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FractalTree.cs
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FractalTree.cs
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using UnityEngine;
using Unity.Mathematics;
using static Unity.Mathematics.math;
using math = Unity.Mathematics;
using System.Collections.Generic;
using System.Linq;
using System;
using UnityEngine.Jobs;
using Unity.Burst;
using Unity.Collections;
using Unity.Jobs;
using UnityEngine.Rendering;
using System.Collections;
using System.Runtime.InteropServices;
using Random = Unity.Mathematics.Random;
public enum FallState
{
Initial = 0,
Attached = 1,
Flying = 2,
Grounded = 3
}
[StructLayout(LayoutKind.Sequential)]
public struct PetalData
{
public FallState FallState;
public float3 Position;
public float3 Velocity;
public quaternion Rotation;
public float3 AngularVelocity;
public float3 Scale;
}
public struct AudioSourceTimer
{
public AudioSource AudioSource;
public float Timer;
}
public class FractalTree : MonoBehaviour
{
[Header("References")]
[SerializeField] MeshFilter meshFilter;
[Header("Generated Data")]
[SerializeField] Mesh treeMesh = null;
[Header("Generation")]
[Range(1, 100)] public uint Seed;
[Range(0, 16)] public int TotalDepth;
[Range(0, 1)] public float BranchTilt;
[Range(0, 2)] public float BranchLength;
[Range(0, 2)] public float TiltVariation;
[Range(0, 2)] public float TangentVariation;
[Range(0, 1)] public float Flatness;
[Range(1, 16)] public float TrunkDepth;
[Range(0, 10)] public float TrunkLength;
[Range(0, 2)] public float LengthVariation;
[Range(0.001f, 1)] public float Radius;
[Range(0, 10)] public float TrunkRadius;
[Range(0, 1)] public float LeafMinSize;
[Range(0, 2)] public float LeafMaxSize;
[Header("Wind")]
public ParticleSystem WindParticleSystem;
[Range(0, 1)] public float WindDirectionVariation;
[Range(0, 1)] public float WindDirectionProbability;
[Range(0, 1)] public float WindDirectionReachDampen;
[Range(0, 1)] public float WindForceBase;
[Range(0, 1)] public float WindForceVariation;
[Range(0, 1)] public float WindForceProbability;
[Range(0, 10)] public float WindForceReachDampen;
[Range(0, 1)] public float Gravity;
[Tooltip("Leaves per second")] [Range(0, 9999)] public float FallRate;
[Range(0, 2)] public float PetalRotationForce;
[Header("Petal Mesh Data")]
public Material PetalMaterial;
public Mesh PetalMesh;
#region Generation
struct Branch
{
public float3 From, To;
public quaternion Rotation;
public int Depth;
public float Trunkness;
}
struct Leaf
{
public float3 Position;
public float3 Normal;
public quaternion LookAt;
public float3 Scale;
}
readonly List<Branch> branches = new List<Branch>();
readonly List<Leaf> leaves = new List<Leaf>();
void Reset()
{
meshFilter = GetComponent<MeshFilter>();
}
void Refresh()
{
#if UNITY_EDITOR
if (!treeMesh || !meshFilter.sharedMesh)
meshFilter.sharedMesh = treeMesh = new Mesh();
#endif
leaves.Clear();
branches.Clear();
var random = new Random(Seed);
BuildSubtree(float3(0, 0, 0), math.quaternion.identity, TotalDepth, random);
var vertices = new List<Vector3>();
var normals = new List<Vector3>();
var indices = new List<int>();
var texCoords = new List<Vector4>();
for (int i = 0; i < branches.Count; i++)
