OpenMW/files/shaders/compatibility/normals.glsl

varying mat3 normalToViewMatrix;

mat3 generateTangentSpace(vec4 tangent, vec3 normal)
{
    vec3 normalizedNormal = normalize(normal);
    vec3 normalizedTangent = normalize(tangent.xyz);
    vec3 binormal = cross(normalizedTangent, normalizedNormal) * tangent.w;
    return mat3(normalizedTangent, binormal, normalizedNormal);
}

vec3 normalToView(vec3 normal)
{
    return normalize(normalToViewMatrix * normal);
}