C++ FVector4函數代碼示例

	// from FStaticLightMesh....
	void FLandscapeStaticLightingMesh::GetStaticLightingVertex(int32 VertexIndex, FStaticLightingVertex& OutVertex) const
	{
		int32 X, Y;
		VertexIndexToXY(VertexIndex, X, Y);

		const int32 LocalX = X - ExpandQuadsX;
		const int32 LocalY = Y - ExpandQuadsY;

		const FColor* Data = GetHeightData( X, Y );

		OutVertex.WorldTangentZ.X = 2.0f / 255.f * (float)Data->B - 1.0f;
		OutVertex.WorldTangentZ.Y = 2.0f / 255.f * (float)Data->A - 1.0f;
		OutVertex.WorldTangentZ.Z = FMath::Sqrt(FMath::Max(1.0f - (FMath::Square(OutVertex.WorldTangentZ.X) + FMath::Square(OutVertex.WorldTangentZ.Y)), 0.f));
		OutVertex.WorldTangentX = FVector4(OutVertex.WorldTangentZ.Z, 0.0f, -OutVertex.WorldTangentZ.X);
		OutVertex.WorldTangentY = OutVertex.WorldTangentZ ^ OutVertex.WorldTangentX;

		// Copied (vaguely) from FLandscapeComponentDataInterface::GetWorldPositionTangents to fix bad lighting when rotated
		const FMatrix LtWNoScale = LocalToWorld.GetMatrixWithoutScale();
		OutVertex.WorldTangentX = LtWNoScale.TransformVector(OutVertex.WorldTangentX);
		OutVertex.WorldTangentY = LtWNoScale.TransformVector(OutVertex.WorldTangentY);
		OutVertex.WorldTangentZ = LtWNoScale.TransformVector(OutVertex.WorldTangentZ);

		const uint16 Height = (Data->R << 8) + Data->G;
		OutVertex.WorldPosition = LocalToWorld.TransformPosition( FVector4( LocalX, LocalY, ((float)Height - 32768.f) * LANDSCAPE_ZSCALE ) );
		//UE_LOG(LogLightmass, Log, TEXT("%d, %d, %d, %d, %d, %d, X:%f, Y:%f, Z:%f "), SectionBaseX + LocalX - ExpandQuadsX, SectionBaseY + LocalY - ExpandQuadsY, ClampedLocalX, ClampedLocalY, SectionBaseX, SectionBaseY, WorldPos.X, WorldPos.Y, WorldPos.Z);

		const int32 LightmapUVIndex = 1;

		OutVertex.TextureCoordinates[0] = FVector2D((float)X / NumVertices, (float)Y / NumVertices); 
		OutVertex.TextureCoordinates[LightmapUVIndex].X = X * UVFactor;
		OutVertex.TextureCoordinates[LightmapUVIndex].Y = Y * UVFactor;
	}

	// from FStaticLightMesh....
	void FLandscapeStaticLightingMesh::GetStaticLightingVertex(int32 VertexIndex, FStaticLightingVertex& OutVertex) const
	{
		int32 X, Y;
		VertexIndexToXY(VertexIndex, X, Y);

		//GetWorldPositionTangents(X, Y, OutVertex.WorldPosition, OutVertex.WorldTangentX, OutVertex.WorldTangentY, OutVertex.WorldTangentZ);
		int32 LocalX = X-ExpandQuadsX;
		int32 LocalY = Y-ExpandQuadsY;

		const FColor* Data = GetHeightData( X, Y );

		OutVertex.WorldTangentZ.X = 2.f / 255.f * (float)Data->B - 1.f;
		OutVertex.WorldTangentZ.Y = 2.f / 255.f * (float)Data->A - 1.f;
		OutVertex.WorldTangentZ.Z = FMath::Sqrt(FMath::Max(1.f - (FMath::Square(OutVertex.WorldTangentZ.X)+FMath::Square(OutVertex.WorldTangentZ.Y)), 0.f));
		OutVertex.WorldTangentX = FVector4(OutVertex.WorldTangentZ.Z, 0.f, -OutVertex.WorldTangentZ.X);
		OutVertex.WorldTangentY = OutVertex.WorldTangentZ ^ OutVertex.WorldTangentX;

		// Assume there is no rotation, so we don't need to do any LocalToWorld.
		uint16 Height = (Data->R << 8) + Data->G;

