Unity抛物线AddForce计算

淡淡的烟草味﹌ 2023-10-16 22:19 43阅读 0赞

/**findInitialVelocity
     * Finds the initial velocity of a projectile given the initial positions and some offsets
     * @param Vector3 startPosition - the starting position of the projectile
     * @param Vector3 finalPosition - the position that we want to hit
     * @param float maxHeightOffset (default=0.6f) - the amount we want to add to the height for short range shots. We need enough clearance so the
     * ball will be able to get over the rim before dropping into the target position
     * @param float rangeOffset (default=0.11f) - the amount to add to the range to increase the chances that the ball will go through the rim
     * @return Vector3 - the initial velocity of the ball to make it hit the target under the current gravity force.
     * 
     * Vector3 tt = findInitialVelocity (gameObject.transform.position, target.transform.position);
            Rigidbody rigidbody = gameObject.GetComponent<Rigidbody> ();
            Debug.Log (tt);
            rigidbody.AddForce(tt*rigidbody.mass,ForceMode.Impulse);
    
     */
        private Vector3 findInitialVelocity(Vector3 startPosition, Vector3 finalPosition, float maxHeightOffset = 0.0f, float rangeOffset = 0.11f)
        {
            // get our return value ready. Default to (0f, 0f, 0f)
            Vector3 newVel = new Vector3();
            // Find the direction vector without the y-component
            /// /找到未经y分量的方向矢量//
            Vector3 direction = new Vector3(finalPosition.x, 0f, finalPosition.z) - new Vector3(startPosition.x, 0f, startPosition.z);
            // Find the distance between the two points (without the y-component)
            //发现这两个点之间的距离（不y分量）//
            float range = direction.magnitude;
            // Add a little bit to the range so that the ball is aiming at hitting the back of the rim.
            // Back of the rim shots have a better chance of going in.
            // This accounts for any rounding errors that might make a shot miss (when we don't want it to).
            range += rangeOffset;
            // Find unit direction of motion without the y component
            Vector3 unitDirection = direction.normalized;
            // Find the max height
            // Start at a reasonable height above the hoop, so short range shots will have enough clearance to go in the basket
            // without hitting the front of the rim on the way up or down.
            float maxYPos = finalPosition.y + maxHeightOffset;
            // check if the range is far enough away where the shot may have flattened out enough to hit the front of the rim
            // if it has, switch the height to match a 45 degree launch angle
            //if (range / 2f > maxYPos)
            //  maxYPos = range / 2f;
            if(maxYPos < startPosition.y)
                maxYPos =  startPosition.y;
    
            // find the initial velocity in y direction
            /// /发现在y方向上的初始速度//
            float ft;
    
    
            ft = -2.0f * Physics.gravity.y * (maxYPos - startPosition.y);
            if(ft<0)
                ft = 0f;
    
            newVel.y = Mathf.Sqrt(ft);
            // find the total time by adding up the parts of the trajectory
            // time to reach the max
            //发现的总时间加起来的轨迹的各部分//
            //时间达到最大//
    
            ft = -2.0f * (maxYPos - startPosition.y) / Physics.gravity.y;
            if(ft<0)
                ft = 0f;
    
            float timeToMax = Mathf.Sqrt(ft);
            // time to return to y-target
            //时间返回到y轴的目标//
    
            ft = -2.0f * (maxYPos - finalPosition.y) / Physics.gravity.y;
            if(ft<0)
                ft = 0f;
    
            float timeToTargetY = Mathf.Sqrt(ft);
            // add them up to find the total flight time
            //把它们加起来找到的总飞行时间//
            float totalFlightTime;
    
            totalFlightTime = timeToMax + timeToTargetY;
    
            // find the magnitude of the initial velocity in the xz direction
            /// /查找的初始速度的大小在xz方向//
            float horizontalVelocityMagnitude = range / totalFlightTime;
            // use the unit direction to find the x and z components of initial velocity
            //使用该单元的方向寻找初始速度的x和z分量//
            newVel.x = horizontalVelocityMagnitude * unitDirection.x;
            newVel.z = horizontalVelocityMagnitude * unitDirection.z;
            return newVel;
        }