Neo Geo CD and Sega CD versions reach beta.

In a one player game, the second frog is controlled by a simple AI. It's able to compete fairly well. It probably needs more tweaking. It's implemented using a finite state machine.

This brings the game to the beta stage. This will not be a feature complete beta, as I would still like to add a few more features before it's release at the CGE and VGXPO being held on August 20-21.

Sega CD PCM sound is working.

I finally got PCM sound working on the Sega CD. It's not very difficult to get Sega CD sound working. The hardest part is figuring out all the little things that were needed. I spent the better part of two days figuring it out. I'm getting really comfortable with the Main/Sub CPU communications. This was always something that worried me when I was looking at Sega CD development.

I also fixed a bug that was causing a problem playing CD audio tracks.

On another note, I've done some work in figuring out how to boot up a NEC PC-FX CD. The limited version of Magic Engine FX (http://www.magicengine.com/) makes it difficult, but I've managed to get around most of it. Now, I have to disassemble the program and figure out how to get it working. Like the 3DO version, this will be done in between versions for now. It's a nice little break from the PCM stuff.

The next thing on the list is game AI.

Neo Geo CD PCM sound working!

Sound is working in the Neo Geo CD version of the game.Thanks to Blastar (Neo Puzzle League & Codename Blut Engle) who found a bug in the MVS Tracker playback routine.To fix the problem:Change location 0xC2 in the *m1.bin file from $02 to $03.

This has been fixed in the latest version of the MVS Tracker program.

Moving onto sound.

I've spent the last two days digging into PCM sound for the Sega CD and Neo Geo CD.

Here's what I've found so far:

The Sega CD uses a signed bit 8 bit PCM format (7 data bits plus a sign bit). Sound Forge supports this format. The resulting PCM has to have the data aligned to even bytes (or each byte is duplicated once). The sample rate is variable.

The Neo Geo CD uses an 18500 KHZ 16 bit mono ADPCM format (similar to a Dialogic ADPCM vox format). MVS Tracker (http://www.neobitz.com/Pages/DevTools/MVSTracker.aspx) has an option to build the PCM roms for this. It can also generate the Sound (Z80) rom, but it plays to the end of a bank, rather than just a sample.

The Sound rom uses the following commands: (Using a byte written to 0x320000)
1 turns the sound off and reset the sound system.
2 plays the introduction song (the one that plays while the spinning NEOGEO letters)
3 turns the sound on and enables the processor to recieve commands.
4+ is Samples
0x7F stop ADPCM.
0x80+ are FM music tracks (at least using MVS Tracker).
0xFF Stops the FM Music.

I've added PCM sound support to the Neo Geo CD version, but still need to find a fix to play just a sample.

Frog Feast mentioned in Tips & Tricks magazine.

Tips and Tricks has the following article on page 69 of the August 2005 issue:


After a short vacation, I'm back to work. I will be wrapping up the Neo Geo CD and Sega CD versions.

Neo Geo CD version has CD audio

The Neo Geo CD verison of Frog Feast can now play CD audio tracks. I used the source from NeoCD (and NeoCD/SDL) to figure out how to play CD audio. The Neo Geo CD is more responsive than the Sega CD.

Sega CD version now working.

I finally got the Sega CD version to boot on the real system. The problem was that I was accessing the HV counter register as a DWORD. It only allows BYTE or WORD access.

I've started adding CD Audio to the Sega CD. It still has some issues, but it's starting to work.

Sega CD issues & Neo Geo CD version

I'm having some problems with the Sega CD version. It will boot to the first part, but is unable to load the second part. It works fine under Gens and Fusion..

The Neo Geo CD version is working perfectly on the real hardware.

I've also started doing some initial research on a 3DO version. I've got a small amount of code to show the title screen, based on the Sonic code from mnemonic. There is still quite a bit to figure out, and I would still have to get it on a CD and get the CD booting correctly. I will continue to work on this inbetween the other versions.

Finishing up.

I'm starting to work on the finishing touches for the game. I've created two boot screens. I've redone the title screen, as the start message will be done with text instead of an image. This will also allow the selection of single or two player mode.

I've created a RasterSoft logo:


I still need to:
1) Add AI for the second player
2) Add sound and music
3) Add some variety. Different bugs, bad bugs, etc...

Mappy

I switched to using Mappy (http://www.tilemap.co.uk/mappy.php) for tilemap processing. Mappy has the ability to generate an optimized timemap from an image. I use this for the title screen and background. I'm also adding in RasterSoft and OlderGames logo screens.

Mappy can save the map in either a DWORD (4 Byte) or WORD (2 Byte) data format. It can also export the tiles to a bmp. There is one gotcha with the export, it exports the transparent tile before the tile data. And, the map format starts with tile 0, which is actually tile 1. There is a checkbox to skip tile 0. This work fine, but took me an hour or so to figure it out.

A Mappy map also has to be created in 8 bit to export 8 bit tiles, regardless of the settings of the input graphics.

Sega CD version of Frog Feast now playable.

The frogs can now eat the flies and scores are updated, and there is a time limit. The game returns to the title screen after the time limit. This will work on all 5 systems, once the DrawString routine is written for each system. This is probably an hours worth of work to do all other systems.

More flying flies...

I've added the flying flies to the Neo Geo CD, Jaguar CD, FM Towns and, CDTV/CD32 versions. The code is now starting to make implementing features easy.

Starting to add gameplay elements.

I've added the flying flies to the Sega CD version of Frog Feast. I also had to add some means of generating a random number. The fly paths are random but do look fairly realistic, within the limits of the gameplay. This should be fairly easy to put into the other versions.

CD32/CDTV text layer working.

Things have been pretty busy over the last few weeks, but I finally got the text layer working in the CD32/CDTV version.

The sprite routines aren't setup correctly to blit 8 pixel blocks, so I had to use a seperate routine for the text layer. The nice thing about the text layer is that it's aligned to 8 pixel boundaries, so it's just a matter of writing the values into memory correctly.

The method I use is to (Commonly referred to as the cookie cutter method):
1) Invert the mask, since I want to keep the area where the text is transparent.

2) And it with the background bitplanes to clear out the areas where the text is to be drawn. This preserves any graphics in the transparent area, and clears the text area to zero.

3) Or the text bitplanes with the display. This overwrites the zeroed area.


On another note, I picked up a Memorex VIS system. I would eventually like to get Frog Feast running on it, but I need to figure out a lot before that will happen. The system runs either a version of Windows or something like DOS.