Undefined reference to vtable with all virtual functions implemented
I have these two structures defined:
#ifndef OBJECT_H_
#define OBJECT_H_
#include <stdio.h>
#include "vector.h"
struct object{
public:
int index; // identifies a object; must be greater than 0
float mat_ambient[3]; // material property used in Phong model
float mat_diffuse[3];
float mat_specular[3];
float mat_shineness;
float reflectance; // this number [0,1] determines how much
// reflected light contributes to the color
// of a pixel
virtual float intersect(Point, Vector, object*, Point*);
virtual Vector normal(Point, object*);
};
#endif /* OBJECT_H_ */
#ifndef SPHERE_H_
#define SPHERE_H_
#include "object.h"
struct sphere: public object {
public:
Point center;
float radius;
// intersect ray with sphere
float intersect(Point, Vector, object*, Point*);
// return the unit normal at a point on sphere
Vector normal(Point, object*);
};
#endif /* SPHERE_H_ */
However, when I try to compile, I get the following two errors:
undefined reference to `vtable for object'
I know this is not my makefile since it has already added sphere.cpp and object.cpp Is there a function or method missing from my structures that is calling this?
object.cpp
#include "object.h"
#include <stdlib.h>
#include <math.h>
#include <iostream>
#include "sphere.h"
using namespace std;
/**********************************************************************
* This function intersects a ray with a given sphere 'sph'. You should
* use the parametric representation of a line and do the intersection.
* The function should return the parameter value for the intersection,
* which will be compared with others to determine which intersection
* is closest. The value -1.0 is returned if there is no intersection
*
* If there is an intersection, the point of intersection should be
* stored in the "hit" variable
**********************************************************************/
float sphere::intersect(Point A, Vector p, object *o, Point *hit) {
cout << "intersect" << endl;
sphere* s = (sphere*) o;
Point C = s->center;
Point B;
B.x = A.x + p.x;
B.y = A.y + p.y;
B.z = A.z + p.z;
float a = pow(B.x - A.x, 2) + pow(B.y - A.y, 2) + pow(B.z - A.z, 2);
float b = 2 * ((B.x - A.x) * (A.x - C.x) + (B.y - A.y) * (A.y - C.y) + (B.z - A.z) * (A.z - C.z));
float c = pow(A.x - C.x, 2) + pow(A.y - C.y, 2) + pow(A.z - C.z, 2) - pow(s->radius, 2);
float delta = pow(b, 2) - 4 * a * c;
if (delta < 0.0) {
//no intersection
return -1.0;
}
if (delta >= 0.0) {
//possibly more then one intersection, but at least one, return the smallest one
float d1 = (-b - sqrt(delta)) / (2 * a);
float d2 = (-b + sqrt(delta)) / (2 * a);
if (d1 < d2) {
hit->x = A.x + (p.x * d1);
hit->y = A.y + (p.y * d1);
hit->z = A.z + (p.z * d1);
return d1;
} else {
hit->x = A.x + (p.x * d2);
hit->y = A.y + (p.y * d2);
hit->z = A.z + (p.z * d2);
return d2;
}
}
return -1.0;
}
/******************************************
* computes a sphere normal - done for you
******************************************/
Vector sphere::normal(Point q, object *o) {
sphere *sph = (sphere *) o;
Vector rc;
rc = get_vec(sph->center, q);
normalize(&rc);
return rc;
}
Makefile
#! /usr/bin/make
SOURCE= scene.cpp image_util.cpp sphere.cpp vector.cpp trace.cpp raycast.cpp object.cpp include/InitShader.cpp
CC= g++
CFLAGS= -O3 -ggdb -O0 -Wall -pedantic -DGL_GLEXT_PROTOTYPES -std=c++11
EXECUTABLE= raycast
LDFLAGS = -lGL -lglut -lGLEW -lXext -lX11 -lm
INCLUDEFLAG= -I. -I$(INCLUDEDIR) -Iinclude/
LIBFLAG= -L$(LIBDIR)
OBJECT= $(SOURCE:.cpp=.o)
all: $(OBJECT) depend
$(CC) $(CFLAGS) $(INCLUDEFLAG) $(LIBFLAG) $(OBJECT) -o $(EXECUTABLE) $(LDFLAGS)
depend:
$(CC) -M $(SOURCE) > depend
$(OBJECT):
$(CC) $(CFLAGS) $(INCLUDEFLAG) -c -o $@ $(@:.o=.cpp)
clean_object:
rm -f $(OBJECT)
clean:
rm -f $(OBJECT) depend $(EXECUTABLE)
include depend
+3
source to share
2 answers
undefined reference to `vtable for object'
You are getting this error because you did not specify a virtual method definition in the object. Basically vtable stores function pointers
Requires virtual function address. Therefore, if you missed the definition of a single virtual function, the compiler will not be able to create a complete vtable for that class.
For your object class, it vtable
will be something like: -
&object::intersect &object::normal
EDIT: -
This means the following: -
virtual float intersect(Point, Vector, object*, Point*);
virtual Vector normal(Point, object*);
You must have: -
float object::intersect(Point, Vector, object*, Point*)
{
}
Vector object::normal(Point, object*)
{
}
+3
source to share
If there is no definition for object :: intersect and object :: normal, you should make them pure virtual functions as shown below:
#ifndef OBJECT_H_
#define OBJECT_H_
#include <stdio.h>
#include "vector.h"
struct object{
public:
int index; // identifies a object; must be greater than 0
float mat_ambient[3]; // material property used in Phong model
float mat_diffuse[3];
float mat_specular[3];
float mat_shineness;
float reflectance; // this number [0,1] determines how much reflected light contributes to the color of a pixel
virtual float intersect(Point, Vector, object*, Point*) = 0;
virtual Vector normal(Point, object*) = 0;
};
#endif /* OBJECT_H_ */
Try it and I think this will figure out your problem.
+1
source to share