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The Southsider

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Star Castle Ship Movement



I have made a little more progress on my Star Castle demo. You can now move the ship around the screen and fire bullets, although there is no collision detection yet. The controls are:

  • Joystick Left/Right - Rotate
  • Joystick Up - Thrust
  • Fire - Fire Bullets

I have been trying to match the ship movement with the arcade version (by comparing with the MAME version). I think it is now reasonably close, but let me know if you think it needs improvement?




The ship sprite is temporary (apologies to Thomas for copying the Thrust+ sprite) and will be replaced in the near future. There are also a few wrinkles, such as firing not working at the edges of the screen, and the bullets being fired from the centre of the ship. These issues should be easy to fix.


The next step is to get the mines following the ship (the green blob at the bottom is what the mines will look like). Then the collision detection, which I'm not looking forward to!


The source code is included below, but it is a big unoptimised mess at the moment. As always, let me know what you think. Unfortunately further progress will be slow now that the holidays have come to an end.






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Thanks - your Thrust+ sprite actually has 32 directions (unless you are only counting the non-reflected ones)!

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In comparing the behavior of the arcade to this: I think the ship is rotating too fast here. I'd say knock it down by about 10%

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Yes! Are you set on the colors? The small ring yellow, med orange, lg red would match the Arcade overlay.

Also, this is one game where I'd USE the BW/Color switch to play in black and white!

Brightness is part of the gameplay -- see how well it's done in the arcade and as shown in the video of that unreleased port.

I wish it were easy to make a star pattern background.

Did you know that the star pattern of the coin op is a nude centerfold? It's true.

The programmers taped one up and put dots outlining the lady! Her head is the upper right and legs point to the bottom left.

It's one of the things that when you see it, you always can see it.

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Thanks for the comments - I'll slow down the rotation in the next version.


The colours of the rings can easily be changed - I'll attempt to match the arcade colours later. However, I'm not sure how brightness is part of the gameplay - do you just mean that the colours need to be brighter?


I didn't know about the image in the star background! Unfortunately there isn't any easy way to replicate this on the 2600.

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However, I'm not sure how brightness is part of the gameplay - do you just mean that the colours need to be brighter?


The ring segments take two hits to be destroyed. When they're hit the first time, they turn bright. Then they're destroyed with the second hit. That way you know which segments have already been shot once.

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OK, I understand the brightness issue now. That isn't going to be possible with this kernel. I don't think this feature is in the

either though?

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True, the ring get brighter and take two hits, but you can leave that out.

What I've noticed about brightness is that, overall, the arcade game is dim, very dim, but explosions and fireballs are max brightness and add drama, and chasing stars are brighter than the rings and player ship.

What I noticed in the original YouTube video about 2:18 was the 30Hz effect in the recording making the rings dull and the explosions bright.

That looked cool, and I thought it should play like that. Just take it as a suggestion to think about.


Go to 2:18 here:


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