Manual/PartIII/Diffuse Shaders
Wikipedia，自由的百科全书
Light striking a surface and then re-irradiated via a Diffusion phenomenon will be scattered, i.e., re-irradiated in all directions isotropically. This means that the camera will see the same amount of light from that surface point no matter what the incident viewing angle is. It is this quality that makes diffuse light viewpoint independent. Of course the amount of light that strikes the surface depends on the incident light angle. If most of the light striking a surface is reflected diffusely, the surface will have a matte appearance (Light re-irradiated in the diffusion phenomenon.). 照射到一个曲面上的光线通过漫反射现象重新被各向同性地散射。这意味着无论什么观察角度，照相机都会从曲面上该点接受到同样数量的光线。这个特性使得漫反射光“视点无关”。当然照射曲面的光线的数量取决于入射角。假如大部分入射光被散射，曲面将有不光滑的外表。 (漫反射现象中光线的重新发射.).
Currently, Blender implements four different mathematical formulae to compute diffusion. And, even more notably, the diffusion and specular phenomena, which are usually bound in a single type of material, have been separated so that it is possible to select diffusion and specular reflection implementation separately. The four Diffusion implementations, or shaders, use two or more parameters each. The first two parameters are shared by all Diffuse Shaders and are the Diffuse color, or simply color, of the material, and the amount of incident light energy that is actually diffused. This latter quantity, given in a [0,1] range, is actually called Refl in the interface. The implemented shaders are:
如今Blender实现了四种不同的数学公式来计算漫反射。而且，更值得注意的是，漫反射和镜面反射现象，通常被绑定在一个单独类型的材质中，已经被分离。所以我们才可能分别选择漫反射和镜面反射的不通实现，或称为着色器，每个着色器使用两个或更多的参数。前两个参数被所有的漫反射着色器共享，就是材质的“漫反射颜色”或简称“颜色”和入射光被实际散射的能量值。后一个数量值被限定在[0,1]的区间内，实际上在界面上被称作反射系数。实现的着色器有 ：
- Lambert - This was Blender's default diffuse shader up to version 2.27. As such, all old tutorials refer to this, and all pre-2.28 images were created with this. This shader has only the default parameters.
兰伯特 - 一直到2.27版本，这都是Blender的缺省漫反射着色器。 同样的，所有老的教程以及所有2.28版本以前创建的图片都是使用它。该着色器仅有两个缺省参数。
- Oren-Nayar - This shader was first introduced in Blender 2.28. It takes a somewhat more 'physical' approach to the diffusion phenomena because, besides the two default parameters, it has a third one which is used to determine the amount of microscopical roughness of the surface.
Oren-Nayar - 该着色器在 Blender 2.28首次被引入。它使用了某种程度上更加自然地产生漫反射现象的方法， 因为除了两个缺省的参数外，它有第三个参数，被用作确定曲面的更加精细的粗糙度。
- Toon - This shader was first introduced in Blender 2.28. It is a very 'un-physical' shader in that it is not meant to fake reality but to produce 'toonish' rendering, with clear light-shadow boundaries and uniformly lit/shadowed regions. Even though it is relatively simple, it still requires two more parameters which define the size of the lit area and the sharpness of the shadow boundaries.
卡通 - 该着色器在 Blender 2.28首次被引入。它是一个非常不自然的着色器，但并不意味着它不仿真现实，而是使用清晰地光影边界和均一的光影区域产生卡通式的渲染效果， 尽管它相对简单，但仍然要求使用两个以上的参数来定义光照区域的尺寸和阴影边界的锐度。
- Minnaert - This shader was first introduced in Blender 2.37. It works by darkening parts of the standard Lambertian model, and is set with a supplementary parameter, called "darkness". Highest darkness values will darken the edges of an object (where they point away from the viewer or the light source), making the surface look more specular or more metallic. Lowest darkness values will lighten the edges of the object, making it look somewhat velvet.
Minnaert - 该着色器在Blender 2.37首次被引入。它作用于标准的兰波特模型的变暗部分，而且用一个补充的称为“暗度”参数来设定。高的暗度值将会使得物体的边缘变暗（），使得曲面看起来更加高光或更加有金属感。低的暗度值使得物体的边缘变亮，使得物体看起来更加光滑。
A subsequent section, devoted to the actual implementation of the material, will analyze all these and their relative settings. 接下来的这一节，致力于材质的实际实现，将会分析所有这些着色器以及他们的相关设置。
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