Method clipPoly

tests/cpp-tests/Source/PhysicsTest/PhysicsTest.cpp:1211–1251

}

void PhysicsDemoSlice::clipPoly(PhysicsShapePolygon* shape, Vec2 normal, float distance)
{
    PhysicsBody* body = shape->getBody();
    int count         = shape->getPointsCount();
    int pointsCount   = 0;
    Vec2* points      = new Vec2[count + 1];

    for (int i = 0, j = count - 1; i < count; j = i, ++i)
    {
        Vec2 a      = body->local2World(shape->getPoint(j));
        float aDist = a.dot(normal) - distance;

        if (aDist < 0.0f)
        {
            points[pointsCount] = a;
            ++pointsCount;
        }

        Vec2 b      = body->local2World(shape->getPoint(i));
        float bDist = b.dot(normal) - distance;

        if (aDist * bDist < 0.0f)
        {
            float t             = std::fabs(aDist) / (std::fabs(aDist) + std::fabs(bDist));
            points[pointsCount] = a.lerp(b, t);
            ++pointsCount;
        }
    }

    Vec2 center          = PhysicsShape::getPolygonCenter(points, pointsCount);
    Node* node           = Node::create();
    PhysicsBody* polygon = PhysicsBody::createPolygon(points, pointsCount, PHYSICSBODY_MATERIAL_DEFAULT, -center);
    node->setPosition(center);
    node->addComponent(polygon);
    polygon->setVelocity(body->getVelocityAtWorldPoint(center));
    polygon->setAngularVelocity(body->getAngularVelocity());
    polygon->setTag(_sliceTag);
    addChild(node);

    delete[] points;
}

void PhysicsDemoSlice::onTouchEnded(Touch* touch, Event* /*event*/)
{