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GeometryUtils: add docs

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Hannes Janetzek 2013-09-28 20:45:01 +02:00
parent ed7ff6e7a1
commit 68cd2f345a
1 changed files with 22 additions and 2 deletions
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vtm/src/org/oscim/utils/GeometryUtils.java
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@ -19,10 +19,30 @@ public final class GeometryUtils {
private GeometryUtils() { private GeometryUtils() {
} }
// from www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
/** /**
* test if point x/y is in polygon defined by vertices[offset ... * Test if point x/y is in polygon defined by vertices[offset ...
* offset+length] * offset+length]
* <p>
* -- from www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
* <p>
* If there is only one connected component, then it is optional to repeat
* the first vertex at the end. It's also optional to surround the component
* with zero vertices.
* <p>
* The polygon may contain multiple separate components, and/or holes,
* provided that you separate the components and holes with a (0,0) vertex,
* as follows.
* <li>First, include a (0,0) vertex.
* <li>Then include the first component' vertices, repeating its first
* vertex after the last vertex.
* <li>Include another (0,0) vertex.
* <li>Include another component or hole, repeating its first vertex after
* the last vertex.
* <li>Repeat the above two steps for each component and hole.
* <li>Include a final (0,0) vertex.
* <p>
* Each component or hole's vertices may be listed either clockwise or
* counter-clockwise.
*/ */
public static boolean pointInPoly(float x, float y, float[] vertices, public static boolean pointInPoly(float x, float y, float[] vertices,
int length, int offset) { int length, int offset) {