Unity組件：Bloom and Lens Flares 泛光和鏡頭眩光

Blooming is the optical effect where light from a bright source (such as a glint) appears to leak into surrounding objects. The Bloom and Lens Flares image effect adds bloom and also automatically generates lens flares in a highly efficient way. Bloom is a very distinctive effect that can make a big difference to a scene and may suggest a magical or dreamlike environment especially when used in conjunction with HDR rendering. Bloom and Lens Flares is actually an enhanced version of the Glow image effect which offers greater control over the bloom at the expense of rendering performance.

泛光特效是一種光學(xué)效應(yīng)，它是指在來(lái)自于強(qiáng)光源（如閃爍）的光線看起來(lái)像是影響到了周圍物體。Bloom and Lens Flares圖像效果通過一種高效的方式添加了泛光效果，并會(huì)自動(dòng)生成鏡頭光暈的效果。泛光是一個(gè)非常獨(dú)特的效果，它與HDR渲染方法一起使用時(shí)可以很大程度地改變場(chǎng)景的氛圍，烘托出神奇、夢(mèng)幻般的環(huán)境。泛光與鏡頭光暈特效實(shí)際上是輝光特效的一個(gè)增強(qiáng)版，它可以對(duì)泛光效果提供更好的控制，但同時(shí)也會(huì)帶來(lái)昂貴的渲染性能開銷。

Example showing how Bloom and Lens Flares can give a soft glow using the new Screen blend mode. The new anamorphic lens flare type helps evoke a cinematic feeling.
例子中顯示了該特效在使用了新的屏幕混合模式后可以提供一個(gè)柔和的輝光效果。新的變形鏡頭光暈類型有助于烘托出電影的感覺。

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.

和其他圖像特效一樣，該特效只能在Unity Pro上進(jìn)行使用，并且在使用之前必須安裝Pro Standard Assets

Properties 屬性

• Tweak Mode 調(diào)整模式
  Choose complex mode for additional options such as lens flares.
  對(duì)于額外的選項(xiàng)選擇復(fù)雜的模式，比如鏡頭光暈效果。
• Blend mode 混合模式
  The method used to add bloom to the color buffer. The softer Screen mode is better for preserving bright image details but doesn't work with HDR.
  將泛光效果添加到顏色緩存上的方法。更加柔順的屏幕模式比較適合于保留明亮的圖像細(xì)節(jié)，但這種模式無(wú)法跟HDR一起使用。
• HDR 高動(dòng)態(tài)范圍
  Whether bloom is using HDR buffers. This will result in a different look as pixel intensities may leave the [0,1] range, see details in tonemapping and HDR.
  決定該特效是否使用HDR緩存。使用HDR將導(dǎo)致一個(gè)不同的視覺感受，因?yàn)橄袼亓炼葘⒊�過[0,1]范圍，具體細(xì)節(jié)可見tonemapping和HDR。
• Cast lens flares 激活鏡頭眩光
  Enable or disable automatic lens flare generation.
  開啟或關(guān)閉自動(dòng)生成的透鏡光暈效果。
• Intensity 強(qiáng)度
  The global light intensity of the added light (affects bloom and lens flares).
  附加光（影響到該特效的光源）的全局光強(qiáng)。
• Threshhold 閾值
  Regions of the image brighter than this threshold receive blooming (and potentially lens flares).
  圖像中亮度高于該閾值的區(qū)域?qū)�產(chǎn)生泛光效果（以及潛在的透鏡光暈效果）。
• Blur iterations 模糊迭代
  The number of times gaussian blur is applied. More iterations improve smoothness but take extra time to process and hide small frequencies.
  高斯模糊應(yīng)用的次數(shù)。更多的迭代次數(shù)會(huì)增強(qiáng)畫面的柔順度，但同樣需要額外的時(shí)間來(lái)處理和隱藏小頻率的細(xì)節(jié)。
• Blur spread 模糊擴(kuò)散
  The max radius of the blur. Does not affect performance.
  模糊的最大半徑。不會(huì)影響性能。
• Use alpha mask 使用alpha通道
  The degree to which the alpha channel acts as a mask for the bloom effect.
  使用alpha通道作為遮罩，來(lái)應(yīng)用于泛光效果。
• Lens flare mode 鏡頭眩光模式
  The type of lens flare. The options are Ghosting, Anamorphic or a mix of the two.
  透鏡光暈的類型，主要有三種：重影、變形或者兩者結(jié)合。
• Lens flare mask 鏡頭眩光蒙版
  Mask used to prevent lens flare artifacts at screen edges.
  防止透鏡光暈在屏幕邊緣造成誤差的遮罩。
• Local intensity 局部強(qiáng)度
  Local intensity used only for lens flares.
  僅用于透鏡光暈效果的局部強(qiáng)度。
• Local threshold 局部閾值
  The accumulative light intensity threshold that defines which image parts are candidates for lens flares.
  累積的光源強(qiáng)度閾值，它限定了圖像中哪些部分對(duì)透鏡光暈產(chǎn)生影響。
• Stretch width 拉伸寬度
  The width for anamorphic lens flares.
  透鏡光暈的變形寬度。
• Blur iterations 模糊迭代
  The number of times blurring is applied to anamorphic lens flares. More iterations improve smoothness but take more processing time.
  應(yīng)用于變形透鏡光暈的模糊次數(shù)。更多的迭代次數(shù)會(huì)增強(qiáng)畫面的柔順度，但同樣會(huì)占用更多的處理時(shí)間。
• Tint Color 色調(diào)顏色
  Color modulation for the anamorphic flare type.
  光暈類型的顏色調(diào)制
• 1st-4th Color
  顏色類型
  Color modulation for all lens flares when Ghosting or Combined is chosen.
  當(dāng)重影或合并被選中時(shí)，所用的調(diào)制顏色。

