C++ Shader matrix question

Question

While examining shader examples I recently found that it's pretty often to pass the world inverse transpose matrix with the world and world-view-projection matrices.

float4x4 worldMatrix;
float4x4 worldViewProjectionMatrix;
float4x4 worldInverseTransposeMatrix;

Unfortunately, I couldn't understand the purpose of that and where it can be used. Could someone explain that?

Thank you.

Answer 1

The world inverse transpose matrix is often used for transforming normals into viewspace.