From b3fdd9d1467e168ba1bdab1563f97ad2e04c27bd Mon Sep 17 00:00:00 2001
From: Erik Onarheim <erik.onarheim@gmail.com>
Date: Thu, 25 Jul 2024 08:45:03 -0500
Subject: [PATCH] fix: rayCast filter called in hit order

---
 CHANGELOG.md                                  |  1 +
 .../Collision/Detection/RayCastOptions.ts     |  4 ++-
 .../SparseHashGridCollisionProcessor.ts       | 34 ++++++++++++-------
 .../SparseHashGridCollisionProcessorSpec.ts   | 27 +++++++++++++++
 4 files changed, 53 insertions(+), 13 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9abdd4ea6..e270a1e39 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -70,6 +70,7 @@ are doing mtv adjustments during precollision.
 
 ### Fixed
 
+- Fixed issue where rayCast `filter` would not be called in hit order
 - Fixed issue where rayCasts would return inconsistent orderings with the `ex.SparseHashGridCollisionProcessor` strategy
 - Fixed issue where CircleCollider tangent raycast did not work correctly
 - Fixed issue where you were required to provide a transition if you provided a loader in the `ex.Engine.start('scene', { loader })`
diff --git a/src/engine/Collision/Detection/RayCastOptions.ts b/src/engine/Collision/Detection/RayCastOptions.ts
index 3898d1412..668059e7d 100644
--- a/src/engine/Collision/Detection/RayCastOptions.ts
+++ b/src/engine/Collision/Detection/RayCastOptions.ts
@@ -15,7 +15,9 @@ export interface RayCastOptions {
    */
   collisionMask?: number;
   /**
-   * Optionally specify to search for all colliders that intersect the ray cast, not just the first which is the default
+   * Optionally search for all colliders that intersect the ray cast.
+   *
+   * Default false
    */
   searchAllColliders?: boolean;
   /**
diff --git a/src/engine/Collision/Detection/SparseHashGridCollisionProcessor.ts b/src/engine/Collision/Detection/SparseHashGridCollisionProcessor.ts
index 4c477e286..c4602c624 100644
--- a/src/engine/Collision/Detection/SparseHashGridCollisionProcessor.ts
+++ b/src/engine/Collision/Detection/SparseHashGridCollisionProcessor.ts
@@ -179,6 +179,7 @@ export class SparseHashGridCollisionProcessor implements CollisionProcessor {
       const key = HashGridCell.calculateHashKey(currentXCoord, currentYCoord);
       const cell = this.hashGrid.sparseHashGrid.get(key);
       if (cell) {
+        const cellHits: RayCastHit[] = [];
         for (let colliderIndex = 0; colliderIndex < cell.proxies.length; colliderIndex++) {
           const collider = cell.proxies[colliderIndex];
           if (!collidersVisited.has(collider.collider.id.value)) {
@@ -197,21 +198,30 @@ export class SparseHashGridCollisionProcessor implements CollisionProcessor {
 
             const hit = collider.collider.rayCast(ray, maxDistance);
 
+            // Collect up all the colliders that hit inside a cell
+            // they can be in any order so we need to sort them next
             if (hit) {
-              if (options?.filter) {
-                if (options.filter(hit)) {
-                  results.push(hit);
-                  if (!searchAllColliders) {
-                    done = true;
-                  }
-                }
-              } else {
-                results.push(hit);
-                if (!searchAllColliders) {
-                  done = true;
-                }
+              cellHits.push(hit);
+            }
+          }
+        }
+        cellHits.sort((hit1, hit2) => hit1.distance - hit2.distance);
+        for (let i = 0; i < cellHits.length; i++) {
+          const hit = cellHits[i];
+          if (options?.filter) {
+            if (options.filter(hit)) {
+              results.push(hit);
+              if (!searchAllColliders) {
+                done = true;
+                break;
               }
             }
+          } else {
+            results.push(hit);
+            if (!searchAllColliders) {
+              done = true;
+              break;
+            }
           }
         }
       }
diff --git a/src/spec/SparseHashGridCollisionProcessorSpec.ts b/src/spec/SparseHashGridCollisionProcessorSpec.ts
index 73ea3000b..90e1e8d24 100644
--- a/src/spec/SparseHashGridCollisionProcessorSpec.ts
+++ b/src/spec/SparseHashGridCollisionProcessorSpec.ts
@@ -340,4 +340,31 @@ describe('A Sparse Hash Grid Broadphase', () => {
     expect(hits[1].distance).toBe(175);
     expect(hits[1].point).toEqual(ex.vec(175, 0));
   });
+
+  it('calls filter in hit order', () => {
+    const sut = new ex.SparseHashGridCollisionProcessor({ size: 200 });
+    const actor3 = new ex.Actor({ x: 104, y: 0, width: 50, height: 50 });
+    sut.track(actor3.collider.get());
+    const actor2 = new ex.Actor({ x: 102, y: 0, radius: 25 });
+    sut.track(actor2.collider.get());
+    const actor1 = new ex.Actor({ x: 100, y: 0, radius: 25 });
+    sut.track(actor1.collider.get());
+
+    const ray = new ex.Ray(ex.vec(0, 0), ex.Vector.Right);
+    const filter = jasmine.createSpy('filter').and.callFake(() => true);
+    const hits = sut.rayCast(ray, {
+      searchAllColliders: true,
+      filter
+    });
+
+    expect(filter.calls.argsFor(0)).toEqual([
+      { point: ex.vec(75, 0), distance: 75, collider: actor1.collider.get(), body: actor1.body, normal: ex.vec(-1, 0) }
+    ]);
+    expect(filter.calls.argsFor(1)).toEqual([
+      { point: ex.vec(77, 0), distance: 77, collider: actor2.collider.get(), body: actor2.body, normal: ex.vec(-1, 0) }
+    ]);
+    expect(filter.calls.argsFor(2)).toEqual([
+      { point: ex.vec(79, 0), distance: 79, collider: actor3.collider.get(), body: actor3.body, normal: ex.vec(-1, -0) }
+    ]);
+  });
 });