body >> (block/cargo) << node

float delta_pos(float velocity, float acceleration);



class block {
public:
    char *name;
    int mass;

    void grav();
    void init();

    block(float pos_x, float pos_y) {
        this->init_x = pos_x;
        this->init_y = pos_y;

        this->curr_x = pos_x;
        this->curr_y = pos_y;

        this->visibility = true;
    }

private:
    float init_x, init_y;
    float curr_x, curr_y;
    bool visibility;

    void draw(float pos_x, float pos_y);
};

void block::draw(float pos_x, float pos_y) {
    glBegin(GL_POLYGON);
    glColor3f(1, 0, 0);
    glVertex2i(pos_x, pos_y);
    glVertex2i(pos_x + 20, pos_y);
    glVertex2i(pos_x + 20, pos_y + 20);
    glVertex2i(pos_x, pos_y + 20);
    glEnd();
}

void block::grav() {
    if (this->curr_y > 0) {

        float pos_x = this->curr_x + delta_pos(0, 0);
        float pos_y = this->curr_y - delta_pos(-2, G_CONST);

        this->curr_x = pos_x;
        this->curr_y = pos_y;

    }
    else {
        this->curr_y = 0;
        this->visibility = false;
    }

    this->draw(this->curr_x, this->curr_y);

    printf("x:%f, y:%f\n", this->curr_x, this->curr_y);
}

void block::init() {
    float pos_x = this->init_x;
    float pos_y = this->init_y;

    this->draw(pos_x, pos_y);
}


float delta_pos(float velocity, float acceleration) {
    //s = s0 + v*t + (a*t^2)/2
    float delta = velocity * t + (acceleration * t * t) / 2;
    printf("delta=%f\n", delta);

    t += 0.0001;

    return delta;
}




class cargo {
public:
    char *name;
    int ord_num;
    int mass;
    int move_direction;
    block* left_block;
    block* right_block;
    cargo* above_cargo;
    cargo* below_cargo;

    void grav(bool);
    void init();
    void add_right_block(block*);
    void add_left_block(block*);
    void add_above_cargo(cargo*);
    void add_below_cargo(cargo*);

    cargo(int n, float pos_x, float pos_y) {
        this->ord_num = n;

        this->init_x = pos_x;
        this->init_y = pos_y;

        this->curr_x = pos_x;
        this->curr_y = pos_y;

        this->velo_x = 0;
        this->velo_y = 0;

        if (this->velo_y == 0) {
            this->move_direction = -1;
        }
    }

private:
    float init_x, init_y;
    float curr_x, curr_y;
    float velo_x, velo_y;

    void draw(float, float);
};

void cargo::draw(float pos_x, float pos_y) {
    glBegin(GL_POLYGON);
    glColor3f(0, 1, 0);
    glVertex2i(pos_x, pos_y);
    glVertex2i(pos_x + 25, pos_y);
    glVertex2i(pos_x + 25, pos_y + 25);
    glVertex2i(pos_x, pos_y + 25);
    glEnd();
}

void cargo::grav(bool fall) {
    if (fall) {

        float pos_y;

        if (this->curr_y <= 0) {

            this->curr_y = 0;

            this->velo_y = sqrt(2 * G_CONST * this->init_y) * 0.8;

            this->move_direction = 1;

        }

        if (this->curr_y >= 0) {

            if (this->move_direction < 0) {

                float pos_y = (G_CONST * t * t) / 2;
                this->curr_y -= pos_y;

            }

            if (this->move_direction > 0) {

                float pos_y = this->velo_y * t - (G_CONST * t * t) / 2;
                this->curr_y += pos_y;

            }

        }
    }

    this->draw(this->curr_x, this->curr_y);

    t += 0.001;

    printf("x:%f, y:%f, v=%f\n", this->curr_x, this->curr_y, this->velo_y);
}

void cargo::init() {
    float pos_x = this->init_x;
    float pos_y = this->init_y;

    this->draw(pos_x, pos_y);
}