plane.h

#pragma once
 
#include "../generic/optional.h"
 
#include "vec3.h"
 
namespace smlt {
 
struct Vec3;
 
enum PlaneClassification {
    PLANE_CLASSIFICATION_IS_BEHIND_PLANE,
    PLANE_CLASSIFICATION_IS_ON_PLANE,
    PLANE_CLASSIFICATION_IS_IN_FRONT_OF_PLANE
};
 
 
struct Plane {
    Vec3 n;
    float d;
 
    Plane():
        n(Vec3()),
        d(0) {
    }
 
    Plane(const Vec3& N, float D):
        n(N),
        d(D) {
 
    }
 
    Plane(const Vec3& N, const Vec3& P):
        n(N),
        d(P.dot(N)) {
    }
 
    Plane(float A, float B, float C, float D):
        n(A, B, C),
        d(D) {
 
    }
 
    Vec3 project(const Vec3& p);
 
    Vec3 normal() const {
        return n;
    }
 
    float distance_to(const Vec3& p) const;
 
    PlaneClassification classify_point(const Vec3& p) const;
 
    static smlt::optional<Vec3> intersect_planes(
        const Plane& p1,
        const Plane& p2,
        const Plane& p3
    );
};
 
 
}