution sprites.   Horizontal shmups just won't look very good with a double wide 8 pixel ship.  Although maybe one day;  I had made some mockups while toying with the idea of a shmup, and would be curious to see some more effort put in.



Very impressive! Feel free to continue down the Konami line after this is completed ;-) I'd love to see Inty ports of Contra, Life Force, Metal Gear :lust:

#4138774 Castlevania for Intellivision - actual gameplay

Posted by skywaffle on Sun Oct 21, 2018 8:17 AM

For the video I just tried to use the Nostalgia emulator.   The framerate seems to be a little better on this old laptop, and you can easily map a controller.   However for all my testing, I use JZIntv, it is a lot more convenient to load the game quickly.  In fact I just use a batch file to compile, assemble, and run my intybasic programs on JZintv.

I may try using the video recording option next time, although I will have to see how much it affects the video, there is a bit of multiplexing and sprite colors changing on odd/even frames.


Right now I am using all the memory locations mentioned in the 42k sample file, although I am only using just over 36k.  I still need to create bitmaps and level data for the last stage, as well as more routines for enemies / bosses.

I have wondered about altering Simon's color based on his health, or maybe have his outline flash a color.   Whenever he takes damage, his health is displayed on the screen briefly.   Another idea was maybe a button to pause the game and display a screen that could show health, number of hearts, and available time (although currently there is no in game timer).


Having a boss health bar is something I have considered, I also had thought about having the boss begin flashing (similar to Konami's arcade beat em ups) after the health is below a certain amount. 


Right now my biggest issue is trying to fit everything I would like without exceeded the 42k limit.   I had reached it a month ago, and since then reworked a large amount of the game to reduce the size.



Very cool!!

Some thoughts:

I think changing Simon's color to red when he's low on health would help let the player know how much health he has.  And you can display the boss's health on screen using tiles since the screen isn't moving anymore.

I would suggest getting Jzintv emulator and a front end. Nostagia is less accurate than jzintv and my 42K mapped game won't boot in Nostagia.  Jzintv does have built in video recording, you can press Win-A to record your gameplay to an AVI file.  The downside, uploading to Youtube will drop the framerate to 30fps(because it's not 720p),loosing the multiplex'd frame.

The game is shaping up really well, keep up the wonderful work!

#4138533 Castlevania for Intellivision - actual gameplay

Posted by skywaffle on Sat Oct 20, 2018 9:35 PM

Hello again,


For anyone that may be interested;  I have posted an updated video showing some of the progress for the game I have been working on.  There is a lot to do, but I felt that it was shaping up a bit over the past few months.



#4091370 Intellivision music - Gradius II and Castlevania

Posted by skywaffle on Tue Aug 14, 2018 11:19 AM

Thank you!  I honestly was not quite understanding how to produce great drum sounds, but did notice that when using m1 or m3 combined with low octave bass (Z), I seemed to get something closer to a drum sound.   I was unaware of the tempo affecting the drum sound, but will need to play around with them more.


Trying to get songs playing at the correct speed has been a big challenge as well.  It seems to be just trial and error.  Between switching tempos, or even adding delays every so many lines seems to have helped get things where they need to be.