How to add noise to lerp

[kind briar]

Hi, I wanted to add a bit of noise to the edge on a Lerp node (image included). How would I go about doing that in Shader Graph? Thanks

[cunning sapphire]

you need to modulate the input to the Lerp node

You'll want to make sure the input doesn't leave the 0..1 range

to do that, you can use the original input value to decide what range the noise is allowed to have

it'd be like this in HLSL:

float lower_bound = lerp(0, -0.3, lerp_input);
float upper_bound = lerp(0.3, 0, lerp_input);
lerp_input += lerp(lower_bound, upper_bound, noise);

when the input is at 0, your noise must be positive

when the input is at 1, your noise must be negative

and in-between, both positive and negative values are acceptable

If your noise isn't in the 0..1 range, remap it first

For the actual noise, I'm pretty sure there's a "gradient noise" node that'll do what you want

Note that this will need a 2D input to calculate the noise value