{
var branch = branches[i];
var baseNormalizedDepth = ((float)branch.Depth + 1) / (TotalDepth + 1);
var topNormalizedDepth = max((float)branch.Depth / (TotalDepth + 1), 0.001f);
var baseRadius = Radius * baseNormalizedDepth;
var topRadius = Radius * topNormalizedDepth;
var baseTrunkness = 1 - saturate(((float)TotalDepth - branch.Depth) / TrunkDepth);
var topTrunkness = 1 - saturate(((float)TotalDepth - (branch.Depth - 1)) / TrunkDepth);
baseRadius *= lerp(1, 1 + TrunkRadius, baseTrunkness);
topRadius *= lerp(1, 1 + TrunkRadius, topTrunkness);
int segments = Mathf.RoundToInt(Mathf.Lerp(4, 7, baseNormalizedDepth));
int fromVertex = vertices.Count;
for (int j = 0; j < segments; j++)
{
var angle = (float)j / segments * Mathf.PI * 2;
var offset = mul(branch.Rotation, float3(cos(angle), 0, sin(angle)) * baseRadius);
vertices.Add(branch.From + offset);
normals.Add(normalize(offset));
var bendability = 1 - baseNormalizedDepth;
texCoords.Add(new Vector4(bendability, 0, 0, 0));
offset = mul(branch.Rotation, float3(cos(angle), 0, sin(angle)) * topRadius);
vertices.Add(branch.To + offset);
normals.Add(normalize(offset));
bendability = 1 - topNormalizedDepth;
texCoords.Add(new Vector4(bendability, 0, 0, 0));
}
int toVertex = vertices.Count;
var range = toVertex - fromVertex;
for (int j = 0; j < range; j += 2)
{
indices.Add(WrapIndex(fromVertex, j, range));
indices.Add(WrapIndex(fromVertex, j + 1, range));
indices.Add(WrapIndex(fromVertex, j + 2, range));
indices.Add(WrapIndex(fromVertex, j + 2, range));
indices.Add(WrapIndex(fromVertex, j + 1, range));
indices.Add(WrapIndex(fromVertex, j + 3, range));
}
}
treeMesh.Clear();
treeMesh.indexFormat = IndexFormat.UInt32;
treeMesh.subMeshCount = 1;
treeMesh.SetVertices(vertices);
treeMesh.SetUVs(0, texCoords);
treeMesh.SetIndices(indices.ToArray(), MeshTopology.Triangles, 0);
treeMesh.SetNormals(normals);
treeMesh.RecalculateBounds();
}
int WrapIndex(int @base, int offset, int limit)
{
return (offset % limit) + @base;
}
void OnValidate()
{
Refresh();
}
void BuildSubtree(float3 origin, quaternion rotation, int depth, math.Random rng)
{
var normalizedDepth = ((float)depth + 1) / (TotalDepth + 1);
var trunkness = 1 - saturate(((float)TotalDepth - depth) / TrunkDepth);
var lengthModifier = lerp(1, 1 + TrunkLength, trunkness);
lengthModifier += rng.NextFloat(-1, 1) * LengthVariation;
var dir = rotate(rotation, float3(0, 1, 0));
var dest = origin + dir * BranchLength * normalizedDepth * lengthModifier;
branches.Add(new Branch
{
From = origin,
To = dest,
Rotation = rotation,
Depth = depth,
Trunkness = trunkness
});
if (depth > 0)
{
var commonYaw = math.quaternion.AxisAngle(new float3(0, 1, 0), rng.NextFloat() * (float)PI * 2);
var flatYaw = math.quaternion.identity;
for (int i = 0; i < 2; i++)
{
var randomYaw = math.quaternion.AxisAngle(new float3(0, 1, 0), rng.NextFloat() * (float)PI * 2);
var actualYaw = slerp(slerp(commonYaw, randomYaw, TangentVariation), flatYaw, Flatness);
var tangent = rotate(actualYaw, float3(0, 0, 1));
var tiltAngle = lerp(BranchTilt, rng.NextFloat() * BranchTilt * 2, TiltVariation);
var actualTiltAngle = lerp(-1, 1, i) * tiltAngle;
var pitch = math.quaternion.AxisAngle(tangent, actualTiltAngle);
