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Intellivision homebrew - Mystery Castle


GroovyBee

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The second is that I can do "SIMD" bounding box checks for collisions.

 

You might also wonder why I did bounding-box compares instead of using hardware collision detection. Two-fold: I use multiplexing for some of the targets, so the mapping of MOBs to actual individuals changes frame to frame. The other is that, while hardware collision detection is fast compute-time wise, it's slow game-time wise.

 

  • On Frame N, we compute the state that will display on Frame N+1.
  • On Frame N+1, the state actually gets displayed. Hardware collision detection happens during display.
  • On Frame N+2, we can finally react to the game state we set up on frame N.

Because of that pipelined process, you could get a lot of "paradoxes", as John Carmack likes to call them, such as being able to fire off an extra bullet after getting hit, or being able to exit a room after being tagged, etc. If you do the bounding box compare at the same time you compute the game state, you short-circuit this 2 frame delay in finding out what happened.

Edited by intvnut
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I'm well versed in bounding box collision detection. Its the only way that you can tell if arbitrary sprites are overlapping on the 7800. The MARIA video chip is very good at handling sprite data and changes in colour depth per video scan line but it offers no help in detecting collisions between sprites.

 

When I get some baddies in this game I'll address the speed of the man movement then. I think more game play elements need to be operational.

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I'm well versed in bounding box collision detection. Its the only way that you can tell if arbitrary sprites are overlapping on the 7800. The MARIA video chip is very good at handling sprite data and changes in colour depth per video scan line but it offers no help in detecting collisions between sprites.

 

When I get some baddies in this game I'll address the speed of the man movement then. I think more game play elements need to be operational.

I figured you probably understood bounding box collision detection. I wasn't sure if you'd seen this 16-bit twist on it, particularly the CP-1600 specific SDBD trick.

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I figured you probably understood bounding box collision detection. I wasn't sure if you'd seen this 16-bit twist on it, particularly the CP-1600 specific SDBD trick.

 

I haven't managed to use the SDBD instruction yet.

 

Fortunately, with 16-bit wide ROMs, it's not nearly as necessary as it was back in the day. :) With 10-bit wide ROMs, you need SDBD to read 16 bit values.

 

My only use for it any more is for hacks like the one above, or when I need to read 16-bit values out of 8-bit RAM, which these days isn't often now that cartridge designs (both the CC3 and my JLP) offer 16 bit RAM.

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  • 2 weeks later...

My CP1600 assembly language is getting up to speed so here's my 2nd WIP. Its provisionally called Mystery Castle.

 

post-21935-128414087577_thumb.gifpost-21935-128414088519_thumb.gif

post-21935-12841408945_thumb.gifpost-21935-128414090157_thumb.gif

 

As soon as I can test on real hardware and there is more of a game, binaries will be available. There's not much going on besides a moveable, animated, multi-colour player sprite at the moment.

 

BusyBee,

 

Any progress on your game? It was looking really good.

 

-dZ.

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keep up the great work groovy!

 

I intend to get the game finished for early next year hopefully.

 

btw....what is an average time for programming a homebrew on any system?

 

There are no hard and fast rules. It depends on the complexity of the game and how much free time you spend on it. If its a team effort you might have to wait for sound, music or graphics too. Real life also has a habit of getting in the way.

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  • 1 month later...

I feel so betrayed! Inty owners have a .bin of this promising game, but 7800 owners must only pine away for the day when they'll get one! :-)

 

:lol: Neither machine has a "game" up to my usual quality. The Inty version is way behind the 7800 version. They'll probably end up as different games to make best use of each machine's architecture.

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  • 2 months later...
  • 8 months later...
  • 3 weeks later...
  • 2 years later...

As I mentioned in a previous post, I had a version going with doors and had some programmer art baddies. Anyways... Blew off the dust :-

 

post-21935-0-95534100-1396693289_thumb.gif <---- Click to animate

 

Its low on the priority list but from the *.gif you can see most of the core game elements. I can't wait to see what nonner does for the title page when the game gets actively worked on again.

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