基于旋转的XNA方向
本文关键字:XNA 方向 旋转 于旋转 | 更新日期: 2023-09-27 18:28:39
我的XNA项目中有一个箭头,我已经成功地用这个代码将其旋转到鼠标的位置-
using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Media;
namespace Test
{
/// <summary>
/// This is the main type for your game
/// </summary>
public class Game1 : Microsoft.Xna.Framework.Game
{
GraphicsDeviceManager graphics;
SpriteBatch spriteBatch;
Texture2D arrowSprite;
float rotation;
Vector2 direction;
Vector2 position;
float speed;
Vector2 mousePos;
SpriteFont font1;
public Game1()
{
graphics = new GraphicsDeviceManager(this);
Content.RootDirectory = "Content";
}
/// <summary>
/// Allows the game to perform any initialization it needs to before starting to run.
/// This is where it can query for any required services and load any non-graphic
/// related content. Calling base.Initialize will enumerate through any components
/// and initialize them as well.
/// </summary>
protected override void Initialize()
{
// TODO: Add your initialization logic here
position = new Vector2(GraphicsDevice.Viewport.Width / 2, GraphicsDevice.Viewport.Height / 5);
speed = 1000.0f;
this.IsMouseVisible = true;
MouseState mouse = Mouse.GetState();
mousePos.X = mouse.X;
mousePos.Y = mouse.Y;
rotation = Angle(position, mousePos);
base.Initialize();
}
/// <summary>
/// LoadContent will be called once per game and is the place to load
/// all of your content.
/// </summary>
protected override void LoadContent()
{
// Create a new SpriteBatch, which can be used to draw textures.
spriteBatch = new SpriteBatch(GraphicsDevice);
arrowSprite = Content.Load<Texture2D>("Sprites''Arrow");
font1 = Content.Load<SpriteFont>("Sprites''Test");
// TODO: use this.Content to load your game content here
}
/// <summary>
/// UnloadContent will be called once per game and is the place to unload
/// all content.
/// </summary>
protected override void UnloadContent()
{
// TODO: Unload any non ContentManager content here
}
/// <summary>
/// Allows the game to run logic such as updating the world,
/// checking for collisions, gathering input, and playing audio.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Update(GameTime gameTime)
{
// Allows the game to exit
if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
this.Exit();
// TODO: Add your update logic here
MouseState mouse = Mouse.GetState();
mousePos.X = mouse.X;
mousePos.Y = mouse.Y;
rotation = Angle(position, mousePos);
direction = new Vector2((float)Math.Cos(rotation), (float)Math.Sin(rotation));
position += direction * 10.0f * (float)gameTime.ElapsedGameTime.TotalSeconds;
base.Update(gameTime);
}
/// <summary>
/// This is called when the game should draw itself.
/// </summary>
/// <param name="gameTime">Provides a snapshot of timing values.</param>
protected override void Draw(GameTime gameTime)
{
GraphicsDevice.Clear(Color.CornflowerBlue);
// TODO: Add your drawing code here
spriteBatch.Begin();
spriteBatch.Draw(arrowSprite, position, null, Color.White, rotation, new Vector2(arrowSprite.Width / 2, arrowSprite.Height / 2), 1.0f, SpriteEffects.None, 1.0f);
spriteBatch.DrawString(font1, mousePos.X.ToString()+ " " + mousePos.Y.ToString(), new Vector2(GraphicsDevice.Viewport.Width / 2, 0), Color.White);
//spriteBatch.DrawString(font1, "Rotation:" + rotation.ToString(), Vector2.Zero, Color.White);
spriteBatch.DrawString(font1, "Direction" + direction.ToString(), Vector2.Zero, Color.White);
spriteBatch.End();
base.Draw(gameTime);
}
public static float Angle(Vector2 from, Vector2 to)
{
return (float)Math.Atan2(from.X - to.X, to.Y - from.Y);
}
}
}
然而,当我运行代码时,箭头只是围绕鼠标旋转,并且随着时间的推移,箭头的半径会稍微扩大。我希望箭头旋转到鼠标,然后它向它旋转到的区域移动。谢谢,任何帮助都将不胜感激。
您的Angle()
计算意味着箭头精灵在其原始状态下指向上方。但是,你对direction
的计算是错误的。计算方向和角度可以如下进行:
private void CalculateAngleAndDirection(Vector2 from, Vector2 to, out Vector2 direction, out float angle)
{
direction = to - from; //get the direction vector
direction.Normalize(); //make it a unit vector
angle = (float)Math.Atan2(-direction.X, direction.Y);
}
protected override void Update(GameTime gameTime)
{
//...
MouseState mouse = Mouse.GetState();
mousePos.X = mouse.X;
mousePos.Y = mouse.Y;
CalculateAngleAndDirection(position, mousePos, out direction, out angle);
position += direction * 10.0f * (float)gameTime.ElapsedGameTime.TotalSeconds;
base.Update(gameTime);
}
我注意到你说
并且它这样做的半径随着时间稍微扩展
发现了这个
position += direction * 10.0f * (float)gameTime.ElapsedGameTime.TotalSeconds;
在xna中,理论上每秒调用60次更新,gameTime.ElapedGameTime.TotalSeconds每秒不断增加。如果将此方程的值添加到可变位置,则由于此增量,它将逐渐改变"轨道"。此外,根据我所能收集到的,你计算旋转的方式可以返回负数(提供向后的"轨道"),当乘以正数时,它将返回不寻常的数字。