Tutorial05.docx

Tutorial 5: 3D TransformationSummaryIn the previous tutorial, we rendered a cube from model space to the screen. In this tutorial, we will extend the concept of transformations and demonstrate simple animation that can be achieved with these transformations.在以前的tutorial，我们render一个方盒子从模块空间到屏幕。在这个tutorial，我们扩展变换的概念和演示一个小动画，用这些变换是高度完美的。The outcome of this tutorial will be an object that orbits around another. It would be useful to demonstrate the transformations and how they can be combined to achieve the desired effect. Future tutorials will be building on this foundation as we introduce new concepts.这个tutorial的结果是一个对象围绕另一个对象旋转。这是非常有用的，演示变换和他们怎样联合获得想要的效果。未来的turorial将建立在我们介绍新的建立概念。Source(SDK root)\Samples\C++\Direct3D10\Tutorials\Tutorial05TransformationIn 3D graphics, transformation is often used to operate on vertices and vectors. It is also used to convert them in one space to another. Transformation is performed via multiplication with a matrix. There are typically three types of primitive transformation that can be performed on vertices: translation (where it lies in space relative to the origin), rotation (its direction in relation to the x, y, z frame), and scaling (its distance from origin). In addition to those, projection transformation is used to go from view space to projection space.The D3DX library contains APIs that can conveniently construct a matrix for many purposes such as translation, rotation, scaling, world-to-view transformation, view-to-projection transformation, etc. An application can then use these matrices to transform vertices in its scene. A basic understanding of matrix transformations is required. We will briefly look at some examples below.在3D图形里，变换经常用来操作在vertices和vectors上。它也用来转换他们从一个空间到另一个。变换被执行通过和一个matrix相乘。有三个典型的原始变换类型，它能够被执行在vertex:转换（获得空间相对位置），旋转（关联的方向x y z框架），和放缩（距离从原点）。这些之外，工程变换用来从view空间到工程空间。D3DX库包含APIs那个能够方便的建立一个matrix有很多目的例如变换，旋转，防缩，world-to-view转换，view-to-projection转换，等等。应用程序然后能用这些矩阵去转换场景里的vertex。明白基础的矩阵转换时必要的。我们将简短的看下面相同的例子。