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Explore the basics of illumination, Phong reflectance, surface shading, Gouraud interpolation, and Phong interpolation in computer graphics. Learn about ambient, diffuse, specular, and reflected light, and how lighting models simplify the representation of light.
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Introduction to Computer Graphics:Lighting & IlluminationRama C. Hoetzlein, 2011Cornell UniversityLecture Notes
Topics Covered1. Illumination Basics2. Phong Reflectance3. Surface Shading4. Gouraud Interpolation5. Phong Interpolation
Ambient light – Global illumination coming from other surfaces direct light only ambient (indirect) light
Specular light – Light reflected directly from a light source along the viewing angle
Reflected light – Light coming from another object due to a reflective surface
A lighting model is a mathematical description oflight which simplifies some aspect of illumination.
Some Observations:1. The ambient term is a constant – This is not physically accurate, as it does not account for bounce lighting.2. The diffuse term depends only on the angle between the surface and the light source. It does not depend on the viewer.3. The specular term depends on the angle between the viewer and the reflection angle of the light on the surface.All terms are a simplification because they consider only point lights,and only particular kinds of surfaces.
Flat Gouraud Phong