Merge pull request #40 from geefr/fix-teleport-demo

Interaction example and user origin fixes

Author: geefr

.gitignore

@@ -1 +1,3 @@
 .vscode
+build
+

examples/interaction_locomotion/game.cpp

@@ -32,7 +32,9 @@ void Game::loadScene()
   _sceneRoot->addChild(_controllerRight);
 
   _teleportMarker = vsg::Switch::create();
-  _teleportMarker->addChild(false, teleport_marker());
+  auto teleportMatrix = vsg::MatrixTransform::create();
+  _teleportMarker->addChild(false, teleportMatrix);
+  teleportMatrix->addChild(teleport_marker());
   _sceneRoot->addChild(_teleportMarker);
 
   // User origin - The regular vsg scene / world space,
@@ -75,19 +77,26 @@ void Game::initVR()
 
 void Game::initActions()
 {
-  // Configure OpenXR action sets and pose bindings - These allow elements of the OpenXR device tree to be located and tracked in space,
+  // Tracking the location of the user's headset is achieved by tracking the VIEW reference space
+  // vsgvr provides a SpaceBinding class for this - Similar to the ActionPoseBindings the head's pose
+  // will be tracked during rendering, and available when performing interactions
+  _headPose = vsgvr::SpaceBinding::create(_xrInstance, XrReferenceSpaceType::XR_REFERENCE_SPACE_TYPE_VIEW);
+  _vr->spaceBindings.push_back(_headPose);
+
+  // Input devices are tracked via ActionPoseBindings - Tracking elements from the OpenXR device tree in the session space,
   // along with binding the OpenXR input subsystem through to usable actions.
   _baseActionSet = vsgvr::ActionSet::create(_xrInstance, "controller_positions", "Controller Positions");
-  // Pose bindings - One for each hand
+  // Pose bindings
   _leftHandPose = vsgvr::ActionPoseBinding::create(_xrInstance, _baseActionSet, "left_hand", "Left Hand");
   _rightHandPose = vsgvr::ActionPoseBinding::create(_xrInstance, _baseActionSet, "right_hand", "Right Hand");
+
   _baseActionSet->actions = {
     _leftHandPose,
     _rightHandPose,
   };
 
-  _interactions.emplace("teleport", new Interaction_teleport(_xrInstance, _leftHandPose, _teleportMarker, _ground));
-  _interactions.emplace("slide", new Interaction_slide(_xrInstance, _leftHandPose, _ground));
+  _interactions.emplace("teleport", new Interaction_teleport(_xrInstance, _headPose, _leftHandPose, _teleportMarker, _ground));
+  _interactions.emplace("slide", new Interaction_slide(_xrInstance, _headPose, _leftHandPose, _ground));
 
   // Ask OpenXR to suggest interaction bindings.
   // * If subpaths are used, list all paths that each action should be bound for

examples/interaction_locomotion/game.h

@@ -6,6 +6,7 @@
 #include <vsgvr/actions/Action.h>
 #include <vsgvr/actions/ActionSet.h>
 #include <vsgvr/actions/ActionPoseBinding.h>
+#include <vsgvr/actions/SpaceBinding.h>
 
 #include "interaction.h"
 
@@ -48,6 +49,7 @@ class Game {
   vsg::ref_ptr<vsgvr::ActionSet> _baseActionSet;
   vsg::ref_ptr<vsgvr::ActionPoseBinding> _leftHandPose;
   vsg::ref_ptr<vsgvr::ActionPoseBinding> _rightHandPose;
+  vsg::ref_ptr<vsgvr::SpaceBinding> _headPose;
 
   std::map<std::string, std::unique_ptr<Interaction>> _interactions;
 

examples/interaction_locomotion/interaction.h

@@ -4,6 +4,7 @@
 #include <vsgvr/actions/Action.h>
 #include <vsgvr/actions/ActionSet.h>
 #include <vsgvr/actions/ActionPoseBinding.h>
+#include <vsgvr/actions/SpaceBinding.h>
 
