cocos_lib/cocos/core/geometry/Sphere.cpp

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#include "core/geometry/Sphere.h"
#include <algorithm>
#include "core/geometry/AABB.h"
#include "math/Vec3.h"

namespace cc {
namespace geometry {

Sphere *Sphere::create(float cx, float cy, float cz, float radius) {
    return ccnew Sphere(cx, cy, cz, radius);
}

Sphere *Sphere::clone(const Sphere &p) {
    return ccnew Sphere(p._center.x, p._center.y, p._center.z, p._radius);
}

Sphere *Sphere::copy(Sphere *out, const Sphere &p) {
    out->_center = p._center;
    out->_radius = p._radius;
    return out;
}

Sphere *Sphere::fromPoints(Sphere *out, const Vec3 &minPos, const Vec3 &maxPos) {
    out->_center = 0.5F * (minPos + maxPos);
    out->_radius = 0.5F * (maxPos - minPos).length();
    return out;
}

Sphere *Sphere::set(Sphere *out, float cx, float cy, float cz, float r) {
    out->_center = {cx, cy, cz};
    out->_radius = r;
    return out;
}

Sphere *Sphere::mergePoint(Sphere *out, const Sphere &s, const Vec3 &point) {
    // if sphere.radius Less than 0,
    // Set this point as anchor,
    // And set radius to 0.
    if (s._radius < 0.0) {
        out->_center = point;
        out->_radius = 0.0F;
        return out;
    }

    auto offset = point - s._center;
    auto dist = offset.length();

    if (dist > s._radius) {
        auto half = (dist - s._radius) * 0.5F;
        out->_radius += half;
        offset.scale(half / dist);
        out->_center = out->_center + offset;
    }

    return out;
}

void Sphere::merge(const ccstd::vector<cc::Vec3> &points) {
    if (points.empty()) return;
    _radius = -1.0F;
    for (const auto &p : points) {
        merge(p);
    }
}

Sphere *Sphere::mergeAABB(Sphere *out, const Sphere &s, const AABB &a) {
    Vec3 aabbMin;
    Vec3 aabbMax;
    a.getBoundary(&aabbMin, &aabbMax);
    Sphere::mergePoint(out, s, aabbMin);
    Sphere::mergePoint(out, s, aabbMax);
    return out;
}

Sphere::Sphere(float cx, float cy, float cz, float radius) : ShapeBase(ShapeEnum::SHAPE_SPHERE) {
    _center = {cx, cy, cz};
    _radius = radius;
}

void Sphere::getBoundary(Vec3 *minPos, Vec3 *maxPos) const {
    Vec3 half = {_radius, _radius, _radius};
    *minPos = _center - half;
    *maxPos = _center + half;
}

void Sphere::transform(const Mat4 &m,
                       const Vec3 & /*pos*/,
                       const Quaternion & /*rot*/,
                       const Vec3 &scale,
                       Sphere *out) const {
    Vec3::transformMat4(_center, m, &out->_center);
    out->_radius = _radius * mathutils::maxComponent(scale);
}

int Sphere::intersect(const Plane &plane) const {
    const float dot = plane.n.dot(_center);
    const float r = _radius * plane.n.length();
    if (dot + r < plane.d) {
        return -1; // Sphere is on the back of the plane
    }

    if (dot - r > plane.d) {
        return 0; // Sphere is on the front of the plane
    }

    return 1; // intersect
}

bool Sphere::intersect(const Frustum &frustum) const {
    const auto &planes = frustum.planes;
    const auto *self = this;
    return std::all_of(planes.begin(),
                       planes.end(),
                       // frustum plane normal points to the inside
                       [self](const Plane *plane) { return self->intersect(*plane) != -1; });
}

void Sphere::mergePoint(const Vec3 &point) {
    if (_radius < 0.0F) {
        _center = point;
        _radius = 0.0F;
        return;
    }

    auto offset = point - _center;
    auto distance = offset.length();

    if (distance > _radius) {
        auto half = (distance - _radius) * 0.5F;
        _radius += half;
        offset.scale(half / distance);
        _center += offset;
    }
}

void Sphere::define(const AABB &aabb) {
    cc::Vec3 minPos;
    cc::Vec3 maxPos;
    aabb.getBoundary(&minPos, &maxPos);

    // Initialize sphere
    _center.set(minPos);
    _radius = 0.0F;

    // Calculate sphere
    const cc::Vec3 offset = maxPos - _center;
    const float dist = offset.length();

    const float half = dist * 0.5F;
    _radius += dist * 0.5F;
    _center += (half / dist) * offset;
}

void Sphere::mergeAABB(const AABB *aabb) {
    cc::Vec3 minPos;
    cc::Vec3 maxPos;
    aabb->getBoundary(&minPos, &maxPos);
    mergePoint(minPos);
    mergePoint(maxPos);
}

int Sphere::spherePlane(const Plane &plane) const {
    return intersect(plane);
}

bool Sphere::sphereFrustum(const Frustum &frustum) const {
    return intersect(frustum);
}

void Sphere::mergeFrustum(const Frustum &frustum) {
    const ccstd::array<Vec3, 8> &vertices = frustum.vertices;
    for (size_t i = 0; i < vertices.max_size(); ++i) {
        merge(vertices[i]);
    }
}

} // namespace geometry
} // namespace cc