C# XNA Matrices - 使用矩阵计算月球绕轴的旋转

发布于 2024-11-13 00:24:46 字数 662 浏览 3 评论 0原文

我正在构建 3D 模拟。

我正在使用一个类来显示太阳、行星和行星。具有不同大小、纹理、速度和轨道的月亮。这是我的代码，它执行计算旋转+旋转的神奇工作

world = Matrix.CreateScale(size,size,size) * Matrix.CreateTranslation(0,0,0) * 
 Matrix.CreateRotationY(rotation) * 
 Matrix.CreateTranslation(position) * 
 Matrix.CreateRotationY(revolution);

尺寸是我的变量，用于单独缩放对象
旋转是我的变量，用于围绕其自己的轴旋转对象
>position 是我将行星定位在轨道上的变量，new Vector3(240,0,0)
revolution 是我将行星围绕原点旋转的变量

，现在我想要显示卫星围绕地球和其他行星，但我只是不知道该怎么做。就矩阵乘法而言。

复杂的是月球绕着一颗行星公转，而这颗行星不在原点并且总是在变化。

怎么做？

原文

I am building a 3D simulation.

I am using one class to display sun, planets & moon with different size, texture, speed and orbit. Here's my code which does the magic job of calculating rotation + revolution

world = Matrix.CreateScale(size,size,size) * Matrix.CreateTranslation(0,0,0) * 
 Matrix.CreateRotationY(rotation) * 
 Matrix.CreateTranslation(position) * 
 Matrix.CreateRotationY(revolution);

size is my variable to scale the object individually
rotation is my variable to rotate the object around its own axis
position is my variable to position the planet on orbit, new Vector3(240,0,0)
revolution is my variable to revolve the planet around the origin

now i want the display the moons around earth and around other planets but i just can't figure out how to do it. In terms of Matrix Multiplication.

The complication is the moon's revolution is around a planet which is not on origin and is always changing.

How to do it ?

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一抹苦笑 2024-11-20 00:24:46

在您的 Draw 方法中，在绘制了您想要绕其运行的行星/月球之后：

Matrix satellite = Matrix.Identity
                 * Matrix.CreateScale(orbitScale)
                 * Matrix.CreateRotationY(orbitSpin)
                 * Matrix.CreateTranslation(0f, orbitDistance, 0f)
                 * Matrix.CreateFromAxisAngle(orbitAxis, orbitRotation);
effect.View = satellite * camera.View;

因此，在您的 Update 方法中，您可以执行以下操作

orbitRotation += MathHelper.PiOver2 * (float)gameTime.ElapsedGameTime.TotalSeconds;
orbitRotation = MathHelper.WrapAngle(orbitRotation);
orbitSpin += MathHelper.TwoPi * (float)gameTime.ElapsedGameTime.TotalSeconds;
orbitSpin = MathHelper.WrapAngle(orbitSpin);

：将orbitAxis定义为Vector3。 orbitDistance、orbitRotation、orbitScale 和 orbitSpin 作为 float。

In your Draw method, after you've drawn the planet/moon that you want to orbit around:

Matrix satellite = Matrix.Identity
                 * Matrix.CreateScale(orbitScale)
                 * Matrix.CreateRotationY(orbitSpin)
                 * Matrix.CreateTranslation(0f, orbitDistance, 0f)
                 * Matrix.CreateFromAxisAngle(orbitAxis, orbitRotation);
effect.View = satellite * camera.View;

So, in your Update method, you can then do:

orbitRotation += MathHelper.PiOver2 * (float)gameTime.ElapsedGameTime.TotalSeconds;
orbitRotation = MathHelper.WrapAngle(orbitRotation);
orbitSpin += MathHelper.TwoPi * (float)gameTime.ElapsedGameTime.TotalSeconds;
orbitSpin = MathHelper.WrapAngle(orbitSpin);

I've defined orbitAxis as a Vector3. orbitDistance, orbitRotation, orbitScale and orbitSpin as float's.

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梦明 2024-11-20 00:24:46

我想通了...

将原点翻译为母行星的当前位置

并在更新方法中继续执行

world = Matrix.CreateScale(size,size,size)
        * Matrix.CreateTranslation(0,0,0) 
        * Matrix.CreateRotationY(rotation)
        * Matrix.CreateTranslation(position)
        * Matrix.CreateRotationY(revolution); 

world *= Matrix.CreateTranslation( parent.getPosition() );

我在这里所做的是让月球围绕原点（太阳）旋转，但是我将其起源翻译为任何行星的当前位置......这对我有用。

i figured it out...

Translate The Origin to the Parent planet's Current Location

and keep doing it in the update method

world = Matrix.CreateScale(size,size,size)
        * Matrix.CreateTranslation(0,0,0) 
        * Matrix.CreateRotationY(rotation)
        * Matrix.CreateTranslation(position)
        * Matrix.CreateRotationY(revolution); 

world *= Matrix.CreateTranslation( parent.getPosition() );

what i am doing here is that i m revolving the moon around the origin (Sun) but i translate its origin to any planet's current location... this worked for me.

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