Add option to change Character Controller capsule origin to start at feet location

Source/Engine/Physics/Colliders/CharacterController.cpp

@@ -21,6 +21,7 @@ CharacterController::CharacterController(const SpawnParams& params)
     , _upDirection(Vector3::Up)
     , _gravityDisplacement(Vector3::Zero)
     , _nonWalkableMode(NonWalkableModes::PreventClimbing)
+    , _originMode(OriginModes::CapsuleCenter)
     , _lastFlags(CollisionFlags::None)
 {
     _contactOffset = 10.0f;
@@ -35,9 +36,7 @@ void CharacterController::SetRadius(const float value)
 {
     if (value == _radius)
         return;
-
     _radius = value;
-
     UpdateSize();
     UpdateBounds();
 }
@@ -51,9 +50,7 @@ void CharacterController::SetHeight(const float value)
 {
     if (value == _height)
         return;
-
     _height = value;
-
     UpdateSize();
     UpdateBounds();
 }
@@ -87,6 +84,23 @@ void CharacterController::SetNonWalkableMode(NonWalkableModes value)
         PhysicsBackend::SetControllerNonWalkableMode(_controller, (int32)value);
 }
 
+CharacterController::OriginModes CharacterController::GetOriginMode() const
+{
+    return _originMode;
+}
+
+void CharacterController::SetOriginMode(OriginModes value)
+{
+    if (_originMode == value)
+        return;
+    _originMode = value;
+    if (_controller)
+    {
+        DeleteController();
+        CreateController();
+    }
+}
+
 float CharacterController::GetStepOffset() const
 {
     return _stepOffset;
@@ -165,13 +179,23 @@ CharacterController::CollisionFlags CharacterController::SimpleMove(const Vector
 CharacterController::CollisionFlags CharacterController::Move(const Vector3& displacement)
 {
     CollisionFlags result = CollisionFlags::None;
-    if (_controller)
+    if (_controller && !_isUpdatingTransform)
     {
+        // Perform move
         const float deltaTime = Time::GetCurrentSafe()->DeltaTime.GetTotalSeconds();
         result = (CollisionFlags)PhysicsBackend::MoveController(_controller, _shape, displacement, _minMoveDistance, deltaTime);
         _lastFlags = result;
-        Vector3 position = PhysicsBackend::GetControllerPosition(_controller) - _center;
+
+        // Update position
+        Vector3 position;
+        if (_originMode == OriginModes::Base)
+            position = PhysicsBackend::GetControllerBasePosition(_controller);
+        else
+            position = PhysicsBackend::GetControllerPosition(_controller);
+        position -= _center;
+        _isUpdatingTransform = true;
         SetPosition(position);
+        _isUpdatingTransform = false;
     }
     return result;
 }
@@ -194,10 +218,21 @@ void CharacterController::Resize(float height, float radius)
         Vector3 positionDelta = _upDirection * centerDiff;
 
         // Change physics position to maintain feet placement (base)
-        Vector3 position = PhysicsBackend::GetControllerPosition(_controller);
-        position += positionDelta;
-        _center += positionDelta;
-        PhysicsBackend::SetControllerPosition(_controller, position);
+        Vector3 position;
+        switch (_originMode)
+        {
+        case OriginModes::CapsuleCenter:
+            position = PhysicsBackend::GetControllerPosition(_controller);
+            position += positionDelta;
+            _center += positionDelta;
+            PhysicsBackend::SetControllerPosition(_controller, position);
+            break;
+        case OriginModes::Base:
+            position = PhysicsBackend::GetControllerBasePosition(_controller);
+            position += positionDelta;
+            PhysicsBackend::SetControllerBasePosition(_controller, position);
+            break;
+        }
 
