Light Probes 光照探针

Only static objects are considered by Unity’s Baked or Precomputed Realtime GI systems. In order for dynamic objects such as interactive scene elements or characters to pick up some of the rich bounced light that our static geometry receives, we need to record this lighting information into a format which can be quickly read and used in our lighting equations during gameplay.

Unity的Baked或预先计算的实时GI系统只考虑静态对象。为了让动态对象（如交互式场景元素或角色）能够拾取静态几何图形接收到的丰富反射光，我们需要将此光照信息记录为一种格式，该格式可以在游戏过程中快速读取并用于我们的照明方程式中。

We do this by placing sample points in the world and then capturing light from all directions. The color information these points record is then encoded into a set of values (or ‘coefficients’) which can be quickly evaluated during gameplay. In Unity, we call these sample points, ‘Light Probes’.

我们通过在世界中放置采样点然后从各个方向捕捉光线来实现这一点。这些点记录的颜色信息随后被编码成一组可以在游戏过程中快速评估的值（或“系数”）。在Unity中，我们将这些采样点称为“光探针”。

Scene using Light Probes. Notice how they have been placed in greater density around areas of lighting change - such as shadows or color transition.

使用光照探针的场景。注意它在光照变化区域以更大密度放置 - 例如阴影或颜色过渡区域。

Light Probes allow moving objects to respond to the same complex bounced lighting which is affecting our lightmaps regardless of whether Baked GI or Precomputed Realtime GI is used. An object’s mesh renderer will look for the Light Probes around its position and blend between their values. This is done by looking for tetrahedrons made up by the position of Light Probes, and then deciding which tetrahedron the object’s pivot falls into. This allows us to place moving characters in scenes and have them appear properly integrated. Without Light Probes, dynamic objects would not receive any global illumination and would appear darker than surrounding, lightmapped geometry.

光照探针允许移动物体响应同样复杂的反射光，无论是使用烘焙GI还是预计算实时GI产生光照贴图。对象的MeshRenderer将在其位置周围寻找Light Probes并在它们的值之间进行混合。这是通过寻找由光探针位置组成的四面体，然后决定该物体的枢轴落入哪个四面体来完成的。这使我们能够在场景中放置移动角色使它们看起来得到恰当的效果。如果没有光探测器，动态物体将不会接收到任何GI（全局照明），并且会比周围的光照贴图几何体看起来更暗。

By default there are no Light Probes in a scene so these will need to be placed using a Light Probe Group (GameObjects>Light>Light Probe Group).

默认情况下场景中没有任何光照探针，需要通过光照探针组来放置(GameObjects>Light>Light Probe Group)。

If the ‘Auto’ box is checked at the bottom of your scene precompute settings (Lighting>Scene>Auto), Light Probes will update whenever changes are made to the scene lighting or static geometry. Otherwise they will be updated when the Build button is clicked.

如果在场景预计算设置(Lighting>Scene>Auto)底部选中“Auto”，则只要对场景照明或静态几何进行更改，光源探针就会更新。否则，它们将在点击生成按钮时更新。

Further Reading 进一步阅读

In this document we have given an overview of the considerations which need to be made prior to setting up a scene for lighting. We have also briefly looked at the tools available for creating various lighting effects. However, there is still a lot which we haven’t yet covered.

在本文中，我们概述了在设置照明场景之前需要考虑的事项。我们还简要介绍了可用于创建各种照明效果的工具。但是，还有很多我们尚未涉及的内容。

For a more in-depth look at optimizing your Scenes for Unity‘s Precomputed Realtime GI please see our tutorial here.

要更深入地了解如何优化Unity的预计算实时GI场景，请参阅我们的教程。

来源： https://unity3d.com/cn/learn/tutorials/topics/graphics/light-probes?playlist=17102

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原文地址：https://www.cnblogs.com/CloudLiu/p/9895499.html