Terminus - Triangle Class

Here is the Triangle class we are using for out navmesh. This is a mesh representing the walkable areas in the game. It is quick to implement and is working well.



#include <string.h>
#include "vec3.h"

#define SMALL_NUM  0.00000001 // anything that avoids division overflow

class Triangle {
    vec3 m_v0,m_v1,m_v2; //verteces
    vec3 m_edge1,m_edge2,m_normal;
  
public:
    Triangle(const vec3 &_v0, const vec3 &_v1, const vec3 &_v2);
    ~Triangle();
  
    bool intersectRay(const vec3 &_rayStart, vec3 *_intersectPoint);
  
    void print() const;
};


//the intersect method

bool Triangle::intersectRay(const vec3 &_rayStart, vec3 *_intersectPoint)
{
    //vec3 _intersectPoint;
    vec3    dir, w0, w;          // ray vectors
    float     r, a, b;             // params to calc ray-plane intersect
  
    dir = vec3(0.0,-100.0,0.0) - _rayStart;             // ray direction vector
    dir.Normalize();
    w0 = _rayStart - m_v0;
    a = -m_normal.Dot(w0);
    b = m_normal.Dot(dir);
  
    if (fabs(b) < SMALL_NUM)
    {     
           // ray is parallel to triangle plane or ray disjoint from plane          
            return false;            
    }
  
    // get intersect point of ray with triangle plane
    r = a / b;
    if (r < 0.0)                   // ray goes away from triangle
        return false;                  // => no intersect
    // for a segment, also test if (r > 1.0) => no intersect
  
    *_intersectPoint = _rayStart + (r * dir);           // intersect point of ray and plane
  
    // is I inside T?
    float    uu, uv, vv, wu, wv, D;
    uu = m_edge1.Dot(m_edge1);
    uv = m_edge1.Dot(m_edge2);
    vv = m_edge2.Dot(m_edge2);
    w = *_intersectPoint - m_v0;
    wu = w.Dot(m_edge1);
    wv = w.Dot(m_edge2);
    D = uv * uv - uu * vv;
  
    // get and test parametric coords
    float s, t;
    s = (uv * wv - vv * wu) / D;
    if (s < 0.0 || s > 1.0)        // I is outside T
        return false;
    t = (uv * wu - uu * wv) / D;
    if (t < 0.0 || (s + t) > 1.0)  // I is outside T
        return false;
  
    return true;                      // I is in T
}

Terminus - group project game.

Here are some images of the game we are currently making as part of a group project at the NCCA. We have built a mini-engine from scratch and built all assets ourselves.