         // Change actor position
         _isUpdatingTransform = true;
@@ -215,7 +250,7 @@ void CharacterController::Resize(float height, float radius)
 void CharacterController::DrawPhysicsDebug(RenderView& view)
 {
     Quaternion rotation = Quaternion::Euler(90, 0, 0);
-    const Vector3 position = _transform.LocalToWorld(_center);
+    const Vector3 position = GetControllerPosition();
     if (view.Mode == ViewMode::PhysicsColliders)
         DEBUG_DRAW_CAPSULE(position, rotation, _radius, _height, Color::LightYellow, 0, true);
     else
@@ -225,23 +260,25 @@ void CharacterController::DrawPhysicsDebug(RenderView& view)
 void CharacterController::OnDebugDrawSelected()
 {
     Quaternion rotation = Quaternion::Euler(90, 0, 0);
-    const Vector3 position = _transform.LocalToWorld(_center);
+    const Vector3 position = GetControllerPosition();
     DEBUG_DRAW_WIRE_CAPSULE(position, rotation, _radius, _height, Color::GreenYellow, 0, false);
     if (_contactOffset > 0)
         DEBUG_DRAW_WIRE_CAPSULE(position, rotation, _radius - _contactOffset, _height, Color::Blue.AlphaMultiplied(0.4f), 0, false);
-#if 0
+#if 1
     // More technical visuals debugging
     if (_controller)
     {
         float height, radius;
         GetControllerSize(height, radius);
-        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(PhysicsBackend::GetControllerBasePosition(_controller), 5.0f), Color::Red, 0, false);
-        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(PhysicsBackend::GetControllerPosition(_controller), 4.0f), Color::Red, 0, false);
-        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(PhysicsBackend::GetControllerPosition(_controller) + Vector3(0, height * 0.5f, 0), 2.0f), Color::Red, 0, false);
-        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(PhysicsBackend::GetControllerPosition(_controller) - Vector3(0, height * 0.5f, 0), 2.0f), Color::Red, 0, false);
-        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(PhysicsBackend::GetControllerPosition(_controller) + Vector3(0, height * 0.5f, 0), radius), Color::Red.AlphaMultiplied(0.5f), 0, false);
-        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(PhysicsBackend::GetControllerPosition(_controller) - Vector3(0, height * 0.5f, 0), radius), Color::Red.AlphaMultiplied(0.5f), 0, false);
-        DEBUG_DRAW_WIRE_CYLINDER(PhysicsBackend::GetControllerPosition(_controller), Quaternion::Identity, radius, height, Color::Red.AlphaMultiplied(0.2f), 0, false);
+        Vector3 base = PhysicsBackend::GetControllerBasePosition(_controller);
+        Vector3 pos = PhysicsBackend::GetControllerPosition(_controller);
+        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(base, 5.0f), Color::Red, 0, false);
+        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(pos, 4.0f), Color::Red, 0, false);
+        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(pos + Vector3(0, height * 0.5f, 0), 2.0f), Color::Red, 0, false);
+        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(pos - Vector3(0, height * 0.5f, 0), 2.0f), Color::Red, 0, false);
+        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(pos + Vector3(0, height * 0.5f, 0), radius), Color::Red.AlphaMultiplied(0.5f), 0, false);
+        DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(pos - Vector3(0, height * 0.5f, 0), radius), Color::Red.AlphaMultiplied(0.5f), 0, false);
+        DEBUG_DRAW_WIRE_CYLINDER(pos, Quaternion::Identity, radius, height, Color::Red.AlphaMultiplied(0.2f), 0, false);
     }
     DEBUG_DRAW_WIRE_SPHERE(BoundingSphere(position, 3.0f), Color::GreenYellow, 0, false);
 #else
@@ -267,7 +304,10 @@ void CharacterController::CreateController()
     _cachedScale = GetScale().GetAbsolute().MaxValue();
     float height, radius;
     GetControllerSize(height, radius);
-    const Vector3 position = _transform.LocalToWorld(_center);
+    Vector3 position = _center;
+    if (_originMode == OriginModes::Base)
+        position += _upDirection * (_height * 0.5f + _radius);
+    position = _transform.LocalToWorld(position);
     _controller = PhysicsBackend::CreateController(GetPhysicsScene()->GetPhysicsScene(), this, this, _contactOffset, position, _slopeLimit, (int32)_nonWalkableMode, Material, radius, height, _stepOffset, _shape);
 
