PPT-Projection and Clipping

網媒所 林宏祥 20121002 Overview Orthogonal Projection Z X x camera x viewport Perspective P rojection Z X x camera x viewport d z View Volumeorthogonal projection. In rendering complex 3D images it has to be done several thousand times Ef64257cient algorithms are therefore very important We present such an ef64257cient algorithm for clipping arbitrary 2D polygons The algorithm can handle arbitrary closed polyg Computer Graphics . :. Viewing In 2D. Contents. Windowing Concepts. Clipping. Introduction . Brute Force. Cohen-Sutherland Clipping Algorithm. Area Clipping. Sutherland-Hodgman Area Clipping Algorithm. Viewing In 2D. Contents. *. Windowing Concepts. *. Clipping. Point Clipping . Line Clipping. . -Cohen-Sutherland Clipping Algorithm. *. Area Clipping. Sutherland-. Hodgman. Area Clipping Algorithm. Images were taken from the book: “Interactive Computer Graphics” by Angel and Shreiner. Normal Vectors. How to compute the normal per . planar. face?.  . Normal Vectors. However, vertex normals are not well defined. 1 Clipping Transform intoframe bufferin frame buffer Clipping in the 2D pipeline Clipping references Clipping references Hearn and Baker Hearn and Baker C C - - S (lines): p 317 S (lines): p 317 L Projection • Projection Arm: The projection arm will rotate to project time on the wall or ceiling. • Focus Wheel: Adjust projection focus by turning the wheel on the back of the CSCI 440. textbook section 8.3-8.7. Starter Question. How do we clip these lines?. X=-5. Y. =-5. Y=5. X=5. [0,0]. [3,3]. [7,-3]. [0,-3]. formula from . wikipedia. Goals of Clipping. Reject, Accept, or Accept a portion. 1. Clipping. Clipping is a process of dividing an object into visible and invisible portions and displaying the visible portion and discarding the invisible portion.. Types of Clipping:. Generally we have Clipping algorithm for the following primitive type:. Eric Lengyel. Outline. Projection Matrix Internals. Infinite Projection Matrix. Depth Modification. Oblique Near Clipping Plane. Slides available at http://www.terathon.com/. From Camera to Screen. Camera. Ouhyoung. 歐陽明. . Professor . Dept. of CSIE and GINM. NTU. 3D Viewing Process. Transform. into viewport. in 2D device. coordinates. for display. Project onto. projection. plane. Clip against. view. 1. of 16 . Clipping - 10/12/17. Clipping endpoints. If . x. min. ≤ x ≤ . x. max. . . and. . y. min. . ≤ . y . ≤ . y. max. . , . the point is inside the clip rectangle.. Endpoint analysis for lines:. CMSC 435/634. Graphics Pipeline. Object-order approach to . rendering. Vertex Processing. Clipping. Rasterization. Fragment Processing. Visibility & Blending. Transformations. Vertex components of shading. Types of Clipping:. Generally we have Clipping algorithm for the following primitive type:. Point Clipping. Line Clipping . Area Clipping (Polygon). Curve Clipping. Text Clipping. . 2. Point Clipping. Clip Coordinates vs. NDC. Clip space (left-handed). Clip. coordinate. Normalized device. coordinate . (NDC). Culling: discarding . invisible. polygons. Back-face culling. Discarding all faces (i.e., polygons) that face “backward” (i.e., whose .