Post by trejkaz on Mar 22, 2022 7:00:36 GMT
Is there a nice geometric argument for why the direction of refraction is calculated the way it is?
In the book it has it as:
The context:
In my new code I can't use n_ratio = n1 / n2 anymore because it's a complex number. So I started wondering whether I could still use sin_t / sin_i in place of it, and it sort of seems like I probably can, but I can't figure out why this formula works in the first place.
It definitely looks like I should be able to compute the refraction direction by combining normalv and eyev in some amounts, but from a diagram on paper I can't figure out how to derive this formula.
In the book it has it as:
direction ← comps.normalv * (n_ratio * cos_i - cos_t) - comps.eyev * n_ratio
The context:
In my new code I can't use n_ratio = n1 / n2 anymore because it's a complex number. So I started wondering whether I could still use sin_t / sin_i in place of it, and it sort of seems like I probably can, but I can't figure out why this formula works in the first place.
It definitely looks like I should be able to compute the refraction direction by combining normalv and eyev in some amounts, but from a diagram on paper I can't figure out how to derive this formula.
Thanks for sharing your work!