Fix crash that happens when loading cooked content with missing Car a…

…ssets by adding more logging information to help user understand what happened, and moving the asset loading to later in the process (non-static).

Unreal/Plugins/AirSim/Source/AirBlueprintLib.cpp

@@ -29,7 +29,6 @@ Methods -> CamelCase
 parameters -> camel_case
 */
 
-
 bool UAirBlueprintLib::log_messages_hidden = false;
 uint32_t UAirBlueprintLib::FlushOnDrawCount = 0;
 msr::airlib::AirSimSettings::SegmentationSettings::MeshNamingMethodType UAirBlueprintLib::mesh_naming_method =
@@ -150,6 +149,7 @@ void UAirBlueprintLib::LogMessage(const FString &prefix, const FString &suffix,
     if (log_messages_hidden)
         return;
 
+
     static TMap<FString, int> loggingKeys;
     static int counter = 1;
 
@@ -161,13 +161,27 @@ void UAirBlueprintLib::LogMessage(const FString &prefix, const FString &suffix,
 
     FColor color;
     switch (level) {
-    case LogDebugLevel::Informational: color = FColor(147, 231, 237); break;
-    case LogDebugLevel::Success: color = FColor(156, 237, 147); break;
-    case LogDebugLevel::Failure: color = FColor(237, 147, 168); break;
-    case LogDebugLevel::Unimportant: color = FColor(237, 228, 147); break;
+    case LogDebugLevel::Informational: 
+        color = FColor(147, 231, 237); 
+        UE_LOG(LogAirSim, Log, TEXT("%s%s"), *prefix, *suffix);
+        break;
+    case LogDebugLevel::Success: 
+        color = FColor(156, 237, 147); 
+        UE_LOG(LogAirSim, Log, TEXT("%s%s"), *prefix, *suffix);
+        break;
+    case LogDebugLevel::Failure: 
+        color = FColor(237, 147, 168);
+        UE_LOG(LogAirSim, Error, TEXT("%s%s"), *prefix, *suffix); 
+        break;
+    case LogDebugLevel::Unimportant: 
+        color = FColor(237, 228, 147);
+        UE_LOG(LogAirSim, Verbose, TEXT("%s%s"), *prefix, *suffix); 
+        break;
     default: color = FColor::Black; break;
     }
-    GEngine->AddOnScreenDebugMessage(key, persist_sec, color, prefix + suffix);
+    if (GEngine) {
+        GEngine->AddOnScreenDebugMessage(key, persist_sec, color, prefix + suffix);
+    }
     //GEngine->AddOnScreenDebugMessage(key + 10, 60.0f, color, FString::FromInt(key));
 }
 
@@ -584,3 +598,16 @@ void UAirBlueprintLib::EnableInput(AActor* actor)
 {
     actor->EnableInput(actor->GetWorld()->GetFirstPlayerController());
 }
+
+UObject* UAirBlueprintLib::LoadObject(const std::string& name)
+{
+    FString str(name.c_str());
+    UObject *obj = StaticLoadObject(UObject::StaticClass(), nullptr, *str);
+    if (obj == nullptr) {
+        std::string msg = "Failed to load asset - " + name;
+        FString fmsg(msg.c_str());
+        LogMessage(TEXT("Load: "), fmsg, LogDebugLevel::Failure);
+        throw std::invalid_argument(msg);
+    }
+    return obj;
+}

Unreal/Plugins/AirSim/Source/AirBlueprintLib.h

@@ -13,6 +13,7 @@
 #include "Kismet/KismetMathLibrary.h"
 #include "Components/MeshComponent.h"
 #include "LandscapeProxy.h"
+#include "AirSim.h"
 #include "common/AirSimSettings.hpp"
 #include "AirBlueprintLib.generated.h"
 
@@ -105,6 +106,8 @@ class UAirBlueprintLib : public UBlueprintFunctionLibrary
     static void resetSimulatePhysics(AActor* actor);
     static std::vector<UPrimitiveComponent*> getPhysicsComponents(AActor* actor);
 
+    static UObject* LoadObject(const std::string& name);
+
 private:
     template<typename T>
     static void InitializeObjectStencilID(T* obj, bool ignore_existing = true);

Unreal/Plugins/AirSim/Source/AirSim.cpp

@@ -1,25 +1,26 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
-// Licensed under the MIT License.
-
-#include "AirSim.h"
-#include "Misc/Paths.h"
-
-DEFINE_LOG_CATEGORY(LogAirSim);
-
-class FAirSim : public IModuleInterface
-{
-    virtual void StartupModule() override;
-    virtual void ShutdownModule() override;
-};
-
-IMPLEMENT_MODULE(FAirSim, AirSim)
-
-void FAirSim::StartupModule()
-{
-    //plugin startup
-}
-
-void FAirSim::ShutdownModule()
-{
-    //plugin shutdown
+// Licensed under the MIT License.
+
+#include "AirSim.h"
+#include "Misc/Paths.h"
+
+DEFINE_LOG_CATEGORY(LogAirSim);
+
+class FAirSim : public IModuleInterface
+{
+    virtual void StartupModule() override;
+    virtual void ShutdownModule() override;
+};
+
+IMPLEMENT_MODULE(FAirSim, AirSim)
+
+void FAirSim::StartupModule()
+{
+    //plugin startup
+    UE_LOG(LogAirSim, Log, TEXT("StartupModule: AirSim plugin"));
+}
+
+void FAirSim::ShutdownModule()
+{
+    //plugin shutdown
 }