		OutVertex.WorldPosition = LocalToWorld.TransformPosition( FVector4( LocalX, LocalY, ((float)Height - 32768.f) * LANDSCAPE_ZSCALE ) );
		//UE_LOG(LogLightmass, Log, TEXT("%d, %d, %d, %d, %d, %d, X:%f, Y:%f, Z:%f "), SectionBaseX+LocalX-ExpandQuadsX, SectionBaseY+LocalY-ExpandQuadsY, ClampedLocalX, ClampedLocalY, SectionBaseX, SectionBaseY, WorldPos.X, WorldPos.Y, WorldPos.Z);

		int32 LightmapUVIndex = 1;

		OutVertex.TextureCoordinates[0] = FVector2D((float)X / NumVertices, (float)Y / NumVertices); 
		OutVertex.TextureCoordinates[LightmapUVIndex].X = X * UVFactor;
		OutVertex.TextureCoordinates[LightmapUVIndex].Y = Y * UVFactor;
	}

void FCanvasTriangleItem::Draw( class FCanvas* InCanvas )
{
	SCOPE_CYCLE_COUNTER(STAT_Canvas_TriItemTime);

	FBatchedElements* BatchedElements = InCanvas->GetBatchedElements(FCanvas::ET_Triangle, BatchedElementParameters, Texture, BlendMode);
	
	FHitProxyId HitProxyId = InCanvas->GetHitProxyId();

	for(int32 i=0; i<TriangleList.Num(); i++)
	{
		const FCanvasUVTri& Tri = TriangleList[i];
		int32 V0 = BatchedElements->AddVertex(FVector4(Tri.V0_Pos.X,Tri.V0_Pos.Y,0,1), Tri.V0_UV, Tri.V0_Color, HitProxyId);
		int32 V1 = BatchedElements->AddVertex(FVector4(Tri.V1_Pos.X,Tri.V1_Pos.Y,0,1), Tri.V1_UV, Tri.V1_Color, HitProxyId);
		int32 V2 = BatchedElements->AddVertex(FVector4(Tri.V2_Pos.X,Tri.V2_Pos.Y,0,1), Tri.V2_UV, Tri.V2_Color, HitProxyId);

		if( BatchedElementParameters )
		{
			BatchedElements->AddTriangle(V0,V1,V2, BatchedElementParameters, BlendMode);
		}
		else
		{
			check( Texture );
			BatchedElements->AddTriangle(V0,V1,V2,Texture, BlendMode);
		}
	}	
}

	virtual void SetMesh(FRHICommandList& RHICmdList, FShader* Shader,const FVertexFactory* VertexFactory,const FSceneView& View,const FMeshBatchElement& BatchElement,uint32 DataFlags) const override
	{
		const bool bInstanced = View.GetFeatureLevel() >= ERHIFeatureLevel::SM4;
		FMeshParticleVertexFactory* MeshParticleVF = (FMeshParticleVertexFactory*)VertexFactory;
		FVertexShaderRHIParamRef VertexShaderRHI = Shader->GetVertexShader();
		SetUniformBufferParameter(RHICmdList, VertexShaderRHI, Shader->GetUniformBufferParameter<FMeshParticleUniformParameters>(), MeshParticleVF->GetUniformBuffer() );

		if (!bInstanced)
		{
			const FMeshParticleVertexFactory::FBatchParametersCPU* BatchParameters = (const FMeshParticleVertexFactory::FBatchParametersCPU*)BatchElement.UserData;
			const FMeshParticleInstanceVertex* Vertex = BatchParameters->InstanceBuffer + BatchElement.UserIndex;
			const FMeshParticleInstanceVertexDynamicParameter* DynamicVertex = BatchParameters->DynamicParameterBuffer + BatchElement.UserIndex;

