spheres

[gong.git] / src / geometry / primitive.hpp

diff --git a/src/geometry/primitive.hpp b/src/geometry/primitive.hpp
index 4711306ab1d0492df33736416fc9cba0199dc586..819ef04e77bd03e948b4c18fd051d817e610b69d 100644 (file)
--- a/src/geometry/primitive.hpp
+++ b/src/geometry/primitive.hpp
@@ -87,7 +87,8 @@ bool Intersection(
        float &depth,
        glm::vec3 &normal) noexcept;
 
-
+/// Plane defined by a surface norml and distance to the origin such that
+/// the point (normal * dist) lies on the plane.
 struct Plane {
        glm::vec3 normal;
        float dist;
@@ -115,6 +116,13 @@ struct Plane {
 
 std::ostream &operator <<(std::ostream &, const Plane &);
 
+/// Shortest distance from point to plane.
+float Distance(const glm::vec3 &point, const Plane &plane);
+/// Shortest distance from point to plane with sign indicating whether
+/// it's in front of (positive, in direction of normal) or behind
+/// (negative, counter direction of normal) the surface.
+float SignedDistance(const glm::vec3 &point, const Plane &plane);
+
 struct Frustum {
        Plane plane[6];
        Plane &Left() noexcept { return plane[0]; }
@@ -154,6 +162,31 @@ std::ostream &operator <<(std::ostream &, const Frustum &);
 bool CullTest(const AABB &box, const glm::mat4 &) noexcept;
 bool CullTest(const AABB &box, const Frustum &) noexcept;
 
+struct Sphere {
+       glm::vec3 origin;
+       float radius;
+};
+
+std::ostream &operator <<(std::ostream &, const Sphere &);
+
+/// Test for intersection of sphere with double sided infinite plane.
+/// If true, dist will hold the smaller interpenetration depth and norm
+/// the respective contact normal.
+bool Intersection(
+       const Sphere &sphere,
+       const Plane &plane,
+       float &dist,
+       glm::vec3 &norm) noexcept;
+
+/// Test for intersection of sphere with half space defined by the
+/// backface of given plane.
+/// In all cases, dist will hold the distance between the near points
+/// of plane and sphere. Contact normal will always be the plane's normal.
+bool Intersection(
+       const Sphere &sphere,
+       const Plane &plane,
+       float &dist) noexcept;
+
 }
 }