Re: [stella] Thrust!

Subject: Re: [stella] Thrust!
From: kurt.woloch@xxxxxxxxx
Date: Fri, 19 Nov 1999 08:25:47 +0100
OK, some more answers to the "Thrust" thread:

>At the moment my kernel is limited to display just
>two missiles (M1 and BL) per frame. One is used for
>guns and the other for the ship. The guns and the ship
>can both fire two missiles which are displayed 
>If the wire is about 12 pixels long, i would need 6
>missles per frame for 30Hz (or 25Hz at PAL-
>systems, i'm from Germany) plus the missiles for 
>gun and ship fire. I don't see a way to put this into
>actual kernel, but there _must_ be a solution to that.

Hmmm, the Kernal (and thus, the timing issues) is another problem, but as I
see it, M2 is still free. Maybe you could do some kind of that trick as used
in Missile Command for the missiles, and Decathlon for the pole, in Pitfall
for the ropes etc. where a missile is displayed which gradually changes
position with HMOVE's on every, or every other, line. As long as the crystal
ball is well under, or over, the ship, this should work, as well as
displaying the ship and the ball with the same player in one frame. If the
ball gets to near vertically, you could switch to another mode where the
ball is displayed alternating with the ship (flickering), and also another
solution's used for the wire.


Ah, another two songs I can sing...
oh, sorry, that wasn't a Stella message...

>Yes it is compressed!
>As you can see there is always one left and one 
>right border. Each border is stored as blocks with a 
>x-starting point, a x-difference to the previous line, the 
>height of the block and the x-distance to the opposite
>border (this allows that it look as if both blocks can
>start at the same line, which is not the case). This 
>makes 4 bytes for each block, and i don't think there's
>much room for improvement.

Sorry, I can't figure out what this means... could you further explain how
you store the terrain data?
How many "blocks", roughly, are used for each level?

>> No playtesting needed... incidently, did you copy
>> some of the code of the
>> C-64 version?
>I didn't, but if you can figure out where and how the
>ball-physics are computed, i might... ;-)

Arrr... this would mean I had to wade through a lot of code there... but if
you're lucky, I just might... but don't rely on my, I've got so many other
things to do... ;-)

>I thought about repeated players, but they would partialy
>appear at the opposite side. Each player is 8 pixel wide 
>and i'm x-scrolling in 4 pixel steps, so that i have to 
>mask out the player data when it reaches the border of
>the screen. With repeated players this would look 
>pretty weird. If someone has a better idea...

Well, you could just disregard that and make an object disappear if only
part of it would be visible at the left or right side.
Other than that, if you really use repeated players, this could also give
difficulties with using the missiles which then would be the same number. So
maybe it'll be better to relocate those fuel stations to other places in the
level, or simply put one fuel station there which has got a bigger capacity
instead of the multiple ones...

>It should open (now) when you just press fire.

Ah. I didn't try that... I thought the fire button was totally inactive...
has it got other functions too?

>> You could just not show the wire and let the player
>> figure it :)
>> I'm not joking, if the ball physics are well done,
>> it could look not bad at
>> all.
>At the moment i want to use the missiles for this.
>The resulting flicker of the wire could look like some
>kind of tractor beam.

This sounds nice. Let's wait what gets out of it...

With love (and many ball motions to compute)
Kurt Woloch

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