Fix incorrect deg->radian conversion

It seems that rotation matrices later expect radians.
This conversion breaks it, and was validated on the conversion of
`cesium_man.glb` --> `cesium_man.fbx`

code/AssetLib/FBX/FBXConverter.cpp

@@ -577,16 +577,17 @@ void FBXConverter::GetRotationMatrix(Model::RotOrder mode, const aiVector3D &rot
     bool is_id[3] = { true, true, true };
 
     aiMatrix4x4 temp[3];
-    if (std::fabs(rotation.z) > angle_epsilon) {
-        aiMatrix4x4::RotationZ(AI_DEG_TO_RAD(rotation.z), temp[2]);
+    const auto rot = AI_DEG_TO_RAD(rotation);
+    if (std::fabs(rot.z) > angle_epsilon) {
+        aiMatrix4x4::RotationZ(rot.z, temp[2]);
         is_id[2] = false;
     }
-    if (std::fabs(rotation.y) > angle_epsilon) {
-        aiMatrix4x4::RotationY(AI_DEG_TO_RAD(rotation.y), temp[1]);
+    if (std::fabs(rot.y) > angle_epsilon) {
+        aiMatrix4x4::RotationY(rot.y, temp[1]);
         is_id[1] = false;
     }
-    if (std::fabs(rotation.x) > angle_epsilon) {
-        aiMatrix4x4::RotationX(AI_DEG_TO_RAD(rotation.x), temp[0]);
+    if (std::fabs(rot.x) > angle_epsilon) {
+        aiMatrix4x4::RotationX(rot.x, temp[0]);
         is_id[0] = false;
     }
 
@@ -3225,7 +3226,6 @@ aiNodeAnim* FBXConverter::GenerateSimpleNodeAnim(const std::string& name,
     aiVector3D defTranslate = PropertyGet(props, "Lcl Translation", aiVector3D(0.f, 0.f, 0.f));
     aiVector3D defRotation = PropertyGet(props, "Lcl Rotation", aiVector3D(0.f, 0.f, 0.f));
     aiVector3D defScale = PropertyGet(props, "Lcl Scaling", aiVector3D(1.f, 1.f, 1.f));
-    aiQuaternion defQuat = EulerToQuaternion(defRotation, rotOrder);
 
     aiVectorKey* outTranslations = new aiVectorKey[keyCount];
     aiQuatKey* outRotations = new aiQuatKey[keyCount];
@@ -3241,8 +3241,9 @@ aiNodeAnim* FBXConverter::GenerateSimpleNodeAnim(const std::string& name,
     }
 
     if (keyframeLists[TransformationComp_Rotation].size() > 0) {
-        InterpolateKeys(outRotations, keytimes, keyframeLists[TransformationComp_Rotation], defRotation, maxTime, minTime, rotOrder);
+        InterpolateKeys(outRotations, keytimes, keyframeLists[TransformationComp_Rotation], AI_DEG_TO_RAD(defRotation), maxTime, minTime, rotOrder);
     } else {
+        aiQuaternion defQuat = EulerToQuaternion(AI_DEG_TO_RAD(defRotation), rotOrder);
         for (size_t i = 0; i < keyCount; ++i) {
             outRotations[i].mTime = CONVERT_FBX_TIME(keytimes[i]) * anim_fps;
             outRotations[i].mValue = defQuat;
@@ -3264,7 +3265,7 @@ aiNodeAnim* FBXConverter::GenerateSimpleNodeAnim(const std::string& name,
 
     const aiVector3D& preRotation = PropertyGet<aiVector3D>(props, "PreRotation", ok);
     if (ok && preRotation.SquareLength() > zero_epsilon) {
-        const aiQuaternion preQuat = EulerToQuaternion(preRotation, Model::RotOrder_EulerXYZ);
+        const aiQuaternion preQuat = EulerToQuaternion(AI_DEG_TO_RAD(preRotation), Model::RotOrder_EulerXYZ);
         for (size_t i = 0; i < keyCount; ++i) {
             outRotations[i].mValue = preQuat * outRotations[i].mValue;
         }
@@ -3272,7 +3273,7 @@ aiNodeAnim* FBXConverter::GenerateSimpleNodeAnim(const std::string& name,
 
     const aiVector3D& postRotation = PropertyGet<aiVector3D>(props, "PostRotation", ok);
     if (ok && postRotation.SquareLength() > zero_epsilon) {
-        const aiQuaternion postQuat = EulerToQuaternion(postRotation, Model::RotOrder_EulerXYZ);
+        const aiQuaternion postQuat = EulerToQuaternion(AI_DEG_TO_RAD(postRotation), Model::RotOrder_EulerXYZ);
         for (size_t i = 0; i < keyCount; ++i) {
             outRotations[i].mValue = outRotations[i].mValue * postQuat;
         }

code/AssetLib/FBX/FBXExporter.cpp

@@ -74,8 +74,6 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 // https://code.blender.org/2013/08/fbx-binary-file-format-specification/
 // https://wiki.blender.org/index.php/User:Mont29/Foundation/FBX_File_Structure
 
-const ai_real DEG = ai_real( 57.29577951308232087679815481 ); // degrees per radian
-
 using namespace Assimp;
 using namespace Assimp::FBX;
 
@@ -2434,7 +2432,7 @@ void FBXExporter::WriteObjects ()
                 aiMatrix4x4 m(k.mValue.GetMatrix());
                 aiVector3D qs, qr, qt;
                 m.Decompose(qs, qr, qt);
-                qr *= DEG;
+                qr = AI_RAD_TO_DEG(qr);
                 xval.push_back(qr.x);
                 yval.push_back(qr.y);
                 zval.push_back(qr.z);
@@ -2515,9 +2513,10 @@ void FBXExporter::WriteModelNode(
             );
         }
         if (r != zero) {
+            r = AI_RAD_TO_DEG(r);
             p.AddP70(
                 "Lcl Rotation", "Lcl Rotation", "", "A",
-                double(DEG*r.x), double(DEG*r.y), double(DEG*r.z)
+                double(r.x), double(r.y), double(r.z)
             );
         }
         if (s != one) {
@@ -2601,8 +2600,7 @@ void FBXExporter::WriteModelNodes(
             transform_chain.emplace_back(elem->first, t);
             break;
         case 'r': // rotation
-            r *= float(DEG);
-            transform_chain.emplace_back(elem->first, r);
+            transform_chain.emplace_back(elem->first, AI_RAD_TO_DEG(r));
             break;
         case 's': // scale
             transform_chain.emplace_back(elem->first, s);