integrated recent commits by Dahlia regarding llLookAt handling

OpenSim/Region/Framework/Scenes/SceneObjectPart.cs

@@ -952,7 +952,13 @@ public Vector3 AngularVelocity
                 }
                 return m_angularVelocity;
             }
-            set { m_angularVelocity = value; }
+            set
+            {
+                m_angularVelocity = value;
+                PhysicsActor actor = PhysActor;
+                if ((actor != null) && actor.IsPhysical)
+                    actor.RotationalVelocity = m_angularVelocity;
+            }
         }
 
         /// <summary></summary>
@@ -4853,18 +4859,42 @@ public void UpdateLookAt()
             {
                 if (APIDTarget != Quaternion.Identity)
                 {
-                    if (m_APIDIterations <= 1)
+                    PhysicsActor pa = ParentGroup.RootPart.PhysActor;
+                    if (pa == null || !pa.IsPhysical || APIDStrength < 0.04)
                     {
-                        UpdateRotation(APIDTarget);
-                        APIDTarget = Quaternion.Identity;
+                        StopLookAt();
                         return;
                     }
 
-                    Quaternion rot = Quaternion.Slerp(RotationOffset,APIDTarget,1.0f/(float)m_APIDIterations);
-                    rot.Normalize();
-                    UpdateRotation(rot);
+                    Quaternion currRot = WorldRotation;
+                    currRot.Normalize();
+
+                    // difference between current orientation and desired orientation
+                    Quaternion dR = new Quaternion(currRot.X, currRot.Y, currRot.Z, -currRot.W) * APIDTarget;
+
+                    // find axis of rotation to rotate to desired orientation
+                    Vector3 axis = Vector3.UnitX;
+                    float s = (float)Math.Sqrt(1.0f - dR.W * dR.W);
+                    if (s >= 0.001)
+                    {
+                        float invS = 1.0f / s;
+                        if (dR.W < 0) invS = -invS;
+                        axis = new Vector3(dR.X * invS, dR.Y * invS, dR.Z * invS) * currRot;
+                        axis.Normalize();
+                    }
+
+                    // angle between current and desired orientation
+                    float angle = 2.0f * (float)Math.Acos(dR.W);
+                    if (angle > Math.PI)
+                        angle = 2.0f * (float)Math.PI - angle;
+
+                    // clamp strength to avoid overshoot
+                    float strength = 1.0f / APIDStrength;
+                    if (strength > 1.0) strength = 1.0f;
 
-                    m_APIDIterations--;
+                    // set angular velocity to rotate to desired orientation
+                    // with velocity proportional to strength and angle
+                    AngularVelocity = axis * angle * strength * (float)Math.PI;
 
                     // This ensures that we'll check this object on the next iteration
                     ParentGroup.QueueForUpdateCheck();

OpenSim/Region/Physics/OdePlugin/ODEPrim.cs

@@ -784,6 +784,14 @@ private void setMass()
             }
         }
 
+        private void setAngularVelocity(float x, float y, float z)
+        {
+            if (Body != (IntPtr)0)
+            {
+                d.BodySetAngularVel(Body, x, y, z);
+            }
+        }
+
         /// <summary>
         /// Stop a prim from being subject to physics.
         /// </summary>
@@ -2650,6 +2658,7 @@ public override Vector3 RotationalVelocity
                 if (value.IsFinite())
                 {
                     m_rotationalVelocity = value;
+                    setAngularVelocity(value.X, value.Y, value.Z);
                 }
                 else
                 {

OpenSim/Region/ScriptEngine/Shared/Api/Implementation/LSL_Api.cs

@@ -3049,20 +3049,17 @@ public void llLookAt(LSL_Vector target, double strength, double damping)
             // Determine where we are looking from
             LSL_Vector from = llGetPos();
 
-            // Work out the normalised vector from the source to the target
-            LSL_Vector delta = llVecNorm(target - from);
-            LSL_Vector angle = new LSL_Vector(0,0,0);
-
-            // Calculate the yaw
-            // subtracting PI_BY_TWO is required to compensate for the odd SL co-ordinate system
-            angle.x = llAtan2(delta.z, delta.y) - ScriptBaseClass.PI_BY_TWO;
-
-            // Calculate pitch
-            angle.y = llAtan2(delta.x, llSqrt((delta.y * delta.y) + (delta.z * delta.z)));
-
-            // we need to convert from a vector describing
-            // the angles of rotation in radians into rotation value
-            LSL_Rotation rot = llEuler2Rot(angle);
+            // normalized direction to target
+            LSL_Vector dir = llVecNorm(target - from);
+            // use vertical to help compute left axis
+            LSL_Vector up = new LSL_Vector(0.0, 0.0, 1.0);
+            // find normalized left axis parallel to horizon
+            LSL_Vector left = llVecNorm(LSL_Vector.Cross(up, dir));
+            // make up orthogonal to left and dir
+            up = LSL_Vector.Cross(dir, left);
+
+            // compute rotation based on orthogonal axes
+            LSL_Rotation rot = new LSL_Rotation(0.0, 0.707107, 0.0, 0.707107) * llAxes2Rot(dir, left, up);
 
             // Per discussion with Melanie, for non-physical objects llLookAt appears to simply
             // set the rotation of the object, copy that behavior
@@ -10090,7 +10087,7 @@ public LSL_List GetPrimParams(SceneObjectPart part, LSL_List rules, ref LSL_List
                         res.Add(new LSL_Vector(textColor.R,
                                                textColor.G,
                                                textColor.B));
-                        res.Add(new LSL_Float(textColor.A));
+                        res.Add(new LSL_Float(1 - textColor.A));
                         break;
                     case (int)ScriptBaseClass.PRIM_NAME:
                         res.Add(new LSL_String(part.Name));