Tangent space basis visualizer

TangentSpaceBasisVisualizer.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class TangentSpaceBasisVisualizer : MonoBehaviour
{
	void GetTangentSpaceBasis(Mesh mesh,  int triangleIndex, Vector3 barycentricCoordinates,out Vector3 tangent,out Vector3 binormal, out Vector3 normal) {
		
		Vector3[] normals = mesh.normals;
		Vector4[] tangents = mesh.tangents;
		int[] triangles = mesh.triangles;

		Vector3 n0 = normals [triangles [triangleIndex * 3 + 0]];
		Vector3 n1 = normals [triangles [triangleIndex * 3 + 1]];
		Vector3 n2 = normals [triangles [triangleIndex * 3 + 2]];


		Vector4 t0 = tangents [triangles [triangleIndex * 3 + 0]];
		Vector4 t1 = tangents [triangles [triangleIndex * 3 + 1]];
		Vector4 t2 = tangents [triangles [triangleIndex * 3 + 2]];

		Vector3 interpolatedNormal = n0 * barycentricCoordinates.x + n1 * barycentricCoordinates.y + n2 * barycentricCoordinates.z;
		interpolatedNormal = interpolatedNormal.normalized;


		Vector3 interpolatedTangent = t0 * barycentricCoordinates.x + t1 * barycentricCoordinates.y + t2 * barycentricCoordinates.z;
		interpolatedTangent = interpolatedTangent.normalized;

		Vector3 interpolatedBinormal = Vector3.Cross (interpolatedNormal, interpolatedTangent) * t0.w;
		interpolatedBinormal = interpolatedBinormal.normalized;

		normal = interpolatedNormal;
		tangent = interpolatedTangent;
		binormal = interpolatedBinormal;

		return;
	}

	void Update() {
			ShowTangentSpaceBasis ();
	}

	void ShowTangentSpaceBasis() {
		
		RaycastHit hit;

		if (!Physics.Raycast (Camera.main.ScreenPointToRay(Input.mousePosition), out hit)) {
			return ;
		}

		if (! (hit.collider is MeshCollider)) {
			Debug.LogWarning ("Can't calculate tangent space in " + hit.collider.gameObject + " because it doesn't contain a mesh collider");
			return ;
		}

		Mesh mesh = hit.collider.GetComponent<MeshFilter>().sharedMesh;

		Vector3 tangent;
		Vector3 normal;
		Vector3 binormal;

		GetTangentSpaceBasis (mesh,hit.triangleIndex,hit.barycentricCoordinate, out tangent, out binormal, out normal);

		Transform hitTransform = hit.collider.transform;

		normal = hitTransform.TransformDirection (normal);
		tangent = hitTransform.TransformDirection (tangent);
		binormal = hitTransform.TransformDirection (binormal);	


		Debug.DrawRay (hit.point, normal, Color.blue);
		Debug.DrawRay (hit.point, tangent, Color.red);
		Debug.DrawRay (hit.point, binormal, Color.green);
	}

}