Redice's questions

这是代码：

import mediapipe as mp
import cv2

cap = cv2.VideoCapture(0)
with mp_hands.Hands(
model_complexity=0,
min_detection_confidence=0.5,
min_tracking_confidence=0.5) as hands:
while cap.isOpened():
success, image = cap.read()
if not success:
    print("Ignoring empty camera frame.")
    continue
image.flags.writeable = False
image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)
results = hands.process(image)

image.flags.writeable = True
image = cv2.cvtColor(image, cv2.COLOR_RGB2BGR)
if results.multi_hand_landmarks:
    for hand_landmarks in results.multi_hand_landmarks:
        mp_drawing.draw_landmarks(
        image,
        hand_landmarks,
        mp_hands.HAND_CONNECTIONS,
        mp_drawing_styles.get_default_hand_landmarks_style(),
        mp_drawing_styles.get_default_hand_connections_style())
cv2.imshow('MediaPipe Hands', cv2.flip(image, 1))
if cv2.waitKey(5) & 0xFF == 27:
    break
cap.release()

该错误是由 cv2 import 的第二行引起的。这是错误的全文：

    cv.gapi.wip.GStreamerPipeline = cv.gapi_wip_gst_GStreamerPipeline
    AttributeError: partially initialized module 'cv2' has no attribute 
    'gapi_wip_gst_GStreamerPipeline' (most likely due to a circular import)

变量rb在这个上下文中是不存在的，如果你在rb之前写了public这个词，那么就会出现另一个错误：Type or namespace defenition, or end-of-file expected。在第一种情况下， rb.AddForce 行会导致错误，而在第二种情况下，会导致关闭类主体的花括号。

void Start()
{
    public Rigidbody2D rb = gameObject.GetComponent<Rigidbody2D>();
}
void FixedUpdate()
{
    RaycastHit2D hit = Physics2D.Raycast(transform.position, Vector2.up);
    Debug.DrawRay(transform.position, Vector2.up*20, Color.white, 1, false);
    if(hit.distance <= 15)
    {
        rb.AddForce(transform.position - hit.transform.position);
    }
}

这段代码，每次迭代，应该从三个点中随机选择一个点，并将第四个点沿所选点的方向移动一半距离，等待几秒钟并留下一个“标记”。该代码不会导致错误，但它不能正常工作，感觉就像点（第四点）并没有从它在上一次迭代期间移动到的位置移动，而是从它的原始位置移动。问题：点从其原始坐标偏移，而不是从前一次迭代中接收到的坐标偏移。

public Transform dot;
public Transform[] points = new Transform[3];
public float seconds = 1;
public float size;
void Start()
{
    StartCoroutine(Coroutine());
}

IEnumerator Coroutine()
{
    for(int t = 0; t<=10000; t++)
    { 
        int point = Random.Range(0,3);
        switch(point)
        {
            case 0:
                dot.position = new Vector2((dot.position.x - (dot.position.x - points[0].position.x))/2,(dot.position.y - (dot.position.y - points[0].position.y))/2);
                Debug.DrawLine(new Vector3(dot.position.x,dot.position.y, 1), new Vector3(dot.position.x + 0.1f, dot.position.y, 0), Color.blue,1000,false);
                yield return new WaitForSeconds(seconds);
                break;
            case 1:
                dot.position = new Vector2((dot.position.x - (dot.position.x - points[1].position.x))/2,(dot.position.y - (dot.position.y - points[1].position.y))/2);
                Debug.DrawLine(new Vector3(dot.position.x,dot.position.y, 1), new Vector3(dot.position.x + 0.1f, dot.position.y, 0), Color.blue,1000,false);
                yield return new WaitForSeconds(seconds);
                break;
            case 2:
                dot.position = new Vector2((dot.position.x - (dot.position.x - points[2].position.x))/2,(dot.position.y - (dot.position.y - points[2].position.y))/2);
                Debug.DrawLine(new Vector3(dot.position.x,dot.position.y, 1), new Vector3(dot.position.x + 0.1f, dot.position.y, 0), Color.blue,1000,false);
                yield return new WaitForSeconds(seconds);   
                break;
        }                
    }   
}