Beach Head, Dev Log (CVBasic)

[shaoth]

Hello,

I've been testing CVBasic from @nanochess for some time now and decided to try porting BEACH HEAD to the Colecovision.
Big job, especially with the scrolling part...

 

I have another more immediate problem, sound creation. I know absolutely nothing about it and I'd like to know if someone could help me reproduce the sounds in the game.

 

here's where I stand at the moment :

 

 

Edited October 15 by shaoth

[shaoth]

Some screenshots

 

[youki]

Cool!  it is one of game i always wanted to adapt on Colecovision , love that game!   Looks very promising.

[shaoth]

When I played it on my Atari 800XL back in the day, I couldn't understand the point of going through the hidden passage, since you had to fight the enemy fleet in any case...
It wasn't until recently, reading the documentation, that I learned the difference. By using the hidden passage, the enemy fleet doesn't see you coming from as far away, and has less time to prepare for battle.
A dozen aircraft will come to attack you, compared with 30 in the other case.

[shaoth]

For zone 2, where we fight squadrons of planes, it's a SPRITES fair!
I need 25 sprites just to simulate the inclination of the gun in 16 positions.

4 more for the 40mm shells to simulate their distance.

And I've hit the jackpot for the enemy planes: I'm up to 22 without having planned the animations for the left and right escapes, 6 each. That's 34 in total!

With 63 of the 64 available sprites in use, that doesn't leave much room for animating an explosion.

Nothing to do with zone 0, the air reconnaissance zone, where 6 sprites do the job.
1 for the player's fleet
1 for the enemy fleet
1 for the hidden passage
1 for the enemy fortress
2 for the barriers

 

⚠️ the limit is 4 sprites per line, so how can you display 8, as in GORF?

[+nanochess]

You could consider doing some enemies as bitmaps on the screen, and redefining characters as needed.

 

 

 

[+5-11under]

49 minutes ago, nanochess said:

You could consider doing some enemies as bitmaps on the screen, and redefining characters as needed.

Perhaps easier to set up the guns as characters, especially because there's only water behind them, and they only move in one direction.

[shaoth]

In this zone the boats are aready displayed as characters.

I only use digits and capitals to display informations ingame.

So I can redefine the ASCII table from 91 to 255, 166 free characters.

The decor uses 80 characters, leaving 86 available for other uses.

I haven't done the math, but reproducing 16 positions of the barrel and planning to move it laterally by pixel is going to take up too many characters.

I'm thinking more of saving the low gun positions, which shoot too low anyway without ever being able to hit a plane, and removing a step or two from the aircraft animation.
After all, I only need 3 or 4 frames to get an explosion, double that if I add a colour...

[Tony Cruise]

1 hour ago, shaoth said:

In this zone the boats are aready displayed as characters.

I only use digits and capitals to display informations ingame.

So I can redefine the ASCII table from 91 to 255, 166 free characters.

The decor uses 80 characters, leaving 86 available for other uses.

I haven't done the math, but reproducing 16 positions of the barrel and planning to move it laterally by pixel is going to take up too many characters.

I'm thinking more of saving the low gun positions, which shoot too low anyway without ever being able to hit a plane, and removing a step or two from the aircraft animation.
After all, I only need 3 or 4 frames to get an explosion, double that if I add a colour...

Two solutions:

1. Make a 2nd tileset with the gun animations, and just copy the tile pattern when you want to change the shape.  So if your gun takes up 4 characters on screen, then it is only 32 bytes being copied. 

 

2. Or you can still have it as a sprite and have the same concept of a 2nd set of sprite shapes and just copy the new pattern data to the sprite.  This would be less data as you can move the sprite in single pixel steps.

[artrag]

You have to define on fly the gun. In this way you will use just a single sprite position (or two if larger than 16x16) at cost of few bytes to move to vram

[shaoth]

Little work at the weekend on Beach Head.
Zone 2 is almost finished.
a little bug, sometimes the plane explodes when it hits the top of the screen...
I need to vary the trajectories available
And of course, sound, lots of sound!
It's a bloody war after all!

 

 

Edited October 28 by shaoth

[Tony Cruise]

Looking good and playing well, fantastic progress, keep up the good work.

[shaoth]

still in wip

 

[shaoth]

I'm continuing to make slow progress at my own pace.
So here's a little video to celebrate and share the next stage with you guys.
There's still the pyrotechnic effects to add, and a bit of aggression for the enemies, and that'll be it.

 

[shaoth]

it was bound to happen one day...
My ROM size has just gone over 32kb and it's a mess!
Never mind, I'll use the bank system.
But I'm wondering... It says in the documentation that each bank is 16kb but I didn't need to deal with this before the 32kb ROM. Is there a link between the size of the rom and the number of banks to use or not? If so, is bank 0 a special size?

[Tony Cruise]

Here is a snippet from my book:
The MegaCart is a special design (originally by Bryan Edward) that allows ROMs to contain up to 1MB if required.

 

The cartridge can be several different sizes as follows:

 

 128K - 8 banks of 16K

 

 256K - 16 banks of 16K

 

 512K - 32 banks of 16K

 

 1MB - 64 banks of 16K

 

The first 16K of ROM is fixed to the last 16k section of the ROM and is located at 8000h to BFFFh on the ColecoVision (and Adam).

 

The 2nd 16K area (C000h to FFFFh) can be changed to any of the banks in the cartridge (including the last one) by reading from memory address FFC0h to FFFFh i.e. each location represents one of the 64 possible memory banks to select.

 

This also means the top 64 bytes (FFC0h to FFFFh) of each 16K ROM bank can’t be used.

 

So basically this means bank 0 stays the same and the other bank is swapped out.  The easiest things to move to extra banks are graphics, and music definitions keeping most of your code in bank 0.

 

I assume you are already using compression for all of your graphics?

[shaoth]

It's clear and obvious when you think about it for a few minutes, which I hadn't done.
It takes talent to explain certain concepts clearly and easily 😉

And no... I don't use compression for my graphic resources...😅

[shaoth]

Ok !

I've set up data compression with PLETTER.

[Tony Cruise]

11 hours ago, shaoth said:

Ok !

I've set up data compression with PLETTER.

Awesome, heaps of room  

[shaoth]

As I like to do things in order, after zones 0, 2 and 3, here's zone 1

 

 

[+nanochess]

23 hours ago, shaoth said:

As I like to do things in order, after zones 0, 2 and 3, here's zone 1

 

 

Wow! I really like the feeling you are getting for this game!