Unreal/Plugins/AirSim/Source/Car/CarPawn.cpp

@@ -32,17 +32,6 @@ ACarPawn::ACarPawn()
     this->AutoPossessPlayer = EAutoReceiveInput::Player0;
     //this->AutoReceiveInput = EAutoReceiveInput::Player0;
 
-    static MeshContructionHelpers helpers(AirSimSettings::singleton().car_mesh_paths);
-
-    GetMesh()->SetSkeletalMesh(helpers.skeleton);
-    GetMesh()->SetAnimationMode(EAnimationMode::AnimationBlueprint);
-    GetMesh()->SetAnimInstanceClass(helpers.bp->GeneratedClass);
-    SlipperyMaterial = helpers.slippery_mat;
-    NonSlipperyMaterial = helpers.non_slippery_mat;
-
-    static ConstructorHelpers::FClassFinder<APIPCamera> pip_camera_class(TEXT("Blueprint'/AirSim/Blueprints/BP_PIPCamera'"));
-    pip_camera_class_ = pip_camera_class.Succeeded() ? pip_camera_class.Class : nullptr;
-
     UWheeledVehicleMovementComponent4W* Vehicle4W = CastChecked<UWheeledVehicleMovementComponent4W>(GetVehicleMovement());
 
     check(Vehicle4W->WheelSetups.Num() == 4);
@@ -148,7 +137,7 @@ ACarPawn::ACarPawn()
     InCarGear->SetVisibility(true);
 
     // Setup the audio component and allocate it a sound cue
-    static ConstructorHelpers::FObjectFinder<USoundCue> SoundCue(TEXT("/AirSim/VehicleAdv/Sound/Engine_Loop_Cue.Engine_Loop_Cue"));
+    ConstructorHelpers::FObjectFinder<USoundCue> SoundCue(TEXT("/AirSim/VehicleAdv/Sound/Engine_Loop_Cue.Engine_Loop_Cue"));
     EngineSoundComponent = CreateDefaultSubobject<UAudioComponent>(TEXT("EngineSound"));
     EngineSoundComponent->SetSound(SoundCue.Object);
     EngineSoundComponent->SetupAttachment(GetMesh());
@@ -176,6 +165,17 @@ void ACarPawn::initializeForBeginPlay(bool enable_rpc, const std::string& api_se
     else
         EngineSoundComponent->Deactivate();
 
+    // load assets
+    MeshContructionHelpers helpers(AirSimSettings::singleton().car_mesh_paths);
+    GetMesh()->SetSkeletalMesh(helpers.skeleton);
+    GetMesh()->SetAnimationMode(EAnimationMode::AnimationBlueprint);
+    GetMesh()->SetAnimInstanceClass(helpers.bp->GeneratedClass);
+    SlipperyMaterial = helpers.slippery_mat;
+    NonSlipperyMaterial = helpers.non_slippery_mat;
+
+    ConstructorHelpers::FClassFinder<APIPCamera> pip_camera_class(TEXT("Blueprint'/AirSim/Blueprints/BP_PIPCamera'"));
+    pip_camera_class_ = pip_camera_class.Succeeded() ? pip_camera_class.Class : nullptr;
+
     //put camera little bit above vehicle
     FTransform camera_transform(FVector::ZeroVector);
     FActorSpawnParameters camera_spawn_params;

Unreal/Plugins/AirSim/Source/Car/CarPawn.h

@@ -10,6 +10,7 @@
 #include "Components/SkeletalMeshComponent.h"
 #include "PhysicalMaterials/PhysicalMaterial.h"
 #include "common/AirSimSettings.hpp"
+#include "AirBlueprintLib.h"
 #include "CarPawn.generated.h"
 
 class UPhysicalMaterial;
@@ -165,15 +166,12 @@ class ACarPawn : public AWheeledVehicle
 
         MeshContructionHelpers(const msr::airlib::AirSimSettings::CarMeshPaths& paths)
         {
-            skeleton = Cast<USkeletalMesh>(StaticLoadObject(UObject::StaticClass(), 
-                nullptr, * (FString(paths.skeletal.c_str()))));
-            bp = Cast<UBlueprint>(StaticLoadObject(UObject::StaticClass(), 
-                nullptr, * (FString(paths.bp.c_str()))));
-            slippery_mat = Cast<UPhysicalMaterial>(StaticLoadObject(UObject::StaticClass(), 
-                nullptr, * (FString(paths.slippery_mat.c_str()))));
-            non_slippery_mat = Cast<UPhysicalMaterial>(StaticLoadObject(UObject::StaticClass(), 
-                nullptr, * (FString(paths.non_slippery_mat.c_str()))));
+            skeleton = Cast<USkeletalMesh>(UAirBlueprintLib::LoadObject(paths.skeletal));
+            bp = Cast<UBlueprint>(UAirBlueprintLib::LoadObject(paths.bp));
+            slippery_mat = Cast<UPhysicalMaterial>(UAirBlueprintLib::LoadObject(paths.slippery_mat));
+            non_slippery_mat = Cast<UPhysicalMaterial>(UAirBlueprintLib::LoadObject(paths.non_slippery_mat));
         }
+
     };