			SetShaderValue(RHICmdList, VertexShaderRHI, Transform1, Vertex->Transform[0]);
			SetShaderValue(RHICmdList, VertexShaderRHI, Transform2, Vertex->Transform[1]);
			SetShaderValue(RHICmdList, VertexShaderRHI, Transform3, Vertex->Transform[2]);
			SetShaderValue(RHICmdList, VertexShaderRHI, SubUVParams, FVector4((float)Vertex->SubUVParams[0], (float)Vertex->SubUVParams[1], (float)Vertex->SubUVParams[2], (float)Vertex->SubUVParams[3]));
			SetShaderValue(RHICmdList, VertexShaderRHI, SubUVLerp, Vertex->SubUVLerp);
			SetShaderValue(RHICmdList, VertexShaderRHI, ParticleDirection, Vertex->Velocity);
			SetShaderValue(RHICmdList, VertexShaderRHI, RelativeTime, Vertex->RelativeTime);
			if (BatchParameters->DynamicParameterBuffer)
			{
				SetShaderValue(RHICmdList, VertexShaderRHI, DynamicParameter, FVector4(DynamicVertex->DynamicValue[0], DynamicVertex->DynamicValue[1], DynamicVertex->DynamicValue[2], DynamicVertex->DynamicValue[3]));
			}
			SetShaderValue(RHICmdList, VertexShaderRHI, ParticleColor, FVector4(Vertex->Color.Component(0), Vertex->Color.Component(1), Vertex->Color.Component(2), Vertex->Color.Component(3)));
		}
	}

	virtual void InitRHI() override
	{
		FRHIResourceCreateInfo CreateInfo;
		VertexBufferRHI = RHICreateVertexBuffer(sizeof(FVector4) * 2, BUF_Static, CreateInfo);
		FVector4* DummyContents = (FVector4*)RHILockVertexBuffer(VertexBufferRHI,0,sizeof(FVector4)*2,RLM_WriteOnly);
		DummyContents[0] = FVector4(0.0f, 0.0f, 0.0f, 0.0f);
		DummyContents[1] = FVector4(1.0f, 1.0f, 1.0f, 1.0f);
		RHIUnlockVertexBuffer(VertexBufferRHI);
	}

void FNiagaraSimulation::Tick(float DeltaSeconds)
{
	SCOPE_CYCLE_COUNTER(STAT_NiagaraTick);
	SimpleTimer TickTime;

	UNiagaraEmitterProperties* PinnedProps = Props.Get();
	if (!PinnedProps || !bIsEnabled || TickState == NTS_Suspended || TickState == NTS_Dead)
	{
		return;
	}

	Age += DeltaSeconds;

	check(Data.GetNumVariables() > 0);
	check(PinnedProps->SpawnScriptProps.Script);
	check(PinnedProps->UpdateScriptProps.Script);
	
	TickEvents(DeltaSeconds);

	// Figure out how many we will spawn.
	int32 OrigNumParticles = Data.GetNumInstances();
	int32 NumToSpawn = CalcNumToSpawn(DeltaSeconds);
	int32 MaxNewParticles = OrigNumParticles + NumToSpawn;
	Data.Allocate(MaxNewParticles);

	ExternalConstants.SetOrAdd(BUILTIN_CONST_EMITTERAGE, FVector4(Age, Age, Age, Age));
	ExternalConstants.SetOrAdd(BUILTIN_CONST_DELTATIME, FVector4(DeltaSeconds, DeltaSeconds, DeltaSeconds, DeltaSeconds));

	// Simulate particles forward by DeltaSeconds.
	if (TickState==NTS_Running || TickState==NTS_Dieing)
	{
		SCOPE_CYCLE_COUNTER(STAT_NiagaraSimulate);
		RunVMScript(PinnedProps->UpdateScriptProps, EUnusedAttributeBehaviour::PassThrough);
	}

	//Init new particles with the spawn script.
	if (TickState==NTS_Running)
	{
		SCOPE_CYCLE_COUNTER(STAT_NiagaraSpawn);
		Data.SetNumInstances(MaxNewParticles);
		//For now, zero any unused attributes here. But as this is really uninitialized data we should maybe make this a more serious error.
		RunVMScript(PinnedProps->SpawnScriptProps, EUnusedAttributeBehaviour::Zero, OrigNumParticles, NumToSpawn);

		if (bGenerateSpawnEvents)
		{
			SpawnEventGenerator.OnSpawned(OrigNumParticles, NumToSpawn);
		}
	}


	CPUTimeMS = TickTime.GetElapsedMilliseconds();

	INC_DWORD_STAT_BY(STAT_NiagaraNumParticles, Data.GetNumInstances());
}

bool FWindSourceSceneProxy::GetDirectionalWindParameters(FVector4& WindDirectionAndSpeed, float& Weight) const 
{ 
	if (bIsPointSource)
	{
		Weight = 0.f;
		WindDirectionAndSpeed = FVector4(0,0,0,0);
		return false;
	}

