Blender 3D:各种各样的教程

Three-dimensional (3D) computer graphics
Fundamentals

In  3D computer graphics ,  Phong shading, Phong interpolation, ^[1]  or  normal-vector interpolation shading ^[2]  is an  interpolation  technique for surface  shading  invented by computer graphics pioneer  Bui Tuong Phong . Phong shading interpolates  surface normals  across  rasterized  polygons and computes  pixel  colors based on the interpolated normals and a reflection model.  Phong shading  may also refer to the specific combination of Phong interpolation and the  Phong reflection model .
::在3D计算机图形中,影,插值[1]或正常向量插值影[2]是计算机图形先驱图发明的表面遮的插值技术.影通过形多边形插值表面常数,并根据插值常数和反射模型计算像素颜色.影也可以指插值和反射模型的特定组合.

Phong shading and the  Phong reflection model  were developed at the  University of Utah  by  Bui Tuong Phong , who published them in his 1973 Ph.D. dissertation ^{[3] [4]}  and a 1975 paper. ^[5]  Phong's methods were considered radical at the time of their introduction, but have since become the  de facto  baseline shading method for many rendering applications. ^{[ citation needed ]}  Phong's methods have proven popular due to their generally efficient use of computation time per rendered pixel. ^{[ citation needed ]}
::影和反射模型是由Bui Tuong Phong在犹他大学开发的,他在1973年发表了他的博士论文[3][4]和1975年的论文.[5] 的方法在引入时被认为是激进的,但后来成为许多染应用的实际基线影方法. 的方法由于它们一般有效地使用计算时间每染像素而变得流行. [需要引用]

Phong shading improves upon  Gouraud shading  and provides a better approximation of the shading of a smooth surface. Phong shading assumes a smoothly varying surface normal vector. The Phong interpolation method works better than Gouraud shading when applied to a reflection model with small  specular highlights  such as the Phong reflection model.
::影比古拉影更好,可以更好地近似平滑表面的影.影假定平滑变化的表面正常向量.当影插入方法应用于像影模型这样的小光谱亮点的反射模型时,它比古拉影更好地工作.

The most serious problem with Gouraud shading occurs when specular highlights are found in the middle of a large polygon. Since these specular highlights are absent from the polygon's  vertices  and Gouraud shading interpolates based on the vertex colors, the specular highlight will be missing from the polygon's interior. This problem is fixed by Phong shading.
::戈劳影对象的最严重的问题是,当在一个大多边形的中间发现镜像亮点时.由于这些镜像亮点不在多边形的顶点上,并且戈劳影对象根据顶点颜色进行插入,因此镜像亮点将在多边形的内部缺失.这个问题是通过Phong影对象解决的.

Unlike Gouraud shading, which interpolates colors across polygons, in Phong shading, a normal vector is  linearly interpolated  across the surface of the polygon from the polygon's vertex normals. The surface normal is interpolated and normalized at each pixel and then used in a reflection model, e.g. the  Phong reflection model , to obtain the final pixel color. Phong shading is more computationally expensive than Gouraud shading since the reflection model must be computed at each pixel instead of at each vertex.
::与Gouraud遮蔽不同,它通过多边形来插入颜色,在Phong遮蔽中,一个正常向量从多边形的顶点正常线性地插入多边形的表面.表面正常在每个像素上被插入并正常化,然后在反射模型中使用,例如Phong反射模型,以获得最终的像素颜色.由于必须在每个像素上计算反射模型,因此Phong遮蔽比Gouraud遮蔽更昂贵.

In modern graphics hardware, variants of this algorithm are implemented using  pixel or fragment shaders .
::在现代图形硬件中,这种算法的变体使用像素或片段遮器实现.

Phong shading  may also refer to the specific combination of Phong interpolation and the  Phong reflection model , which is an empirical model of local illumination. It describes the way a surface reflects light as a combination of the  diffuse reflection  of rough surfaces with the  specular reflection  of shiny surfaces. It is based on  Bui Tuong Phong 's informal observation that shiny surfaces have small intense  specular highlights , while dull surfaces have large highlights that fall off more gradually. The reflection model also includes an  ambient  term to account for the small amount of light that is scattered about the entire scene.
::影也可以指插值和反射模型的特定组合,这是局部照明的经验模型.它描述了表面反射光的方式,即粗表面的分散反射与光亮表面的反射的组合.它基于Bui Tuong Phong的非正式观察,即光亮表面具有小的强烈光亮点,而淡的表面具有更逐渐下降的大的亮点.反射模型还包括一个环境术语来解释整个场景中散射的少量光.