Request for Normalized Float Uniform Parameter for Loop Animations

[yanorei32]

Original Issue: https://github.com/exeldro/obs-shaderfilter/issues/64

I appreciate the idea of using an integer to represent absolute time, especially for time-dependent applications. However, in my shader code, I have been using elapsed_time for short loop animations. I realized it would be ideal to have a normalized float uniform parameter that loops between 0.0 and 1.0 over a specified number of seconds.

Using non-normalized seconds makes it challenging to handle the continuity during the rollover, as the transition timing can be tricky to manage.

I apologize for the lack of explanation in the original issue and any inconvenience it may have caused.

Therefore, I kindly request the addition of such a uniform parameter to enhance the functionality of short loop animations and better support time-dependent applications.

The fake rotation animation ( for top-right "LIVE" )

float4 mainImage(VertData v_in) : TARGET {
	v_in.uv.x -= 0.5;
	v_in.uv.x *= rcp(sin(elapsed_time * 2));
	v_in.uv.x += 0.5;
	return image.Sample(textureSampler, v_in.uv) + float4(1, 1, 1, 0) * 0.3 * sin(elapsed_time * 4 + 3.14 / 4 - 3.14 / 8);
}

Expected Behaviour

https://github.com/user-attachments/assets/c9227912-2ae1-42a2-8e23-3aecc6103ce1

Actual Behaviour (After few days)

https://github.com/user-attachments/assets/e7ad95ee-45d6-49ba-a061-1caeb4d89841

[exeldro]

Can't you use loop_second and loop instead of elapsed_time?

[yanorei32]

Using loop_second and loop seems like a great idea!

However, I couldn't understand how to implement them from the current documentation. Specifically, I'm unclear on the relationship between loop_second and loops, and how to determine the duration in seconds for the loop.

Could you please provide more detailed guidance or examples on this?

[exeldro]

ah, loop_second was broken, I fixed it now, you can find a test build at the bottom of this page when logged in: https://github.com/exeldro/obs-shaderfilter/actions/runs/13356749210

I tested with this, have not had it running for days yet

float4 mainImage(VertData v_in) : TARGET {
	float t = (loops - 314 * floor(loops /  314) + loop_second);
	v_in.uv.x -= 0.5;
	v_in.uv.x *= rcp(sin(t *2));
	v_in.uv.x += 0.5;
	return image.Sample(textureSampler, v_in.uv) + float4(1, 1, 1, 0) * 0.3 * sin(t * 4 + 3.14 / 4 - 3.14 / 8);
}

loop_second is a float going from 0.0 to 1.0 each second loops is incremented by 1 each second so the code above loops every 314 seconds

[yanorei32]

Thank you!

In my case, that problem is completely resolved, because I don't stream longer than 48.545 days.

And I simplified example code as the following:

float t = loops % 314 + loop_second;

Is there any side-effects?

P.S. I think, users can face the stuttering each 48.545 days if streams more than 48.545 days. https://github.com/exeldro/obs-shaderfilter/blob/40886208c618733521cd5832e430db00e76f80b2/obs-shaderfilter.c#L2571-L2574