	Weight = Strength;
	WindDirectionAndSpeed = FVector4(Direction * Strength, Speed); 
	return true;
}

	/** Initialization constructor. */
	explicit FNiagaraCompilerContext(FCompilerResultsLog& InLog)
		: Log(InLog)
	{
		ConstantNames.Add(TEXT("__zero__"));
		Constants.Add(FVector4(0.0f, 0.0f, 0.0f, 0.0f));

		// Setup built-in constants.
		for (uint32 i = 0; i < NiagaraConstants::NumBuiltinConstants; i++)
		{
			ConstantNames.Add(NiagaraConstants::ConstantNames[i]);
			Constants.Add(FVector4(0.0f, 0.0f, 0.0f, 0.0f));
		}
	}

void FSceneView::DeprojectScreenToWorld(const FVector2D& ScreenPos, const FIntRect& ViewRect, const FMatrix& InvViewMatrix, const FMatrix& InvProjectionMatrix, FVector& out_WorldOrigin, FVector& out_WorldDirection)
{
	int32 PixelX = FMath::TruncToInt(ScreenPos.X);
	int32 PixelY = FMath::TruncToInt(ScreenPos.Y);

	// Get the eye position and direction of the mouse cursor in two stages (inverse transform projection, then inverse transform view).
	// This avoids the numerical instability that occurs when a view matrix with large translation is composed with a projection matrix

	// Get the pixel coordinates into 0..1 normalized coordinates within the constrained view rectangle
	const float NormalizedX = (PixelX - ViewRect.Min.X) / ((float)ViewRect.Width());
	const float NormalizedY = (PixelY - ViewRect.Min.Y) / ((float)ViewRect.Height());

	// Get the pixel coordinates into -1..1 projection space
	const float ScreenSpaceX = (NormalizedX - 0.5f) * 2.0f;
	const float ScreenSpaceY = ((1.0f - NormalizedY) - 0.5f) * 2.0f;

	// The start of the raytrace is defined to be at mousex,mousey,1 in projection space (z=1 is near, z=0 is far - this gives us better precision)
	// To get the direction of the raytrace we need to use any z between the near and the far plane, so let's use (mousex, mousey, 0.5)
	const FVector4 RayStartProjectionSpace = FVector4(ScreenSpaceX, ScreenSpaceY, 1.0f, 1.0f);
	const FVector4 RayEndProjectionSpace = FVector4(ScreenSpaceX, ScreenSpaceY, 0.5f, 1.0f);

	// Projection (changing the W coordinate) is not handled by the FMatrix transforms that work with vectors, so multiplications
	// by the projection matrix should use homogeneous coordinates (i.e. FPlane).
	const FVector4 HGRayStartViewSpace = InvProjectionMatrix.TransformFVector4(RayStartProjectionSpace);
	const FVector4 HGRayEndViewSpace = InvProjectionMatrix.TransformFVector4(RayEndProjectionSpace);
	FVector RayStartViewSpace(HGRayStartViewSpace.X, HGRayStartViewSpace.Y, HGRayStartViewSpace.Z);
	FVector RayEndViewSpace(HGRayEndViewSpace.X,   HGRayEndViewSpace.Y,   HGRayEndViewSpace.Z);
	// divide vectors by W to undo any projection and get the 3-space coordinate 
	if (HGRayStartViewSpace.W != 0.0f)
	{
		RayStartViewSpace /= HGRayStartViewSpace.W;
	}
	if (HGRayEndViewSpace.W != 0.0f)
	{
		RayEndViewSpace /= HGRayEndViewSpace.W;
	}
	FVector RayDirViewSpace = RayEndViewSpace - RayStartViewSpace;
	RayDirViewSpace = RayDirViewSpace.GetSafeNormal();

	// The view transform does not have projection, so we can use the standard functions that deal with vectors and normals (normals
	// are vectors that do not use the translational part of a rotation/translation)
	const FVector RayStartWorldSpace = InvViewMatrix.TransformPosition(RayStartViewSpace);
	const FVector RayDirWorldSpace = InvViewMatrix.TransformVector(RayDirViewSpace);

