Another Last Amazon front end

Tuesday 7th April 2009 + Wednesday 8th April 2009

Bah, TV sucks. Well that doesn't surprise me. I had nothing else too exciting to do, so I decided to work on a new front end for Last Amazon 2. This time it was a bit of a challenge, but I knew that it should be possible. I prepared a work disk .D64 and transferred all the C64 files into the cross-assembly directory for use with ACME, the same way as I did with The Last Amazon.

Kenz had shown me the mock up screen shot of what he would like me to do for the front end. Oh no ... raster splits :( Seriously, I hate doing raster bars, due to having to get those blasted things timed correctly inside $D012 splits. Ah well, it has to be done, and I shall do that.

I loaded up the Relaunch64 tool and then I created a main source file which will link all the c64 program files (including the game) and got started on the programming side of things. I started off with the IRQ interrupt player routine to see if it will run. The good news was that the player routine did play the music after assembled and crunched with PuCrunch. Now it was time for the serious part of the programming. Getting the bitmap logo and all chars displaying. To do this, I changed the background colour ($D021) so that all small text was white and all large text was yellow. So I built 10 raster splits in total. Everything displayed successfully.

Now it was time to add those raster bars into the text. Well, this I must stress was one of the worse parts of the front end programming. So I built a colour table and a raster timing table for each raster split. It took a lot of time to time out the raster splits so that the text chars looked much more tidier. As soon as I was happy with the result, I worked on the scroll text routine (Which uses raster splits as well) and then added a routine for which the player can press fire in either joystick port to play a 1 or 2 player game. Those worked okay, but sadly timing had altered again. So I moved the raster timing table and also moved the scroll text to a higher location and got everything working. Looks perfect now. Hope Alf and Kenz likes this one.

Once again in the Amazon

28th February 2009

Well it seems as if I have been rather busy on the programming side of things today. Kenz has sent me a .d64 with the enhanced version of The Last Amazon. (See his blog here) The game sure was cool with bonus weaponry, and also the animation of the flowing water was excellent.


Kenz showed me a .gif preview of the type of Front End he would like for this game. It seems to me that he wants a very simple front end with a bitmap logo at the top, a 2x2 charset in the middle of the screen and 1x1 charset at the bottom of the screen. So I took all of the main SEUCK game files , relocated the tunes for the game, and also the other bits of data and created an ACME cross assembler project then I worked on the main code and compressed it, and my result turned out the same as what Kenz expected on the the .gif image example he showed.

Although Kenz did send a text file for me to add to the message lines, I was unable to add the eyes graphics, and numbers, because the text data was being used as !SCR commands in ACME cross assembler. So some of the things had to be left out! After all programming and testing, it seems that I have got a nice result!

Lost in the Amazon!

22nd February 2009

Today I have been busy, programming a new front for a Psytronik software SEUCK game. I was given a .c64 image one of the games in the The Last Amazon series. Because I am not all that comfortable with CCS64, I decided to make a .tap of the Sideways Scrolling SEUCK game (Left version as there was no right scrolling version) and then save i to the .tap image.

After I saved the SEUCK game on to a .tap image, I loaded the .tap into WinVice which took some time to load - the stripes are strange? I thought SEUCK used multicoloured stripes like Novaload originally did.

After the game loaded, I filled unwanted data with zeroes (Between $6580-$b6c0) and edited $54EF from LDA $8000,y to LDA $5000,y so that the enemy bullets in the SEUCK game will fire on a random basis. I created a work disk and saved 2 separate files for the SEUCK game. From $0900-$6580 and $B6C0-$FFFF.

Next I loaded a disk with a few different files which Kenz supplied me. The disk contained the logo files, and loaded up the Vidcom paint image and saved the image as three separate files on to my work disk and I also saved the 2x1 charset on to the disk as well. Then I drew some sprites using Faces's Sprite Editor.



Now the next thing for me to do was to extract the title and game music by WAZ, from the very first Last Amazon game (Which was suggested by Kenz that I should use this music for the front end of this game). So I saved two separate music files in Voicetracker/Music Assembler format. Then I loaded up the Dutch USA Team Music Assembler and relocated the tunes to estimated possible locations for when I write my new front end for the game.


