Computer Graphics Lecture: Diffuse and Specular Reflection, BRDF - Prof. Pradeep Sen, Study notes of Computer Graphics

Download Computer Graphics Lecture: Diffuse and Specular Reflection, BRDF - Prof. Pradeep Sen and more Study notes Computer Graphics in PDF only on Docsity! 1 ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Advanced Graphics Lab Class 23 November 19, 2008 ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Announcements ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Last time Started talking about illumination Diffuse reflection ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Today More on illumination ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Diffuse reflection Aka Lambertian reflection Diffuse reflection is only dependent on the incident light direction and the surface normal, not the view direction A measure of the irradiance on the surface Image source: Wikipedia ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Diffuse reflection Goniometric diagrams radiant intensity (exiting power per unit solid angle) V N radiance (exiting power per unit solid angle per unit area) V N I = cos θ L is constant 2 ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Specular reflection “Mirror” reflection ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Glossy reflection Phong model Assumes that there is a “preferred” direction for the highlight View dependent! ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Glossy objects Image source: Eugene Lee, Cornell ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Glossy objects Image source: Eugene Lee, Cornell ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 Arbitrary materials How do you simulate materials that are neither specular nor diffuse? BRDFs ECE/CS 412 Introduction to Computer Graphics Pradeep Sen Class 23– November 19, 2008 BRDF The Bi-directional Reflectance Distribution Function First defined by Nicodemus in 1970 Ratio of outgoing radiance to incident irradiance Units: 1/sr