	// Finally, store the results in the hitcheck inputs.  The start position is the eye, and the end position
	// is the eye plus a long distance in the direction the mouse is pointing.
	out_WorldOrigin = RayStartWorldSpace;
	out_WorldDirection = RayDirWorldSpace.GetSafeNormal();
}

void FSceneRenderer::InitFogConstants()
{
	// console command override
	float FogDensityOverride = -1.0f;
	float FogStartDistanceOverride = -1.0f;

#if !(UE_BUILD_SHIPPING || UE_BUILD_TEST)
	{
		// console variable overrides
		FogDensityOverride = CVarFogDensity.GetValueOnAnyThread();
		FogStartDistanceOverride = CVarFogStartDistance.GetValueOnAnyThread();
	}
#endif // !(UE_BUILD_SHIPPING || UE_BUILD_TEST)

	for(int32 ViewIndex = 0;ViewIndex < Views.Num();ViewIndex++)
	{
		FViewInfo& View = Views[ViewIndex];
		// set fog consts based on height fog components
		if(ShouldRenderFog(*View.Family))
		{
			if (Scene->ExponentialFogs.Num() > 0)
			{
				const FExponentialHeightFogSceneInfo& FogInfo = Scene->ExponentialFogs[0];
				const float CosTerminatorAngle = FMath::Clamp(FMath::Cos(FogInfo.LightTerminatorAngle * PI / 180.0f), -1.0f + DELTA, 1.0f - DELTA);
				const float CollapsedFogParameterPower = FMath::Clamp(
						-FogInfo.FogHeightFalloff * (View.ViewMatrices.ViewOrigin.Z - FogInfo.FogHeight),
						-126.f + 1.f, // min and max exponent values for IEEE floating points (http://en.wikipedia.org/wiki/IEEE_floating_point)
						+127.f - 1.f
						);
				const float CollapsedFogParameter = FogInfo.FogDensity * FMath::Pow(2.0f, CollapsedFogParameterPower);
				View.ExponentialFogParameters = FVector4(CollapsedFogParameter, FogInfo.FogHeightFalloff, CosTerminatorAngle, FogInfo.StartDistance);
				View.ExponentialFogColor = FVector(FogInfo.FogColor.R, FogInfo.FogColor.G, FogInfo.FogColor.B);
				View.FogMaxOpacity = FogInfo.FogMaxOpacity;

				View.DirectionalInscatteringExponent = FogInfo.DirectionalInscatteringExponent;
				View.DirectionalInscatteringStartDistance = FogInfo.DirectionalInscatteringStartDistance;
				View.bUseDirectionalInscattering = false;
				View.InscatteringLightDirection = FVector(0);

				for (TSparseArray<FLightSceneInfoCompact>::TConstIterator It(Scene->Lights); It; ++It)
				{
					const FLightSceneInfoCompact& LightInfo = *It;

					// This will find the first directional light that is set to be used as an atmospheric sun light of sufficient brightness.
					// If you have more than one directional light with these properties then all subsequent lights will be ignored.
					if (LightInfo.LightSceneInfo->Proxy->GetLightType() == LightType_Directional
						&& LightInfo.LightSceneInfo->Proxy->IsUsedAsAtmosphereSunLight()
						&& LightInfo.LightSceneInfo->Proxy->GetColor().ComputeLuminance() > KINDA_SMALL_NUMBER
						&& FogInfo.DirectionalInscatteringColor.ComputeLuminance() > KINDA_SMALL_NUMBER)
					{
						View.InscatteringLightDirection = -LightInfo.LightSceneInfo->Proxy->GetDirection();
						View.bUseDirectionalInscattering = true;
						View.DirectionalInscatteringColor = FogInfo.DirectionalInscatteringColor * LightInfo.LightSceneInfo->Proxy->GetColor().ComputeLuminance();
						break;
					}
				}
			}
		}
	}
}

void FIndirectLightingCache::UpdateTransitionsOverTime(const TArray<FIndirectLightingCacheAllocation*>& TransitionsOverTimeToUpdate, float DeltaWorldTime) const
{
	for (int32 AllocationIndex = 0; AllocationIndex < TransitionsOverTimeToUpdate.Num(); AllocationIndex++)
	{
		FIndirectLightingCacheAllocation* Allocation = TransitionsOverTimeToUpdate[AllocationIndex];
		const float TransitionDistance = (Allocation->SingleSamplePosition - Allocation->TargetPosition).Size();