 #include <list>
 #include <map>

examples/interaction_locomotion/interactions/interaction_slide.cpp

@@ -7,10 +7,12 @@
 #include <iostream>
 
 Interaction_slide::Interaction_slide(
-  vsg::ref_ptr<vsgvr::Instance> xrInstance, 
+  vsg::ref_ptr<vsgvr::Instance> xrInstance,
+  vsg::ref_ptr<vsgvr::SpaceBinding> headPose,
   vsg::ref_ptr<vsgvr::ActionPoseBinding> leftHandPose, 
   vsg::ref_ptr<vsg::Group> ground)
-    : _leftHandPose(leftHandPose)
+    : _headPose(headPose)
+    , _leftHandPose(leftHandPose)
     , _ground(ground)
 {
   _actionSet = vsgvr::ActionSet::create(xrInstance, "slide", "Slide");
@@ -45,18 +47,36 @@ Interaction_slide::~Interaction_slide() {}
 
 void Interaction_slide::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, double deltaT)
 {
+  bool updateOrigin = false;
+
+  // The player's position in vr space, at 'ground' level
+  // In most cases this will simply be playerPosOrigin.z = 0,
+  // though an intersection to the scene would be more appropriate in many cases
+  auto playerPosUser = _headPose->getTransform() * vsg::dvec3{ 0.0, 0.0, 0.0 };
+  playerPosUser.z = 0.0;
+  
+  // Player's position in the scene - Strafing is performed in scene space
+  auto newPositionScene = game.userOrigin()->userToScene() * playerPosUser;
+
   if (_rotateAction->getStateValid())
   {
     auto state = _rotateAction->getStateFloat();
     if (state.isActive && fabs(state.currentState) > deadZone)
     {
       _rotation += state.currentState * rotateSensitivity * deltaT * -1.0;
-      game.userOrigin()->orientation = vsg::dquat(_rotation, { 0.0, 0.0, 1.0 });
+      updateOrigin = true;
     }
   }
 
   if (_leftHandPose->getTransformValid() && _strafeXAction->getStateValid() && _strafeYAction->getStateValid())
   {
+    // Direction vectors in scene space, based on left controller
+    // (User may point controller to modify strafe direction)
+    // Alternatively the head's pose could be used to determine forward,
+    // but that would prevent strafing sideways while looking sideways
+    //
+    // Here all strafing is performed in the xy plane, ignoring height differences
+    // of the ground.
     auto lt = game.userOrigin()->userToScene() * _leftHandPose->getTransform();
     auto lForward = (lt * vsg::dvec3{0.0, 0.0, -1.0}) - (lt * vsg::dvec3{0.0, 0.0, 0.0});
     lForward.z = 0;
@@ -73,8 +93,20 @@ void Interaction_slide::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, double
       if (vsg::length(d) > deadZone)
       {
         d *= strafeSensitivity * deltaT;
-        game.userOrigin()->position += d;
+        newPositionScene += d;
+        updateOrigin = true;
       }
     }
   }
+
+  if( updateOrigin )
+  {
+    // Update the vsg scene's transform to strafe player as needed
+    game.userOrigin()->setUserInScene(
+      playerPosUser,
+      newPositionScene,
+      vsg::dquat(_rotation, { 0.0, 0.0, 1.0 }),
+      { 1.0, 1.0, 1.0 }
+    );
+  }
 }

examples/interaction_locomotion/interactions/interaction_slide.h

@@ -9,7 +9,8 @@ class Interaction_slide : public Interaction
 {
   public:
     Interaction_slide() = delete;
-    Interaction_slide(vsg::ref_ptr<vsgvr::Instance> xrInstance, 
+    Interaction_slide(vsg::ref_ptr<vsgvr::Instance> xrInstance,
+      vsg::ref_ptr<vsgvr::SpaceBinding> headPose,
       vsg::ref_ptr<vsgvr::ActionPoseBinding> leftHandPose, 
       vsg::ref_ptr<vsg::Group> ground);
 
