Login [Register]
Don't have an account? Register now to chat, post, use our tools, and much more.
Ti-Basic greyscale exploit
This is an archived, read-only copy of the United-TI subforum , including posts and topic from May 2003 to April 2012. If you would like to discuss any of the topics in this forum, you can visit Cemetech's TI-BASIC subforum. Some of these topics may also be directly-linked to active Cemetech topics. If you are a Cemetech member with a linked United-TI account, you can link United-TI topics here with your current Cemetech topics.

This forum is locked: you cannot post, reply to, or edit topics. TI-Basic => TI-BASIC
Ti-Basic greyscale exploit
United-TI Archives -> TI-Basic
 
    »
» View previous topic :: View next topic  
Author Message
idiot0000


Newbie


Joined: 13 Apr 2009
Posts: 4
Posted: 22 Jun 2010 02:38:12 pm    Post subject:
Hey there!

I recently discovered a little exploit on the TI 84+. With the contrast set to 4 I ran this program:

Code:
ClrDraw
For(m,0,94,2
For(n,0,62,2
Pxl-On(n,m
End
End

Now I won't try to explain it because the forum on TI|BD shows that a linguistic explanation is rather confusing. You can of course read ithere but you better just follow these steps:

1.write the program
2.run it
3.move the cursor in the graph screen around and notice some strange effects on the overlapping elements of the cursor and the pixels just drawn. What you should see is that the just drawn pixels are grey and that the cursor on some points is black!
I have no funded clue how this works or why but I do suspect it is a hardware 'fault'. When you make the step in the for loop 1 or >2 it will not work. Now, if indeed this is a hardware fault then maybe this can be further used in assembly language to make greyscale without having to turn pixels on and off that fast...
In fact the intensity of the pixel is determined by the amount of power on the cathode (or anode) of a certain pixel. If this somehow someway can be regulated (maybe we can figure out how by exploring this exploit further) then greyscale is so much easier and less CPU intensive!

P.s.
The last part is merely an assumption I do not claim anything to be true of it but I have my suspicions based on my megre asm experience...(notice that I put it in the basic section because the program causing this is in basic however, further discussion about this may be going more in the direction of asm programming, I leave it to the moderators to decide the proper place for this topic)
Back to top
calcdude84se


Member


Joined: 09 Aug 2009
Posts: 207
Posted: 22 Jun 2010 08:17:13 pm    Post subject:
As mentioned, we are already aware of this. Note that this is not the driver, but rather the display itself. Certain patterns (like the one you have, and alternating columns) cause the LCD to display those pixels with less power. The main thing to do, then, is to see which patterns produce this graying out, and how, and then to see if those patterns are at all useful. Maybe someone else has more info on the LCD and what types of patterns cause this to occur?
Back to top
Galandros


Active Member


Joined: 29 Aug 2008
Posts: 565
Posted: 23 Jun 2010 03:28:06 am    Post subject:
On a "normal" contrast of 5 I noted some strange grey lines appearing but I forgot them over some time.

It is quite funny to see those effects. It also happens some interesting effects in higher contrasts like 6.
Back to top
idiot0000


Newbie


Joined: 13 Apr 2009
Posts: 4
Posted: 23 Jun 2010 02:23:33 pm    Post subject:
Well basicaly this is the greyscale version of something that is extremely obvious. Sometimes on the homescreen I get strange lines that 'sore' through my equations or expressions. They just darkne or lighten parts that are not "blocked" by other text. This happens most in HomeScreen based games. I still think it must be the driver cause the driver litterlay decides which lines are powered. The screen itself can never cause this albeit it can lose power somehow somewhere.

it reamains intresting, maybe we should list all of the discovered events that trigger this type of greyscale to occur?
Back to top
cjgone
Aw3s0m3


Active Member


Joined: 24 May 2006
Posts: 693
Posted: 24 Jun 2010 12:42:48 am    Post subject:
I've noticed these, never knew the reason why though. Razz

Last edited by Guest on 24 Jun 2010 12:42:57 am; edited 1 time in total
Back to top
Display posts from previous:   
Register to Join the Conversation
Have your own thoughts to add to this or any other topic? Want to ask a question, offer a suggestion, share your own programs and projects, upload a file to the file archives, get help with calculator and computer programming, or simply chat with like-minded coders and tech and calculator enthusiasts via the site-wide AJAX SAX widget? Registration for a free Cemetech account only takes a minute.

» Go to Registration page
Ti-Basic greyscale exploit
    »
» View previous topic :: View next topic  
Page 1 of 1 » All times are GMT - 5 Hours

 

Advertisement



© Copyright 2000-2019 Cemetech & Christopher Mitchell :: Page Execution Time: 0.091984 seconds.