在pygam中计算二维平面上命中目标的X和Y速度

Question

我正在用Python和Pygame创建一个游戏。在

在使用JS与p5.JS和Java与libwjgl一起使用之前，我曾使用过这个函数，但由于某些原因，它不能用于Pygame。在

我正试图击中一个静止的目标从一个移动的物体。 现在我错过了目标。你可以在gif中看到它。每一颗子弹都应该击中目标（现在一切都没打中，但射向正确的方向）

一旦玩家点击鼠标按钮，子弹就会发射。在

我是这样做的：

def shoot(self):
  posX, posY = 100, 100 # Static target coordinates

  diffX = self.player.x - posX               
  diffY = self.player.y - posY                 

  distance = math.sqrt((diffX * diffX) + (diffY * diffY)) # Calculate the distance

  velX = float((-1 / distance * diffX * 6)) # Calculate volocity required to hit the target
  velY = float((-1 / distance * diffY * 6)) # Calculate volocity required to hit the target 

  # Bullet(x, y, width, height, velocityX, velocityY)
  # Will be rendered on the screen
  self.bullets.append(Bullet(self.player.x, self.player.y, 10, 10,  velX, velY)) # The bullet is added to array, which later gets rendered on the screen

子弹等级：

^{pr2}$

这与我提到的其他语言完美地结合在一起，但是在Python中，发射的炮弹是关闭的。。。在

下面是它的样子。红场是目标：

谢谢大家的帮助。非常感谢：）

编辑： 完整游戏代码

import pygame
from PodSixNet.Connection import connection, ConnectionListener
from objects.Button import Button
from time import sleep
from STATE import STATE
import sys, os
from objects.Text import Text
from resources.hubColours import ColoursClass
from pathlib import Path
from objects.Bullet import Bullet
import math

class DefenseGame(ConnectionListener):
def __init__(self, hub, width, height, soundController, fontController, fps=60):
    #Hub
    self.hub = hub

    #COLOURS
    self.color = ColoursClass("alt")

    #SOUNDS
    self.soundController = soundController

    #SCREEN
    self.width = width
    self.height = height
    self.background = pygame.Surface((self.width, self.height), pygame.HWSURFACE | pygame.DOUBLEBUF).convert()  
    self.background.fill(self.color.getColour(7)) # fill background white

    #INFO
    self.fps = fps
    self.playtime = 0.0

    #FONTS
    self.fontController = fontController

    #STATE
    # All player related stuff is stored in the HUB.
    # TODO:
    # Player class
    self.isRunning = True


    self.moveLeft = False
    self.moveRight = False
    self.moveUp = False
    self.moveDown = False

    self.bullets = []

    self.moveAmnt = 5

    self.timeLeft = "Waiting for players..."


    self.clock = pygame.time.Clock()

    #OBJECTS
    self.on_init()

#Initialize game objects
def on_init(self):
  self.char = pygame.transform.smoothscale(pygame.image.load(str(Path("character.png"))), (50, 50))

# Draws on screen
def render(self, screen):                               # Update all objects (through object handler)                                            # This will update the contents of the entire display
    screen.blit(self.background, (0, 0))
    self.drawInfoText("Color: " + self.hub.playerColorName, 10, 10, self.fontController.tiny, screen)
    self.drawInfoText("Player Count: " + str(self.hub.getInGamePlayerCount()), 10, 20, self.fontController.tiny, screen)
    self.drawInfoText("FPS: " + str(round(self.getFPS(), 2)), 10, 30, self.fontController.tiny, screen)
    self.drawInfoText("Network Status: " + self.hub.statusLabel, 10, 40, self.fontController.tiny, screen)
    self.player.render(screen)
    self.player2.render(screen)
    # screen.blit(self.char, (self.posX, self.posY))

    if len(self.bullets) > 0:
      for b in self.bullets:
        b.render(screen)

def onMove(self):
  connection.Send({"action": "playerMove", 'x': self.player.x , 'y': self.player.y, 'id': self.hub.playerId})


def shoot(self):
  posX, posY = pygame.mouse.get_pos()

  diffX = self.player.x - posX               
  diffY = self.player.y - posY                 

  distance = math.sqrt((diffX * diffX) + (diffY * diffY))
  print("DISTANCE: ", distance)

  velX = float((-1 / distance * diffX * 20))
  velY = float((-1 / distance * diffY * 20))  

  print(velX, velY)

  self.bullets.append(Bullet(self.player.x, self.player.y, 10, 10,  velX, velY))

