The microfacet theory is a fundamental component of physically based rendering. Unfortunately, it is often perceived as being rather complicated. There are several reasons for this. The first one is that most papers only focus on a single component (such as the distribution of normals or the masking function), while glossing over the rest. The second problem is the lack of the geometrical interpretations of mathematical expressions, which inhibits understanding at the intuitive level. In the ...| zero-radiance.github.io
I have previously covered the basics of the volume scattering process. It models the macroscopic interaction of light and matter, with the latter represented as a distribution of small particles. Fundamentally, the volume scattering process arises from the microscopic interaction of light with individual atoms, and is typically described using Maxwell’s electromagnetic theory. It is the domain of optics, and, in my experience, the connection with the radiative transfer equation is neither a...| zero-radiance.github.io
High Z-buffer precision is something that we take for granted these days. Since the introduction of reversed floating-point Z-buffering (and, assuming you use the standard tricks like camera-relative transforms), most depth precision issues are a thing of the past. You ask the rasterizer to throw triangles at the screen and, almost magically, and they appear at the right place and in the right order.| zero-radiance.github.io
Rendering of participating media is an important aspect of every modern renderer. When I say participating media, I am not just talking about fog, fire, and smoke. All matter is composed of atoms, which can be sparsely (e.g. in a gas) or densely (e.g. in a solid) distributed in space. Whether we consider the particle or the wave nature of light, it penetrates all matter (even metals) to a certain degree and interacts with its atoms along the way. The nature and the degree of “participation...| zero-radiance.github.io
A couple of years ago, I worked on an implementation of Burley’s Normalized Diffusion (a.k.a. Disney SSS). The original paper claims that the CDF is not analytically invertible. I have great respect for both authors, Brent Burley and Per Christensen, so I haven’t questioned their claim for a second. Turns out, “Question Everything” is probably a better mindset.| zero-radiance.github.io
Realistic rendering at high frame rates remains at the core of real-time computer graphics. High performance and high fidelity are often at odds, requiring clever tricks and approximations to reach the desired quality bar.| zero-radiance.github.io
Pre-filtered cubemaps remain an important source of indirect illumination for those of us who still haven’t purchased a Turing graphics card.| zero-radiance.github.io
Most graphics programmers are familiar with the concept of alpha. It has two interpretations - geometrical and optical. The former corresponds to coverage, while the latter refers to opacity.| zero-radiance.github.io