diff options
Diffstat (limited to 'src/jogl/classes/com/jogamp/graph/math')
| -rwxr-xr-x | src/jogl/classes/com/jogamp/graph/math/VectorUtil.java | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/src/jogl/classes/com/jogamp/graph/math/VectorUtil.java b/src/jogl/classes/com/jogamp/graph/math/VectorUtil.java index b91969745..2b4a7fd9d 100755 --- a/src/jogl/classes/com/jogamp/graph/math/VectorUtil.java +++ b/src/jogl/classes/com/jogamp/graph/math/VectorUtil.java @@ -287,6 +287,36 @@ public class VectorUtil { public static float triArea(Vertex a, Vertex b, Vertex c){
return (b.getX() - a.getX()) * (c.getY() - a.getY()) - (b.getY() - a.getY())*(c.getX() - a.getX());
}
+
+ /** Check if a vertex is in triangle using
+ * barycentric coordinates computation.
+ * @param a first triangle vertex
+ * @param b second triangle vertex
+ * @param c third triangle vertex
+ * @param p the vertex in question
+ * @return true if p is in triangle (a, b, c), false otherwise.
+ */
+ public static boolean vertexInTriangle(float[] a, float[] b, float[] c, float[] p){
+ // Compute vectors
+ float[] ac = computeVector(a, c); //v0
+ float[] ab = computeVector(a, b); //v1
+ float[] ap = computeVector(a, p); //v2
+
+ // Compute dot products
+ float dot00 = dot(ac, ac);
+ float dot01 = dot(ac, ab);
+ float dot02 = dot(ac, ap);
+ float dot11 = dot(ab, ab);
+ float dot12 = dot(ab, ap);
+
+ // Compute barycentric coordinates
+ float invDenom = 1 / (dot00 * dot11 - dot01 * dot01);
+ float u = (dot11 * dot02 - dot01 * dot12) * invDenom;
+ float v = (dot00 * dot12 - dot01 * dot02) * invDenom;
+
+ // Check if point is in triangle
+ return (u > 0) && (v > 0) && (u + v < 1);
+ }
/** Check if points are in ccw order
* @param a first vertex
|