BuildSubtree(dest, mul(pitch, rotation), depth - 1, rng);
}
}
else
{
var leaf = new Leaf
{
Position = dest,
Normal = dest - origin,
};
leaf.LookAt = Quaternion.LookRotation(leaf.Normal);
leaf.Scale = float3(rng.NextFloat(LeafMinSize, LeafMaxSize));
leaves.Add(leaf);
}
}
#endregion
NativeArray<PetalData> petalData;
NativeQueue<int> groundedIndices, risingIndices;
JobHandle petalUpdateJobHandle;
Queue<int> detachableIndices;
Pool<AudioSource> audioSources;
readonly List<AudioSourceTimer> audioDisableQueue = new List<AudioSourceTimer>();
NativeArray<Matrix4x4> petalMatrices;
readonly Matrix4x4[] matrixBuffer = new Matrix4x4[1022];
CommandBuffer depthCommandBuffer;
CommandBuffer opaqueCommandBuffer;
NativeArray<float> instanceData;
readonly float[] instanceDataBuffer = new float[1022];
readonly List<MaterialPropertyBlock> instanceDataPropertyBlocks = new List<MaterialPropertyBlock>();
int shadowCasterPassId, attachStatePropertyId;
float fallTimer;
float3 windBaseDirection, windBaseTangent;
float3 windDirectionRandomTarget;
Vector3 windDirectionVelocity;
float3 windDirection;
float windForce;
float windForceRandomTarget;
float windForceVelocity;
Random windRng;
float shakeAccumulator;
float shake;
float bendAngle;
Vector3 bendAxis;
public bool DoRise { private get; set; }
float sinceTrig;
Camera mainCamera;
void Awake()
{
audioSources = new Pool<AudioSource>(() =>
{
var audioSourceGO = new GameObject("Petal AudioSource");
var audioSource = audioSourceGO.AddComponent<AudioSource>();
audioSource.playOnAwake = false;
audioSource.spatialBlend = 1;
audioSource.minDistance = 2;
audioSource.maxDistance = 100;
audioSource.rolloffMode = AudioRolloffMode.Logarithmic;
audioSource.enabled = false;
audioSourceGO.transform.SetParent(transform);
return audioSource;
},
audioSource =>
{
audioSource.Stop();
audioSource.clip = null;
audioSource.enabled = false;
}
)
{
Capacity = 1500
};
Seed = new uint[] { 43, 4, 12, 25, 70, 81, 92, 100 }.Shuffle(new Random((uint) DateTime.Now.Ticks)).First();
Refresh();
windRng = new Random(Seed);
PetalMesh = new Mesh
{
vertices = new Vector3[]
{
float3(-0.5f, -0.5f, 0), float3(0.5f, -0.5f, 0), float3(-0.5f, 0.5f, 0), float3(0.5f, 0.5f, 0),
float3(-0.5f, -0.5f, 0), float3(0.5f, -0.5f, 0), float3(-0.5f, 0.5f, 0), float3(0.5f, 0.5f, 0)
},
triangles = new int[]
{
0, 1, 2, 2, 1, 3,
4, 6, 5, 6, 7, 5
},
normals = new Vector3[]
{
float3(0, 0, 1), float3(0, 0, 1), float3(0, 0, 1), float3(0, 0, 1),
float3(0, 0, -1), float3(0, 0, -1), float3(0, 0, -1), float3(0, 0, -1)
}
};
PetalMesh.UploadMeshData(true);
depthCommandBuffer = new CommandBuffer();
opaqueCommandBuffer = new CommandBuffer();
mainCamera = Camera.main;
mainCamera.AddCommandBuffer(CameraEvent.AfterDepthTexture, depthCommandBuffer);
mainCamera.AddCommandBuffer(CameraEvent.AfterForwardOpaque, opaqueCommandBuffer);
FindObjectOfType<Light>().AddCommandBuffer(LightEvent.AfterShadowMapPass, depthCommandBuffer);
shadowCasterPassId = PetalMaterial.FindPass("ShadowCaster");
attachStatePropertyId = Shader.PropertyToID("_AttachState");
}
void Start()
{
petalData = new NativeArray<PetalData>(leaves.Count, Allocator.Persistent);
groundedIndices = new NativeQueue<int>(Allocator.Persistent);
