From 03268d85c41c94e7b35802b9dea1ce08299e5426 Mon Sep 17 00:00:00 2001 From: Robert Adams Date: Sun, 2 Jun 2013 10:04:15 -0700 Subject: BulletSim: comments and non-functional changes working toward the center-of-gravity implementation. --- .../Physics/BulletSPlugin/BSLinksetCompound.cs | 11 +++++---- OpenSim/Region/Physics/BulletSPlugin/BSParam.cs | 3 +++ .../Physics/BulletSPlugin/BSPrimDisplaced.cs | 26 +++++++++++++--------- .../Region/Physics/BulletSPlugin/BSPrimLinkable.cs | 19 ++++++++++++---- 4 files changed, 39 insertions(+), 20 deletions(-) (limited to 'OpenSim/Region/Physics/BulletSPlugin') diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSLinksetCompound.cs b/OpenSim/Region/Physics/BulletSPlugin/BSLinksetCompound.cs index 308cf13..30f6c8c 100755 --- a/OpenSim/Region/Physics/BulletSPlugin/BSLinksetCompound.cs +++ b/OpenSim/Region/Physics/BulletSPlugin/BSLinksetCompound.cs @@ -315,7 +315,6 @@ public sealed class BSLinksetCompound : BSLinkset // Note that this works for rebuilding just the root after a linkset is taken apart. // Called at taint time!! private bool UseBulletSimRootOffsetHack = false; // Attempt to have Bullet track the coords of root compound shape - private bool disableCOM = true; // For basic linkset debugging, turn off the center-of-mass setting private void RecomputeLinksetCompound() { try @@ -331,9 +330,7 @@ public sealed class BSLinksetCompound : BSLinkset // There is no reason to build all this physical stuff for a non-physical linkset. if (!LinksetRoot.IsPhysicallyActive) { - // Clean up any old linkset shape and make sure the root shape is set to the root object. DetailLog("{0},BSLinksetCompound.RecomputeLinksetCompound,notPhysical", LinksetRoot.LocalID); - return; // Note the 'finally' clause at the botton which will get executed. } @@ -347,9 +344,9 @@ public sealed class BSLinksetCompound : BSLinkset OMV.Quaternion invRootOrientation = OMV.Quaternion.Normalize(OMV.Quaternion.Inverse(LinksetRoot.RawOrientation)); - // 'centerDisplacement' is the value to subtract from children to give physical offset position + // 'centerDisplacementV' is the value to subtract from children to give physical offset position OMV.Vector3 centerDisplacementV = (centerOfMassW - LinksetRoot.RawPosition) * invRootOrientation; - if (UseBulletSimRootOffsetHack || disableCOM) + if (UseBulletSimRootOffsetHack || !BSParam.LinksetOffsetCenterOfMass) { centerDisplacementV = OMV.Vector3.Zero; LinksetRoot.ClearDisplacement(); @@ -357,6 +354,8 @@ public sealed class BSLinksetCompound : BSLinkset else { LinksetRoot.SetEffectiveCenterOfMassDisplacement(centerDisplacementV); + // The actual center-of-mass could have been set by the user. + centerDisplacementV = LinksetRoot.PositionDisplacement; } DetailLog("{0},BSLinksetCompound.RecomputeLinksetCompound,COM,rootPos={1},com={2},comDisp={3}", LinksetRoot.LocalID, LinksetRoot.RawPosition, centerOfMassW, centerDisplacementV); @@ -409,7 +408,7 @@ public sealed class BSLinksetCompound : BSLinkset { // Enable the physical position updator to return the position and rotation of the root shape. // This enables a feature in the C++ code to return the world coordinates of the first shape in the - // compound shape. This eleviates the need to offset the returned physical position by the + // compound shape. This aleviates the need to offset the returned physical position by the // center-of-mass offset. m_physicsScene.PE.AddToCollisionFlags(LinksetRoot.PhysBody, CollisionFlags.BS_RETURN_ROOT_COMPOUND_SHAPE); } diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSParam.cs b/OpenSim/Region/Physics/BulletSPlugin/BSParam.cs index d17c8e7..0f84bf7 100755 --- a/OpenSim/Region/Physics/BulletSPlugin/BSParam.cs +++ b/OpenSim/Region/Physics/BulletSPlugin/BSParam.cs @@ -176,6 +176,7 @@ public static class BSParam // Linkset implementation parameters public static float LinksetImplementation { get; private set; } + public static bool LinksetOffsetCenterOfMass { get; private set; } public static bool LinkConstraintUseFrameOffset { get; private set; } public static bool LinkConstraintEnableTransMotor { get; private set; } public static float LinkConstraintTransMotorMaxVel { get; private set; } @@ -684,6 +685,8 @@ public static class BSParam new ParameterDefn("LinksetImplementation", "Type of linkset implementation (0=Constraint, 1=Compound, 2=Manual)", (float)BSLinkset.LinksetImplementation.Compound ), + new ParameterDefn("LinksetOffsetCenterOfMass", "If 'true', compute linkset center-of-mass and offset linkset position to account for same", + false ), new ParameterDefn("LinkConstraintUseFrameOffset", "For linksets built with constraints, enable frame offsetFor linksets built with constraints, enable frame offset.", false ), new ParameterDefn("LinkConstraintEnableTransMotor", "Whether to enable translational motor on linkset constraints", diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrimDisplaced.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrimDisplaced.cs index f5ee671..9a05349 100755 --- a/OpenSim/Region/Physics/BulletSPlugin/BSPrimDisplaced.cs +++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrimDisplaced.cs @@ -44,12 +44,12 @@ namespace OpenSim.Region.Physics.BulletSPlugin { public class BSPrimDisplaced : BSPrim { - // The purpose of this module is to do any mapping between what the simulator thinks + // The purpose of this subclass is to do any mapping between what the simulator thinks // the prim position and orientation is and what the physical position/orientation. // This difference happens because Bullet assumes the center-of-mass is the <0,0,0> - // of the prim/linkset. The simulator tracks the location of the prim/linkset by - // the location of the root prim. So, if center-of-mass is anywhere but the origin - // of the root prim, the physical origin is displaced from the simulator origin. + // of the prim/linkset. The simulator, on the other hand, tracks the location of + // the prim/linkset by the location of the root prim. So, if center-of-mass is anywhere + // but the origin of the root prim, the physical origin is displaced from the simulator origin. // // This routine works by capturing the Force* setting of position/orientation/... and // adjusting the simulator values (being set) into the physical values. @@ -61,6 +61,7 @@ public class BSPrimDisplaced : BSPrim public virtual OMV.Vector3 PositionDisplacement { get; set; } public virtual OMV.Quaternion OrientationDisplacement { get; set; } + public virtual OMV.Quaternion OrientationDisplacementOrigInv { get; set; } public BSPrimDisplaced(uint localID, String primName, BSScene parent_scene, OMV.Vector3 pos, OMV.Vector3 size, OMV.Quaternion rotation, PrimitiveBaseShape pbs, bool pisPhysical) @@ -99,7 +100,8 @@ public class BSPrimDisplaced : BSPrim // Remember the displacement from root as well as the origional rotation of the // new center-of-mass. PositionDisplacement = comDisp; - OrientationDisplacement = OMV.Quaternion.Identity; + OrientationDisplacement = Quaternion.Normalize(RawOrientation); + OrientationDisplacementOrigInv = Quaternion.Inverse(OrientationDisplacement); } } @@ -110,7 +112,7 @@ public class BSPrimDisplaced : BSPrim { if (PositionDisplacement != OMV.Vector3.Zero) { - OMV.Vector3 displacedPos = value - (PositionDisplacement * RawOrientation); + OMV.Vector3 displacedPos = value - (PositionDisplacement * (OrientationDisplacementOrigInv * RawOrientation)); DetailLog("{0},BSPrimDisplaced.ForcePosition,val={1},disp={2},newPos={3}", LocalID, value, PositionDisplacement, displacedPos); base.ForcePosition = displacedPos; } @@ -126,7 +128,8 @@ public class BSPrimDisplaced : BSPrim get { return base.ForceOrientation; } set { - // TODO: + // Changing orientation also changes the position of the center-of-mass since + // the orientation passed is for a rotation around the root prim's center. base.ForceOrientation = value; } } @@ -150,10 +153,13 @@ public class