I just implemented some interpolated texture sampling by sampling the 4x4 nearest pixels then doing Lagrange interpolation across the x axis to get four values to use Lagrange interpolation on across the y axis.

Is this the same as bicubic interpolation or is it different? Or are there different kinds of bicubic interpolation, and this is just one of them perhaps?

Webgl Shadertoy implementation here: https://www.shadertoy.com/view/MllSzX

Thanks!