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Light-year demo


Asmusr

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I see some Moon Patrol - type of foreground/background type of scrolling... nice.

It's a great concept, I cannot wait to see what you'll do with it once the stars match and there does not seem to be a noticeable line.

BTW- The music is AWESOME! I think you'll have another winner here!

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Although this is a nice effect, my visual mind seems to get confused and cannot make sense of it. Why are stars running faster near the ground? Are they closer to the observer than the ones at the top?

 

In my opinion it would be better to have a very slow speed for the stars from the top to the bottom, and close objects passing by fast.

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Although this is a nice effect, my visual mind seems to get confused and cannot make sense of it. Why are stars running faster near the ground? Are they closer to the observer than the ones at the top?

 

In my opinion it would be better to have a very slow speed for the stars from the top to the bottom, and close objects passing by fast.

It is meant to create depth based on true physics where items that are closer to you appear to move faster, I'm not sure it works with stars though, I think the best example I have seen of side scrolling star fields was on the intro screen to the Atari 8bit version of Warhawk.

Rasmus has still done a great job here though-I think the central band of stars and planets needs thinned out a bit though-as it seems to be the density of objects in the central band that makes the effect more obvious.

 

Still better than Parsec!!!!!

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Wow! That is incredible!! How is it done? I can't even begin to fathom it! Can you post an article on it?

 

It actually sent me back in my mind to the 80's. I recalled the Commodore 64. The C64 wasn't that technically impressive (though it did have a *great* sound chip). However, what made it so great was the tricks that programmers learned on that machine to make it do things that it wasn't *supposed* to be capable of. Looking at this demo, in the early to mid 80's one could expect to see something similar to Light Year running on a Commodore 64, and we'd all say "Wow! I wish the TI could do that!".

 

And it could. All these years, and only now are we beginning to see just what the TI was capable of in the right hands. This would send the C64 guys back to the stores to trade them in for TI's!!! Imagine if it talked (through the speech synth) at the same time!!

 

Totally blown away! I wish I could do stuff like this!

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Very Nice Rasmus, and it's not needed for the F18A upgrade ! WOW ! ... Multicolor Sprite and background and all is very Fast... incredible to think that it's our TI99 ! :D :)

 

very very good: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup: :thumbsup:

First thing I thought when I seen the sprites was that this was obviously an F18 demo-just goes to show what I know.

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I watched it wrap :).

 

Nicely done, can you give a bit more tech info?

 

The demo is using what you could call 2/3 bitmap mode - one color table and three pattern tables (@artrag described it here and used it in his brilliant Uridium game for the MSX). Usually the problem with scrolling in bitmap mode is that 256 characters are only enough to store the transitions between a very limited set of base characters, e.g. you can store 8x32 transitions. The 2/3 bitmap mode gives you four times as many characters to play around with.

 

In this configuration you can have two pattern tables covering the middle an bottom parts of the screen at >0800 and >1000 and two more at >2800 and >3000. When you use the first set of pattern tables the colors are stored at >2000 and when you use the second set the colors are stored at >0000. You can flip between the sets by updating two registers. You cannot use the top third for patterns because that would overwrite the colors of the alternative set, so in my demo the top third of the name table is filled with a blank character that has all zeros for both colors and patterns (the stars are sprites).

 

If you want to use different characters in the second and third parts of the screen you have to deal with the fact that they share the same colors. In the demo you will see that the green planet and the fuel tank share colors, likewise the big planet and the ground, etc. It takes a bit of fiddling to match them up.

 

My technique is not nearly as advanced as in artrag's. I simply divide each pattern table into 4 banks of 64 character transitions. When I flip between the two sets I have the 8 banks required for 1 pixel scrolling. Once all the characters are uploaded all that is required to scroll the screen is to update the last 512 bytes of the name table. This case be done in about 2/3 of a 60Hz cycle. To scroll the screen faster you simply move more pixels. The light speed effect could just as well be obtained with character scrolling as long as you do it at 60Hz.

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Very impressive scrolling :)

I do agree with the previous comments about the background stars though as it is best to have the entire star field scrolling at the same speed.

Will this turn into a full-fledged game?

 

No, this is just a demo, I will not develop this set of graphics any further. But the same technique could be used in a new game. It would be perfect for a sideways scrolling platform game where the top third of the screen could be filled with clouds made of sprites.

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I have added a video showing the demo to YouTube and the first post in this thread. But YouTube videos are restricted to 15Hz AFAIK and this is running at 60Hz so you won't see 3 out of 4 frames. Much better to run this on your real TI or in an emulator. If you have a new PC with Chrome or Firefox try my emulator and choose light-year demo from Preloads/Demos.

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You did it!! Awesome ! My greetings, I was sure that the TI was able to move 512 bytes of vram in a frame !

And with this configuration you can freely use all sprites (no sprite cloning glitch)

 

Now what is missing is a nice pc tool to design tiles and levels....

(if you are interested we could port some of the algorithms I have in matlab to do the optimizations matching colors and extracting meta data, to Magellan)

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