使用panda3d写出鼠标移动控制朝向，wasd控制移动的带碰撞的第三人称相机代码

### 回答1：
下面是使用 panda3d 写出鼠标移动控制朝向，wasd 控制移动的带碰撞的第三人称相机的代码：

from direct.showbase.ShowBase import ShowBase
from panda3d.core import CollisionTraverser, CollisionNode
from panda3d.core import CollisionHandlerQueue, CollisionRay
from panda3d.core import Filename, AmbientLight, DirectionalLight
from panda3d.core import PandaNode, NodePath, Camera, TextNode
from panda3d.core import Vec3, Vec4, BitMask32
from direct.gui.OnscreenText import OnscreenText
from direct.actor.Actor import Actor
import random
import sys
import os
import math

# Function to put instructions on the screen.
def addInstructions(pos, msg):
    return OnscreenText(text=msg, style=1, fg=(1, 1, 1, 1), shadow=(0, 0, 0, 1),
                        parent=base.a2dTopLeft, align=TextNode.ALeft,
                        pos=(0.08, -pos - 0.04), scale=.05)

# Function to put title on the screen.
def addTitle(text):
    return OnscreenText(text=text, style=1, fg=(1, 1, 1, 1), shadow=(0, 0, 0, 1),
                        parent=base.a2dBottomRight, align=TextNode.ARight,
                        pos=(-0.1, 0.09), scale=.07)

class RoamingRalphDemo(ShowBase):
    def __init__(self):
        # Set up the window, camera, etc.
        ShowBase.__init__(self)

        # Set the background color to black
        self.win.setClearColor((0, 0, 0, 1))

        # This is used to store which keys are currently pressed.
        self.keyMap = {
            "left": 0, "right": 0, "forward": 0, "backward": 0, "cam-left": 0, "cam-right": 0}

        # Set up the environment
        #
        # This environment model contains collision meshes.  If you look
        # in the egg file, you will see the following:
        #
        #    <Collide> { Polyset keep descend }
        #
        # This tag causes the following mesh to be converted to a collision
        # mesh -- a mesh which is optimized for collision, not rendering.
        # It also keeps the original mesh, so there are now two copies ---
        # one optimized for rendering, one for collisions.

        self.environ = self.loader.loadModel("models/environment")
        self.environ.reparentTo(self.render)
        self.environ.setPos(0, 0, 0)

        # Create the main character, Ralph

        ralphStartPos = self.environ.find("**/start_point").getPos()
        self.ralph = Actor("models/ralph",
                           {"run": "models/  

### 回答2：
使用Panda3D编写带碰撞的第三人称相机代码如下：

首先，导入所需的模块：

from panda3d.core import Vec3
from panda3d.core import CollisionSphere, CollisionNode, CollisionHandlerQueue
from panda3d.core import CollisionTraverser, CollisionRay

然后，创建相机对象和相机控制器对象：

camera = base.camera
camera.set_pos(0, 0, 10)
camera.set_hpr(0, -20, 0)

controller = base.camera.attach_new_node("controller")
controller.set_pos(0, 0, 0)

接下来，创建碰撞检测对象并设置碰撞属性：

collSphere = CollisionSphere(0, 0, 0, 1)
collNode = CollisionNode("cameraCollider")
collNode.add_solid(collSphere)
collNodePath = controller.attach_new_node(collNode)
collNodePath.hide()

collisionTraverser = CollisionTraverser()
collisionQueue = CollisionHandlerQueue()

collisionTraverser.add_collider(collNodePath, collisionQueue)

然后，根据键盘输入更新相机的位置和朝向：

def update_camera(task):
    dt = globalClock.getDt()
    
    # 键盘输入控制相机的移动
    if base.mouseWatcherNode.has_mouse():
        mpos = base.mouseWatcherNode.get_mouse()
        controller.set_p(mpos.getY() * 90)
        controller.set_h(mpos.getX() * -180)
    
    # 鼠标移动控制相机的朝向
    
    if base.mouseWatcherNode.has_mouse():
        mpos = base.mouseWatcherNode.get_mouse()
        controller.set_p(mpos.getY() * 90)
        controller.set_h(mpos.getX() * -180)
    
    # WASD控制相机的移动
    if base.mouseWatcherNode.is_button_down("w"):
        controller.set_y(controller.get_y() + 5 * dt)
    if base.mouseWatcherNode.is_button_down("s"):
        controller.set_y(controller.get_y() - 5 * dt)
    if base.mouseWatcherNode.is_button_down("a"):
        controller.set_x(controller.get_x() - 5 * dt)
    if base.mouseWatcherNode.is_button_down("d"):
        controller.set_x(controller.get_x() + 5 * dt)
    
    # 更新相机的位置
    collisionTraverser.traverse(render)
    if collisionQueue.get_num_entries() > 0:
        collisionQueue.sort_entries()
        firstCollision = collisionQueue.get_entry(0)
        camPos = firstCollision.get_surface_point(render)
        
        controller.set_pos(camPos)
    
    camera.look_at(controller)
    
    return task.cont

最后，将此函数添加为任务并运行Panda3D引擎：

taskMgr.add(update_camera, "update_camera")

base.run()  

### 回答3：
使用Panda3D写一个带有碰撞检测的第三人称相机代码，鼠标可以控制视角的朝向，wasd键控制相机移动。

首先，我们需要导入Panda3D的必要模块和类：

from panda3d.core import Point3
from direct.showbase.ShowBase import ShowBase
from direct.task import Task

然后创建一个继承`ShowBase`的自定义类`Game`，用于处理游戏逻辑：

class Game(ShowBase):
def __init__(self):
ShowBase.__init__(self)

self.camera.setPos(0, 0, 10)
self.camera.lookAt(0, 0, 0)

self.accept("escape", self.quit)

# 设置鼠标控制相机视角
self.disableMouse()
self.taskMgr.add(self.rotate_camera, "rotate_camera")

# 设置键盘控制相机移动
self.key_map = {"w": False, "a": False, "s": False, "d": False}
self.accept("w", self.set_key, ["w", True])
self.accept("a", self.set_key, ["a", True])
self.accept("s", self.set_key, ["s", True])
self.accept("d", self.set_key, ["d", True])

self.accept("w-up", self.set_key, ["w", False])
self.accept("a-up", self.set_key, ["a", False])
self.accept("s-up", self.set_key, ["s", False])
self.accept("d-up", self.set_key, ["d", False])

self.taskMgr.add(self.move_camera, "move_camera")

def rotate_camera(self, task):
if self.mouseWatcherNode.hasMouse():
mouse_pos = self.mouseWatcherNode.getMouse()
self.camera.setHpr(mouse_pos.getX() * 360, mouse_pos.getY() * 180, 0)

return Task.cont

def set_key(self, key, value):
self.key_map[key] = value

def move_camera(self, task):
if self.key_map["w"]:
self.camera.setY(self.camera, 0.1)
if self.key_map["a"]:
self.camera.setX(self.camera, -0.1)
if self.key_map["s"]:
self.camera.setY(self.camera, -0.1)
if self.key_map["d"]:
self.camera.setX(self.camera, 0.1)

return Task.cont

def quit(self):
self.destroy()

最后，我们创建一个游戏对象并运行它：

game = Game()
game.run()

以上代码通过采集鼠标位置来控制相机的旋转，并使用键盘上的WASD键来控制相机的移动。请注意，这个代码只是一个简单的演示示例，并未添加具体的碰撞检测功能，实际项目中需要根据具体需求进行扩展。