71 lines
2.7 KiB
C
71 lines
2.7 KiB
C
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// Copyright 2013 Howling Moon Software. All rights reserved.
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// See http://chipmunk2d.net/legal.php for more information.
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// Polylines are just arrays of vertexes.
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// They are looped if the first vertex is equal to the last.
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// cpPolyline structs are intended to be passed by value and destroyed when you are done with them.
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typedef struct cpPolyline {
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int count, capacity;
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cpVect verts[];
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} cpPolyline;
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/// Destroy and free a polyline instance.
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CP_EXPORT void cpPolylineFree(cpPolyline *line);
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/// Returns true if the first vertex is equal to the last.
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CP_EXPORT cpBool cpPolylineIsClosed(cpPolyline *line);
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/**
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Returns a copy of a polyline simplified by using the Douglas-Peucker algorithm.
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This works very well on smooth or gently curved shapes, but not well on straight edged or angular shapes.
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*/
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CP_EXPORT cpPolyline *cpPolylineSimplifyCurves(cpPolyline *line, cpFloat tol);
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/**
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Returns a copy of a polyline simplified by discarding "flat" vertexes.
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This works well on straight edged or angular shapes, not as well on smooth shapes.
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*/
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CP_EXPORT cpPolyline *cpPolylineSimplifyVertexes(cpPolyline *line, cpFloat tol);
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/// Get the convex hull of a polyline as a looped polyline.
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CP_EXPORT cpPolyline *cpPolylineToConvexHull(cpPolyline *line, cpFloat tol);
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/// Polyline sets are collections of polylines, generally built by cpMarchSoft() or cpMarchHard().
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typedef struct cpPolylineSet {
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int count, capacity;
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cpPolyline **lines;
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} cpPolylineSet;
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/// Allocate a new polyline set.
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CP_EXPORT cpPolylineSet *cpPolylineSetAlloc(void);
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/// Initialize a new polyline set.
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CP_EXPORT cpPolylineSet *cpPolylineSetInit(cpPolylineSet *set);
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/// Allocate and initialize a polyline set.
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CP_EXPORT cpPolylineSet *cpPolylineSetNew(void);
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/// Destroy a polyline set.
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CP_EXPORT void cpPolylineSetDestroy(cpPolylineSet *set, cpBool freePolylines);
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/// Destroy and free a polyline set.
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CP_EXPORT void cpPolylineSetFree(cpPolylineSet *set, cpBool freePolylines);
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/**
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Add a line segment to a polyline set.
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A segment will either start a new polyline, join two others, or add to or loop an existing polyline.
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This is mostly intended to be used as a callback directly from cpMarchSoft() or cpMarchHard().
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*/
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CP_EXPORT void cpPolylineSetCollectSegment(cpVect v0, cpVect v1, cpPolylineSet *lines);
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/**
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Get an approximate convex decomposition from a polyline.
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Returns a cpPolylineSet of convex hulls that match the original shape to within 'tol'.
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NOTE: If the input is a self intersecting polygon, the output might end up overly simplified.
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*/
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CP_EXPORT cpPolylineSet *cpPolylineConvexDecomposition(cpPolyline *line, cpFloat tol);
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#define cpPolylineConvexDecomposition_BETA cpPolylineConvexDecomposition
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