Sprite priorities

[Wrathchild]

Hi,

 

I've managed to ressurect a game I wrote over ten years ago (!)

It was on an ST Floppy (as I'd used MadMac to develop it), but 2

sectors couldn't be read and so some of the main game loop was

missing. I just ported it to CA65 and got most of it working again,

but have a question.

 

I'm using a missle for a star-field on the game screen which is using

gr.10 but I can't get the missles to appear behind the playfield colours.

The PRIOR value I used was $b4. I recall trying many values but none

seemed to work so can this be done?

 

Thanks,

 

Mark

[Wrathchild]

After a bit of thought I decided to avoid the problem altogether.

The DLI just decides if the star should be plotted, so if the xpos

is in the play area then it doesn't display a star. A touch of colour

depth has been added too, based on the star's velocity.

 

I guess the last version didn't work as missiles = Playfield 3 colour

and so in Gr.10 all colours are at the same level?

 

STAR_DLI:

PHA

TXA

PHA

LDX #0

@1:

LDA STAR_X,X

CMP #109

BCC @2

CMP #149

BCS @2

CPX #11

BCC @2

LDA #0

@2:

STA WSYNC

STA HPOSM0

LDA STAR_V,X

ASL

ASL

ADC #2

STA COLPF3

INX

CPX #MAX_STARS

BNE @1

LDA #0

STA WSYNC

STA HPOSM0

PLA

TAX

PLA

RTI

 

I'll release the game (and sources) once I've put the high-score chart back in.

 

Regards,

 

Mark

[Heaven/TQA]

all well done... the game looks extremly good! all people involved have my full support.

 

if you need help (in coding questions, etc...) just drop me a line... i have not much time for coding right now but this may change...

 

cheers, hve

[Sheddy]

Looks neat Mark

[Heaven/TQA]

oops.... posted in the wrong forum... i ment ADVII... but this tetris thingy looks extremly good as well!

 

hve

[Thelen]

Looks nice ! releasing the source is a great idea, so new atari 8 bit programmers can see some example of code

 

Thelen

[Wrathchild]

Hi,

 

I've got the main bits and pieces together and so here's an ATR to keep you busy over the weekend.

 

I'll get the sources commented and then upload them to the homebrew section.

 

For now, a bit of background:

 

History:

 

The game was written around 1992/3, the idea coming from Paul Saunders (a university friend with a great 8-bit collection at the time and also had a Porsche 911 that we used to travel to the AMS Micro shows and help out Dean Garraghty on a few occasions). He had an Acorn Archimedes Basic listing for the game called 'Columns' but we didn't have such a box to see the game on! This code is around 98% unchanged from my original sources that I took off the disk.

 

Design:

 

As the title implied, the game needed to be colourful. To achieve this, gr.10 was chosen in order to give 9 colours but allow palette control. Additional touches were given with simple DLI bar effects on Gr.1 and 2 text. A star-field was used a-la Warhawk, a missile being split each DLI with the VBI updating positions. Its direction can be toggled with SELECT and OPTION. The DLI actually takes up most of the game loop's time as a game like this doesn't require anything intensive.

 

Game:

 

The game has speed 10 levels and you start with 4 different coloured blocks. Every 2 levels you get new colour added (upto 8 ). Each new level the speed gets a little faster, typically every 500 points.

 

Scoring works by 5 points a block removed, although bonuses are added for how high the blocks were when they were dropped.

 

New pieces appear randomly from the middle 4 columns until no piece can be placed at which point the game ends (I've just added a neat 'wipe' that reveals the stars but there's a bug in it ). A Hi-Score is checked and you can enter you name using an arcade like circular letter entry.

 

Demo:

 

The game also had a novel demo mode if the titles are left alone. This was not in the Archimedes game but worked by simply picking the left-lowest blank square and introducing the block to that column. The computer doesn't move left or right but randomly toggles the block's colour sequence. It plays until no more pieces can be introduced or the user presses the fire button.

 

The Future:

 

Pause mode + quit game (via START key)

Music + effects

Confirm + rubout on the high-score entry

 

+ whatever else you guys can come up with??!!

 

Enjoy!

 

Mark

[Wrathchild]

Hi,

 

I just found out that the level speeds for level 6 onwards wasn't defined due to the disk corruption

 

Fixed zip attached

colours.zip

[Avram]

What's the progress on your game? The demo is great fun to play!

[Wrathchild]

Thanks!

 

No progress on this one I'm afraid (I got distracted onto other bits like the Os-B->XL game fixes and having fun with the Infocom interpreter).

 

I should have some free time next week as I'm off work and will have a bash at commenting the sources as promised - then these can be posted here for others to add too

 

Regards,

 

Mark

[+Philsan]

Very nice game!