refract

taichi_glsl.vector.refract(I, N, eta)

Calculate the refraction direction for an incident vector.

For a given incident vector I, surface normal N and ratio of indices of refraction, eta, refract returns the refraction vector, R.

Parameters

• I – Specifies the incident vector.

• N – Specifies the normal vector.

• eta – Specifies the ratio of indices of refraction.

Returns

The return value is calculated as:

k = 1 - eta * eta * (1 - dot(N, I) * dot(N, I))
R = I * 0
if k >= 0:
    R = eta * I - (eta * dot(N, I) + sqrt(k)) * N
return R

Note

The input parameters I and N should be normalized in order to achieve the desired result.

See also

reflect(), normalize(), dot().