Animations :

- Created a nlerp function in quaternion (thanks to Lyzards)
- Used it for rotation interpolation when blending animations (fixed the testAnimBlendBug thanks again to Lyzard)
see related post http://jmonkeyengine.org/groups/graphics/forum/topic/ogrexml-model-and-animation-blending/?topic_page=2&num=15#post-127813

git-svn-id: https://jmonkeyengine.googlecode.com/svn/trunk@7499 75d07b2b-3a1a-0410-a2c5-0572b91ccdca

engine/src/core/com/jme3/animation/Bone.java

@@ -449,7 +449,7 @@ public final class Bone implements Savable {
 
         //rotation
         tmpQ.set(initialRot).multLocal(rotation);
-        localRot.slerp(tmpQ, weight);
+        localRot.nlerp(tmpQ, weight);
 
         //scale
         if (scale != null) {

engine/src/core/com/jme3/animation/BoneTrack.java

@@ -175,7 +175,7 @@ public final class BoneTrack implements Savable {
             if (scales != null) {
                 scales.get(endFrame, tempS2);
             }
-            tempQ.slerp(tempQ2, blend);
+            tempQ.nlerp(tempQ2, blend);
             tempV.interpolate(tempV2, blend);
             tempS.interpolate(tempS2, blend);
         }

engine/src/core/com/jme3/math/Quaternion.java

@@ -29,7 +29,6 @@
  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-
 package com.jme3.math;
 
 import com.jme3.export.InputCapsule;
@@ -60,7 +59,6 @@ import java.util.logging.Logger;
 public final class Quaternion implements Savable, Cloneable {
 
     private static final Logger logger = Logger.getLogger(Quaternion.class.getName());
-
     /**
      * Represents the identity quaternion rotation (0, 0, 0, 1).
      */
@@ -71,7 +69,6 @@ public final class Quaternion implements Savable, Cloneable {
     static {
         DIRECTION_Z.fromAxes(Vector3f.UNIT_X, Vector3f.UNIT_Y, Vector3f.UNIT_Z);
     }
-
     protected float x, y, z, w;
 
     /**
@@ -214,11 +211,12 @@ public final class Quaternion implements Savable, Cloneable {
      * @return true if this Quaternion is {0,0,0,1}
      */
     public boolean isIdentity() {
-        if (x == 0 && y == 0 && z == 0 && w == 1) 
+        if (x == 0 && y == 0 && z == 0 && w == 1) {
             return true;
-        else
+        } else {
             return false;
         }
+    }
 
     /**
      * <code>fromAngles</code> builds a quaternion from the Euler rotation
@@ -228,9 +226,10 @@ public final class Quaternion implements Savable, Cloneable {
      *            the Euler angles of rotation (in radians).
      */
     public Quaternion fromAngles(float[] angles) {
-        if (angles.length != 3)
+        if (angles.length != 3) {
             throw new IllegalArgumentException(
                     "Angles array must have three elements");
+        }
 
         return fromAngles(angles[0], angles[1], angles[2]);
     }
@@ -290,10 +289,11 @@ public final class Quaternion implements Savable, Cloneable {
      * @return the float[] in which the angles are stored.
      */
     public float[] toAngles(float[] angles) {
-		if (angles == null)
+        if (angles == null) {
             angles = new float[3];
-		else if (angles.length != 3)
+        } else if (angles.length != 3) {
             throw new IllegalArgumentException("Angles array must have three elements");
+        }
 
         float sqw = w * w;
         float sqx = x * x;
@@ -351,24 +351,21 @@ public final class Quaternion implements Savable, Cloneable {
             y = (m02 - m20) * s;
             z = (m10 - m01) * s;
         } else if ((m00 > m11) && (m00 > m22)) {
-            float s = FastMath
+            float s = FastMath.sqrt(1.0f + m00 - m11 - m22); // |s|>=1
-                    .sqrt(1.0f + m00 - m11 - m22); // |s|>=1
             x = s * 0.5f; // |x| >= .5
             s = 0.5f / s;
             y = (m10 + m01) * s;
             z = (m02 + m20) * s;
             w = (m21 - m12) * s;
         } else if (m11 > m22) {
-            float s = FastMath
+            float s = FastMath.sqrt(1.0f + m11 - m00 - m22); // |s|>=1
-                    .sqrt(1.0f + m11 - m00 - m22); // |s|>=1
             y = s * 0.5f; // |y| >= .5
             s = 0.5f / s;
             x = (m10 + m01) * s;
             z = (m21 + m12) * s;
             w = (m02 - m20) * s;
         } else {
-            float s = FastMath
+            float s = FastMath.sqrt(1.0f + m22 - m00 - m11); // |s|>=1
-                    .sqrt(1.0f + m22 - m00 - m11); // |s|>=1
             z = s * 0.5f; // |z| >= .5
             s = 0.5f / s;
             x = (m02 + m20) * s;
@@ -505,8 +502,9 @@ public final class Quaternion implements Savable, Cloneable {
      * @return the column specified by the index.
      */
     public Vector3f getRotationColumn(int i, Vector3f store) {
-        if (store == null)
+        if (store == null) {
             store = new Vector3f();
+        }
 
