问题描述
我已经尝试了好几个月来了解 IDirect3DVertexBuffer9 和 IDirect3DIndexBuffer9 工作。我读了多本书，电子书和论坛，我仍然不能得到他们的工作方式。
I've tried for many months to learn how IDirect3DVertexBuffer9 and IDirect3DIndexBuffer9 work. I've read multiple books, e-books and forums and I still can't get the hang of how they work. Can somebody help me understand how they work and how they link together?
PS：我试过搜索相关问题，但没有感兴趣的。
PS: I've tried searching through the related questions but nothing interested me.
感谢。
推荐答案
IndexBuffers用于内存和速度优化。 indexbuffer是一个索引列表，用于索引vertexBuffer中的顶点。
IndexBuffers are used for memory & speed optimizations. A indexBuffer is a list of indices that index the vertices in the vertexBuffer.
所以说我要在屏幕上用2个三角形渲染一个平面四边形。每个三角形占据3个顶点，所以要渲染的四边形只有一个VertexBuffer我将需要6个顶点。
So say I'm going to render a Flat Quad on the screen with 2 triangles. Each triangle takes up 3 vertices, so to render the quad with just a VertexBuffer I will need 6 vertices.
现在如果我使用IndexBuffer虽然，我只需要使用4个顶点（每个角的一个四边形）。但是我需要6个索引，每个三角形有3个索引，它们将索引其中一个顶点。
Now if I use a IndexBuffer though, I would only need to use 4 vertices(one for each corner of the quad). But I would need 6 indices, 3 indices for each triangle, that will index one of the corner vertices.
在大型模型上，这可以节省内存。大大提高了速度，因为GPU将处理较少的顶点。
On large models this can save memory & greatly improve speed as the GPU will be processing fewer vertices.
这里是一个网站有一些很好的示例代码::
在其中下载称为索引几何的示例。
Here is a site with some good sample code:: http://www.codesampler.com/dx9src.htmIn there download the sample called "Indexed Geometry".
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