Tengo codigo

NSMutableArray *vertices = [[NSMutableArray alloc] init];

//Getting mouse coordinates
loc = [self convertPoint: [event locationInWindow] fromView:self];
[vertices addObject:loc]; // Adding coordinates to NSMutableArray

//Converting from NSMutableArray to GLfloat to work with OpenGL
int count = [vertices count] * 2; // * 2 for the two coordinates of a loc object
GLFloat []glVertices = (GLFloat *)malloc(count * sizeof(GLFloat));
int currIndex = 0;
for (YourLocObject *loc in vertices) {
    glVertices[currIndex++] = loc.x;
    glVertices[currIndex++] = loc.y;        
}

loc es CGPoint, así que necesito cambiar de CGPoint a NSValue para agregarlo a NSMutableArray y luego volver a convertirlo en CGPoint. ¿Cómo podría hacerse?