# Looks for events
def handle_events(self, events):
    for event in events:
        if event.type == pygame.QUIT: 
            self.exitGame(event)
            self.hub.setState(STATE.Home)
        elif event.type == pygame.KEYDOWN:
            if event.key == pygame.K_ESCAPE:
                self.exitGame(event)
                self.hub.setState(STATE.SelectGame)

            if event.key == pygame.K_w:
              self.moveUp = True
            if event.key == pygame.K_a:
              self.moveLeft = True
            if event.key == pygame.K_s:
              self.moveDown = True
            if event.key == pygame.K_d:
              self.moveRight = True

        elif event.type == pygame.KEYUP:
            if event.key == pygame.K_w:
              self.moveUp = False
            if event.key == pygame.K_a:
              self.moveLeft = False
            if event.key == pygame.K_s:
              self.moveDown = False
            if event.key == pygame.K_d:
              self.moveRight = False

        elif event.type == pygame.MOUSEBUTTONDOWN:
            if event.button == 1:          # Mouse first button
                self.shoot()

# Update stuff (loop)
def update(self):
    self.Pump()                 # Connection
    connection.Pump()           # Connection

    timer = self.clock.tick(self.fps)
    if self.moveLeft:
      self.player.x -= timer
      self.onMove()
    if self.moveRight:
      self.player.x += timer
      self.onMove()
    if self.moveUp:
      self.player.y -= timer
      self.onMove()
    if self.moveDown:
      self.player.y += timer
      self.onMove()

    if len(self.bullets) > 0:
      for b in self.bullets:
        b.update()
    # sleep(0.001)


# returns FPS
def getFPS(self):
    self.clock.tick(self.fps)
    return  self.clock.get_fps()

# Helper for quickly drawing on screen
def drawInfoText(self, text, x, y, font, screen):
    surface = font.render(str(text), 1, self.color.getColour(8))
    screen.blit(surface, (x, y))

# Exits the game to home
def exitGame(self, e):
    self.soundController.stopSoundEffects()
    connection.Send({"action":"exitGame", "isInGame": False})
    self.hub.isInGame = False

Answer 1

self.bullet是一个^{}对象。项目符号的位置由矩形（self.bullet.x，self.bullet.y）的位置跟踪。由于矩形位置是整数，因此每次更新位置时都会导致不准确。在

使用浮点数据跟踪位置。使用c

将子弹的位置和速度存储到pygame.math.Vector2对象。在

class Bullet(object):
    def __init__(self, x, y, width, height, velX, velY):
        self.width = width
        self.height = height
        self.x = x
        self.y = y
        self.bullet = pygame.Rect(self.x, self.y, self.width, self.height)
        self.pos = pygame.math.Vector2(self.bullet.center)
        self.vel = pygame.math.Vector2(velX, velY)

更新位置属性而不是矩形位置：

^{pr2}$

在绘制项目符号之前更新矩形的位置：

class Bullet(object):

    # [...]

    def render(self, screen):
        self.bullet.center = (int(self.pos[0]), int(self.pos[1]))
        pygame.draw.rect(screen, (255, 255, 255), self.bullet)

使用^{}计算速度：

def shoot(self):
    posX, posY = 100, 100 # Static target coordinates

    traget = pygame.math.Vector2(posX, posY)
    start  = pygame.math.Vector2(self.player.x, self.player.y)

    delta = traget - start
    distance = delta.length() 
    direction = delta.normalize()

    vel = direction * 6
    self.bullets.append(Bullet(self.player.x, self.player.y, 10, 10, vel[0], vel[1]))