Computer Graphics · Cluster
Shading Models
BRDFs, global illumination, and materials.
- 01 Radiance, Irradiance, and the Units a BRDF Is Written In How solid angle separates radiance from irradiance, why a BRDF is a ratio of two different radiometric quantities, and what the resulting numbers look like for ordinary surfaces.
- 02 Fresnel Reflectance for Dielectrics and Conductors Why reflectance rises to one at grazing angles, how the index of refraction and extinction coefficient determine the normal-incidence value, and how Schlick approximation departs from the exact curves.
- 03 The Rendering Equation as a Linear Operator How the rendering equation is written as a fixed-point problem, what the Neumann series expansion means physically, and why convergence depends on the spectral radius of the transport operator.
- 04 Microfacet Distributions and the Shadowing Term That Balances Them Why a half-vector distribution alone gives the wrong energy, how Smith masking accounts for one microsurface occluding another, and what correlated visibility changes.
- 05 Compensating for Multiple Scattering in Rough Specular Models Why a single-scattering microfacet lobe loses energy as roughness rises, and how a tabulated directional albedo plus a complement lobe restores the budget without breaking reciprocity.
- 06 Sampling BRDF Lobes and Choosing Between Them How a probability density over outgoing directions turns a reflectance integral into a weighted average, why GGX sampling has a closed form, and how lobe selection probabilities affect variance.
- 07 Spherical Harmonics for Irradiance Probes How low-order spherical harmonic coefficients compress a lighting environment, what convolution by the clamped cosine does to those coefficients, and why ringing appears at sharp boundaries.
- 08 Subsurface Scattering and the Diffusion Approximation How multiple scattering inside a translucent medium turns a BRDF into a spatial integral, what the reduced scattering coefficient measures, and where the dipole solution stops applying.
- 09 The Split-Sum Approximation for Specular Image-Based Lighting How a prefiltered environment map plus a two-channel BRDF lookup table replaces a per-shading-point integral, what assumptions the factorization hides, and where the grazing-angle error appears.
- 10 Layered Materials and the Fresnel Coupling Between Coats and Substrates How a clear coat sits on a base material, why the transmitted share at each interface is not simply one minus the reflected share, and how internal reflection traps light inside a layer.