[PD] GEM : GLSL Mixer - working 2 channel video mixer example

[Anton Marini]

if you use feedback with a low alpha for the gl_clear_color, the double/quadruple  buffering for FSAA actually erases your previous frame. Thats one technique.

:)
 
On Tuesday, December 25, 2007, at 06:43PM, "cyrille henry" <cyrille.henry at la-kitchen.fr> wrote:
>
>
>vade a écrit :
>> Yes, very efficient, and also give you LOTS of flexibility . the  
>> regular GL_BLEND_MODES do not offer that many variations (not many are  
>> useful for video). Want to make a GPU powered chroma key - shader.  
>> Want to make feedback but have FSAA on, probably shader :)
>why can't you do a feedback with FSAA?
>
>cyrille
>
>> etc etc. Want to make 4 way mixer? shader! See where I am going here? :)
>> 
>> 
>> On Dec 24, 2007, at 3:29 PM, Hans-Christoph Steiner wrote:
>> 
>>> Nice, works for me.  Is the idea that shaders are a efficient way of  
>>> mixing video?
>>>
>>> .hc
>>>
>>> On Dec 24, 2007, at 12:04 PM, vade wrote:
>>>
>>>> Hello
>>>>
>>>> Here is a 2 channel mixer using overlay blend mode with GLSL. This  
>>>> works, is decently fast and gives me the expected result.
>>>>
>>>> If you want more blend modes, feel free to grab them from http://001.vade.info 
>>>>  (or elsewhere, most are trivial to figure out)- the glsl shaders  
>>>> for the mixers use the same subroutine layout in the glsl, so it is  
>>>> trivial to swap. I did not include them out of sheer laziness.
>>>>
>>>> Caveats with PD 0.4.03 Extended nightly from Dec 24th (Mac OS X  
>>>> 10.5.1, QT 7.3, Intel):
>>>>
>>>> - had to edit the GLSL program to fix multitexture coordinate  
>>>> issue. Only can use the texture dims from the zeroths texture unit.
>>>> - could not get sampler2DRect working at all - only had a single  
>>>> texel mapped it seemed.
>>>> - had weird issue where I would sometimes have to close the gemwin  
>>>> (0, destroy) and then re create it to see the textures assigned to  
>>>> texture units.
>>>> 	this happened most often after closing and re-opening the patch.
>>>>
>>>> Please see the included question(s) within the PD patch concerning  
>>>> using framebuffer to grab the output of the rendered shader and  
>>>> send it to yet another shader. Ive included an exposure shader in  
>>>> an attempt to make a chain of GLSL effects. I however could not get  
>>>> gemframebuffer to output any usable texture after using glslprogram.
>>>>
>>>> Thanks, hope this is helpful to those out there
>>>>
>>>> FUDDLE DUDDLE !@#!@#!@#()*!@#(*@#
>>>>
>>>> :)
>>>>
>>>> <GEM_glsl_2_channel_mixer.zip>
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>>>
>>>
>>> ----------------------------------------------------------------------------
>>>
>>> Using ReBirth is like trying to play an 808 with a long stick.    - 
>>> David Zicarelli
>>>
>>>
>> 
>> 
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