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Prioritized raycaster for casting against 3D Physics components. https://twitter.com/shanecelis/status/1146822575978373120
/* Original code[1] Copyright (c) 2019 Shane Celis[2]
Licensed under the MIT License[3]
This comment generated by code-cite[4].
[1]: https://gist.github.com/shanecelis/5379ed7c634222dc979e09e728ef0a6c
[2]: https://github.com/shanecelis
[3]: https://opensource.org/licenses/MIT
[4]: https://github.com/shanecelis/code-cite
*/
using System.Collections.Generic;
using System.Linq;
using UnityEngine.UI;
namespace UnityEngine.EventSystems {
/// <summary>
/// Simple event system using prioritized physics raycasts.
/// </summary>
[AddComponentMenu("Event/Priority Physics Raycaster")]
[RequireComponent(typeof(Camera))]
/// <summary>
/// Prioritized raycaster for casting against 3D Physics components.
/// </summary>
public class PriorityPhysicsRaycaster : PhysicsRaycaster {
[System.Serializable]
protected class Entry {
public LayerMask mask = kNoEventMaskSet;
public int sortingOrder = 1;
}
[Header("Define masks that have higher priority.")]
[SerializeField]
protected Entry[] priorityMasks;
protected PriorityPhysicsRaycaster() { }
protected override void Awake() {
// Check for issues.
if (priorityMasks.Length == 0)
Debug.LogWarning("No priority masks set. Consider setting or using regular PhysicsRaycaster.");
for (int i = 0; i < priorityMasks.Length; i++) {
// Log warning if it prioritizes layers that are not in the raycast eventMask.
int mask = Normalize(priorityMasks[i].mask.value);
int maskedValue = mask & Normalize(eventMask.value);
if (maskedValue != mask) {
var layers = MaskToBits(~maskedValue & mask)
.Select(j => LayerToName(j))
.ToArray();
if (layers.Length == 0)
throw new System.InvalidOperationException("Internal error. Layers should not be zero for priorityMask {mask} and eventMask {eventMask.value} but it is.");
if (layers.Length == 1)
Debug.LogWarning($"Priority mask {i} has a layer that is not in the eventMask: {layers[0]}.");
else
Debug.LogWarning($"Priority mask {i} has {layers.Length} layers that are not in the eventMask: {string.Join(", ", layers)}.");
}
// Log warning if it prioritizes everything.
if (priorityMasks[i].mask.value == -1)
Debug.LogWarning($"Priority mask {i} prioritizes everything.");
// Log warning if it prioritizes nothing.
if (priorityMasks[i].mask.value == 0)
Debug.LogWarning($"Priority mask {i} prioritizes nothing.");
if (priorityMasks[i].sortingOrder == 0)
Debug.LogWarning($"Priority mask {i} sets the sorting order to 0: no priority, the default.");
}
}
private static string LayerToName(int layer) {
var str = LayerMask.LayerToName(layer);
if (string.IsNullOrEmpty(str))
return layer.ToString();
else
return layer + " " + str;
}
/** Account for the everything mask and turn it into a mask. */
protected static int Normalize(int mask) {
if (mask == -1) {
// XXX: Why is the layerMask.value an int and not a uint? It doesn't seem
// like it can represent layer 31, can it?
//mask = ~0;
mask = 0x7fffffff;
}
return mask;
}
protected static IEnumerable<int> MaskToBits(int mask) {
mask = Normalize(mask);
int i = 0;
while (mask > 0 && i < 32) {
if ((mask & 1) != 0)
yield return i;
i++;
mask = mask >> 1;
}
}
public override void Raycast(PointerEventData eventData, List<RaycastResult> resultAppendList) {
base.Raycast(eventData, resultAppendList);
if (priorityMasks.Length == 0)
return;
for (int i = 0; i < resultAppendList.Count; i++) {
var r = resultAppendList[i];
var layer = 1 << r.gameObject.layer;
for (int j = 0; j < priorityMasks.Length; j++) {
var mask = priorityMasks[j].mask.value;
mask = mask == -1 ? 0x7fffffff : mask; // Handle everything layer.
if ((layer & mask) != 0) {
/*
First thought was to reorder the resultAppendList,
but EventSystem.RaycastComparer reorders all the RaycastResults.
XXX: sortingOrder isn't used by the PhysicsRaycaster at all.
sortingOrder is one criteria we're overloading to ensure our high
priority layer comes out on top.
*/
r.sortingOrder = priorityMasks[j].sortingOrder;
resultAppendList[i] = r;
}
}
}
}
}
}
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