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

#pragma once

#define DYNAMIC_WIND_INVALID_BONE_INDEX 65535

#define DYNAMIC_WIND_DIRECTIONALITY_SLICES 8

#ifdef __cplusplus
namespace UE::HLSL
{
#endif //__cplusplus

struct FDynamicWindSkeletonData
{
	/** The index of the first element of the FDynamicWindBoneData for this skeleton */
	uint BoneDataOffset;

	/** The height (in units) of the skeleton */
	float SkeletonHeight;

	/** How much to attenuate trunk bones in the skeleton (0-1) */
	float GustAttenuation;

	/** The maximum SimulationGroupIndex value for all bones in the skeleton */
	uint MaxSimulationGroupIndex : 31;

	/** Whether or not this object is ground cover */
	uint bIsGroundCover : 1;
};

struct FDynamicWindBoneData
{
	/** The index of this bone's parent bone, in the skeleton */
	uint ParentBoneIndex;

	/** The wind influence of this bone */
	float Influence;

	/** The simulation group for this bone */
	int SimulationGroupIndex;

	/** The length of bone chain that this bone is a member of */
	float BoneChainLength;

	/** Initial local-space orientation of the bone */
	float4 BindPoseRotation;

	/** Initial local-space position of the bone */
	float3 BindPosePosition;

	/** Whether this bone is to be considered part of a tree trunk */
	uint bIsTrunkBone;
};

struct FDynamicWindBlockHeader
{	
	/** Index of the related FDynamicWindSkeletonData for the block */
	uint SkeletonDataIndex;

	/** Byte offset of the transforms to be written in the transform buffer */
	uint BlockDstTransformOffset;

	/** Number of bones in this block */
	uint BlockNumBones : 8;

	/** Index of the first bone (in the skeleton) of the block */
	uint BlockBoneOffset : 24;

	/** Index of the unique directional anim this block is associated with */
	uint BlockDirectionalityIndex : 8;

	/** Total number of transforms to be written for this skeleton anim. */
	uint TotalTransformCount : 24;
};

#ifdef __cplusplus
} // namespace UE::HLSL

using FDynamicWindSkeletonData = UE::HLSL::FDynamicWindSkeletonData;
using FDynamicWindBoneData = UE::HLSL::FDynamicWindBoneData;
using FDynamicWindBlockHeader = UE::HLSL::FDynamicWindBlockHeader;

#endif //__cplusplus