help with tinyptc . . .

[DrewPee]

Hello,
I need a little help please? Not sure if this has been covered before . . .

In tinyptc, how can you check if a pixel is a certain colour? is there a way to read each pixel on the screen and return as a value . . . ?

Regards and appreciation

Andy aka DrewPee

[hellfire]

Have a look at the example files of TinyPTC Ext.
There's a buffer (of 32bit integers) which stores the rgb-color (8bit per component) of each pixel:

Code: [Select]

dim shared buffer(640*480) as integer
If you want to display anything, you just have to write it into the buffer.
The whole buffer is then copied to the screen:

Code: [Select]

ptc_update @buffer(0)
So it's really simple to find out the color of a pixel at position x,y:

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col= buffer(y*640+x)
red= (col shr 16) and 255
green= (col shr 8) and 255
blue= col and 255
(assuming your resolution is 640 * something)

[DrewPee]

@Hellfire
Thanks! I knew it could be done - just couldn't figure out how!
Very much appreciated!

Andy

[DrewPee]

Still having problems . . .

Sub DrawStars1
    for a=0 to ns-1
        testpixel=buffer(y(a)*640+x(a))
        red= (testpixel shr 16) and 255
        green= (testpixel shr and 255
        blue= testpixel and 255
        total = red+green+blue
        'if total=white then dont print! any other colour print?
        if total>0 then pp(x(a),y(a),rgb(r,g,b))
        if total>0 then pp(x1(a),y1(a),rgb(r1,g1,b1))
        if total>0 then pp(x2(a),y2(a),rgb(r2,g2,b2))
        if total>0 then pp(x3(a),y3(a),rgb(r3,g3,b3))
    next a
End Sub

am i doing something really obviously wrong?

Andy

[hellfire]

"white" means that every color-component is set to maximum (255), so "total" would be 255*3.
Of course you don't have to test every component separately:

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if testpixel<>&hffffff
  pp(x(a),y(a),rgb(r,g,b))


[Clyde]

Btw, if you use the [ code ] and [ / code ] tags, it'll do away with mr smiley.

[DrewPee]

Hellfire,
Thanks for your help on this. It is now working! Cheers

Clyde,
Thanks to you too . . . i always forget about the [ code ] tags!!!