Chapter 2 The Graphics Rendering Pipeline

第二章 图形渲染管线

This chapter presents the core component of real-time graphics, namely the graphics rendering pipeline, also known simply as “the pipeline.” The main function of the pipeline is to generate, or render, a two-dimensional image, given a virtual camera, three-dimensional objects, light sources, and more. The rendering pipeline is thus the underlying tool for real-time rendering. The process of using the pipeline is depicted in Figure 2.1. The locations and shapes of the objects in the image are determined by their geometry, the characteristics of the environment, and the placement of the camera in that environment. The appearance of the objects is affected by material properties, light sources, textures (images applied to surfaces), and shading equations.

本章介绍实时图形的核心组件，即图形渲染管线，也简称为“管线”。 管线的主要功能是在给定虚拟相机、三维物体、光源等的情况下生成或渲染二维图像。 因此，渲染管线是实时渲染的底层工具。 使用管线的过程如图2.1所示。 图像中物体的位置和形状由它们的几何形状、环境特征以及相机在该环境中的位置决定。 对象的外观受材料属性、光源、纹理（应用于表面的图像）和着色方程式的影响。

Figure 2.1. In the left image, a virtual camera is located at the tip of the pyramid (where four lines converge). Only the primitives inside the view volume are rendered. For an image that is rendered in perspective (as is the case here), the view volume is a frustum (plural: frusta), i.e., a truncated pyramid with a rectangular base. The right image shows what the camera “sees.” Note that the red donut shape in the left image is not in the rendering to the right because it is located outside the view frustum. Also, the twisted blue prism in the left image is clipped against the top plane of the frustum.

图 2.1。 在左图中，一个虚拟相机位于金字塔的顶端（四条线会聚的地方）。 仅渲染视图体积(view volume)内的基元(primitives)。 对于以透视图呈现的图像（如此处的情况），视图体积是一个平截头锥体(frustum)（复数：frusta），即具有矩形底边的截头金字塔。 右图显示了相机“看到”的内容。 请注意，左侧图像中的红色圆环形状不在右侧的渲染中，因为它位于视锥之外。 此外，左图中扭曲的蓝色棱镜被裁剪到平截头体的顶平面上。

We will explain the different stages of the rendering pipeline, with a focus on function rather than implementation. Relevant details for applying these stages will be covered in later chapters.

我们将解释渲染管线的不同阶段，重点是功能而不是实现。 应用这些阶段的相关细节将在后面的章节中介绍。