Tangent and Bitangent in Custom Shader

Questions
1

Do was have access to these readily in the CustomShader, or will I have to construct them myself?

2

I was about to jack this:

vec3 random = texture2D(randomSampler, vUV * randTextureTiles).rgb;
vec3 vNormal = normal;
vec3 rvec = random * 2.0 - 1.0;
rvec.z = 0.0;
float dotProduct = dot(rvec, normal);
rvec = 1.0 - abs(dotProduct) > 1e-2 ? rvec : vec3(-rvec.y, 0.0, rvec.x);
vec3 vTangent = normalize(rvec - normal * dot(rvec, normal));
vec3 vBitangent = cross(normal, tangent);
mat3 vTMN = mat3(tangent, bitangent, normal);

but I am not sure about this line:
vec3 random = texture2D(randomSampler, vUV * randTextureTiles).rgb;

Can I just replace with any random function?

3

So I was not able to make that work.

I tried including the attribute
attributes: [“position”, “normal”, “uv”, “tangent”]
and then passing it as a vTangent to the fx and vx but to no avail as well… it seems the attribute does not get passed with the compilation of the custom shader?

4

Are you sure the initial mesh data contains tangent values?

5

Ahhh I thought that the attribute was generated when requested by the shader, so I will need to add it to the models buffer manually?

6

Yes sir