Farseer，MonoGame，球不反弹答案

【问题标题】：Farseer, MonoGame, ball does not bounceFarseer，MonoGame，球不反弹
【发布时间】：2013-05-27 17:37:19
【问题描述】：

我已经成功地将 Farseer for XNA 集成到 MonoGame 中，几乎没有遇到任何问题。堆叠、复杂的动力学等似乎都工作得很好，但我绝对不能让球在地板上弹跳。 当球接触地面时，它会停在那里，只有在被另一个球推动时才会离开。

我的代码（在 F# 中，但应该足够清楚；

  member physics.CreateBall(x:float32<m>,y:float32<m>,r:float32<m>,m:float32<kg>,dynamic:bool) =
    let myBody = Factories.BodyFactory.CreateBody(physics.Physics, Microsoft.Xna.Framework.Vector2(x * 1.0f<1/m> + random_range -30.0f 30.0f, y * 1.0f<1/m>) * PhysicsWorld.Scale)
    do myBody.LastFrameUpdate <- Casanova.Core.get_frame_counter()
    do myBody.BodyType <- if dynamic then BodyType.Dynamic else BodyType.Static
    do myBody.Restitution <- 1.0f
    do myBody.Friction <- 0.0f
    do myBody.Mass <- m * 1.0f<_>
    let circleShape = new CircleShape(r * PhysicsWorld.Scale * 1.0f<1/m>, 1.0f)
    let fixture = myBody.CreateFixture(circleShape)
    { Body = myBody; Tick = Rule.Create 0 }
  member physics.CreateBox(x:float32<m>,y:float32<m>,w:float32<m>,h:float32<m>,m:float32<kg>,dynamic:bool) =
    let myBody = Factories.BodyFactory.CreateBody(physics.Physics, Microsoft.Xna.Framework.Vector2(x * 1.0f<1/m>, y * 1.0f<1/m>) * PhysicsWorld.Scale)
    do myBody.LastFrameUpdate <- Casanova.Core.get_frame_counter()
    do myBody.BodyType <- if dynamic then BodyType.Dynamic else BodyType.Static
    do myBody.Restitution <- 1.0f
    do myBody.Friction <- 0.0f
    do myBody.Mass <- m * 1.0f<_>
    let rectangle = PolygonTools.CreateRectangle(w * PhysicsWorld.Scale * 1.0f<1/m>, h * PhysicsWorld.Scale * 1.0f<1/m>)
    let boxShape = PolygonShape(rectangle, 1.0f)
    let fixture = myBody.CreateFixture(boxShape)
    { Body = myBody; Tick = Rule.Create 0 }

【问题讨论】：

body 和 fixture 对象都具有 Restitution 和 Friction 属性。确保两者都已设置。因为我只设置了 body 属性，所以遇到了同样的问题。

标签： f# monogame farseer

【解决方案1】：

最简单的解决方案。上面的代码几乎是正确的，减去了初始化顺序。这是供将来参考的工作版本：

let myBody = Factories.BodyFactory.CreateBody(physics.Physics, Microsoft.Xna.Framework.Vector2(x * 1.0f<1/m>, y * 1.0f<1/m>) * PhysicsWorld.Scale)
let rectangle = PolygonTools.CreateRectangle(w * PhysicsWorld.Scale * 1.0f<1/m>, h * PhysicsWorld.Scale * 1.0f<1/m>)
let boxShape = PolygonShape(rectangle, 1.0f)
let fixture = myBody.CreateFixture(boxShape)
do myBody.LastFrameUpdate <- Casanova.Core.get_frame_counter()
do myBody.BodyType <- if dynamic then BodyType.Dynamic else BodyType.Static
do myBody.Restitution <- restitution
do myBody.Friction <- friction
do myBody.Mass <- m * 1.0f<_>

【讨论】：