Environment
In this section we will cover how you can control in Evergine the environmental light.
Image Based Lighting (IBL)
Image Based lighting (IBL) is a rendering technique which 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 analogously to environment mapping, and this is used to simulate the lighting for the 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): Now, when we get to specular illumination, we need a texture called Pre-filtered Mip-Mapped Radiance Environment Map (PMREM). This is another cubemap that pre-calculate the reflected environment. An as an addition, it store in its MipMap levels different reflections for roughness values.
Credits LearnOpenGL
Evergine will use Image Based Lighting to create environmental illumination.