detachableIndices = new Queue<int>();
petalMatrices = new NativeArray<Matrix4x4>(leaves.Count, Allocator.Persistent);
instanceData = new NativeArray<float>(leaves.Count, Allocator.Persistent);
risingIndices = new NativeQueue<int>(Allocator.Persistent);
var orderedLeaves = leaves.Shuffle(windRng).ToArray();
for (int i = 0; i < leaves.Count; i++)
{
detachableIndices.Enqueue(i);
instanceData[i] = 1;
petalData[i] = new PetalData
{
Position = orderedLeaves[i].Position,
Rotation = orderedLeaves[i].LookAt,
Scale = orderedLeaves[i].Scale
};
}
for (int i = 0; i < leaves.Count; i += instanceDataBuffer.Length)
instanceDataPropertyBlocks.Add(new MaterialPropertyBlock());
windDirection = windBaseDirection = WindParticleSystem.transform.forward;
windBaseTangent = WindParticleSystem.transform.right;
windForceRandomTarget = WindForceBase + windRng.NextFloat(-WindForceVariation, WindForceVariation);
windDirectionRandomTarget = mul(math.quaternion.AxisAngle(windBaseTangent, (float)windRng.NextDouble(-PI, PI) * WindDirectionVariation),
(mul(math.quaternion.AxisAngle(Vector3.up, (float)windRng.NextDouble(-PI, PI) * WindDirectionVariation),
windBaseDirection)));
windForce = 0;
}
void OnDestroy()
{
instanceData.Dispose();
petalData.Dispose();
groundedIndices.Dispose();
petalMatrices.Dispose();
risingIndices.Dispose();
}
IEnumerator CloseIn(float seconds)
{
yield return new WaitForSeconds(seconds);
CameraControl.Instance.DoClose(5);
}
void QueueReturnAudioSource(AudioSource audioSource, float time)
{
audioDisableQueue.Add(new AudioSourceTimer { AudioSource = audioSource, Timer = time });
}
void Update()
{
if (Probability(WindDirectionProbability))
{
windDirectionRandomTarget = mul(math.quaternion.AxisAngle(windBaseTangent, (float)windRng.NextDouble(-PI, PI) * WindDirectionVariation),
(mul(math.quaternion.AxisAngle(Vector3.up, (float)windRng.NextDouble(-PI, PI) * 0.5f * WindDirectionVariation),
windBaseDirection)));
}
windDirection = normalize(Vector3.SmoothDamp(windDirection, windDirectionRandomTarget, ref windDirectionVelocity, WindDirectionReachDampen));
if (Probability(WindForceProbability))
windForceRandomTarget = WindForceBase + pow(windRng.NextFloat(), 2) * WindForceVariation;
windForce = Mathf.SmoothDamp(windForce, windForceRandomTarget, ref windForceVelocity, WindForceReachDampen);
bendAngle = -windForce / (WindForceBase + WindForceVariation) * 0.17f;
shakeAccumulator += Time.deltaTime * 30 * abs(bendAngle);
bendAxis = cross(windDirection, float3(0, 1, 0));
shake = sin(shakeAccumulator) * cos(shakeAccumulator / 2) * sin(shakeAccumulator / 4) * sin(shakeAccumulator / 8);
// detach petals
fallTimer += Time.deltaTime;
while (fallTimer > 1 / FallRate && detachableIndices.Count > 0)
{
fallTimer -= 1 / FallRate;
var petalIndex = detachableIndices.Dequeue();
var data = petalData[petalIndex];
data.FallState = FallState.Flying;
instanceData[petalIndex] = 0;
// bake the vertex shader animation in its transform
float variation = shake * 0.15f * abs(bendAngle);
var rotationQuat = math.quaternion.AxisAngle(bendAxis, (bendAngle + variation) * 0.5f);
data.Position = mul(rotationQuat, data.Position);
data.Rotation = mul(data.Rotation, rotationQuat);
petalData[petalIndex] = data;
// no more petals!
