Graphics Programming

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Graphics Programming. Lee Byung-Gook Dongseo Univ. http://kowon.dongseo.ac.kr/~lbg/. Affine combination. Linear combinations Affine(Barycentric) combinations Convex combinations Barycentric coordinates. Affine combination. Euclidean coordinate system. Coordinate-free system. - PowerPoint PPT Presentation

Transcript of Graphics Programming

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Graphics Programming

Lee Byung-GookDongseo Univ.

http://kowon.dongseo.ac.kr/~lbg/

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Affine combination

• Linear combinations

• Affine(Barycentric) combinations

• Convex combinations

• Barycentric coordinates

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Affine combination

Euclidean coordinate system

Coordinate-free system

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Polynomial interpolation

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Polynomial interpolation

• Lagrange polynomials

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Examples of cubic interpolation

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Bezier

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Representation Bezier

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Properties of Bezier

• Affine invariance• Convex hull property• Endpoint interpolation• Symmetry• Linear precision• Pseudo-local control• Variation Diminishing Property

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Bezier

• Paul de Faget de Casteljau, Citroen, 1959• Pierre Bezier, Renault, UNISUF system, 1962• A.R. Forrest, Cambridge, 1970

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Piecewise cubic hermite interpolation

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Cubic spline interpolation

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Cubic spline interpolation

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Spline interpolation based on the 1-norm

Cubic Spline Interpolation with Natural boundary condition

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Spline curves

• J. Ferguson , Boeing Co., 1963• C. de Boor, W. Gordon, General Motors, 1963

• to interpolate given data • piecewise polynomial curves with certain

differentiability constraints • not to design free form curves

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

B-spline

• C. de Boor, 1972• W. Gordon, Richard F. Riesenfeld, 1974

• Larry L. Schumaker• Tom Lyche• Nira Dyn

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Linear splines

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Quadratic splines

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Quadratic splines

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Representation splines

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

B-spline

• Recurrence Relation

• Bernstein polynomial

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

B-spline

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

B-spline

• Smoothness=Degree-Multiplicity

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

B-spline basis functions

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Refinement relation for B-spline

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Repeated integration for B-spline

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Truncated powers for B-spline

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Cross-sectional Volumes

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Cross-sectional Volumes for subcubes

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Box-spline as Cross-sectional Volumes

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Bivariate Box spline over triangular grid

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Spline space

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Univariate spline

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Cubic splines

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Condition number

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Condition number of B-spline basis

Tom Lyche and Karl Scherer, On the p-norm condition number of the multivariate triangular Bernstein basis, Journal of Computational and Applied Mathematics 119(2000) 259-273

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Stability

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Blossom

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

Blossom

Graphics Programming 2003, Lee Byung-Gook, Dongseo Univ., E-mail:lbg@dongseo.ac.kr

B-spline problems

• Degree Elevation• Degree Reduction• Knot Insertion• Knot Deletion

Gerald Farin, Curves and Surfaces for Computer Aided Geometric Design, 4 th ed, Academic Press (1996)Ronald N. Goldman, Tom Lyche, editors, Knot Insertion and Deletion Algorithms for B-Spline Curves and Surfaces, SIAM (1993)