Luna::refract

Float4 refract(const Float4 &ivec, const Float4 &nvec, f32 refraction_index)

Computes the refracted vector of the input vector.

This function performs the following operations:

[f32](group___runtime_base_type_1gad34d88453d37b65a09797bad37f2f527.md) proj = [dot](group___runtime_math_vector_1ga59253c111957a8ea29144ec873bcdc1c.md)(ivec, nvec);
[f32](group___runtime_base_type_1gad34d88453d37b65a09797bad37f2f527.md) deter = 1.0f - refraction_index * refraction_index * (1.0f - proj * proj);
if (deter >= 0.0f)
{
    return ivec * refraction_index - nvec * (refraction_index * proj + sqrtf(deter));
}
return Float4(0.0f);

Parameters

• in ivec

  The direction of the incident ray.

• in nvec

  The direction of the surface normal.

• in refraction_index

  The refraction index.

Return value

Returns the direction of the refracted ray. The length of the refracted ray is normalized. Returns {0, 0} if the incident angle of ivec is too big that no refraction can occur (full reflection).

Valid Usage

• Both ivec and nvec must be normalized vectors.

• refraction_index must be a value greater than 0.