In this lesson, you will learn how to transition between procedural and cubemap skyboxes to create a cohesive, reactive lighting environment for your game world.
While a static skybox is fine for simple scenes, a dynamic atmosphere requires that your ambient lighting shifts in tandem with the visuals. In Unity, the skybox isn't just a background image; it serves as the primary source of Ambient Light for your Global Illumination (GI) system. When you change your skybox material, you must also ensure the lighting environment updates to match the new color palette.
Blending Skybox Settings
To create a dynamic atmosphere, you typically manage two types of skyboxes: the Procedural Skybox, which uses parameters like Sun Size and Atmosphere Thickness, and the Cubemap Skybox, which uses 6-sided textures.
You can influence the scene’s ambient lighting via the RenderSettings class. If you are building a system that transitions from day to night, you can interpolate between skybox properties. For example, you can manipulate the Exposure or Tint of a material to simulate a sunset:
// Accessing the current skybox material
RenderSettings.skybox.SetFloat("_Exposure", currentExposure);
RenderSettings.skybox.SetColor("_Tint", sunsetColor);
// Important: Notify the engine to rebake ambient lighting
DynamicGI.UpdateEnvironment();
Establishing the Lighting Foundation
When you swap or modify skyboxes, the scene's ambient color often lags behind, leading to a jarring disconnect where the objects remain lit as if it were midday while the sky turns dark. By calling DynamicGI.UpdateEnvironment() after modifying your skybox parameters, you force the engine to recalculate the light probes and ambient terms.
For advanced control, keep your Procedural Skybox as the base for standard weather conditions, but use a Cubemap layer for unique events like an aurora or a cosmic nebula. By layering these (or using a material-based blending approach in the Shader Graph), you ensure that your world’s ambient foundation remains physically plausible even as the visual aesthetic shifts.
Key Takeaway: A dynamic atmosphere is only as consistent as its lighting; always link your skybox parameter changes to DynamicGI.UpdateEnvironment() to ensure your ambient lighting foundation reflects the current sky state.