// Copyright Epic Games, Inc. All Rights Reserved.

#include "ThumbnailRendering/StaticMeshThumbnailRenderer.h"
#include "Misc/App.h"
#include "ShowFlags.h"
#include "SceneView.h"
#include "ThumbnailHelpers.h"
#include "Engine/StaticMesh.h"

UStaticMeshThumbnailRenderer::UStaticMeshThumbnailRenderer(const FObjectInitializer& ObjectInitializer)
    : Super(ObjectInitializer)
{
    ThumbnailScene = nullptr;
}

void UStaticMeshThumbnailRenderer::Draw(UObject* Object, int32 X, int32 Y, uint32 Width, uint32 Height, FRenderTarget* RenderTarget, FCanvas* Canvas, bool bAdditionalViewFamily)
{
    UStaticMesh* StaticMesh = Cast<UStaticMesh>(Object);
    if (StaticMesh != nullptr && !StaticMesh->IsPendingKill())
    {
        if (ThumbnailScene == nullptr || ensure(ThumbnailScene->GetWorld() != nullptr) == false)
        {
            if (ThumbnailScene)
            {
                FlushRenderingCommands();
                delete ThumbnailScene;
            }
            ThumbnailScene = new FStaticMeshThumbnailScene();
        }

        ThumbnailScene->SetStaticMesh(StaticMesh);
        ThumbnailScene->GetScene()->UpdateSpeedTreeWind(0.0);

        FSceneViewFamilyContext ViewFamily(FSceneViewFamily::ConstructionValues(RenderTarget, ThumbnailScene->GetScene(), FEngineShowFlags(ESFIM_Game))
                                               .SetWorldTimes(FApp::GetCurrentTime() - GStartTime, FApp::GetDeltaTime(), FApp::GetCurrentTime() - GStartTime)
                                               .SetAdditionalViewFamily(bAdditionalViewFamily));

        ViewFamily.EngineShowFlags.DisableAdvancedFeatures();
        ViewFamily.EngineShowFlags.MotionBlur = 0;
        ViewFamily.EngineShowFlags.LOD        = 0;

        ThumbnailScene->GetView(&ViewFamily, X, Y, Width, Height);
        RenderViewFamily(Canvas, &ViewFamily);
        ThumbnailScene->SetStaticMesh(nullptr);
    }
}

void UStaticMeshThumbnailRenderer::BeginDestroy()
{
    if (ThumbnailScene != nullptr)
    {
        delete ThumbnailScene;
        ThumbnailScene = nullptr;
    }

    Super::BeginDestroy();
}