		if (TransitionDistance > DELTA)
		{
			// Compute a frame rate independent transition by maintaining a constant world space speed between the current sample position and the target position
			const float LerpFactor = FMath::Clamp(GSingleSampleTransitionSpeed * DeltaWorldTime / TransitionDistance, 0.0f, 1.0f);
			Allocation->SingleSamplePosition = FMath::Lerp(Allocation->SingleSamplePosition, Allocation->TargetPosition, LerpFactor);

			for (int32 VectorIndex = 0; VectorIndex < ARRAY_COUNT(Allocation->SingleSamplePacked); VectorIndex++)
			{
				Allocation->SingleSamplePacked[VectorIndex] = FMath::Lerp(Allocation->SingleSamplePacked[VectorIndex], Allocation->TargetSamplePacked[VectorIndex], LerpFactor);
			}

			Allocation->CurrentDirectionalShadowing = FMath::Lerp(Allocation->CurrentDirectionalShadowing, Allocation->TargetDirectionalShadowing, LerpFactor);

			const FVector CurrentSkyBentNormal = FMath::Lerp(
				FVector(Allocation->CurrentSkyBentNormal) * Allocation->CurrentSkyBentNormal.W, 
				FVector(Allocation->TargetSkyBentNormal) * Allocation->TargetSkyBentNormal.W, 
				LerpFactor);

			const float BentNormalLength = CurrentSkyBentNormal.Size();

			Allocation->CurrentSkyBentNormal = FVector4(CurrentSkyBentNormal / FMath::Max(BentNormalLength, .0001f), BentNormalLength);
		}
	}
}

void FPixelShaderUsageExample::ExecutePixelShader(UTextureRenderTarget2D* RenderTarget, FTexture2DRHIRef InputTexture, FColor EndColor, float TextureParameterBlendFactor)
{
	check(IsInGameThread());

	if (bIsUnloading || bIsPixelShaderExecuting) //Skip this execution round if we are already executing
		return;

	if (!RenderTarget)
		return;

	bIsPixelShaderExecuting = true;

	if (TextureParameter != InputTexture)
		bMustRegenerateSRV = true;

	//Now set our runtime parameters!
	VariableParameters.EndColor = FVector4(EndColor.R / 255.0, EndColor.G / 255.0, EndColor.B / 255.0, EndColor.A / 255.0);
	VariableParameters.TextureParameterBlendFactor = TextureParameterBlendFactor;

	CurrentRenderTarget = RenderTarget;
	TextureParameter = InputTexture;

	//This macro sends the function we declare inside to be run on the render thread. What we do is essentially just send this class and tell the render thread to run the internal render function as soon as it can.
	//I am still not 100% Certain on the thread safety of this, if you are getting crashes, depending on how advanced code you have in the start of the ExecutePixelShader function, you might have to use a lock :)
	ENQUEUE_UNIQUE_RENDER_COMMAND_ONEPARAMETER(
		FPixelShaderRunner,
		FPixelShaderUsageExample*, PixelShader, this,
		{
			PixelShader->ExecutePixelShaderInternal();
		}

void FShadowMap2D::Serialize(FArchive& Ar)
{
	FShadowMap::Serialize(Ar);
	
	if( Ar.IsCooking() && !Ar.CookingTarget()->SupportsFeature(ETargetPlatformFeatures::DistanceFieldShadows) )
	{
		UShadowMapTexture2D* Dummy = NULL;
		Ar << Dummy;
	}
	else
	{
		Ar << Texture;
	}

	Ar << CoordinateScale << CoordinateBias;

	for (int Channel = 0; Channel < ARRAY_COUNT(bChannelValid); Channel++)
	{
		Ar << bChannelValid[Channel];
	}

	if (Ar.UE4Ver() >= VER_UE4_STATIC_SHADOWMAP_PENUMBRA_SIZE)
	{
		Ar << InvUniformPenumbraSize;
	}
	else if (Ar.IsLoading())
	{
		const float LegacyValue = 1.0f / .05f;
		InvUniformPenumbraSize = FVector4(LegacyValue, LegacyValue, LegacyValue, LegacyValue);
	}
}

