Circles, spheres and capsules. Most circle and sphere operations are just point operations with a bias to the distance, which is why relevant "point" functions are included in this file. typedef struct { vec3 center; float r; } Sphere; typedef struct { vec3 a, b; // the two centroids float r; // radius } Capsule;

Not all distance and intersection functions have systematic names yet. In general, functions are named in the pattern [operation][lesser]N[greater]N(l, g, [args], out*) where operation is something like dist or intersect, lesser is the argument with fewer dimensions, greater is the argument with more dimensions, and N is the number of dimensions if otherwise unclear (lines and triangles can exist in 2 or 3 dimensions, for example, but spheres and circles imply their dimensionality). Functions with "T" in the name return a normalized value along with whatever other results.

Primitives

Line: An infinite line, unless otherwise specified, with no implied direction.
Ray: A line with a start location that extends inifinitely in some specified direction.
Rect: An axis-aligned rectangle defined by two opposing corners.
Quad: An arbitrary quadrilateral in 2 or 3 dimensions defined by a loop of consecutive corners. May or may not need to be planar or rectangular (right angles) depending on the function.
Circle: A circle defined by a center and a radius in 2 dimensions.
Plane: An infinite plane in 3 dimensions defined by a normal vector and a distance from the origin.
PlaneP: An infinite plane in 3 dimensions defined by a normal vector and a point on the plane.
Sphere: A sphere in 3 dimensions defined by a center and a radius.
Capsule: A pill-shaped 3D object defined by the center points of the two connected end spheres and a radius.

Operation Stubs

dist: Shortest distance between the two objects.
intersect: Determines if the two objects intersect.
findIntersect: Finds the point (or line) of intersection between two objects. Unless otherwise specified, it's the closest point of intersection if there are multiple.
proj: Projects the first object onto the second, whatever that means for the objects involved.

Functions

float distPoint2Triangle2(vec2 a, vec2 tri[3])

Two dimensional closest distance between a point a triangle.

int intersectPoint2Rect2(vec2 a, Quad2 q)

Must be a rectangle, not an arbitrary quadrilateral. Returns C3DLAS_INTERSECT or C3DLAS_DISJOINT.

float distPoint2Rect2(vec2 a, Quad2 q)

Quad must be a rectangle, and the vertices must be ordered in a loop

float distTPointRay3(vec3 p, Ray3 r, float* T)

float dist2TPointRay3(vec3 p, Ray3 r, float* T)

float distPoint2Line2(vec2 p, Line2 ls)

float distTPoint2Line2(vec2 p, Line2 ls)

float distPoint3Line3(vec3 p, Line3 ls)

float distTPoint3Line3(vec3 p, Line3 ls)

int intersectRay2Circle(Ray2 a, vec2 center, float radius, vec2 out[2])

Returns the number of intersecting points, [0-2], in both directions of the ray.

int intersectVec2Circle(vec2 lorigin, vec2 ldir, vec2 center, float radius, vec2 out[2])

Returns the number of intersecting points, [0-2], in both directions of the ray.

// circle utilities int findCircleTangents(Vector2 c, float r, Vector2 p, Vector2 out[2]); // returns the radius float circleFromPoints(vec2 a, vec2 b, vec2 c, vec2* center); // returns C3DLAS_INTERSECT or C3DLAS_DISJOINT int pointInsideCircleFromPoints(vec2 p1, vec2 p2, vec2 p3, vec2 test);