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Index › Programming Questions & Help › Syntax Questions › dynamic alpha masking (mouse controlled)
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dynamic alpha masking (mouse controlled) (Read 549 times)
nufets
dynamic alpha masking (mouse controlled)
Dec 7th, 2007, 4:19pm  
hello,

at http://basislager.org/dynamic_alpha_mask/v1.html you find a first experiment i've done in processing (source-code attached to the website). in this example i'd like to have an effect like wiping off snow from a window. until now i've (kind of) managed to get working with a square - moving the mouse of the applet while having the left key of the mouse pressed reveales the background image by continiously setting the pixels of the dynamically generated alphamask to 255 (the script is in a very preliminary state ...

i'd like to do this in a more 'naturally' looking way - not square fields being reveiled but unregular forms. but before i get into this (probably) tricky part of programming i'd like to know if there wouldn't be an easier way of doing this - e.g. applying another image (like a big unregular snowflake) that passes its alpha-information to the alphamask, continiously extending transparency will dragging the mouse? (hope you understood what i mean ...).

thanks a lot in advance for help,

stefan
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« Last Edit: Dec 16th, 2007, 4:16pm by nufets »  
 
nufets
Re: dynamic alpha masking (mouse controlled)
Reply #1 - Dec 11th, 2007, 11:55pm  
it's cost me some time, but i've figured out this solution: http://basislager.org/dynamic_alpha_mask/v2.html

still somewhat preliminary and much too slow ... maybe someone can give a hint how to do that more efficiantly ...

thanks, stefan
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« Last Edit: Dec 16th, 2007, 4:17pm by nufets »  
 
Sparragus
Re: dynamic alpha masking (mouse controlled)
Reply #2 - Dec 12th, 2007, 1:35am  
I'm pretty sure that what is slowing you is that you're loading the bg.jpg every time draw() loops. Try loading it in setup().
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nufets
Re: dynamic alpha masking (mouse controlled)
Reply #3 - Dec 12th, 2007, 3:39pm  
thanks for this hint. i tried to put
Code:

bg = loadImage("bg.jpg");

into setup(). yet that prevents the mask from being updated when i move the mouse (mask stays at the position where i first clicked with the mouse).
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nufets
Re: dynamic alpha masking (mouse controlled)
Reply #4 - Dec 12th, 2007, 3:52pm  
btw.: why are the applets running significantly slower if embedded into a website?
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