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PhantomicalPhantomical
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perf: Pre-compute harvester raycasts at frame start (#170)
Before this commit about 1/4 of the runtime of the various harvesters is spent running raycasts. This can also end up being much worse because occasionally a raycast will trigger a transform sync. Instead of doing this, we can use RaycastCommand.ScheduleBatch to queue all of these up at the start of FixedUpdate, and then individual consumers can look up the result later on when they need it. Consumers subscribe for a single ray trace per part module, with a transform that defines where the array originates from. The RaycastManager seems to take ~22us with 16 active drills, most of which is spent scheduling the 3 resulting jobs. The actual jobs themselves take about 50us, so this work should scale pretty well to much larger vessels if needed.
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‎Source/Addons/RaycastManager.cs‎

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using System;
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using System.Collections.Generic;
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using Unity.Collections;
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using Unity.Jobs;
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using UnityEngine;
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using UnityEngine.Jobs;
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namespace SystemHeat.Addons;
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[DefaultExecutionOrder(-1)]
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[KSPAddon(KSPAddon.Startup.AllGameScenes, once: false)]
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internal class RaycastManager : MonoBehaviour
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{
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public static RaycastManager Instance { get; private set; }
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struct RaycastParams
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{
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public float range;
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public int layerMask;
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}
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const int DefaultCap = 128;
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private TransformAccessArray transforms;
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private NativeArray<RaycastParams> args;
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private NativeArray<RaycastHit> hits;
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private readonly Dictionary<int, int> mapping = [];
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private readonly Dictionary<int, int> reverse = [];
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private JobHandle handle = default;
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public void Register(PartModule module, Transform transform, float range, int layerMask = -5)
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{
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if (module == null || transform == null || this == null)
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return;
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handle.Complete();
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if (!enabled)
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enabled = true;
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var moduleID = module.GetInstanceID();
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var arg = new RaycastParams
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{
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range = range,
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layerMask = layerMask
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};
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// If the module is already registered then this overrides its existing
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// raycast request.
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if (mapping.TryGetValue(moduleID, out int index))
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{
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transforms[index] = transform;
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args[index] = arg;
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return;
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}
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EnsureCapacity();
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index = transforms.length;
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transforms.Add(transform);
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args[index] = arg;
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mapping.Add(moduleID, index);
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reverse.Add(index, moduleID);
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}
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public void Unregister(PartModule module)
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{
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if (module == null)
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return;
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handle.Complete();
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var moduleID = module.GetInstanceID();
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if (!mapping.TryGetValue(moduleID, out var index))
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return;
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mapping.Remove(moduleID);
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reverse.Remove(index);
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transforms.RemoveAtSwapBack(index);
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int last = transforms.length;
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if (reverse.TryGetValue(last, out var swappedID))
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{
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args[index] = args[last];
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if (hits.IsCreated && last < hits.Length)
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hits[index] = hits[last];
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mapping[swappedID] = index;
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reverse.Remove(last);
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reverse[index] = swappedID;
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}
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}
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/// <summary>
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/// Get the precomputed raycast hit for <paramref name="module"/>.
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/// </summary>
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/// <param name="module"></param>
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/// <returns><c>null</c> if there is no hit, and the hit otherwise.</returns>
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/// <remarks>
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/// <see cref="RaycastHit.collider" /> will be <c>null</c> if the raycast did
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/// not hit anything.
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/// </remarks>
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public RaycastHit? GetRaycastHit(PartModule module)
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{
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var moduleID = module.GetInstanceID();
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if (!mapping.TryGetValue(moduleID, out var index))
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return null;
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if ((uint)index >= (uint)hits.Length)
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return null;
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if (!handle.IsCompleted)
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handle.Complete();
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return hits[index];
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}
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void EnsureCapacity()
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{
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int length = transforms.length;
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if (length < transforms.capacity)
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return;
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var newcap = Math.Max(length * 2, 128);
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var nt = new TransformAccessArray(newcap, desiredJobCount: 1);
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var na = new NativeArray<RaycastParams>(newcap, Allocator.Persistent, NativeArrayOptions.UninitializedMemory);
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for (int i = 0; i < length; ++i)
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nt.Add(transforms[i]);
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NativeArray<RaycastParams>.Copy(args, na, length);
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transforms.Dispose();
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args.Dispose();
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transforms = nt;
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args = na;
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}
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void Awake()
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{
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Instance = this;
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}
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void OnDestroy()
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{
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if (Instance == this)
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Instance = null;
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}
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void OnEnable()
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{
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transforms = new TransformAccessArray(DefaultCap, desiredJobCount: 1);
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args = new NativeArray<RaycastParams>(DefaultCap, Allocator.Persistent);
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}
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void OnDisable()
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{
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try
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{
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if (!handle.IsCompleted)
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handle.Complete();
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}
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catch (Exception e)
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{
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Debug.LogException(e);
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}
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transforms.Dispose();
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args.Dispose();
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if (hits.IsCreated)
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hits.Dispose();
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transforms = default;
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args = default;
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hits = default;
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mapping.Clear();
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reverse.Clear();
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}
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void FixedUpdate()
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{
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if (!handle.IsCompleted)
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handle.Complete();
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var count = mapping.Count;
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if (count == 0)
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{
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handle = default;
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return;
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}
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var commands = new NativeArray<RaycastCommand>(count, Allocator.Temp, NativeArrayOptions.UninitializedMemory);
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hits = new NativeArray<RaycastHit>(count, Allocator.Temp, NativeArrayOptions.UninitializedMemory);
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// RaycastCommand.ScheduleBatch reads maxHits immediately but the remaining
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// fields are not read until the job runs. So we need to initialize maxHits
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// immediately but the rest can happen in a job.
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for (int i = 0; i < count; ++i)
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commands[i] = new() { maxHits = 1 };
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handle = new BuildCommandJob { args = args, commands = commands }
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.Schedule(transforms, handle);
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handle = RaycastCommand.ScheduleBatch(commands, hits, 64, handle);
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JobHandle.ScheduleBatchedJobs();
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}
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void Update()
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{
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handle.Complete();
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if (mapping.Count == 0)
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enabled = false;
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}
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struct BuildCommandJob : IJobParallelForTransform
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{
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[ReadOnly]
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public NativeArray<RaycastParams> args;
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[WriteOnly]
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public NativeArray<RaycastCommand> commands;
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public void Execute(int index, TransformAccess transform)
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{
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var arg = args[index];
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var command = new RaycastCommand
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{
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from = transform.position,
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direction = transform.rotation * Vector3.forward,
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distance = arg.range,
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layerMask = arg.layerMask,
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maxHits = 1
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};
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commands[index] = command;
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}
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}
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}

