有没有办法在世界空间的一个轴心点上旋转多个模型矩阵？

Question

我将 OpenGL 与 GLFW 一起使用，我正在尝试旋转多个对象，每个对象都在同一轴心点上具有各自的模型矩阵。我为我的兔子准备了三种不同的模型，一种是身体，一种是前腿，另一种是后腿，我试图将它们都旋转到 Y 轴的最后面朝一个方向。然而，当我试图将它们旋转到位时，腿看起来像是在“移动”。如果我不沿 Y 轴旋转它们，那么它们就可以了。我想找到一种在一个轴心点上旋转所有三个模型矩阵的方法，这样当它们最终旋转时，它们就不会在自己的原点上旋转。这是我的主要代码：

class rabbit {
public:
    std::vector<colored_model_object*> rabbit_renderers;
    std::vector<glm::mat4> rabbit_models;

    glm::vec3 position = glm::vec3(0.0f);
    float fore_leg_rotation = 0;
    float hind_leg_rotation = 0;

    float whole_rotation = 0;

    int jump_phase = 0;
    float jump_lerp = 0.0f;
    float jump_speed = 0.003f;
    glm::vec3 jump_start, jump_end;

    float y_velocity = 0;
    
    rabbit() {
        rabbit_renderers.push_back(new colored_model_object("res/objects/rabbit/rabbit_body.obj"));
        rabbit_renderers.push_back(new colored_model_object("res/objects/rabbit/rabbit_front_legs.obj"));
        rabbit_renderers.push_back(new colored_model_object("res/objects/rabbit/rabbit_hind_legs.obj"));
    }

    void jump(glm::vec3 direction, float magnitude) {
        if (jump_phase >= 1) return;
        glm::vec3 jump_power = glm::normalize(direction) * magnitude;
        jump_start = position;
        jump_end = position + jump_power;
        jump_phase = 1;
        jump_lerp = 0;
        fore_leg_rotation = 0.0f;
        hind_leg_rotation = 0.0f;
        y_velocity = 1;

        glm::vec2 dir_2d = glm::normalize(glm::vec2(direction.x, direction.z));
        glm::vec2 up = glm::vec2(0, 1);
        float dot = dir_2d.x * up.x + dir_2d.y * up.y;
        float det = dir_2d.x * up.y - dir_2d.y * up.x;
        float body_angle = atan2(det, dot);
        whole_rotation = body_angle;
    }

    void update() {
        position.y += y_velocity;
        y_velocity -= 0.008f;
        if (position.y < 0) position.y = 0;
        if (jump_phase> 0) {
            glm::vec2 jump_start_xz = glm::vec2(jump_start.x, jump_start.z);
            glm::vec2 jump_end_xz = glm::vec2(jump_end.x, jump_end.z);
            glm::vec2 position_xz = glm::mix(jump_start_xz, jump_end_xz, jump_lerp);
            position.x = position_xz.x;
            position.z = position_xz.y;
            jump_lerp += jump_speed;
        }
        if (jump_phase == 1) {
            fore_leg_rotation += 1;
            hind_leg_rotation += 1;
            if (fore_leg_rotation > 45.0f) {
                jump_phase = 2;
            }
        }
        if (jump_phase == 2) {
            fore_leg_rotation -= 0.2f;
            hind_leg_rotation -= 0.2f;
            if (fore_leg_rotation < 0.0f) {
                jump_phase = 3;
            }
        }
        if (jump_lerp > 1) {
            jump_phase = 0;
            jump_lerp = 0;
            fore_leg_rotation = 0.0f;
            hind_leg_rotation = 0.0f;
        }
    }

    void update_models() {
        update();

        rabbit_models.clear();
        rabbit_models.push_back(system3d::get_model());
        rabbit_models.push_back(system3d::get_model());
        rabbit_models.push_back(system3d::get_model());
        rabbit_models.at(0) = (system3d::create_model(rabbit_models.at(0),glm::vec3(0.1f, 0.1f, 0.1f), glm::vec3(-100 + position.x, 310.5f + position.y, 0 + position.z), 0.0f, glm::vec3(1, 1, 1)));
        rabbit_models.at(1) = (system3d::create_model(rabbit_models.at(1), glm::vec3(0.1f, 0.1f, 0.1f), glm::vec3(-100 + position.x, 310.5f + position.y, 0 + position.z), fore_leg_rotation, glm::vec3(1, 0, 0), glm::vec3(0, -42.0f, 0)));
        rabbit_models.at(2) = (system3d::create_model(rabbit_models.at(2), glm::vec3(0.1f, 0.1f, 0.1f), glm::vec3(-100 + position.x, 310.5f + position.y, 0 + position.z), hind_leg_rotation, glm::vec3(1, 0, 0), glm::vec3(0, -42.0f, 17.0f)));
        for (int i = 0; i < rabbit_models.size(); i++) {
            rabbit_models.at(i) = glm::rotate(rabbit_models.at(i), glm::radians(whole_rotation), glm::vec3(0, 1, 0));
        }
    }
};

这里是引用的 system3d 类：

class system3d {
public:
    static glm::mat4 get_model(glm::vec3 scale_vec, glm::vec3 translate_vec, float rotation, glm::vec3 rotation_vec) {
        glm::mat4 model = glm::mat4(1.0f);
        model = glm::scale(model, scale_vec);
        model = glm::rotate(model, glm::radians(rotation), rotation_vec);
        model = glm::translate(model, translate_vec);

        return model;
    }

    static glm::mat4 get_model(glm::vec3 scale_vec, glm::vec3 translate_vec, float rotation, glm::vec3 rotation_vec, glm::vec3 rotation_pivot) {
        glm::mat4 model = glm::mat4(1.0f);
        model = glm::scale(model, scale_vec);
        model = glm::translate(model, translate_vec);


        model = glm::translate(model, -rotation_pivot);
        model = glm::rotate(model, glm::radians(rotation), rotation_vec);
        model = glm::translate(model, rotation_pivot);


        return model;
    }

    static glm::mat4 create_model(glm::mat4 existing, glm::vec3 scale_vec, glm::vec3 translate_vec, float rotation, glm::vec3 rotation_vec) {
        glm::mat4 model = existing;
        model = glm::scale(model, scale_vec);
        model = glm::rotate(model, glm::radians(rotation), rotation_vec);
        model = glm::translate(model, translate_vec);

        return model;
    }

    static glm::mat4 create_model(glm::mat4 existing, glm::vec3 scale_vec, glm::vec3 translate_vec, float rotation, glm::vec3 rotation_vec, glm::vec3 rotation_pivot) {
        glm::mat4 model = existing;
        model = glm::scale(model, scale_vec);
        model = glm::translate(model, translate_vec);


        model = glm::translate(model, -rotation_pivot);
        model = glm::rotate(model, glm::radians(rotation), rotation_vec);
        model = glm::translate(model, rotation_pivot);


        return model;
    }


    static glm::mat4 get_model() {
        glm::mat4 model = glm::mat4(1.0f);
        return model;
    }
};

几个小时以来，我一直在努力寻找解决方案，但我还没有找到不涉及四元数的解决方案。 （我发现四元数真的很令人困惑，我个人无法编写有效的四元数代码。）

这是一个视频，首先是当他们 Y 轴旋转为 0 时，然后当 y 轴旋转不为 0 时：

有人知道我能做什么吗？