CPCWiki forum

General Category => General Discussion - Introductions => Topic started by: AMSDOS on 12:05, 16 October 10

Title: Optical Illusions
Post by: AMSDOS on 12:05, 16 October 10
Just for a bit of fun, I was curious to see how the CPC would handle an image which would produce an Optical Illusion. The attached Disk Image is the result. For this one ("Illusion.SCR") it uses MODE 2, INK 0,26 & INK 1,0 I also set it to PAPER 1 & PEN 1 - just to avoid the Bright White Screen & BORDER 0. I chose MODE 2 for detail cause the original had a resolution greater than MODE 1, the only problem I had was the vertical axis is 200. Maybe more effective in Overscan, though it's bit beyond it. What I did find though, was Indeed some Illusion is evident in this image which was all I wanted to test to see if it would work!  ;D  Hasn't quite got the same bite as the original on the PCs, it maybe because the PC version uses True Grey between the Black & White to get the effect, instead of what I did which was cross-hatch between the Black and White Pixels to get a greyish effect. I put it in Winape with the PAL Mode on and it seems to improve the Illusion a little bit.  ;D
Title: Re: Optical Illusions
Post by: Gryzor on 09:17, 18 October 10
Screenies? :) Or webCPC?
Title: Re: Optical Illusions
Post by: redbox on 09:25, 18 October 10
Interesting, and you're right the effect does look better with PAL emulation.

Title: Re: Optical Illusions
Post by: Gryzor on 09:52, 18 October 10
GAAAAAAAAAAAAAAAAA I'M BLIND!
Title: Re: Optical Illusions
Post by: AMSDOS on 09:54, 18 October 10
Gryzor wrote:

Screenies? :) Or webCPC?

Well it's a Disk Image, so you can just insert it into your favourite emulator or Disk Utility program and run it on your CPC!  :)  Perhaps try and see what happens when different colours are used, I found the illusive effect to alternate!
Title: Re: Optical Illusions
Post by: AMSDOS on 09:55, 18 October 10
Gryzor wrote:

GAAAAAAAAAAAAAAAAA I'M BLIND!

Really?!  ???
Title: Re: Optical Illusions
Post by: Devilmarkus on 11:28, 18 October 10
Nice effect.
Would be interesting to know if the illusion is better in MODE 1 and the lines would be grey (INK 13)

I also wrote once a small effect. Just digged it out:
10 MODE 2
20 INK 0,26:INK 1,26:BORDER 26
30 PLOT 0,220,1:DRAW 640,220
40 PLOT 0,300:DRAW 640,300
50 PLOT 320,200:DRAW 320,320
60 FOR t=320 TO 0 STEP -40
70 PLOT 320,160:DRAW t,260:DRAW 320,360
80 PLOT 320,160:DRAW 640-t,260:DRAW 320,360
90 NEXT
100 FOR t=0 TO 20 STEP 2
110 PLOT 0,160+t,0:DRAW 640,160+t
120 PLOT 0,360-t,0:DRAW 640,360-t
130 NEXT
140 INK 1,0
Title: Re: Optical Illusions
Post by: Devilmarkus on 11:51, 18 October 10
Here's your first effect but in MODE 1:

10 MODE 1
20 a$=CHR$(231)
30 LOCATE 1,1:PRINT CHR$(23);CHR$(1)
40 INK 0,0:BORDER 0:INK 1,26:INK 2,13:INK 3,26
50 FOR t=0 TO 640 STEP 60
60 FOR k=1 TO 8 STEP 2
70 PLOT k+t,0,2:DRAW k+t,400
80 PLOT 0,k+t:DRAW 640,k+t
90 NEXT
100 NEXT
110 PLOT -4,-4,1:TAG:FOR y=10 TO 400 STEP 60:FOR g=-4 TO 640 STEP 60:MOVE g,y:PRINT a$;:NEXT
120 NEXT
130 CALL &BB18
Title: Re: Optical Illusions
Post by: AMSDOS on 12:46, 18 October 10
I was worried someone would come out with 13 lines of code to demonstrate it. Smucks like me spend an hour in Advanced Art Studio drawing the cross stitching in!  ;)  But yeah the effect works just as well from your program (no idea how you can just make it happen!)

You should check this site out (http://www.eyetricks.com/illusions.htm) and see what else you can come up with!  ;)  Unfortunately it's riddled with Popups, flashy ads, etc. I did knock off a few just to put in an email, but I seemed to have lost them.  :-[
Title: Re: Optical Illusions
Post by: Devilmarkus on 12:48, 18 October 10
Well I'll check this site.
Maybe I can do a small Optical Illusions demo. (I know there already exist one but I forgot it's name)
Title: Re: Optical Illusions
Post by: Devilmarkus on 12:52, 18 October 10
Found them:
http://www.cpc-power.com/cpcdemos/index.php?page=detail&num=140
http://www.cpc-power.com/cpcdemos/index.php?page=detail&num=718
http://www.cpc-power.com/cpcdemos/index.php?page=detail&num=1324
Title: Re: Optical Illusions
Post by: redbox on 12:56, 18 October 10
There is an article on the BBC News website (http://www.bbc.co.uk/news/magazine-11553099) today about optical illusions.
Title: Re: Optical Illusions
Post by: AMSDOS on 09:59, 07 November 12
Have a look at this one I've attached. It's not CPC specific though I'm somewhat baffled how it works, it's like when your not directly looking at the circles they appear to be moving (but of course their not moving). I wonder if this trick could be applied in a demo or something as a visual teaser?
Title: Re: Optical Illusions
Post by: Bryce on 10:05, 07 November 12
The more coffee I drink, the more they seem to move  :o

Bryce.
Title: Re: Optical Illusions
Post by: arnoldemu on 10:44, 07 November 12
Quote from: Bryce on 10:05, 07 November 12
The more coffee I drink, the more they seem to move  :o

Bryce.
works with tea too  :laugh:
Title: Re: Optical Illusions
Post by: mr_lou on 12:30, 07 November 12
Quote from: Bryce on 10:05, 07 November 12
The more coffee I drink, the more they seem to move  :o
Quote from: arnoldemu on 10:44, 07 November 12
works with tea too  :laugh:

Well, I guess we've found the drive behind optical illusions then, because it's not doing anything at all here - and I drink neither coffee nor tea.
Title: Re: Optical Illusions
Post by: Gryzor on 13:01, 07 November 12
Whoa. Headache-inducing.
Title: Re: Optical Illusions
Post by: AMSDOS on 06:31, 08 November 12
Quote from: mr_lou on 12:30, 07 November 12
Well, I guess we've found the drive behind optical illusions then, because it's not doing anything at all here - and I drink neither coffee nor tea.
I found the Illusion works better when you view the full size image, though I must confess I'm a tea drinker.
Does the earlier Optical Illusion I made on the Amstrad have any effect?

Quote from: Gryzor on 13:01, 07 November 12
Whoa. Headache-inducing.
Not sure it recommended for prolong exposure.
Powered by SMFPacks Menu Editor Mod