坐下并进行2D射击游戏,我的玩家需要能够使用角度向左和向上射击。我遇到的问题是我找不到办法让这项工作。
那么如何计算射出子弹特定角度的角度呢?
我在播放器类中的代码
class Player
{
//Player
public Rectangle playercollisionbox;
public Texture2D Playertexture;
public Vector2 Position = new Vector2(470, 850);
//Bullet
public Texture2D bulletTexture;
//How fast you shoot
public float bulletDelay = 1;
public List<Bullet> bulletList;
//Angle bullet
public float spriterotation = 0;
public float speed = 1;
public Vector2 bulletposition;
//Health
public int Health;
public Vector2 healthbarposition = new Vector2(20, 40);
public Texture2D healthbartexture;
public Rectangle healthrectangle;
//Contructor
public Player()
{
bulletList = new List<Bullet>();
Health = 200;
}
public void LoadContent(ContentManager Content)
{
bulletTexture = Content.Load<Texture2D>(@"images/projectile2");
healthbartexture = Content.Load<Texture2D>(@"images/HealthBar");
}
public void Update(GameTime gameTime)
{
KeyboardState keyboardState = Keyboard.GetState();
playercollisionbox = new Rectangle((int)Position.X, (int)Position.Y, Playertexture.Width, Playertexture.Height);
//Player movement
if (keyboardState.IsKeyDown(Keys.Up))
{
Position.Y -= 7;
}
if (keyboardState.IsKeyDown(Keys.Left))
{
Position.X -= 7;
}
if (keyboardState.IsKeyDown(Keys.Down))
{
Position.Y += 7;
}
if (keyboardState.IsKeyDown(Keys.Right))
{
Position.X += 7;
}
//Player movement
healthrectangle = new Rectangle((int)healthbarposition.X, (int)healthbarposition.Y, Health, 25);
//Off-screen block
if (Position.X < 0)
{
Position.X = 0;
}
if (Position.Y < 0)
{
Position.Y = 0;
}
if (Position.X > 943)
{
Position.X = 943;
}
if (Position.Y > 904)
{
Position.Y = 904;
}
//Bullet
if (keyboardState.IsKeyDown(Keys.Space))
{
Shoot();
}
UpdateBullet();
}
public virtual void Draw(SpriteBatch spriteBatch)
{
spriteBatch.Draw(Playertexture, Position, Color.White);
foreach (Bullet b in bulletList)
{
b.Draw(spriteBatch);
}
spriteBatch.Draw(healthbartexture, healthrectangle, Color.White);
}
//Shooting method
public void Shoot()
{
if (bulletDelay >= 0)
{
bulletDelay--;
}
if (bulletDelay <= 0)
{
//First Bullet
Bullet newBullet = new Bullet(bulletTexture);
newBullet.position = new Vector2(Position.X + 40 - newBullet.texture.Width / 2, Position.Y - 40);
newBullet.isVisible = true;
//Second Bullet
if (bulletDelay == 0)
{
bulletDelay = 20;
}
if (bulletList.Count() < 20)
{
bulletList.Add(newBullet);
}
}
}
//Updating bullet after shooting
public void UpdateBullet()
{
//speed on nullet
foreach (Bullet b in bulletList)
{
b.position.Y = b.position.Y - b.speed;
b.bulletcollisionbox = new Rectangle((int)b.position.X, (int)b.position.Y, b.texture.Width, b.texture.Height);
//outside screen removes it
if (b.position.Y <= 0)
{
b.isVisible = false;
}
}
for (int i = 0; i < bulletList.Count; i++)
{
if (!bulletList[i].isVisible)
{
bulletList.RemoveAt(i);
i--;
}
}
}
}
My Bullet Class
public class Bullet
{
public Texture2D texture;
public Vector2 origin;
public Vector2 position;
public bool isVisible;
public float speed;
public Rectangle bulletcollisionbox;
public Bullet(Texture2D newTexture)
{
speed = 10;
texture = newTexture;
isVisible = false;
}
public void Draw(SpriteBatch spriteBatch)
{
spriteBatch.Draw(texture, position, Color.White);
}
}
答案 0 :(得分:1)
我实际上有一个我在所有XNA项目中使用的自制库。其中一个辅助函数是:
/// <summary>
/// Converts a given angle into a Vector2.
/// </summary>
/// <param name="angle">The angle (in radians).</param>
/// <param name="normalize">True to normalize the resultant vector, otherwise false.</param>
/// <returns>A vector representing the specified angle.</returns>
public static Vector2 Vector2FromAngle(double angle, bool normalize = true)
{
Vector2 vector = new Vector2((float)Math.Cos(angle), (float)Math.Sin(angle));
if (vector != Vector2.Zero && normalize)
vector.Normalize();
return vector;
}
随意使用它!它返回的矢量将是你子弹的轨迹。
如果您不熟悉如何将度数转换为弧度,radians = degrees * pi / 180
并将其转换为degrees = radians * 180 / pi
。
答案 1 :(得分:1)
以弧度为单位的2个向量之间的角度
Math.Atan2(b.Y - a.Y,b.X - a.X);
子弹方向
Vector2 direction = playerPosition - enemyPosition;
direction.Normalize();
然后按方向向量增加子弹位置