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

cyrille henry cyrille.henry at la-kitchen.fr
Wed Dec 26 00:40:14 CET 2007



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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