UnrealEngineUWP/Engine/Shaders/Private/InstancedStereo.ush

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

/*=============================================================================
	InstancedStereo.usf: Resolve which view uniforms in a stereo pair to use.
=============================================================================*/

#pragma once

// Explictly include view uniform buffers
#include "/Engine/Generated/UniformBuffers/View.ush"
#include "/Engine/Generated/UniformBuffers/InstancedView.ush"

// ViewState, GetPrimaryView and GetInstancedView are generated by the shader compiler to ensure View uniform buffer changes are up to date.
// see GenerateInstancedStereoCode()
#include "/Engine/Generated/GeneratedInstancedStereo.ush"

static ViewState ResolvedView;

ViewState ResolveView()
{
	return GetPrimaryView();
}

#if INSTANCED_STEREO
static const float EyeOffsetScale[2] = { -1.0, 1.0 };
static const float4 EyeClipEdge[2] = { float4(-1.0, 0.0, 0.0, 1.0), float4(1.0, 0.0, 0.0, 1.0) };
#endif

// Generated for Metal in GeneratedInstancedStereo.usf
#if !(COMPILER_METAL && (COMPILER_HLSLCC == 1)) && (INSTANCED_STEREO || MOBILE_MULTI_VIEW)
ViewState ResolveView(uint ViewIndex)
{
	if (ViewIndex == 0)
	{
		return GetPrimaryView();
	}
	else
	{
		return GetInstancedView();
	}
}
#endif

bool IsInstancedStereo()
{
#if INSTANCED_STEREO
	return InstancedView_StereoPassIndex > 0;
#else
	return false;
#endif
}

uint GetEyeIndex(uint InstanceId)
{
#if INSTANCED_STEREO
	return IsInstancedStereo() ? InstanceId & 1 : 0;
#else
	return 0;
#endif
}

uint GetInstanceId(uint InstanceId)
{
#if INSTANCED_STEREO
	return IsInstancedStereo() ? InstanceId / 2 : InstanceId;
#else
	return InstanceId;
#endif
}