Once the music was saved, all I had to do was prepare my cross-assembly project, by making a new folder and put all the C64 data into that folder, along with the and also the ACME cross-assembler and also the brilliant Exomizer cruncher.

Now that all files were prepared, I opened Relaunch 64 and I did a test build of the game, by linking all C64 data into the source, using the !bin "filename.prg",,2 command. So as a small test I entered the two SEUCK files and compiled the source then used the Exomizer to compress the data down and tested it all in WinVice.

It seems that the SEUCK game worked, so now I linked all C64 files to possible locations in the source and got ready to program my new front end for the game.

The first thing which I had to do was make some source files for the scroll text and also the front end text. After that was done, I worked on a once at a time run routine. This is where defaults will be set on the title screen for the very first time after decompression had finished. Next I added a routine that turns off all interrupts and a delay routine, so when game is over, the title screen is delayed for a very short amount of time.


Next I added a colour and screen routine, for displaying the colour data for the title screen text and also the logo's colour data. Then I worked on with the main IRQ interrupt routines. Before I did this, I switched off the KERNAL by setting #$35 at $01. This allowed me to use higher memory after $a000-$ffff, except for memory between $d000-$e000, which obviously needs to be used as POKE storage lines anyway!

Now I programmed the raster interrupt init routine. Usually I use the KERNAL $0314-$0315, but this time I used something more complex, which was $FFFE and $FFFF. This made IRQs longer, but I did not need to use KERNAL.

I used 3 IRQs to make 3 raster splits. The first one was for the scroll text, the second was for the bitmap logo and the last one was for the still text. I had to fiddle around with the charset values, so that I could display a charset that was at $7000 while screen memory is at $7c00. I managed to succeed to display the logo and the static 2x1 text.

After the success of the splits, I was programming the 2x1 scroll text, until I came across a problem. After assembling and compressing the program, no scroll text displayed. There was a problem there. I was scratching my head wondering what was up with the routine. Well, the routine was correct, but the scroll text was being pasted at the wrong screen memory. I used the $0400-$07e8 screen RAM instead of the $7C00-$7FE8 screen RAM. Hahahaha, how dumb was that? :oD. After I changed the scroll's screen memory I got the text to tick along the screen. There was no smooth scroll, but I managed to fix this problem by updating the bottom split, so that $D016 was run by the scroll control code.

My next step was to add and position the sprites and expand the sprite positions. So I used the typical software sprite expansion mode which I used for many of my games and programs, by ROR-ing $D010 as usual. I got the sprites to display, so now it was time for me to do some functions for the sprites.

So my next job was to program the options routine. This had to be done where the joystick direction from either joystick port can choose the number of players or to choose music or sound effects, pressing fire will take the player to the game. This was done by creating some labels and routines, that could display the correct sprites that correspond to the option the player selects. There is more to it though, because as well as sprite options, I needed to program the functions for each option, by building some extra routines. Just simple pokes really.

Where I had to program the in game music function. I had to put BIT routines where the SEUCK was playing the sound memory for the game sound effects. I also had to add a poke that would initialize and play the in game music, without being interrupted by the sound effects. When I tried this, the routine unfortunately crashed. I found out where I went wrong here. I was POKEing the wrong address, which was somewhere in the SEUCK's IRQ memory. That was bad! I managed to fix the routine by using the correct address to POKE for initializing the in game music.

The sound effects bit was similar to the in game music method, but I had to restore the correct poke values for the where sounds originally had BIT next to them and should be replaced with STA only for sound effects. This worked successfully.

The only thing that was missing in the game options was the player options, so I added some routines to select between 1 or 2 players by using the standard SEUCK player mode pokes. This worked a treat, and I was happy with the final result.

To end it all, I added the typical Richard Bayliss colour wash routine on to the scroll text, so that there is something interesting going on in the front end. Hahahahaha.

Now all I had to do was have a quick test to see if the game is working. Well, seems it is working at the moment. After game was over, I decided to test the whole game to see if all works. Well fantastic news. The game works, no crashes or missing sprites. Fantastic!

Now I shall send it off to Kenz to look at and also pass to Alf to see what he thinks of the new front end bolted to his magnificent sideways SEUCK game.