UTexture::UTexture(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
{
	SRGB = true;
	Filter = TF_Default;
#if WITH_EDITORONLY_DATA
	AdjustBrightness = 1.0f;
	AdjustBrightnessCurve = 1.0f;
	AdjustVibrance = 0.0f;
	AdjustSaturation = 1.0f;
	AdjustRGBCurve = 1.0f;
	AdjustHue = 0.0f;
	AdjustMinAlpha = 0.0f;
	AdjustMaxAlpha = 1.0f;
	MaxTextureSize = 0; // means no limitation
	MipGenSettings = TMGS_FromTextureGroup;
	CompositeTextureMode = CTM_NormalRoughnessToAlpha;
	CompositePower = 1.0f;
	bUseLegacyGamma = false;
	AlphaCoverageThresholds = FVector4(0, 0, 0, 0);
	PaddingColor = FColor::Black;
	ChromaKeyColor = FColorList::Magenta;
	ChromaKeyThreshold = 1.0f / 255.0f;
	
#endif // #if WITH_EDITORONLY_DATA

	if (FApp::CanEverRender() && !IsTemplate())
	{
		TextureReference.BeginInit_GameThread();
	}
}

// Render onto tt (using renderer) sitting @ cameraPos,
// facing cameraDir, an object with radiusWorldUnits.
void ATheHUD::RenderScreen( USceneCaptureComponent2D* renderer, FVector lookPos, float radiusWorldUnits, FVector cameraDir )
{
  UTextureRenderTarget2D* tt = renderer->TextureTarget;
  // http://stackoverflow.com/questions/3717226/
  // radiusOnScreenPX = radiusWorldUnits*SW/(tan(fov / 2) * Z);
  // ZBack = radiusWorldUnits*SW/(tan( fovy / 2 )*radiusOnScreenPX)
  // Calculate Z distance back for a given pixel radius
  // Set particular render properties & render the screen
  // to texture in w.
  float D = GetZDistance( radiusWorldUnits, tt->GetSurfaceWidth(), tt->GetSurfaceHeight(), renderer->FOVAngle );
  FVector eyePos = lookPos - cameraDir * D;
  FQuat quat = cameraDir.Rotation().Quaternion();
  renderer->SetRelativeLocationAndRotation( eyePos, quat );
  
  FVector2D screenSize = ui->gameChrome->gameCanvas->Size;
  screenSize.X -= ui->gameChrome->rightPanel->Size.X;

  FVector up = renderer->GetUpVector();
  FLookAtMatrix lookAt( eyePos, lookPos, up );
  FPerspectiveMatrix persp( rendererMinimap->FOVAngle/2.f, 1.f, 1.f, 0.5f );
  FMatrix mvp1 = lookAt * persp;

  vector<Ray> rays = Game->pc->GetFrustumRays( FBox2DU( 0.f, 0.f, screenSize.X, screenSize.Y ) );
  float zValue = lookPos.Z;
  FPlane plane( FVector(0.f, 0.f, 1.f), zValue );
  vector<FVector> pts;
  for( int i = 0; i < rays.size(); i++ )
  {
    FVector pt = FMath::LinePlaneIntersection( rays[i].start, rays[i].end, plane );
    //Game->flycam->DrawDebug( pt, 25.f, FLinearColor::White, .25f );
    pts.push_back( pt );
  }

  //FLinearColor Cyan(0,1,1,1);
  //for( int i = 0; i < pts.size() - 1; i++ )
  //{
  //  Game->flycam->DrawDebug( pts[i], pts[i+1], 25.f, Cyan, .25f );
  //}
  //if( pts.size() > 1 )
  //{
  //  Game->flycam->DrawDebug( pts[pts.size()-1], pts[0], 25.f, Cyan, .25f );
  //}

  ui->gameChrome->rightPanel->minimap->pts.clear();
  FVector2D minimapSize = ui->gameChrome->rightPanel->minimap->Size;
  for( int i = 0; i < pts.size(); i++ )
  {
    FVector4 transformedPt = mvp1.TransformPosition( pts[i] );
    float div = transformedPt.W;
    transformedPt /= FVector4( div, div, div, div );
    FVector2D p( transformedPt.X, transformedPt.Y ); // between [-1,1]
    p *= 4.f/3.f; //!! Multiplying P by 4./3 req'd.. double-check
    p *= minimapSize/2.f;
    p.Y *= -1.f;
    p += minimapSize/2.f;

    p += ui->gameChrome->rightPanel->minimap->GetAbsPos();
    ui->gameChrome->rightPanel->minimap->pts.push_back( p );
  }
}