What does physically based rendering (PBR) use to simulate realistic lighting?

Physically Based Rendering (PBR) is a rendering technique that aims to create a more realistic depiction of materials by simulating the real-world behavior of light. The core principle behind PBR is to replicate how light interacts with surfaces in an accurate and physically plausible manner. This involves using shaders that calculate lighting based on the physical properties of the materials being rendered, such as their roughness, metallicity, and reflectivity.

Shaders play a crucial role in PBR as they are responsible for computing how light bounces off surfaces and interacts with materials in a way that mimics real-life physics. This results in materials that respond to light sources dynamically, yielding more believable results under various lighting conditions.

While textures that mimic real-world scenarios can enhance the visual quality, they do not directly contribute to the foundational principles of PBR. Similarly, having lower polygon counts can improve performance but does not inherently affect the realism of lighting. Additionally, utilizing older lighting models from previous versions of Unity would not take full advantage of the advancements made in PBR techniques, which are specifically designed to enhance realism in modern rendering workflows.