@@ -24,6 +25,7 @@ class Interaction_slide : public Interaction
     vsg::ref_ptr<vsgvr::Action> _strafeXAction;
     vsg::ref_ptr<vsgvr::Action> _strafeYAction;
     vsg::ref_ptr<vsgvr::Action> _rotateAction;
+    vsg::ref_ptr<vsgvr::SpaceBinding> _headPose;
     vsg::ref_ptr<vsgvr::ActionPoseBinding> _leftHandPose;
 
     vsg::ref_ptr<vsg::Group> _ground;

examples/interaction_locomotion/interactions/interaction_teleport.cpp

@@ -7,10 +7,12 @@
 #include <iostream>
 
 Interaction_teleport::Interaction_teleport(vsg::ref_ptr<vsgvr::Instance> xrInstance,
+  vsg::ref_ptr<vsgvr::SpaceBinding> headPose,
   vsg::ref_ptr<vsgvr::ActionPoseBinding> leftHandPose,
   vsg::ref_ptr<vsg::Switch> teleportTarget,
   vsg::ref_ptr<vsg::Group> ground)
-  : _leftHandPose(leftHandPose)
+  : _headPose(headPose)
+  , _leftHandPose(leftHandPose)
   , _teleportTarget(teleportTarget)
   , _ground(ground)
 {
@@ -42,6 +44,9 @@ Interaction_teleport::~Interaction_teleport() {}
 
 void Interaction_teleport::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, double deltaT)
 {
+  auto applyRotation = false;
+  auto applyTeleport = false;
+
   if (_teleportAction->getStateValid())
   {
     auto state = _teleportAction->getStateBool();
@@ -50,6 +55,7 @@ void Interaction_teleport::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, dou
       _teleportButtonDown = true;
     }
   }
+
   double rotThresh = 0.25;
   if (_rotateAction->getStateValid())
   {
@@ -62,11 +68,11 @@ void Interaction_teleport::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, dou
       if (_rotateActionState != 0)
       {
         _playerRotation += (- 15.0 * _rotateActionState);
-        game.userOrigin()->orientation = vsg::dquat(vsg::radians(_playerRotation), { 0.0, 0.0, 1.0 });
+        applyRotation = true;
       }
     }
   }
-    
+
   if (_teleportButtonDown && _leftHandPose->getTransformValid())
   {
     // Raycast from controller aim to world, colliding with anything named "ground"
@@ -79,8 +85,8 @@ void Interaction_teleport::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, dou
 
     auto intersector = vsg::LineSegmentIntersector::create(intersectStart, intersectEnd);
     // TODO: Intersect whole scene, or sub-scene matched on tags? For now we can't be anywhere but the ground plane
-    // TODO: Intersections appear to be in reverse-distance order. Should double check this but intersections.back()
-    //       seems to always get the ground plane (and not fences, trees, houses, or the underside of the ground plane.
+    // TODO: Should sort intersections as well - For now intersections.back() seems to always get the ground plane,
+    //       and not other geometry within the world.
     _ground->accept(*intersector);
     if (!intersector->intersections.empty())
     {
@@ -93,7 +99,7 @@ void Interaction_teleport::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, dou
       {
         if (auto m = child.node->cast<vsg::MatrixTransform>())
         {
-          m->matrix = vsg::translate(_teleportPosition) * vsg::rotate(vsg::radians(90.0), {1.0, 0.0, 0.0});
+          m->matrix = vsg::translate(_teleportPosition);
         }
       }
     }
@@ -112,7 +118,8 @@ void Interaction_teleport::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, dou
       if (_teleportTargetValid)
       {
         // Teleport position within the child scene
-        game.userOrigin()->position = game.userOrigin()->userToScene() * _teleportPosition;
+        // Here the origin is being moved, by the difference between the teleport target, and where the user currently is (left hand)
+        applyTeleport = true;
       }
       _teleportButtonDown = false;
       _teleportTargetValid = false;
@@ -127,4 +134,34 @@ void Interaction_teleport::frame(vsg::ref_ptr<vsg::Group> scene, Game& game, dou
       if( fabs(state.currentState) < rotThresh) _rotateActionState = 0;
     }
   }
+
+  if( applyRotation || applyTeleport )
+  {
+    // The player's position in vr space, at 'ground' level
+    // In this case we know the level if the ground from the teleport target
+    auto playerPosOrigin = _headPose->getTransform() * vsg::dvec3{ 0.0, 0.0, 0.0 };
+    playerPosOrigin.z = _teleportPosition.z;
+
+    vsg::dvec3 newPlayerPosScene;
+    if (!applyTeleport)
+    {
+      // The player hasn't moved
+      newPlayerPosScene = game.userOrigin()->userToScene() * playerPosOrigin;
+    }
+    else
+    {
+      // The player has moved - Center on the teleport target
+      newPlayerPosScene = game.userOrigin()->userToScene() * _teleportPosition;
+    }
+
+    // Set the transform from vr origin to position/rotation within scene
+    // The initial translate is important as the user is rarely positioned 
+    // at the origin of their vr space.
+    game.userOrigin()->setUserInScene(
+      playerPosOrigin, 
+      newPlayerPosScene,
+      vsg::dquat(vsg::radians(_playerRotation), { 0.0, 0.0, 1.0 }),
+      {1.0, 1.0, 1.0}
+    );
+  }
 }

