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global shader uniforms (ie. u_time)


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Is there a way to globally set the values of certain uniforms, so they don't need to be set on a per shader basis? ie.:

uniform vec2 u_resolution;
uniform float u_time;

It seems to be it might be inconvenient to have to update every shader each when we change resolution, or to update the time


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Two-part answer


u_resolution is actually part of filter uniforms that depend on temporary pow2-sized texture. In v5 its available under another name for all filters.

v5: http://pixijs.download/dev/docs/PIXI.Filter.html

working on new docs: https://github.com/pixijs/pixi.js/pull/5555

one of latest filter-related threads


In v5 its possible to add stuff to global uniforms. Related code: https://github.com/pixijs/pixi.js/search?q=globalUniforms&unscoped_q=globalUniforms

Maybe you can put something in "renderer.globalUniforms" before you create the shader.

I did not test this approach so I do not know additional actions are required for it. You have to guess and debug.


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Thanks for your reply!

I'm using version 4.8.7 which I got from npm. Is version 5 ready to use already?

Even after checking the docs I don't understand how u_resolution is already defined, as I don't seem to be there unless I define it. Is there any sample code I can check?

>u_resolution is actually part of filter uniforms that depend on temporary pow2-sized texture

does this mean it only works for pow2-sized textures?


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Look, I specified in  https://github.com/pixijs/pixi.js/pull/5555 that we have 5 different spaces for coordinates. Its hell. There is u_resolution (sometimes called `dimensions`) that is needed for conversion between some of them, and it has special name in v5, but in v4 you have to add a hack to "Filter.apply" method to use it.

The problem is discussed so many times that I really dont have time to discuss it right now unless you have a demo for me to fix. All that links I posted should help you to make your case, then I can help you to fix it :)

"container.filterArea = renderer.screen" makes everything significantly easier, because all normalized coords are in screen, maybe that helps you.

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