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Added ray/cone intersection.

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This commit is contained in:
Branimir Karadžić 2017-09-24 19:12:18 -07:00
parent b5af383cf8
commit 7b94b8dcb4
2 changed files with 96 additions and 0 deletions
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86
examples/common/bounds.cpp
View File

@ -647,6 +647,92 @@ bool intersect(const Ray& _ray, const Cylinder& _cylinder, bool _capsule, Inters
return false;
}
bool intersect(const Ray& _ray, const Cone& _cone, Intersection* _intersection)
{
float axis[3];
bx::vec3Sub(axis, _cone.m_end, _cone.m_pos);
float normal[3];
const float len = bx::vec3Norm(normal, axis);
Disk disk;
bx::vec3Move(disk.m_center, _cone.m_pos);
bx::vec3Neg(disk.m_normal, normal);
disk.m_radius = _cone.m_radius;
if (intersect(_ray, disk, _intersection) )
{
return true;
}
float rs[3];
bx::vec3Sub(rs, _ray.m_pos, _cone.m_end);
const float hyp = bx::fsqrt(bx::fsq(_cone.m_radius) + bx::fsq(len) );
const float cosa = len/hyp;
const float cosaSq = bx::fsq(cosa);
const float rsdotaxis = bx::vec3Dot(rs, normal);
const float rdota = bx::vec3Dot(normal, _ray.m_dir);
const float aa = bx::fsq(rdota) - cosaSq;
const float bb = 2.0f * (rdota*rsdotaxis - bx::vec3Dot(_ray.m_dir, rs)*cosaSq);
const float cc = bx::fsq(rsdotaxis) - bx::vec3Dot(rs, rs)*cosaSq;
float det = bb*bb - 4.0f*aa*cc;
if (0.0f > det)
{
return false;
}
det = bx::fsqrt(det);
float t1 = (-bb - det) / (2.0f * aa);
float t2 = (-bb + det) / (2.0f * aa);
float tt = t1;
if (0.0f > t1
|| (0.0f < t2 && t2 < t1) )
{
tt = t2;
}
if (0.0f > tt)
{
return false;
}
float point[3];
getPointAt(point, _ray, tt);
const float hh = bx::vec3Dot(normal, point);
if (0.0f > hh
|| len < hh)
{
return false;
}
if (NULL != _intersection)
{
_intersection->m_dist = tt;
bx::vec3Move(_intersection->m_pos, point);
const float scale = hh / bx::vec3Dot(point, point);
float pointScaled[3];
bx::vec3Mul(pointScaled, point, scale);
float tmp[3];
bx::vec3Sub(tmp, pointScaled, normal);
bx::vec3Norm(_intersection->m_normal, tmp);
}
return true;
}
bool intersect(const Ray& _ray, const Plane& _plane, Intersection* _intersection)
{
float equation = bx::vec3Dot(_ray.m_pos, _plane.m_normal) + _plane.m_dist;

10
examples/common/bounds.h
View File

@ -19,6 +19,13 @@ struct Cylinder
float m_radius;
};
struct Cone
{
float m_pos[3];
float m_end[3];
float m_radius;
};
struct Disk
{
float m_center[3];
@ -118,6 +125,9 @@ bool intersect(const Ray& _ray, const Aabb& _aabb, Intersection* _intersection =
/// Intersect ray / cylinder.
bool intersect(const Ray& _ray, const Cylinder& _cylinder, bool _capsule, Intersection* _intersection = NULL);
/// Intersect ray / cone.
bool intersect(const Ray& _ray, const Cone& _cone, Intersection* _intersection = NULL);
/// Intersect ray / disk.
bool intersect(const Ray& _ray, const Disk& _disk, Intersection* _intersection = NULL);