if (detachableIndices.Count == 0)
{
Debug.Log("No more petals, closing...");
StartCoroutine(CloseIn(15));
break;
}
}
groundedIndices.Clear();
risingIndices.Clear();
var petalUpdateJob = new PetalUpdateJob
{
DeltaTime = Time.deltaTime,
Gravity = Gravity,
PetalRotationForce = Mathf.Deg2Rad * PetalRotationForce,
WindDirection = windDirection,
WindForce = windForce,
GroundedIndices = groundedIndices.ToConcurrent(),
DataArray = petalData,
MatricesArray = petalMatrices,
RisingIndices = risingIndices.ToConcurrent(),
CameraPosition = mainCamera.transform.localPosition,
RandomSeed = (uint)Time.frameCount,
DoRise = DoRise
};
DoRise = false;
petalUpdateJobHandle = petalUpdateJob.Schedule(petalData.Length, petalData.Length / 16);
JobHandle.ScheduleBatchedJobs();
var normalizedWindForce = saturate(abs(windForce) / (WindForceBase + WindForceVariation));
AudioManager.Instance.NoiseSource.volume = normalizedWindForce;
var mainModule = WindParticleSystem.main;
mainModule.startSpeed = new ParticleSystem.MinMaxCurve(1, normalizedWindForce * 10);
WindParticleSystem.transform.LookAt(WindParticleSystem.transform.position + new Vector3(windDirection.x, 0, windDirection.z), Vector3.up);
Shader.SetGlobalVector("_BendAxis", bendAxis);
Shader.SetGlobalFloat("_BendAngle", bendAngle);
Shader.SetGlobalFloat("_Shake", shake);
for (int i = audioDisableQueue.Count - 1; i >= 0; i--)
{
var queueElement = audioDisableQueue[i];
queueElement.Timer -= Time.deltaTime;
if (queueElement.Timer <= 0)
{
audioSources.Return(queueElement.AudioSource);
audioDisableQueue.RemoveAtSwapBack(i);
}
else
audioDisableQueue[i] = queueElement;
}
}
void LateUpdate()
{
petalUpdateJobHandle.Complete();
sinceTrig += Time.deltaTime;
if (sinceTrig > 0.15f && risingIndices.TryDequeue(out int risingPetalIndex))
{
PlayAudioClip(OneShotGroup.B, risingPetalIndex);
sinceTrig = 0;
}
while (groundedIndices.TryDequeue(out int groundedPetalIndex))
{
PlayAudioClip((OneShotGroup)UnityEngine.Random.Range(0, 3), groundedPetalIndex);
}
depthCommandBuffer.Clear();
opaqueCommandBuffer.Clear();
for (int i = 0, blockIndex = 0; i < leaves.Count; i += matrixBuffer.Length, blockIndex++)
{
var batchSize = Math.Min(leaves.Count - i, 1022);
var propertyBlock = instanceDataPropertyBlocks[blockIndex];
instanceData.Slice(i, batchSize).CopyToFast(instanceDataBuffer);
propertyBlock.SetFloatArray(attachStatePropertyId, instanceDataBuffer);
petalMatrices.Slice(i, batchSize).CopyToFast(matrixBuffer);
depthCommandBuffer.DrawMeshInstanced(PetalMesh, 0, PetalMaterial, shadowCasterPassId, matrixBuffer, batchSize, propertyBlock);
opaqueCommandBuffer.DrawMeshInstanced(PetalMesh, 0, PetalMaterial, 0, matrixBuffer, batchSize, propertyBlock);
}
}
void PlayAudioClip(OneShotGroup group, int petalIndex)
{
var petalPosition = petalData[petalIndex].Position;
var distanceToCamera = distance(petalPosition, mainCamera.transform.position);
if (distanceToCamera >= 100)
return;
var audioSource = audioSources.Take();
audioSource.enabled = true;
audioSource.transform.position = petalPosition;
audioSource.priority = 2 + (int) floor(distanceToCamera);
var clip = AudioManager.Instance.GetOneShot(group);
audioSource.clip = clip;
