Bug 1650714 - Part 2: Correct XRRigidTransform inverse math r=daoshen…

…gmu,kip,lsalzman Differential Revision: https://phabricator.services.mozilla.com/D82433
dothq · Jul 10, 2020 · a0b1223 · a0b1223
1 parent 088f996
commit a0b1223
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Showing 3 changed files with 15 additions and 12 deletions.
diff --git a/dom/vr/XRFrame.cpp b/dom/vr/XRFrame.cpp
@@ -79,7 +79,7 @@ already_AddRefed<XRViewerPose> XRFrame::GetViewerPose(
 
     gfx::Matrix4x4Double originTransform;
     originTransform.SetRotationFromQuaternion(
-        aReferenceSpace.GetEffectiveOriginOrientation());
+        aReferenceSpace.GetEffectiveOriginOrientation().Inverse());
     originTransform.PreTranslate(-aReferenceSpace.GetEffectiveOriginPosition());
 
     headTransform *= originTransform;
@@ -155,7 +155,8 @@ already_AddRefed<XRPose> XRFrame::GetPose(const XRSpace& aSpace,
 
   const bool emulatedPosition = aSpace.IsPositionEmulated();
   gfx::Matrix4x4Double base;
-  base.SetRotationFromQuaternion(aBaseSpace.GetEffectiveOriginOrientation());
+  base.SetRotationFromQuaternion(
+      aBaseSpace.GetEffectiveOriginOrientation().Inverse());
   base.PreTranslate(-aBaseSpace.GetEffectiveOriginPosition());
 
   gfx::Matrix4x4Double matrix = aSpace.GetEffectiveOriginTransform() * base;

diff --git a/dom/vr/XRRigidTransform.cpp b/dom/vr/XRRigidTransform.cpp
@@ -140,11 +140,9 @@ void XRRigidTransform::UpdateInternal() {
     mOrientation->SetW(mRawOrientation.w);
   }
   if (mInverse) {
-    gfx::QuaternionDouble q(mRawOrientation);
-    gfx::PointDouble3D p = -mRawPosition;
-    p = q.RotatePoint(p);
-    q.Invert();
-    mInverse->Update(p, q);
+    gfx::Matrix4x4Double inverseMatrix = mRawTransformMatrix;
+    Unused << inverseMatrix.Invert();
+    mInverse->Update(inverseMatrix);
   }
 }
 
@@ -175,11 +173,9 @@ void XRRigidTransform::GetMatrix(JSContext* aCx,
 
 already_AddRefed<XRRigidTransform> XRRigidTransform::Inverse() {
   if (!mInverse) {
-    gfx::QuaternionDouble q(mRawOrientation);
-    gfx::PointDouble3D p = -mRawPosition;
-    p = q.RotatePoint(p);
-    q.Invert();
-    mInverse = new XRRigidTransform(mParent, p, q);
+    gfx::Matrix4x4Double inverseMatrix = mRawTransformMatrix;
+    Unused << inverseMatrix.Invert();
+    mInverse = new XRRigidTransform(mParent, inverseMatrix);
   }
 
   RefPtr<XRRigidTransform> inverse = mInverse;

diff --git a/gfx/2d/Quaternion.h b/gfx/2d/Quaternion.h
@@ -122,6 +122,12 @@ class BaseQuaternion {
 
   BaseQuaternion& Invert() { return Conjugate().Normalize(); }
 
+  BaseQuaternion Inverse() const {
+    BaseQuaternion q = *this;
+    q.Invert();
+    return q;
+  }
+
   Point3DTyped<UnknownUnits, T> RotatePoint(
       const Point3DTyped<UnknownUnits, T>& aPoint) const {
     T uvx = T(2.0) * (y * aPoint.z - z * aPoint.y);