Week 9 - Parametric Representations Flashcards
What are Bezier curves?
Polynomial curves defined by control vertices, usually cubic, and the curve lies within the convex hull of the control vertices
How can you join Bezier curves, and how is smoothness maintained?
Join curves by co-locating end control points
Smoothness maintained by keeping end pairs of control points co-linear
What is continuity in terms of Bezier curves?
Smoothness at the join
What is geometric continuity?
Relax equality of derivatives to proportionality of derivatives on either side of join
What does approximating cubic splines do?
They pass only through end points
What does interpolating cubic splines do?
They pass through every control point
What are cubic splines?
Cubic polynomials with continuous first and second derivatives at knot points
What are two ways to process subdivision curves?
C2 continuity and Chaikin
What is Doo-Sabin subdivision?
Generalisation to two dimensions of Chaikin curve subdivision
What is an extraordinary polygon?
A polygon that is not a quadrilateral
Why is tessellation used?
To offload refinement of triangles into more vertices from CPU to GPU
What does tessellation in OpenGL depend on?
Tessellation control shaders and tessellation evaluation shaders
What does TCS stand for?
Tessellation Control Shader
What does the TCS do?
Determines how much tessellation to do
What does TES stand for?
Tessellation Evaluation Shader
