Environment
In this section, we will cover how you can control the environmental light in Evergine.
Image Based Lighting (IBL)
Image Based Lighting (IBL) is a rendering technique that involves capturing an omnidirectional representation of real-world light information as an image, typically using a 360° camera. This image is then projected onto a dome or sphere, similar to environment mapping, and is used to simulate the lighting for objects in the scene. This allows highly detailed real-world lighting to be used to light a scene instead of trying to accurately model illumination using an existing rendering technique.
Image-based lighting often uses high-dynamic-range (HDR) imaging for greater realism.
IBL involves the creation of two lighting components:
- Irradiance map (Diffuse): For the diffuse illumination, we need what is called an Irradiance Map. This usually involves a cubemap (or Spherical Harmonics) that stores the amount of light coming from each direction.
- Radiance map (Specular): For specular illumination, we need a texture called Pre-filtered Mip-Mapped Radiance Environment Map (PMREM). This is another cubemap that pre-calculates the reflected environment. Additionally, it stores different reflections for various roughness values in its MipMap levels.
Credits LearnOpenGL
Evergine will use Image Based Lighting to create environmental illumination.