fastest but doesnt do 3d clipping polygons clipping

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Unformatted text preview: is only done once • Algorithm doesn’t consider trivial accepts/rejects • Best when many lines must be clipped Liang-Barsky: Optimized Cyrus-Beck Nicholl et al.: Fastest, but doesn’t do 3D Clipping Polygons Clipping polygons is more complex than clipping Clipping the individual lines the • Input: polygon • Output: original polygon, new polygon, or nothing When can we trivially accept/reject a polygon as When opposed to the line segments that make up the polygon? polygon? Why Is Clipping Hard? What happens to a triangle during clipping? What Possible outcomes: triangle triangle triangle quad triangle 5-gon How many sides can a clipped triangle have? How many sides? Seven… Why Is Clipping Hard? A really tough case: Why Is Clipping Hard? A really tough case: concave polygon multiple polygons Sutherland-Hodgeman Clipping Basic idea: • Consider each edge of the viewport individually • Clip the polygon against the viewport edge’s equation Sutherland-Hodgeman Clipping Basic idea: • Consider each edge of the viewport individually • Clip the polygon against the edge equation • After doing all edges, the polygon is fully clipped Sutherland-Hodgeman Clipping Basic idea: • Consider each edge of the viewport individually • Clip the polygon against the edge equation • After doing all edges, the polygon is fully clipped Sutherland-Hodgeman Clipping Basic idea: • Consider each edge of the viewport individually • Clip the polygon against the edge equatio...
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