GI探针

简介

注解

此功能仅在使用 GLES3 后端时可用。：ref：’doc_baked_lightmap’可用作使用GLES2渲染器时的替代方法。

就像 反射探针，并且如 空间材质 中所述，对象可以显示反射光或漫反射光。 GI探针类似于反射探针，但它们使用不同且更复杂的技术来产生间接光和反射。

GI探针的强度是实时，高质量，间接光。 虽然场景需要对将要使用的静态对象进行快速预烘焙，但可以添加，更改或删除灯光，并且这将实时更新。 在其中一个探针内移动的动态对象也将自动从场景接收间接光照。

Just like with ReflectionProbe, GIProbe can be blended (in a bit more limited way), so it is possible to provide full real-time lighting for a stage without having to resort to lightmaps.

The main downsides of GIProbe are:

  • 如果没有仔细设计水平，可能会发生少量漏光。 这必须是艺术家调整的。
  • 性能要求高于光照贴图，因此在低端集成GPU中可能无法正常运行(可能需要降低分辨率)。
  • Reflections are voxelized, so they don’t look as sharp as with ReflectionProbe. However, in exchange they are volumetric, so any room size or shape works for them. Mixing them with Screen Space Reflection also works well.
  • They consume considerably more video memory than Reflection Probes, so they must be used with care in the right subdivision sizes.

设置

Just like a ReflectionProbe, simply set up the GIProbe by wrapping it around the geometry that will be affected.

../../_images/giprobe_wrap.png

Afterwards, make sure to enable the geometry will be baked. This is important in order for GIProbe to recognize objects, otherwise they will be ignored:

../../_images/giprobe_bake_property.png

Once the geometry is set up, push the Bake button that appears on the 3D editor toolbar to begin the pre-baking process:

../../_images/giprobe_bake.png

添加灯光

Unless there are materials with emission, GIProbe does nothing by default. Lights need to be added to the scene to have an effect.

可以快速查看间接光的效果(建议您关闭所有环境/天空照明以调整它，但如下所示):

../../_images/giprobe_indirect.png

但在某些情况下，间接光线可能太弱。 灯具有间接乘数来调整:

../../_images/giprobe_light_indirect.png

And, as GIProbe lighting updates in real-time, this effect is immediate:

../../_images/giprobe_indirect_energy_result.png

反射

For very metallic materials with low roughness, it’s possible to appreciate voxel reflections. Keep in mind that these have far less detail than Reflection Probes or Screen Space Reflections, but fully reflect volumetrically.

../../_images/giprobe_voxel_reflections.png

GIProbes can be easily mixed with Reflection Probes and Screen Space Reflections, as a full 3-stage fallback-chain. This allows to have precise reflections where needed:

../../_images/giprobe_ref_blending.png

内部与外部

GI探头通常允许与来自天空的照明混合。 打开* Interior *设置时可以禁用此功能。

../../_images/giprobe_interior_setting.png

在下面的图像中，差异变得清晰，来自天空的光从内部传播到被忽略。

../../_images/giprobe_interior.png

由于复杂的建筑物可能将室内和室外混合在一起，因此将两个部件的GIProbes结合起来非常有效。

扭捏

GI探针支持一些调整参数:

../../_images/giprobe_tweaking.png

  • Subdiv Subdivision used for the probe. The default (128) is generally good for small- to medium-sized areas. Bigger subdivisions use more memory.
  • **范围**探头大小。 可以从Gizmo调整。
  • **动态范围**探头可以吸收的最大光能。 值越高，光线越亮，但颜色细节越少。
  • **能量**所有探头的倍增器。 可用于使间接光更亮(尽管最好从灯本身调整它)。
  • **传播**内部有多少光通过探头传播。
  • **偏差**用于避免在进行体素锥体追踪时自我遮挡的值，通常应高于1.0(1 ==体素大小)。
  • **普通偏差**对某些场景有用的替代偏见类型。 如果常规偏差不起作用，请尝试使用此方法。
  • Interior Allows mixing with lighting from the sky.
  • Compress Currently broken. Do not use.
  • Data Contains the light baked data after baking. If you are saving the data it should be saved as a .res file.

质量

GIProbes are quite demanding. It is possible to use lower quality voxel cone tracing in exchange for more performance.

../../_images/giprobe_quality.png