Unity3D图像后处理特效——Glow image effect

Glow (sometimes called "Bloom") can dramatically enhance the rendered image by making overbright parts "glow" (e.g. sun, light sources, strong highlights). The Bloom and Lens Flares image effect gives greater control over the bloom but has a higher processing overhead.

辉光（有时称为" Bloom "）通过让过渡明亮部分"（例如太阳，光源，强高光）“发光”，可以大大增强渲染图像的效果。Bloom and Lens Flares图像特效对于辉光效果具有更大的控制，但也具有更高的处理开销。

 

As with the other image effects, this effect is only available in Unity Pro and you must have the Pro Standard Assets installed before it becomes available

和其他图像特效一样，该特效只能在Unity Pro上进行使用，并且在使用之前必须安装Pro Standard Assets。

 

Glow effect applied to the scene

应用到场景的辉光特效

 

Properties           属性

Glow Intensity 辉光亮度	Total brightness at the brightest spots of the glowing areas 辉光区域最亮点的全部亮度值.
Blur Iterations 模糊迭代次数	Number of times the glow is blurred when being drawn. Each iteration requires processing time. 辉光的模糊次数，每次迭代都需要消耗一定的处理时间
Blur Spread 模糊半径	The pixel distance over which pixels are combined to produce blurring 产生blur的像素距离.
Glow Tint 辉光提示	Color tint applied to the glow 应用于辉光的颜色提示.
Downsample Shader 下采样着色器	The shader used for the glow. You generally should not have to change this. 用于辉光效果的着色器，您一般不需要改变它

 

Details       细节

Glow uses the alpha channel of the final image to represent "color brightness". All colors are treated as RGB, multiplied by the alpha channel. You can view the contents of the alpha channel in Scene View.

辉光效果使用最终图像的alpha通道来表现“颜色的明亮度”，所有的颜色都被当成RGB处理，并与alpha通道的数值相乘，你可以在Scene View中查看alpha通道的内容。

 

All built-in shaders write the following information to alpha:

所有内建着色器都在alpha通道中写入如下的信息：

       Main texture's alpha multiplied by main color's alpha (not affected by lighting).

       主纹理的alpha值乘以主颜色的alpha值（不受光照影响）

       Specular shaders add specular highlight multiplied by specular color's alpha.

       反射着色器将颜色加上反射高光与反射光颜色的alpha通道相乘后的颜色值

       Transparent shaders do not modify alpha channel at all.

       透明着色器不修改alpha通道的值

       Particle shaders do not modify alpha channel, except for Particles/Multiply which darkens anything that is in alpha. 

       粒子着色器不修改alpha通道的值，除非是调暗alpha通道的Particles/Multiply着色器

       Skybox shaders write alpha of the texture multiplied by tint alpha

       天空盒着色器将色调alpha值与纹理的apha值相乘

 

Most of the time you'll want to do this to get reasonable glow:

大多数情况下你会为了获得合理的辉光效果进行如下的操作：

       Set material's main color alpha to zero or use a texture with zero alpha channel. In the latter case, you can put non-zero alpha in the texture to cause these parts to glow.

      将材质的主颜色的alpha值变成0，或者使用一个零alpha通道的纹理。对于后者，你可以在纹理中产生辉光效果的地方设置非零alpha值。

      Set the specular color alpha for Specular shaders to be 100%.

      对于反射着色器，将反射的颜色alpha值设成100%。

      Keep in mind what alpha the camera clears to (if it clears to a solid color), or what alpha the skybox material uses.

      切记去掉了哪些alpha值（即变成一个不透明颜色），或者天空盒材质使用了哪些alpha。

      Add the Glow image effect to the camera. Tweak Glow Intensity and Blur Iterations values, you can also take a look at the comments in the shader script source.

      将辉光图像特效加入到照相机上，调整辉光亮度和模糊迭代次数。

      The alpha channel on the Skybox can be used to great effect to add more glow when looking at the sun

      使用天空盒的alpha值，可以让你在看到太阳时添加更多的光辉。

 

Tips:

提示：

      Use the alpha rendering mode in the scene view toolbar to quickly see which objects output different values to the alpha channel.

      在场景窗口下使用透明度渲染模式，可以快速地看到物体的不同alpha通道。

 

Hardware support        硬件支持

This effect requires a graphics card with pixel shaders (2.0) or OpenGL ES 2.0. PC: NVIDIA cards since 2003 (GeForce FX), AMD cards since 2004 (Radeon 9500), Intel cards since 2005 (GMA 900); Mobile: OpenGL ES 2.0; Consoles: Xbox 360, PS3.

这个特效需要显卡拥有像素着色器（2.0）或者OpenGL ES 2.0。台式机：2003年以后的NVIDIA显卡（GeForce FX），2004年以后的AMD显卡（Radeon 9500），2005年以后的Intel卡（GMA 900）；移动设备：OpenGL ES 2.0；控制台： Xbox 360、 PS3。

 

All image effects automatically disable themselves when they can not run on end-users graphics card.

所有图像特效如果无法在用户显卡上运行时将会自动被关闭。