Optical Illusions

[AMSDOS]

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!    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. 

[Gryzor]

Screenies? Or webCPC?

[redbox]

Interesting, and you're right the effect does look better with PAL emulation.

[Gryzor]

GAAAAAAAAAAAAAAAAA I'M BLIND!

[AMSDOS]

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!

[AMSDOS]

Gryzor wrote:

GAAAAAAAAAAAAAAAAA I'M BLIND!

Really?! 

[Devilmarkus]

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:

Code Select Expand

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


[Devilmarkus]

Here's your first effect but in MODE 1:

Code Select Expand


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


[AMSDOS]

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 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. 

[Devilmarkus]

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)

[Devilmarkus]

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

[redbox]

There is an article on the BBC News website today about optical illusions.

[AMSDOS]

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?

[Bryce]

The more coffee I drink, the more they seem to move 

Bryce.

[arnoldemu]

The more coffee I drink, the more they seem to move 

Bryce.

works with tea too 

[mr_lou]

The more coffee I drink, the more they seem to move 

works with tea too 

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.

[Gryzor]

Whoa. Headache-inducing.

[AMSDOS]

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?

Whoa. Headache-inducing.

Not sure it recommended for prolong exposure.