UnrealEngineUWP/Engine/Shaders/Private/AreaLightCommon.ush

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

#pragma once

#include "RectLight.ush"

struct FAreaLight
{
	float		SphereSinAlpha;
	float		SphereSinAlphaSoft;
	float		LineCosSubtended;

	float3		FalloffColor;

	FRect		Rect;
	FRectTexture Texture;
	bool		bIsRect;
};

struct FAreaLightIntegrateContext
{
	FAreaLight AreaLight;
	float3 L;
	float NoL;
	float Falloff;
};

bool IsAreaLight(FAreaLight AreaLight)
{
	return (
		AreaLight.bIsRect ||
		AreaLight.SphereSinAlpha > 0.0f ||
		AreaLight.SphereSinAlphaSoft > 0.0f ||
		AreaLight.LineCosSubtended < 1.0f
		) ? true : false;
}

FAreaLightIntegrateContext InitAreaLightIntegrateContext()
{
	// Manual initialization of the area light as the compiler is unhappy otherwise
	FAreaLightIntegrateContext Out;
	Out.AreaLight.SphereSinAlpha = 0;
	Out.AreaLight.SphereSinAlphaSoft = 0;
	Out.AreaLight.LineCosSubtended = 0;
	Out.AreaLight.FalloffColor = 0;
	Out.AreaLight.Rect = (FRect)0;
	Out.AreaLight.bIsRect = false;
//	Out.AreaLight.Texture;
	Out.L = 0;
	Out.NoL = 0;
	Out.Falloff = 0;
	return Out;
}