BSPrimDisplaced : BSPrim // Undo any center-of-mass displacement that might have been done. if (PositionDisplacement != OMV.Vector3.Zero || OrientationDisplacement != OMV.Quaternion.Identity) { - // Correct for any rotation around the center-of-mass - // TODO!!! + // The origional shape was offset from 'zero' by PositionDisplacement and rotated by OrientationDisplacement. + // These physical locations and rotation must be back converted to be centered around the displaced + // root shape. + + // The root position is the reported position displaced by the rotated displacement. + OMV.Vector3 displacedPos = entprop.Position + (PositionDisplacement * (entprop.Rotation * OrientationDisplacementOrigInv)); - OMV.Vector3 displacedPos = entprop.Position + (PositionDisplacement * entprop.Rotation); DetailLog("{0},BSPrimDisplaced.ForcePosition,physPos={1},disp={2},newPos={3}", LocalID, entprop.Position, PositionDisplacement, displacedPos); entprop.Position = displacedPos; // entprop.Rotation = something; diff --git a/OpenSim/Region/Physics/BulletSPlugin/BSPrimLinkable.cs b/OpenSim/Region/Physics/BulletSPlugin/BSPrimLinkable.cs index 87eed98..6d7de35 100755 --- a/OpenSim/Region/Physics/BulletSPlugin/BSPrimLinkable.cs +++ b/OpenSim/Region/Physics/BulletSPlugin/BSPrimLinkable.cs @@ -37,6 +37,12 @@ namespace OpenSim.Region.Physics.BulletSPlugin { public class BSPrimLinkable : BSPrimDisplaced { + // The purpose of this subclass is to add linkset functionality to the prim. This overrides + // operations necessary for keeping the linkset created and, additionally, this + // calls the linkset implementation for its creation and management. + + // This adds the overrides for link() and delink() so the prim is linkable. + public BSLinkset Linkset { get; set; } // The index of this child prim. public int LinksetChildIndex { get; set; } @@ -69,8 +75,8 @@ public class BSPrimLinkable : BSPrimDisplaced BSPrimLinkable parent = obj as BSPrimLinkable; if (parent != null) { - BSPhysObject parentBefore = Linkset.LinksetRoot; - int childrenBefore = Linkset.NumberOfChildren; + BSPhysObject parentBefore = Linkset.LinksetRoot; // DEBUG + int childrenBefore = Linkset.NumberOfChildren; // DEBUG Linkset = parent.Linkset.AddMeToLinkset(this); @@ -85,8 +91,8 @@ public class BSPrimLinkable : BSPrimDisplaced // TODO: decide if this parent checking needs to happen at taint time // Race condition here: if link() and delink() in same simulation tick, the delink will not happen - BSPhysObject parentBefore = Linkset.LinksetRoot; - int childrenBefore = Linkset.NumberOfChildren; + BSPhysObject parentBefore = Linkset.LinksetRoot; // DEBUG + int childrenBefore = Linkset.NumberOfChildren; // DEBUG Linkset = Linkset.RemoveMeFromLinkset(this); @@ -128,6 +134,7 @@ public class BSPrimLinkable : BSPrimDisplaced get { return Linkset.LinksetMass; } } + // Refresh the linkset structure and parameters when the prim's physical parameters are changed. public override void UpdatePhysicalParameters() { base.UpdatePhysicalParameters(); @@ -139,6 +146,7 @@ public class BSPrimLinkable : BSPrimDisplaced Linkset.Refresh(this); } + // When the prim is made dynamic or static, the linkset needs to change. protected override void MakeDynamic(bool makeStatic) { base.MakeDynamic(makeStatic); @@ -155,6 +163,8 @@ public class BSPrimLinkable : BSPrimDisplaced base.RemoveDependencies(); } + // Called after a simulation step for the changes in physical object properties. + // Do any filtering/modification needed for linksets. public override void UpdateProperties(EntityProperties entprop) { if (Linkset.IsRoot(this)) @@ -176,6 +186,7 @@ public class BSPrimLinkable : BSPrimDisplaced Linkset.UpdateProperties(UpdatedProperties.EntPropUpdates, this); } + // Called after a simulation step to post a collision with this object. public override bool Collide(uint collidingWith, BSPhysObject collidee, OMV.Vector3 contactPoint, OMV.Vector3 contactNormal, float pentrationDepth) { -- cgit v1.1