Can you see where my Undefined Identifier error is coming from?

Question

I have a struct 'GLpoint', defined in my NormalCalculator.h. For some reason when I define a function in the .cpp file that returns a GLpoint, the red squiggly line tells me that "identifier GLpoint is undefined". Literally on the return type of the function. The function that this occurs-in is:

GLpoint NormalCalculator::computeFaceNormal(GLface faceToNormal)

The error log also tells me that there is a missing ";" before the function definition. I cannot see where either of these are coming from. Especially as the last thing that happens before the definition of computeFaceNormals is

else return false;

The code can be found below.

NormalCalculator.h

#pragma once

#include <vector>
#include <GL/glut.h>


class NormalCalculator
{

struct GLpoint
{
    GLfloat x,y,z;
};

struct GLface
{
    GLfloat x1,y1,z1,x2,y2,z2,x3,y3,z3;
};

public:
    NormalCalculator(void);
    ~NormalCalculator(void);
    //put all of the face normal functions together 
    void generateFaceNormals(std::vector<GLfloat>* vertexArray, std::vector<GLubyte>* indexArray, std::vector<GLfloat>* normalArray);


private:
    //creates the line vectors from the the 3 points passed in as a part of the GLface
    void createLineVectorsFromFace(GLface facePassedIn, GLpoint* l_vec1, GLpoint* l_vec2); 
    //generates a normal vector for the 2 line vectors made by createLineVectorsFromFace
    void crossProductOfVecs(GLpoint* l_vec1, GLpoint* l_vec2, GLpoint* outPutNormal);
    //alters the normal vector so that it is of Unit length
    bool normalizeVector(GLpoint* normalVector, GLpoint* normalizedNormalVecContainer);
    GLpoint computeFaceNormal(GLface faceToNormal);
};

NormalCalculator.cpp

#include "NormalCalculator.h"
#include <gl/glut.h>
#include <math.h>
#include <iostream>





void NormalCalculator::createLineVectorsFromFace(GLface facePassedIn, GLpoint* l_vec1, GLpoint* l_vec2)
{
    //from verts 1 & 2 initialize l_vec1
    l_vec1->x = facePassedIn.x1 - facePassedIn.x2;
    l_vec1->y = facePassedIn.y1 - facePassedIn.y2;
    l_vec1->z = facePassedIn.z1 - facePassedIn.z2;
    //do that same for l_vec2 from face 2 and 3
    l_vec2->x = facePassedIn.x2 - facePassedIn.x3;
    l_vec2->y = facePassedIn.y2 - facePassedIn.y3;
    l_vec2->z = facePassedIn.z2 - facePassedIn.z3;
}


void NormalCalculator::crossProductOfVecs(GLpoint* l_vec1, GLpoint* l_vec2, GLpoint* outPutNormal)
{
    //cross product dat hoe
    outPutNormal->x = (l_vec1->y * l_vec2->z) - (l_vec1->z * l_vec2->y);//x = aybz-byaz
    outPutNormal->y = (l_vec1->z * l_vec2->x) - (l_vec1->x - l_vec2->z);//y = azbx-bzax
    outPutNormal->z = (l_vec1->x * l_vec2->y) - (l_vec1->y - l_vec2->x);//z = axby-bxay
}


bool NormalCalculator::normalizeVector(GLpoint* normalVector, GLpoint* normalizedNormalVecContainer)
{
    //first we must work out the magnitude of the normal vector
    GLfloat mag = (sqrt((float) pow(normalVector->x,2) + pow(normalVector->y,2) + pow(normalVector->z,2)));

    if(mag)
    {
        normalizedNormalVecContainer->x = normalVector->x/mag;
        normalizedNormalVecContainer->y = normalVector->y/mag;
        normalizedNormalVecContainer->z = normalVector->z/mag;
        return true;
    }

    else return false;

}

GLpoint NormalCalculator::computeFaceNormal(GLface faceToNormal)
{
    //first we create a couple of container GLpoints for our 2 line vectors
    GLpoint a;
    GLpoint b;
    createLineVectorsFromFace(faceToNormal, &a, &b);
    //Create a container for our origional normal
    GLpoint firstNorm;
    //We have our line vectors, and a container. Now cross product them and put them in the container.
    crossProductOfVecs(&a, &b, &firstNorm);
    //create out last normal container
    GLpoint finalNorm;
    //normalize it
    normalizeVector(&firstNorm, &finalNorm);

    return finalNorm;
}



NormalCalculator::NormalCalculator(void)
{
}

NormalCalculator::~NormalCalculator(void)
{
}

Answer 1

GLpoint NormalCalculator::computeFaceNormal(GLface faceToNormal)

should be

NormalCalculator::GLpoint NormalCalculator::computeFaceNormal(GLface faceToNormal)

In the parameter list, the qualification is not required.