Blend Modes: Add and Screen
混合模式：增加模式和屏幕模式

Blend modes determine the way that two images will be combined when overlaid. Each pixel from the base image is combined mathematically with the pixel in the corresponding position in the overlay image. Two blend modes are available for Unity image effects, Add and Screen.

混合模式?jīng)Q定了當(dāng)兩張圖片重疊式的合并方法�；鶊D像上的每個(gè)像素都根據(jù)數(shù)學(xué)公式與重疊圖像上的相應(yīng)像素進(jìn)行合并。目前Unity支持兩種混合模式：增加模式和屏幕模式。

Add Mode 增加模式

When the images are blended in Add mode, the values of the color channels (red, green and blue) are simply added together and clamped to the maximum value of 1. The overall effect is that areas of each image that aren't especially bright can easily blend to maximum brightness in the result. The final image tends to lose color and detail and so Add mode is useful when a dazzling "white out" effect is required.

當(dāng)圖片是通過增加模式進(jìn)行混合時(shí)，各個(gè)顏色通道（紅、綠、藍(lán)）的值只需要簡(jiǎn)單相加即可，同時(shí)將最大值限制為1。這樣，總體效果就是使每幅圖片上本來(lái)不是特別明亮的區(qū)域在混合結(jié)果中會(huì)被很容易地達(dá)到最大亮度值，以至于最終圖片可能會(huì)失去顏色和細(xì)節(jié)信息，所以，增加模式比較適合于生成"泛白"的效果。

Screen Mode 屏幕模式

Screen mode is so named because it simulates the effect of projecting the two source images onto a white screen simultaneously. Each color channel is combined separately but identically to the others. Firstly, the channel values of the two source pixels are inverted (ie, subtracted from 1). Then, the two inverted values are multiplied together and the result is inverted. The result is brighter than either of the two source pixels but it will be at maximum brightness only if one of the source colors was also. The overall effect is that more color variation and detail from the source images is preserved, leading to a gentler effect than Add mode.

之所以叫屏幕模式是因?yàn)樗�主要是通過將兩幅圖片同時(shí)投影到一個(gè)屏幕上來(lái)模擬該特效。每個(gè)顏色通道各自分別融合，首先，對(duì)兩個(gè)源圖片上的像素進(jìn)行求逆運(yùn)算（用1來(lái)減每個(gè)通道的值），然后將兩個(gè)值相乘，并將結(jié)果再次取逆，結(jié)果將比兩個(gè)源像素都要明亮，但只有當(dāng)其中一個(gè)像素為最大亮度時(shí)，結(jié)果才會(huì)達(dá)到最大亮度。同時(shí)，整體效果也會(huì)展現(xiàn)出更多的顏色變化以及保留更多的細(xì)節(jié)信息。

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.

這個(gè)特效需要顯卡擁有像素著色器（2.0）或者OpenGL ES 2.0。臺(tái)式機(jī)：2003年以后的NVIDIA顯卡（GeForce FX），2004年以后的AMD顯卡（Radeon 9500），2005年以后的Intel卡（GMA 900）；移動(dòng)設(shè)備：OpenGL ES 2.0；控制臺(tái)： Xbox 360、 PS3。

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

所有圖像特效如果無(wú)法在用戶顯卡上運(yùn)行時(shí)將會(huì)自動(dòng)被關(guān)閉。