     // Setup
@@ -297,14 +337,25 @@ void CharacterController::UpdateSize() const
     }
 }
 
+Vector3 CharacterController::GetControllerPosition() const
+{
+    Vector3 position = _center;
+    if (_originMode == OriginModes::Base)
+        position += _upDirection * (_height * 0.5f + _radius);
+    position = _transform.LocalToWorld(position);
+    return position;
+}
+
 void CharacterController::GetControllerSize(float& height, float& radius) const
 {
+    // Use absolute values including scale
     height = Math::Abs(_height) * _cachedScale;
     radius = Math::Abs(_radius) * _cachedScale;
-    {
-        // Exclude contact offset around the capsule (otherwise character floats in the air)
-        radius = radius - Math::Max(_contactOffset, 0.0f);
-    }
+
+    // Exclude contact offset around the capsule (otherwise character floats in the air)
+    radius = radius - Math::Max(_contactOffset, 0.0f);
+
+    // Prevent too small controllers
     height = Math::Max(height, CC_MIN_SIZE);
     radius = Math::Max(radius, CC_MIN_SIZE);
 }
@@ -319,7 +370,7 @@ void CharacterController::UpdateBounds()
     _cachedScale = GetScale().GetAbsolute().MaxValue();
     float height, radius;
     GetControllerSize(height, radius);
-    const Vector3 position = _transform.LocalToWorld(_center);
+    const Vector3 position = GetControllerPosition();
     const Vector3 extent(radius, height * 0.5f + radius, radius);
     _box = BoundingBox(position - extent, position + extent);
     BoundingSphere::FromBox(_box, _sphere);
@@ -376,7 +427,12 @@ void CharacterController::OnActiveTransformChanged()
     // Change actor transform (but with locking)
     ASSERT(!_isUpdatingTransform);
     _isUpdatingTransform = true;
-    const Vector3 position = PhysicsBackend::GetControllerPosition(_controller) - _center;
+    Vector3 position;
+    if (_originMode == OriginModes::Base)
+        position = PhysicsBackend::GetControllerBasePosition(_controller);
+    else
+        position = PhysicsBackend::GetControllerPosition(_controller);
+    position -= _center;
     SetPosition(position);
     _isUpdatingTransform = false;
 
@@ -458,7 +514,10 @@ void CharacterController::OnTransformChanged()
     const Vector3 position = _transform.LocalToWorld(_center);
     if (!_isUpdatingTransform && _controller)
     {
-        PhysicsBackend::SetControllerPosition(_controller, position);
+        if (_originMode == OriginModes::Base)
+            PhysicsBackend::SetControllerBasePosition(_controller, position);
+        else
+            PhysicsBackend::SetControllerPosition(_controller, position);
         const float scale = GetScale().GetAbsolute().MaxValue();
         if (_cachedScale != scale)
             UpdateGeometry();

Source/Engine/Physics/Colliders/CharacterController.h

@@ -41,6 +41,22 @@ public:
         Below = 1 << 2,
     };
 
+    /// <summary>
+    /// Specifies how a character controller capsule placement.
+    /// </summary>
+    API_ENUM() enum class OriginModes
+    {
+        /// <summary>
+        /// Character origin starts at capsule center (including Center offset properly).
+        /// </summary>
+        CapsuleCenter,
+
+        /// <summary>
+        /// Character origin starts at capsule base position aka character feet placement.
+        /// </summary>
+        Base,
+    };
+
     /// <summary>
     /// Specifies how a character controller interacts with non-walkable parts.
     /// </summary>
@@ -69,6 +85,7 @@ private:
     Vector3 _upDirection;
     Vector3 _gravityDisplacement;
     NonWalkableModes _nonWalkableMode;
+    OriginModes _originMode;
     CollisionFlags _lastFlags;
 
 public:
@@ -116,6 +133,17 @@ public:
     /// </summary>
     API_PROPERTY() void SetNonWalkableMode(NonWalkableModes value);
 
