GLSL: Get current time in millis

Question

Hello, is there any way that in fragment or vertex shader we can get the current time? I wanted to use it as a random seed and also as a incremental variable to animate shaders in a simple way.

Is it possible? If not, is there any way to get random and sequentially incrementated vars?

Thnaks!

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Answer by aldonaletto · Nov 22, 2012 at 02:44 AM

Unity gently gives us the vec4 variable _Time at shader level: _Time.y is the current time, while _Time.x = time/20, _Time.z = time 2 and _Time.w = time 3.
Additionally, you can pass values from scripts to the shaders with SetFloat:

 function Start(){
   renderer.material.SetFloat("_Seed", Time.time);
 }

From what I've read about GLSL shaders, you have only to declare the uniform variable with the same name used in the script:

 ...
 GLSLPROGRAM

   uniform float _Seed; // declare the _Seed uniform float

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NeMewSys · Nov 22, 2012 at 11:31 PM 0

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I cannot get _Time to work... Im doing this: http://pastebin.com/1uf7xPAN

What is wrong?

Thanks!

NeMewSys · Nov 22, 2012 at 11:33 PM 0

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Oh, it only works on play mode activated... Cool!! Thanks!!!

GLSL: Get current time in millis

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