         float norm = norm();
         if (norm != 1.0f) {
@@ -733,6 +731,28 @@ public final class Quaternion implements Savable, Cloneable {
         this.w = (scale0 * this.w) + (scale1 * q2.w);
     }
 
+    /**
+     * Sets the values of this quaternion to the nlerp from itself to q2 by blend.
+     * @param q2
+     * @param blend
+     */
+    public void nlerp(Quaternion q2, float blend) {
+        float dot = dot(q2);
+        float blendI = 1.0f - blend;
+        if (dot < 0.0f) {
+            x = blendI * x - blend * q2.x;
+            y = blendI * y - blend * q2.y;
+            z = blendI * z - blend * q2.z;
+            w = blendI * w - blend * q2.w;
+        } else {
+            x = blendI * x + blend * q2.x;
+            y = blendI * y + blend * q2.y;
+            z = blendI * z + blend * q2.z;
+            w = blendI * w + blend * q2.w;
+        }
+        normalizeLocal();
+    }
+
     /**
      * <code>add</code> adds the values of this quaternion to those of the
      * parameter quaternion. The result is returned as a new quaternion.
@@ -818,8 +838,9 @@ public final class Quaternion implements Savable, Cloneable {
      * @return the new quaternion.
      */
     public Quaternion mult(Quaternion q, Quaternion res) {
-        if (res == null)
+        if (res == null) {
             res = new Quaternion();
+        }
         float qw = q.w, qx = q.x, qy = q.y, qz = q.z;
         res.x = x * qw + y * qz - z * qy + w * qx;
         res.y = -x * qz + y * qw + z * qx + w * qy;
@@ -859,9 +880,10 @@ public final class Quaternion implements Savable, Cloneable {
      *            coordinate system.
      */
     public Quaternion fromAxes(Vector3f[] axis) {
-        if (axis.length != 3)
+        if (axis.length != 3) {
             throw new IllegalArgumentException(
                     "Axis array must have three elements");
+        }
         return fromAxes(axis[0], axis[1], axis[2]);
     }
 
@@ -991,8 +1013,9 @@ public final class Quaternion implements Savable, Cloneable {
      * @return the result vector.
      */
     public Vector3f mult(Vector3f v, Vector3f store) {
-        if (store == null)
+        if (store == null) {
             store = new Vector3f();
+        }
         if (v.x == 0 && v.y == 0 && v.z == 0) {
             store.set(0, 0, 0);
         } else {
@@ -1168,10 +1191,18 @@ public final class Quaternion implements Savable, Cloneable {
         }
 
         Quaternion comp = (Quaternion) o;
-        if (Float.compare(x,comp.x) != 0) return false;
+        if (Float.compare(x, comp.x) != 0) {
-        if (Float.compare(y,comp.y) != 0) return false;
+            return false;
-        if (Float.compare(z,comp.z) != 0) return false;
+        }
-        if (Float.compare(w,comp.w) != 0) return false;
+        if (Float.compare(y, comp.y) != 0) {
+            return false;
+        }
+        if (Float.compare(z, comp.z) != 0) {
+            return false;
+        }
+        if (Float.compare(w, comp.w) != 0) {
+            return false;
+        }
         return true;
     }
 
@@ -1287,8 +1318,9 @@ public final class Quaternion implements Savable, Cloneable {
      *         direction of this Quaternion.
      */
     public Quaternion opposite(Quaternion store) {
-        if (store == null)
+        if (store == null) {
             store = new Quaternion();
+        }
 
         Vector3f axis = new Vector3f();
         float angle = toAngleAxis(axis);
@@ -1315,4 +1347,3 @@ public final class Quaternion implements Savable, Cloneable {
         }
     }
 }
-