## intersect (`lygia`/`geometry`/`triangle`/`intersect`)

based on https://www.iquilezles.org/www/articles/intersectors/intersectors.htm

Dependencies:

Use:

``````<float> intersect(<Triangle> tri, <vec3> rayOrigin, <vec3> rayDir, out <vec3> intersectionPoint)
``````

Check it on Github

``````

#ifndef FNC_TRIANGLE_INTERSECT
#define FNC_TRIANGLE_INTERSECT

float intersect(Triangle _tri, vec3 _rayOrigin, vec3 _rayDir, inout vec3 _point) {
vec3 v1v0 = _tri.b - _tri.a;
vec3 v2v0 = _tri.c - _tri.a;
vec3 rov0 = _rayOrigin - _tri.a;
_point = cross(v1v0, v2v0);
vec3 q = cross(rov0, _rayDir);
float d = 1.0f / dot(_rayDir, _point);
float u = d * -dot(q, v2v0);
float v = d *  dot(q, v1v0);
float t = d * -dot(_point, rov0);
if (u < 0.0f || u > 1.0f || v < 0.0f || (u+v) > 1.0f || t < 0.0f)
t = 9999999.9f; // No intersection

return t;
}

float intersect(Triangle _tri, Ray _ray, inout vec3 _point) { return intersect(_tri, _ray.origin, _ray.direction, _point); }
float intersect(Triangle _tri, Ray _ray) {
vec3 p;
return intersect(_tri, _ray, p);
}

#endif
``````

Dependencies:

Use:

``````<float> intersect(<Triangle> tri, <float3> rayOrigin, <float3> rayDir, out <float3> intersectionPoint)
``````

Check it on Github

``````

#ifndef FNC_TRIANGLE_INTERSECT
#define FNC_TRIANGLE_INTERSECT

float intersect(Triangle _tri, float3 _rayOrigin, float3 _rayDir, inout float3 _point) {
float3 v1v0 = _tri.b - _tri.a;
float3 v2v0 = _tri.c - _tri.a;
float3 rov0 = _rayOrigin - _tri.a;
_point = cross(v1v0, v2v0);
float3 q = cross(rov0, _rayDir);
float d = 1.0f / dot(_rayDir, _point);
float u = d * -dot(q, v2v0);
float v = d *  dot(q, v1v0);
float t = d * -dot(_point, rov0);
if (u < 0.0f || u > 1.0f || v < 0.0f || (u+v) > 1.0f || t < 0.0f)
t = 9999999.9f; // No intersection

return t;
}

float intersect(Triangle _tri, Ray _ray, inout float3 _point) { return intersect(_tri, _ray.origin, _ray.direction, _point); }
float intersect(Triangle _tri, Ray _ray) {
float3 p;
return intersect(_tri, _ray, p);
}

#endif
``````

Dependencies:

Use:

``````<float> intersect(<Triangle> tri, <float3> rayOrigin, <float3> rayDir, out <float3> intersectionPoint)
``````

Check it on Github

``````

#ifndef FNC_TRIANGLE_INTERSECT
#define FNC_TRIANGLE_INTERSECT

inline __host__ __device__ float intersect(const Triangle& _tri, const float3& _rayOrigin, const float3& _rayDir, float3& _point) {
float3 v1v0 = _tri.b - _tri.a;
float3 v2v0 = _tri.c - _tri.a;
float3 rov0 = _rayOrigin - _tri.a;
_point = cross(v1v0, v2v0);
float3 q = cross(rov0, _rayDir);
float d = 1.0f / dot(_rayDir, _point);
float u = d * -dot(q, v2v0);
float v = d *  dot(q, v1v0);
float t = d * -dot(_point, rov0);
if (u < 0.0f || u > 1.0f || v < 0.0f || (u+v) > 1.0f || t < 0.0f)
t = MAX_FLOAT_VALUE; // No intersection

return t;
}

inline __host__ __device__ float intersect(const Triangle& _tri, const Ray& _ray, float3& _point) { return intersect(_tri, _ray.origin, _ray.direction, _point); }
inline __host__ __device__ float intersect(const Triangle& _tri, const Ray& _ray) {
float3 p;
return intersect(_tri, _ray, p);
}

#endif
``````