audioSource.Play();
QueueReturnAudioSource(audioSource, clip.length);
}
[BurstCompile(FloatMode = FloatMode.Fast)]
private struct PetalUpdateJob : IJobParallelFor
{
[ReadOnly] public float Gravity;
[ReadOnly] public float DeltaTime;
[ReadOnly] public float3 WindDirection;
[ReadOnly] public float3 WindForce;
[ReadOnly] public float PetalRotationForce;
[ReadOnly] public float3 CameraPosition;
[ReadOnly] public uint RandomSeed;
[ReadOnly] public bool DoRise;
public NativeArray<PetalData> DataArray;
[WriteOnly] public NativeQueue<int>.Concurrent GroundedIndices;
[WriteOnly] public NativeQueue<int>.Concurrent RisingIndices;
[WriteOnly] public NativeArray<Matrix4x4> MatricesArray;
public void Execute(int i)
{
bool dirty = false;
var petalData = DataArray[i];
// TODO it would be more cache-friendly to have petals with the same state close together in memory... how?
if (petalData.FallState == FallState.Initial)
{
// initial copy
petalData.FallState = FallState.Attached;
dirty = true;
}
else if (petalData.FallState == FallState.Flying)
{
// flying leaves
petalData.Velocity.y -= Gravity * DeltaTime;
petalData.Velocity += WindDirection * WindForce * DeltaTime;
petalData.AngularVelocity += WindDirection * DeltaTime * PetalRotationForce;
petalData.Position += petalData.Velocity;
petalData.Rotation = mul(petalData.Rotation, math.quaternion.Euler(petalData.AngularVelocity));
if (petalData.Position.y <= 0)
{
// newly grounded
petalData.Position.y = 0;
petalData.FallState = FallState.Grounded;
petalData.Velocity.y = 0;
GroundedIndices.Enqueue(i);
}
dirty = true;
}
else if (DoRise && petalData.FallState == FallState.Grounded && distance(petalData.Position, CameraPosition) < 6)
{
// rising leaves
petalData.AngularVelocity = Mathf.Deg2Rad * new Random(RandomSeed + (uint)i).NextFloat3Direction();
petalData.Velocity = normalize(petalData.Position - CameraPosition) * 0.05f;
petalData.Velocity.y = 0.05f;
petalData.Position.y += 0.001f;
petalData.FallState = FallState.Flying;
dirty = true;
RisingIndices.Enqueue(i);
}
else if (petalData.FallState == FallState.Grounded && (lengthsq(petalData.Velocity.xz) > 0.001f || lengthsq(petalData.AngularVelocity.xz) > 0.001f))
{
// roll & decay
petalData.Velocity = Damp(petalData.Velocity, 0.001f, DeltaTime);
petalData.AngularVelocity = Damp(petalData.AngularVelocity, 0.001f, DeltaTime);
petalData.Position += petalData.Velocity;
petalData.Rotation = mul(petalData.Rotation, math.quaternion.Euler(petalData.AngularVelocity));
dirty = true;
}
if (dirty)
{
DataArray[i] = petalData;
MatricesArray[i] = math.float4x4.TRS(petalData.Position, petalData.Rotation, petalData.Scale);
}
}
}
static bool Probability(float aP)
{
return UnityEngine.Random.value < 1f - Mathf.Pow(1f - aP, Time.deltaTime);
}
static float3 Damp(float3 source, float smoothing, float dt)
{
return source * pow(smoothing, dt);
}
}
public static class EnumerableExtensions
{
public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source, Random rng)
{
T[] elements = source.ToArray();
for (int i = elements.Length - 1; i >= 0; i--)
{
int swapIndex = rng.NextInt(i + 1);
yield return elements[swapIndex];
elements[swapIndex] = elements[i];
}
}
}