examples/interaction_locomotion/interactions/interaction_teleport.h

@@ -10,6 +10,7 @@ class Interaction_teleport : public Interaction
   public:
     Interaction_teleport() = delete;
     Interaction_teleport(vsg::ref_ptr<vsgvr::Instance> xrInstance, 
+      vsg::ref_ptr<vsgvr::SpaceBinding> headPose,
       vsg::ref_ptr<vsgvr::ActionPoseBinding> leftHandPose,
       vsg::ref_ptr<vsg::Switch> teleportTarget,
       vsg::ref_ptr<vsg::Group> ground);
@@ -23,11 +24,13 @@ class Interaction_teleport : public Interaction
 
     vsg::dvec3 _teleportPosition = {0.0, 0.0, 0.0};
     vsg::ref_ptr<vsg::Switch> _teleportTarget;
+    vsg::ref_ptr<vsgvr::SpaceBinding> _headPose;
     vsg::ref_ptr<vsgvr::ActionPoseBinding> _leftHandPose;
 
     bool _teleportButtonDown = false;
     bool _teleportTargetValid = false;
     int _rotateActionState = 0; // -1 is rot left, 1 is rot right
+
     double _playerRotation = 0.0;
 
     vsg::ref_ptr<vsg::Group> _ground;

vsgvr/CMakeLists.txt

@@ -2,6 +2,7 @@
 set( HEADERS_ACTIONS
   include/vsgvr/actions/Action.h
   include/vsgvr/actions/ActionPoseBinding.h
+  include/vsgvr/actions/SpaceBinding.h
   include/vsgvr/actions/ActionSet.h
 )
 
@@ -25,6 +26,7 @@ set( HEADERS_XR
 set( SOURCES
   src/vsgvr/actions/Action.cpp
   src/vsgvr/actions/ActionPoseBinding.cpp
+  src/vsgvr/actions/SpaceBinding.cpp
   src/vsgvr/actions/ActionSet.cpp
   src/vsgvr/app/Viewer.cpp
   src/vsgvr/app/UserOrigin.cpp

vsgvr/include/vsgvr/actions/SpaceBinding.h

@@ -0,0 +1,62 @@
+/*
+Copyright(c) 2022 Gareth Francis
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+*/
+
+#pragma once
+
+#include <vsg/core/Inherit.h>
+
+#include <vsgvr/xr/Common.h>
+#include <vsgvr/xr/Instance.h>
+
+namespace vsgvr {
+    class Session;
+
+    /**
+     * A binding class allowing an XrSpace to be tracked by the Viewer.
+     * The specified reference space will be kept updated during rendering (along with any ActionPoseBindings)
+     * in order to track elements such as the position of the headset (view) space, or user's local space.
+     */
+    class VSGVR_DECLSPEC SpaceBinding : public vsg::Inherit<vsg::Object, SpaceBinding>
+    {
+        public:
+            SpaceBinding(vsg::ref_ptr<Instance> instance, XrReferenceSpaceType spaceType);
+            virtual ~SpaceBinding();
+
+            XrSpace getSpace() const { return _space; }
+
+            bool getTransformValid() const { return _transformValid; }
+            vsg::dmat4 getTransform() const { return _transform; }
+            XrReferenceSpaceType getSpaceType() const { return _spaceType; }
+
+            void createSpace(Session* session);
+            void destroySpace();
+
+            void setSpaceLocation(XrSpaceLocation location);
+        private:
+            XrSpace _space = XR_NULL_HANDLE;
+            XrReferenceSpaceType _spaceType;
+
+            bool _transformValid = false;
+            vsg::dmat4 _transform;
+    };
+}
+
+EVSG_type_name(vsgvr::SpaceBinding);