Sondas de reflexión

Introducción

Como se indica en el Material Spatial, los objetos pueden mostrar luz reflejada o difusa. Las sondas de reflexión se utilizan como fuente de luz reflejada y ambiental para los objetos dentro de su área de influencia.

Una sonda de este tipo captura los alrededores (como una especie de imagen de 360 grados), y almacena versiones de la misma con niveles crecientes de blur. Se utiliza para simular la rugosidad de los materiales, así como la iluminación ambiental.

Si bien estas sondas son una forma eficiente de almacenar los reflejos, tienen algunas deficiencias:

  • Son eficientes en la representación, pero caros en el cálculo. Esto lleva a un comportamiento por defecto donde sólo capturan en la carga de la escena.
  • Funcionan mejor para habitaciones o lugares rectangulares, de lo contrario los reflejos que se muestran no son tan fieles (especialmente cuando la rugosidad es 0).

Configurando

Crea un nodo ReflectionProbe y haz que envuelva el área donde quieres tener reflejos:

../../_images/refprobe_setup.png

Esto debería dar como resultado reflexiones locales inmediatas. Si estás usando una textura del cielo, los reflejos se mezclan por defecto con ella.

Por defecto, en interiores, los reflejos pueden parecer poco consistentes. En este escenario, asegúrate de marcar la propiedad "Box Correct" .

../../_images/refprobe_box_property.png

This setting changes the reflection from an infinite skybox to reflecting a box the size of the probe:

../../_images/refprobe_boxcorrect.png

Adjusting the box walls may help improve the reflection a bit, but it will always look best in box shaped rooms.

The probe captures the surrounding from the center of the gizmo. If, for some reason, the room shape or contents occlude the center, it can be displaced to an empty place by moving the handles in the center:

../../_images/refprobe_center_gizmo.png

By default, shadow mapping is disabled when rendering probes (only in the rendered image inside the probe, not the actual scene). This is a simple way to save on performance and memory. If you want shadows in the probe, they can be toggled on/off with the Enable Shadow setting:

../../_images/refprobe_shadows.png

Finally, keep in mind that you may not want the Reflection Probe to render some objects. A typical scenario is an enemy inside the room which will move around. To keep objects from being rendered in the reflections, use the Cull Mask setting:

../../_images/refprobe_cullmask.png

Interior vs exterior

If you are using reflection probes in an interior setting, it is recommended that the Interior property be enabled. This stops the probe from rendering the sky and also allows custom ambient lighting settings.

../../_images/refprobe_ambient.png

When probes are set to Interior, custom constant ambient lighting can be specified per probe. Just choose a color and an energy.

Optionally, you can blend this ambient light with the probe diffuse capture by tweaking the Ambient Contribution property (0.0 means pure ambient color, while 1.0 means pure diffuse capture).

Blending

Multiple reflection probes can be used, and Godot will blend them where they overlap using a smart algorithm:

../../_images/refprobe_blending.png

As you can see, this blending is never perfect (after all, these are box reflections, not real reflections), but these artifacts are only visible when using perfectly mirrored reflections. Normally, scenes have normal mapping and varying levels of roughness, which can hide this.

Alternatively, Reflection Probes work well blended together with Screen Space Reflections to solve these problems. Combining them makes local reflections appear more faithful, while probes are only used as a fallback when no screen-space information is found:

../../_images/refprobe_ssr.png

Finally, blending interior and exterior probes is the recommended approach when making levels that combine both interiors and exteriors. Near the door, a probe can be marked as exterior (so it will get sky reflections) while on the inside, it can be interior.

Reflection atlas

In the current renderer implementation, all probes are the same size and are fit into a Reflection Atlas. The size and amount of probes can be customized in Project Settings -> Quality -> Reflections

The default setting of Atlas Subdiv: 8 will allow up to 16 reflection probes in a scene. This value needs to be increased if you need more reflection probes.

../../_images/refprobe_atlas.png