Speed!

[IntrnalDsK]

I am working on a greyscale routine for TI-BASIC, and i was wondering if I could get some tips on speed, like is Pxl-On() faster than PxlChange()?

I heard that using : like "While 1:End" slowed it down. Is this true?



I will be using the technique that I thought of a while ago. It does stuff like this:
Black:
Pt-On(A,B)
Pt-On(A,B)
Pt-On(A,B)
Pt-On(A,B)
Dark Grey:
Pt-On(A,B)
Pt-On(A,B)
Pt-On(A,B)
Pt-Off(A,B)
Grey:
Pt-On(A,B)
Pt-On(A,B)
Pt-Off(A,B)
Pt-Off(A,B)
Light Grey:
Pt-On(A,B)
Pt-Off(A,B)
Pt-Off(A,B)
Pt-Off(A,B)
White:
Pt-Off(A,B)
Pt-Off(A,B)
Pt-Off(A,B)
Pt-Off(A,B)
But black and white will be optimized for size and speed. I will try to post the source to a greyscale demo that I made soon.

edit by arcane wizard: I turned of smileys for you since they replace all the B) 's

[Arcane Wizard]

Well, you could test the speeds yourself:

For(X,1,500
Pxl-On(1,1
End

Check how long it takes to run that, then check how long the following runs:

For(X,1,500
Pxl-Change(1,1
End

You can use a similar method to check if while 1:End slows it down.

I was planning on writing a document with such timings for all the basic commands a while ago but I didn't have any accurate enough means to clock with and it looked like too much work and nobody would use it.

I'd check it all for you but my batteries are dead.

[Tyler]

But even if you got it to work, what would you do with it because you can't make the screen 'flash grey' or anything...

[IntrnalDsK]

but those commands up there give the illusion of grey pixels. They are somewhat flickery, but it will do.

I also have no efficent way of clocking it, besides a broken watch I'll try, though...

[Tyler]

Double click on the time on your start bar (you don't have a Mac right?) and watch the seconds go up, it shouldn't be that far off

[IntrnalDsK]

The thing is, they go so fast anyway that there isn't too much of a difference.

[KD5YTX]

Greyscale in BASIC? Make an ASM addon that accepts inputs via calc vars for a rectangular formation to shade grey, and a number between 1-5 or 1-10 stating the darkness of the shape.

[IntrnalDsK]

I was also thinking about that. It does seem interesting, but the completely BASIC one was looking cool, untill it horribly collapsed under the weight of the slow TI-BASIC interpretor of my calc. Oh well.. so much for that.

Note: For() commands are the slowest things that I have ever seen in my life. Expecially nested.

[JesusFreak]

what if you wanted to do a whole screen? it would be slow, no?

[Arcane Wizard]

Yes, it would be increadibly slow, espessially since there is no box drawing function in basic so you have to use lines or draw individual pixels.

[Ben Trettel]

Or you could invert text and draw some spaces. That should be faster, especially with big text.

[Arcane Wizard]

Which requires assembly, so you might as well just draw the screen black with assembly instead... or draw the screen black, save it as a pic and recall it when needed.