Projectile Motion (拋物線運動)

利用物理公式:
Vx = Vx
Vy = Vy + a*t

X = X + Vx*t
Y = Y + Vy*t + 1/2*a*t*^2


'宣告
Dim Position As Vector2
Dim V As Vector2
Dim a As Integer





'初始
Position = New Vector2(0, 420)
a = 60
V = New Vector2(150, -150)




'update
V.Y = V.Y + CInt(a * gameTime.ElapsedGameTime.TotalSeconds)

Position.X = Position.X + CInt(V.X * gameTime.ElapsedGameTime.TotalSeconds)
Position.Y = Position.Y + CInt(V.Y * gameTime.ElapsedGameTime.TotalSeconds) + CInt(0.5 * a * (gameTime.ElapsedGameTime.TotalSeconds) ^ 2)




'draw
spriteBatch.DrawString(txtFont, txt, Position, Color.Red)



影片
http://www.youtube.com/watch?v=3_k08C-Rwsw