+    /// <summary>
+    /// Gets the position origin placement mode.
+    /// </summary>
+    API_PROPERTY(Attributes="EditorOrder(216), DefaultValue(OriginModes.CapsuleCenter), EditorDisplay(\"Character Controller\")")
+    OriginModes GetOriginMode() const;
+
+    /// <summary>
+    /// Sets the position origin placement mode.
+    /// </summary>
+    API_PROPERTY() void SetOriginMode(OriginModes value);
+
     /// <summary>
     /// Gets the step height. The character will step up a stair only if it is closer to the ground than the indicated value. This should not be greater than the Character Controller’s height or it will generate an error.
     /// </summary>
@@ -218,6 +246,7 @@ protected:
     void UpdateSize() const;
 
 private:
+    Vector3 GetControllerPosition() const;
     void GetControllerSize(float& height, float& radius) const;
 
 public:

Source/Engine/Physics/PhysX/PhysicsBackendPhysX.cpp

@@ -3155,10 +3155,9 @@ void* PhysicsBackend::CreateController(void* scene, IPhysicsActor* actor, Physic
         desc.material = (PxMaterial*)((PhysicalMaterial*)material->Instance)->GetPhysicsMaterial();
     else
         desc.material = DefaultMaterial;
-    const float minSize = 0.001f;
-    desc.height = Math::Max(height, minSize);
-    desc.radius = Math::Max(radius, minSize);
-    desc.stepOffset = Math::Min(stepOffset, desc.height + desc.radius * 2.0f - minSize);
+    desc.height = height;
+    desc.radius = radius;
+    desc.stepOffset = Math::Min(stepOffset, desc.height + desc.radius * 2.0f - 0.001f);
     auto controllerPhysX = (PxCapsuleController*)scenePhysX->ControllerManager->createController(desc);
     PxRigidActor* actorPhysX = controllerPhysX->getActor();
     ASSERT(actorPhysX && actorPhysX->getNbShapes() == 1);
@@ -3207,7 +3206,15 @@ void PhysicsBackend::SetControllerStepOffset(void* controller, float value)
 Vector3 PhysicsBackend::GetControllerBasePosition(void* controller)
 {
     auto controllerPhysX = (PxCapsuleController*)controller;
-    return P2C(controllerPhysX->getFootPosition());
+    const Vector3 origin = SceneOrigins[controllerPhysX->getScene()];
+    return P2C(controllerPhysX->getFootPosition()) + origin;
+}
+
+void PhysicsBackend::SetControllerBasePosition(void* controller, const Vector3& value)
+{
+    auto controllerPhysX = (PxCapsuleController*)controller;
+    const Vector3 sceneOrigin = SceneOrigins[controllerPhysX->getScene()];
+    controllerPhysX->setFootPosition(PxExtendedVec3(value.X - sceneOrigin.X, value.Y - sceneOrigin.Y, value.Z - sceneOrigin.Z));
 }
 
 Vector3 PhysicsBackend::GetControllerUpDirection(void* controller)

Source/Engine/Physics/PhysicsBackend.h

@@ -249,6 +249,7 @@ public:
     static void SetControllerNonWalkableMode(void* controller, int32 value);
     static void SetControllerStepOffset(void* controller, float value);
     static Vector3 GetControllerBasePosition(void* controller);
+    static void SetControllerBasePosition(void* controller, const Vector3& value);
     static Vector3 GetControllerUpDirection(void* controller);
     static void SetControllerUpDirection(void* controller, const Vector3& value);
     static Vector3 GetControllerPosition(void* controller);