cocos_lib/cocos/core/geometry/AABB.cpp

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#include "AABB.h"
#include "base/Macros.h"
#include "cocos/core/geometry/Enums.h"
#include "cocos/core/geometry/Sphere.h"

namespace cc {
namespace geometry {

Sphere *AABB::toBoundingSphere(Sphere *out, const AABB &a) {
    out->setCenter(a.getCenter());
    out->setRadius(a.getHalfExtents().length());
    return out;
}

AABB *AABB::fromPoints(const Vec3 &minPos, const Vec3 &maxPos, AABB *dst) {
    Vec3 center{(minPos + maxPos) * 0.5F};
    Vec3 halfExtents{(maxPos - minPos) * 0.5F};
    dst->setCenter(center);
    dst->setHalfExtents(halfExtents);
    return dst;
}

AABB *AABB::merge(AABB *out, const AABB &a, const AABB &b) {
    Vec3 minCornor;
    Vec3 maxCorner;
    Vec3::max(a.getCenter() + a.getHalfExtents(), b.getCenter() + b.getHalfExtents(), &maxCorner);
    Vec3::min(a.getCenter() - a.getHalfExtents(), b.getCenter() - b.getHalfExtents(), &minCornor);
    return AABB::fromPoints(minCornor, maxCorner, out);
}

void AABB::merge(const cc::Vec3 &point) {
    cc::Vec3 minPos = getCenter() - getHalfExtents();
    cc::Vec3 maxPos = getCenter() + getHalfExtents();
    if (point.x < minPos.x) {
        minPos.x = point.x;
    }
    if (point.y < minPos.y) {
        minPos.y = point.y;
    }
    if (point.z < minPos.z) {
        minPos.z = point.z;
    }
    if (point.x > maxPos.x) {
        maxPos.x = point.x;
    }
    if (point.y > maxPos.y) {
        maxPos.y = point.y;
    }
    if (point.z > maxPos.z) {
        maxPos.z = point.z;
    }

    const Vec3 center = (minPos + maxPos) * 0.5F;
    setCenter(center);
    setHalfExtents(maxPos.x - center.x, maxPos.y - center.y, maxPos.z - center.z);
}

void AABB::merge(const ccstd::vector<cc::Vec3> &points) {
    for (const auto &p : points) {
        merge(p);
    }
}

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

bool AABB::aabbAabb(const AABB &aabb) const {
    Vec3 aMin;
    Vec3 aMax;
    Vec3 bMin;
    Vec3 bMax;
    Vec3::subtract(getCenter(), getHalfExtents(), &aMin);
    Vec3::add(getCenter(), getHalfExtents(), &aMax);
    Vec3::subtract(aabb.getCenter(), aabb.getHalfExtents(), &bMin);
    Vec3::add(aabb.getCenter(), aabb.getHalfExtents(), &bMax);
    return (aMin.x <= bMax.x && aMax.x >= bMin.x) &&
           (aMin.y <= bMax.y && aMax.y >= bMin.y) &&
           (aMin.z <= bMax.z && aMax.z >= bMin.z);
}

int AABB::aabbPlane(const Plane &plane) const {
    auto r = getHalfExtents().x * std::abs(plane.n.x) +
             getHalfExtents().y * std::abs(plane.n.y) +
             getHalfExtents().z * std::abs(plane.n.z);
    auto dot = Vec3::dot(plane.n, getCenter());
    if (dot + r < plane.d) {
        return -1;
    }
    if (dot - r > plane.d) {
        return 0;
    }
    return 1;
}

bool AABB::aabbFrustum(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->aabbPlane(*plane) != -1; });
}

void AABB::getBoundary(cc::Vec3 *minPos, cc::Vec3 *maxPos) const {
    *maxPos = getCenter() + getHalfExtents();
    *minPos = getCenter() - getHalfExtents();
}

void AABB::merge(const AABB &aabb) {
    AABB::merge(this, aabb, *this);
}

void AABB::set(const cc::Vec3 &centerVal, const cc::Vec3 &halfExtentVal) {
    setCenter(centerVal);
    setHalfExtents(halfExtentVal);
}

void AABB::transform(const Mat4 &m, AABB *out) const {
    Vec3::transformMat4(center, m, &out->center);
    transformExtentM4(&out->halfExtents, getHalfExtents(), m);
}

bool AABB::contain(const cc::Vec3 &point) const {
    cc::Vec3 minPos = getCenter() - getHalfExtents();
    cc::Vec3 maxPos = getCenter() + getHalfExtents();

    return !(point.x > maxPos.x || point.x < minPos.x ||
             point.y > maxPos.y || point.y < minPos.y ||
             point.z > maxPos.z || point.z < minPos.z);
}

// https://zeuxcg.org/2010/10/17/aabb-from-obb-with-component-wise-abs/
void AABB::transformExtentM4(Vec3 *out, const Vec3 &extent, const Mat4 &m4) {
    Mat3 m3Tmp;
    m3Tmp.m[0] = std::abs(m4.m[0]);
    m3Tmp.m[1] = std::abs(m4.m[1]);
    m3Tmp.m[2] = std::abs(m4.m[2]);
    m3Tmp.m[3] = std::abs(m4.m[4]);
    m3Tmp.m[4] = std::abs(m4.m[5]);
    m3Tmp.m[5] = std::abs(m4.m[6]);
    m3Tmp.m[6] = std::abs(m4.m[8]);
    m3Tmp.m[7] = std::abs(m4.m[9]);
    m3Tmp.m[8] = std::abs(m4.m[10]);
    out->transformMat3(extent, m3Tmp);
}

AABB::AABB(float px, float py, float pz, float hw, float hh, float hl) : AABB() {
    setCenter(px, py, pz);
    setHalfExtents(hw, hh, hl);
}

} // namespace geometry
} // namespace cc