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Fix to bezier curve length computation.

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git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@7100 75d07b2b-3a1a-0410-a2c5-0572b91ccdca
This commit is contained in:
Kae..pl 2011-03-24 11:41:50 +00:00
parent b17d5d3706
commit a343fef6ea
2 changed files with 11 additions and 25 deletions
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34
engine/src/core/com/jme3/math/FastMath.java
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@ -335,37 +335,23 @@ final public class FastMath {
} }
/** /**
* Compute the length on a Bezier spline between control point 1 and 2. * Compute the lenght on a bezier spline between control point 1 and 2
* @param p0 control point 0 * @param p0 control point 0
* @param p1 control point 1 * @param p1 control point 1
* @param p2 control point 2 * @param p2 control point 2
* @param p3 control point 3 * @param p3 control point 3
* @param startRange the starting range on the segment (use 0)
* @param endRange the end range on the segment (use 1)
* @return the length of the segment * @return the length of the segment
*/ */
public static float getBezierP1toP2Length(Vector3f p0, Vector3f p1, Vector3f p2, Vector3f p3, float startRange, float endRange) { public static float getBezierP1toP2Length(Vector3f p0, Vector3f p1, Vector3f p2, Vector3f p3) {
float epsilon = 0.001f; float delta = 0.02f, t = 0.0f, result = 0.0f;
float middleValue = (startRange + endRange) * 0.5f; Vector3f v1 = p0.clone(), v2 = new Vector3f();
Vector3f start = p1.clone(); while(t<=1.0f) {
if (startRange != 0) { FastMath.interpolateBezier(t, p0, p1, p2, p3, v2);
FastMath.interpolateBezier(startRange, p0, p1, p2, p3, start); result += v1.subtractLocal(v2).length();
v1.set(v2);
t += delta;
} }
Vector3f end = p2.clone(); return result;
if (endRange != 1) {
FastMath.interpolateBezier(endRange, p0, p1, p2, p3, end);
}
Vector3f middle = FastMath.interpolateBezier(middleValue, p0, p1, p2, p3);
float l = end.subtract(start).length();
float l1 = middle.subtract(start).length();
float l2 = end.subtract(middle).length();
float len = l1 + l2;
if (l + epsilon < len) {
l1 = FastMath.getBezierP1toP2Length(p0, p1, p2, p3, startRange, middleValue);
l2 = FastMath.getBezierP1toP2Length(p0, p1, p2, p3, middleValue, endRange);
}
l = l1 + l2;
return l;
} }
/** /**

2
engine/src/core/com/jme3/math/Spline.java
View File

@ -231,7 +231,7 @@ public class Spline implements Savable {
if (controlPoints.size() > 1) { if (controlPoints.size() > 1) {
for (int i = 0; i < controlPoints.size() - 1; i+=3) { for (int i = 0; i < controlPoints.size() - 1; i+=3) {
l = FastMath.getBezierP1toP2Length(controlPoints.get(i), l = FastMath.getBezierP1toP2Length(controlPoints.get(i),
controlPoints.get(i + 1), controlPoints.get(i + 2), controlPoints.get(i + 3), 0, 1); controlPoints.get(i + 1), controlPoints.get(i + 2), controlPoints.get(i + 3));
segmentsLength.add(l); segmentsLength.add(l);
totalLength += l; totalLength += l;
} }