Custom collision function with mesh class not outputting vector - c++

Question

I am working on a custom 3D renderer engine based on Javidx9 3D engine tutorial. I'm trying to get some collision detection with rays and segments and it's not properly working.
I've tried implementing different methods trying to make it work the way I want it to but either the function is not working or its the way im using the function after it has been implemented. The current algorithm I am using is based on "Real-Time Collision Detection", by Christer Ericson, Pg 191. However, when the program is run I am getting no triangles intercepted triangles (the return vector is always zero). Is there something wrong with my code?
Note: I have some predefined functions that are self-explanatory based on the name.
#include <iostream>
#include <fstream>
#include <strstream>
#include <algorithm>
#include <string>
#include <vector>
#define SMALL_NUM 0.00000001 // anything that avoids division overflow
using namespace std;
// Created a 2D structure to hold texture coordinates
struct vec2d
{
float u = 0;
float v = 0;
float w = 1;
};
struct vec3d
{
float x = 0;
float y = 0;
float z = 0;
float w = 1; // Need a 4th term to perform sensible matrix vector multiplication
bool operator==(vec3d a) const
{
if (a.x == x && a.y == y && a.z == z && a.w == w)
return true;
else
return false;
}
vec3d operator+(const vec3d& a) const
{
return vec3d{ a.x + x, a.y + y, a.z + z, w };
}
vec3d operator-(const vec3d& a) const
{
return vec3d{ a.x - x, a.y - y, a.z - z, w };
}
vec3d operator*(const vec3d& a) const
{
return vec3d{ a.x * x, a.y * y, a.z * z, w };
}
vec3d operator/(const vec3d& a) const
{
return vec3d{ a.x / x, a.y / y, a.z / z, w };
}
vec3d operator+(const float& a) const
{
return vec3d{ a + x, a + y, a + z, w };
}
vec3d operator-(const float& a) const
{
return vec3d{ a - x, a - y, a - z, w };
}
vec3d operator*(const float& a) const
{
return vec3d{ a * x, a * y, a * z, w };
}
vec3d operator/(const float& a) const
{
return vec3d{ a / x, a / y, a / z, w };
}
};
struct triangle
{
vec3d p[3];
vec2d t[3]; // added a texture coord per vertex
int triid = 0;
wchar_t sym;
short col;
bool calculated = false;
};
struct mesh
{
vector<triangle> tris;
};
struct collision
{
bool plane = false;
triangle tris;
vec3d points;
};
float Vector_DotProduct(vec3d v1, vec3d v2)
{
return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
}
float Vector_Length(vec3d v)
{
return sqrtf(Vector_DotProduct(v, v));
}
vec3d Vector_Normalise(vec3d v)
{
float l = Vector_Length(v);
return { v.x / l, v.y / l, v.z / l };
}
vec3d Vector_CrossProduct(vec3d v1, vec3d v2)
{
vec3d v;
v.x = v1.y * v2.z - v1.z * v2.y;
v.y = v1.z * v2.x - v1.x * v2.z;
v.z = v1.x * v2.y - v1.y * v2.x;
return v;
}
vector<collision> CollisionSegment(vec3d ray, vec3d rayend, mesh* m)
{
vector<collision> ret; // The return varaible
vec3d raydir = Vector_Normalise(rayend - ray); // The ray direction
for (auto tri : m->tris)
{
vec3d ab = tri.p[1] - tri.p[0];
vec3d ac = tri.p[2] - tri.p[0];
vec3d qp = rayend - ray;
vec3d n = Vector_CrossProduct(ab, ac);
float d = Vector_DotProduct(qp, n);
if (d <= SMALL_NUM) continue;
vec3d ap = ray - tri.p[0];
float t = Vector_DotProduct(ap, n);
if (t < SMALL_NUM) continue;
if (t < d) continue;
vec3d e = Vector_CrossProduct(qp, ap);
float v = Vector_DotProduct(ac, e);
if (v < SMALL_NUM || v > d) continue;
float w = -Vector_DotProduct(ab, e);
if (w < SMALL_NUM || v + w > d) continue;
float ood = 1.0f / d;
t *= ood;
v *= ood;
w *= ood;
float u = 1.0f - v - w;
ret.push_back(collision{ false, tri, vec3d() });
}
return ret;
}
int main()
{
mesh meshCube;
meshCube.tris = {
// SOUTH
{ 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// EAST
{ 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// NORTH
{ 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// WEST
{ 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// TOP
{ 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
// BOTTOM
{ 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 1.0f,},
{ 1.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,},
};
vec3d p1 = { -1.5f, -1.5f, -1.5f };
vec3d p2 = { 1.5f, 1.5f, 1.5f };
vector<collision> hits = CollisionSegment(p1, p2, &meshCube);
return 0;
}
What I want is whenever I look at a mesh I want a vector of the triangles that come between me and my camera segment.