‎Source/Modules/ModuleSystemHeatAsteroidHarvester.cs‎

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@@ -1,5 +1,6 @@
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using UnityEngine;
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using KSP.Localization;
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using SystemHeat.Addons;
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using Unity.Profiling;
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namespace SystemHeat
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protected ModuleSystemHeat heatModule;
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// Stock ModuleAsteroidDrill uses Physics.DefaultRaycastLayers (no mask).
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private const int ImpactLayerMask = -5;
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private static readonly ProfilerMarker BaseFixedUpdateMarker = new("ModuleAsteroidDrill.FixedUpdate");
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public override string GetInfo()
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Utils.Log("[ModuleSystemHeatAsteroidHarvester] Setup completed", LogType.Modules);
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Fields["HarvesterEfficiency"].guiName = Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_Field_Efficiency", ConverterName);
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RegisterImpactRaycast();
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}
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void OnEnable()
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{
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RegisterImpactRaycast();
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}
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public override void FixedUpdate()
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{
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heatModule?.AddFlux(moduleID, 0f, 0f, false);
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HarvesterEfficiency = "-";
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RaycastManager.Instance?.Unregister(this);
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}
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void RegisterImpactRaycast()
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{
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if (!HighLogic.LoadedSceneIsFlight || impactTransformCache == null)
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return;
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RaycastManager.Instance?.Register(this, impactTransformCache, ImpactRange, ImpactLayerMask);
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}
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protected override bool CheckForImpact()
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{
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if (string.IsNullOrEmpty(ImpactTransform) || impactTransformCache == null)
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return true;
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var hit = RaycastManager.Instance?.GetRaycastHit(this);
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if (hit is not RaycastHit raycastHit)
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{
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// If we're not registered for whatever reason then do the raycast ourselves.
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var origin = impactTransformCache.position;
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if (!Physics.Raycast(new Ray(origin, impactTransformCache.forward), out raycastHit, ImpactRange, ImpactLayerMask))
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return false;
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}
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var collider = raycastHit.collider;
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if (collider == null)
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return false;
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return collider.gameObject.GetComponentUpwards<ModuleAsteroid>() != null;
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}
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void FixedUpdateFlight()

‎Source/Modules/ModuleSystemHeatCometHarvester.cs‎

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using KSP.Localization;
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using SystemHeat.Addons;
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using Unity.Profiling;
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using UnityEngine;
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namespace SystemHeat
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{
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protected ModuleSystemHeat heatModule;
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// Stock ModuleCometDrill uses Physics.DefaultRaycastLayers (no mask).
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private const int ImpactLayerMask = -5;
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private static readonly ProfilerMarker BaseFixedUpdateMarker = new("ModuleCometDrill.FixedUpdate");
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public override string GetInfo()
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Utils.Log("[ModuleSystemHeatCometHarvester] Setup completed", LogType.Modules);
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Fields["HarvesterEfficiency"].guiName = Localizer.Format("#LOC_SystemHeat_ModuleSystemHeatHarvester_Field_Efficiency", ConverterName);
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RegisterImpactRaycast();
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}
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void OnEnable()
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{
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RegisterImpactRaycast();
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}
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public override void FixedUpdate()
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{
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heatModule?.AddFlux(moduleID, 0f, 0f, false);
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HarvesterEfficiency = "-";
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RaycastManager.Instance?.Unregister(this);
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}
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void RegisterImpactRaycast()
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{
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if (!HighLogic.LoadedSceneIsFlight || impactTransformCache == null)
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return;
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RaycastManager.Instance?.Register(this, impactTransformCache, ImpactRange, ImpactLayerMask);
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}
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protected override bool CheckForImpact()
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{
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if (string.IsNullOrEmpty(ImpactTransform) || impactTransformCache == null)
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return true;
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Collider collider;
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var hit = RaycastManager.Instance?.GetRaycastHit(this);
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if (hit != null)
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{
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collider = hit.Value.collider;
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}
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else
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{
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// If we're not registered for whatever reason then do the raycast ourselves.
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var origin = impactTransformCache.position;
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if (!Physics.Raycast(new Ray(origin, impactTransformCache.forward), out var fallback, ImpactRange, ImpactLayerMask))
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return false;
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collider = fallback.collider;
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}
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if (collider == null)
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return false;
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return collider.gameObject.GetComponentUpwards<ModuleComet>() != null;
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}
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void FixedUpdateFlight()

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