Phong reflection model - Wikipedia
Phong reflection is an empirical model of local illumination. It describes the way a surface reflects light as a combination of the diffuse reflection of rough surfaces with the specular reflection of shiny surfaces.
We present a new BRDF model that attempts to combine the advantages of the various empirical models currently in use. In particular, it has intuitive pa rameters, is anisotropic, energy-conserving, reciprocal, has an appropriate non Lambertian diffuse term, and is well-suited for use in a Monte Carlo framework.
Bidirectional reflectance distribution function - Wikipedia
The bidirectional reflectance distribution function (BRDF), symbol (,), is a function of four real variables that defines how light from a source is reflected off an opaque surface. It is employed in the optics of real-world light, in computer graphics algorithms, and in computer vision algorithms.
We first describe the Phong reflectance model and it’s associated brdf. We then offer practical advice regarding the implementation of importance sampling in the context of this reflectance model for a Monte Carlo path tracer.
The sum of the areas of the illuminated surface projected onto the plane normal to the direction of incidence is independent of the roughness of the surface, and equal to the projected area of the underlying mean plane.
reflectance distribution function (BRDF) [3]. At a given point on a surface the BRDF is a function of two directions, one toward the light and one toward the viewer. The characteristics of the BRDF will determine what “type” of material the viewer thinks the displayed object is composed of, so the choice of BRDF model and its parameters
We present a BRDF model that combines several advantages of the various empirical models cur-rently in use. In particular, it has intuitive parameters, is anisotropic, conserves energy, is reciprocal, has an appropriate non-Lambertian diffuse term, and is well-suited for use in Monte Carlo renderers.
Real-Time Shading with Phong BRDF Model - ResearchGate
2019年1月1日 · Our proposed BRDF shading interface allows users to generate new BRDFs by tweaking parameters of underlying BRDF model, which is Phong BRDF model. The implementation of our BRDF shading...
Assignment 3: Phong and Multiple Importance Sampling
In this assignment, you'll implement BRDF importance sampling for the Phong reflectance model, as well as a direct illumination integrator combining both BRDF and emitter importance sampling using multiple importance sampling (MIS).
Introduction to Shaders and BRDFs - Scratchapixel
A good BRDF is a BRDF that complies with these three rules. The problem with the Phong model is that it is essentially not energy-conserving. It would be too long to demonstrate this in this lesson, though if you read the lesson on BRDF, you will learn why.