From a343fef6eae9f014db20f36f67b028a59bb06ad0 Mon Sep 17 00:00:00 2001
From: "Kae..pl" <Kaelthas_Spellsinger@o2.pl>
Date: Thu, 24 Mar 2011 11:41:50 +0000
Subject: [PATCH] Fix to bezier curve length computation.

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@7100 75d07b2b-3a1a-0410-a2c5-0572b91ccdca
---
 engine/src/core/com/jme3/math/FastMath.java | 34 ++++++---------------
 engine/src/core/com/jme3/math/Spline.java   |  2 +-
 2 files changed, 11 insertions(+), 25 deletions(-)

diff --git a/engine/src/core/com/jme3/math/FastMath.java b/engine/src/core/com/jme3/math/FastMath.java
index 14f343a75..ce3e46f1e 100644
--- a/engine/src/core/com/jme3/math/FastMath.java
+++ b/engine/src/core/com/jme3/math/FastMath.java
@@ -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 p1 control point 1
      * @param p2 control point 2
      * @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
      */
-    public static float getBezierP1toP2Length(Vector3f p0, Vector3f p1, Vector3f p2, Vector3f p3, float startRange, float endRange) {
-        float epsilon = 0.001f;
-        float middleValue = (startRange + endRange) * 0.5f;
-        Vector3f start = p1.clone();
-        if (startRange != 0) {
-        	FastMath.interpolateBezier(startRange, p0, p1, p2, p3, start);
-        }
-        Vector3f end = p2.clone();
-        if (endRange != 1) {
-        	FastMath.interpolateBezier(endRange, p0, p1, p2, p3, end);
+    public static float getBezierP1toP2Length(Vector3f p0, Vector3f p1, Vector3f p2, Vector3f p3) {
+        float delta = 0.02f, t = 0.0f, result = 0.0f;
+        Vector3f v1 = p0.clone(), v2 = new Vector3f();
+        while(t<=1.0f) {
+        	FastMath.interpolateBezier(t, p0, p1, p2, p3, v2);
+        	result += v1.subtractLocal(v2).length();
+        	v1.set(v2);
+        	t += delta;
         }
-        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;
+        return result;
     }
 
     /**
diff --git a/engine/src/core/com/jme3/math/Spline.java b/engine/src/core/com/jme3/math/Spline.java
index 4779a1d19..942ad39fa 100644
--- a/engine/src/core/com/jme3/math/Spline.java
+++ b/engine/src/core/com/jme3/math/Spline.java
@@ -231,7 +231,7 @@ public class Spline implements Savable {
         if (controlPoints.size() > 1) {
             for (int i = 0; i < controlPoints.size() - 1; i+=3) {
                 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);
                 totalLength += l;
             }