Apply Euler Rotation on position & normals in GLSL

eulerRotation.c

/*
vec3 rot    = vec3( 90.0, 90.0, 0.0 );
vec3 pos    = position * scale;
vec3 norm   = normal;
eulerRotation( rot * DEG2RAD, pos, norm );
*/

const float DEG2RAD = 0.01745329251; // PI / 180

// Apply YXZ radian rotation
vec3 eulerRotation( vec3 rot, out vec3 pos, out vec3 norm ){
  float s;
  float c;
  vec3  v;

  if( rot.z != 0.0 ){
    c     = cos( rot.z );
    s     = sin( rot.z );
    v     = pos;
    pos.x = v.x * c - v.y * s;
    pos.y = v.x * s + v.y * c;

    v      = norm;
    norm.x = v.x * c - v.y * s;
    norm.y = v.x * s + v.y * c;
  }

  if( rot.x != 0.0 ){
    c     = cos( rot.x );
    s     = sin( rot.x );
    v     = pos;
    pos.y = v.y * c - v.z * s;
    pos.z = v.y * s + v.z * c;

    v      = norm;
    norm.y = v.y * c - v.z * s;
    norm.z = v.y * s + v.z * c;
  }

  if( rot.y != 0.0 ){
    c    = cos( rot.y );
    s    = sin( rot.y );
    v    = pos;
    pos.x = v.z * s + v.x * c;
    pos.z = v.z * c - v.x * s;

    v    = norm;
    norm.x = v.z * s + v.x * c;
    norm.z = v.z * c - v.x * s;
  }

  return pos;
}