Add toggle for showing only intersecting particles

frontend/src/app/pages/particles/components/render-container/render-container.component.html

@@ -12,6 +12,11 @@
         <mat-icon>location_searching</mat-icon>
       </button>
 
+      <button mat-mini-fab color="primary" (click)="toggleShowParticlesWhenIntersectingPlane()"
+              [matTooltip]="onlyIntersecting ? 'Show all particles' : 'Show only intersecting particles'">
+        <mat-icon>{{ onlyIntersecting ? 'visibility_off' : 'visibility' }}</mat-icon>
+      </button>
+
       <button mat-mini-fab color="primary" (click)="togglePlaneLock()"
               [matTooltip]="isPlaneLocked ? 'Unlock Plane' : 'Lock Plane'">
         <mat-icon>{{ isPlaneLocked ? 'lock' : 'lock_open' }}</mat-icon>

frontend/src/app/pages/particles/components/render-container/render-container.component.ts

@@ -1,4 +1,4 @@
-import {AfterViewInit, Component, ElementRef, OnDestroy, ViewChild} from '@angular/core';
+import {AfterViewInit, Component, ElementRef, inject, OnDestroy, ViewChild} from '@angular/core';
 import {MatMiniFabButton} from '@angular/material/button';
 
 import {IntersectionPlaneService, PlaneOrientation} from '../../services/intersection-plane.service';
@@ -9,6 +9,7 @@ import {PlayerModelService} from '../../services/player-model.service';
 import {InputHandlerService} from '../../services/input-handler.service';
 import {FormsModule} from '@angular/forms';
 import {MatFormField, MatInput, MatLabel} from '@angular/material/input';
+import {ParticleManagerService} from '../../services/particle-manager.service';
 
 @Component({
   selector: 'app-render-container',
@@ -27,13 +28,11 @@ import {MatFormField, MatInput, MatLabel} from '@angular/material/input';
 export class RenderContainerComponent implements AfterViewInit, OnDestroy {
   @ViewChild('rendererContainer') rendererContainer!: ElementRef;
 
-  constructor(
-    private intersectionPlaneService: IntersectionPlaneService,
-    private playerModelService: PlayerModelService,
-    private inputHandlerService: InputHandlerService,
-    private rendererService: RendererService,
-  ) {
-  }
+  private readonly intersectionPlaneService = inject(IntersectionPlaneService);
+  private readonly playerModelService = inject(PlayerModelService);
+  private readonly inputHandlerService = inject(InputHandlerService);
+  private readonly rendererService = inject(RendererService);
+  private readonly particleManagerService = inject(ParticleManagerService);
 
   ngAfterViewInit(): void {
     this.initializeScene();
@@ -99,6 +98,10 @@ export class RenderContainerComponent implements AfterViewInit, OnDestroy {
     this.rendererService.resetCamera();
   }
 
+  public toggleShowParticlesWhenIntersectingPlane(): void {
+    this.particleManagerService.onlyIntersectingParticles = !this.particleManagerService.onlyIntersectingParticles;
+  }
+
   /**
    * Get the current plane orientation
    */
@@ -106,6 +109,13 @@ export class RenderContainerComponent implements AfterViewInit, OnDestroy {
     return this.intersectionPlaneService.getCurrentOrientation();
   }
 
+  /**
+   * Retrieves the value indicating whether only intersecting particles are being considered.
+   */
+  public get onlyIntersecting(): boolean {
+    return this.particleManagerService.onlyIntersectingParticles;
+  }
+
   /**
    * Set the plane orientation
    */

frontend/src/app/pages/particles/services/intersection-plane.service.ts

@@ -1,6 +1,7 @@
 import {Injectable} from '@angular/core';
 import * as THREE from 'three';
 import {RendererService} from './renderer.service';
+import {Subject} from 'rxjs';
 
 /**
  * Represents the possible orientations of the intersection plane
@@ -27,6 +28,10 @@ export class IntersectionPlaneService {
   private planeLocked: boolean = false;
   private opacity: number = 0.05;
 
+  // Emits whenever plane position, orientation, or lock-affecting orientation updates change visuals
+  public readonly planeChanged$ = new Subject<void>();
+  private lastPlaneSignature: string | null = null;
+
   constructor(private rendererService: RendererService) {
   }
 
@@ -144,6 +149,13 @@ export class IntersectionPlaneService {
         this.intersectionPlane.position.x = -position;
         break;
     }
+
+    // Notify listeners only if signature changed to avoid spamming during animation frames
+    const signature = `${this.currentOrientation}|${this.planePosition}`;
+    if (signature !== this.lastPlaneSignature) {
+      this.lastPlaneSignature = signature;
+      this.planeChanged$.next();
+    }
   }
 
   /**

frontend/src/app/pages/particles/services/particle-manager.service.ts

@@ -1,7 +1,8 @@
-import {Injectable} from '@angular/core';
+import {inject, Injectable} from '@angular/core';
 import * as THREE from 'three';
 import {RendererService} from './renderer.service';
 import {Particle, ParticleData, ParticleInfo, ParticleType} from '../models/particle.model';
+import {IntersectionPlaneService, PlaneOrientation} from './intersection-plane.service';
 
 /**
  * Service responsible for managing particles in the scene
@@ -33,8 +34,18 @@ export class ParticleManagerService {
   private selectedColor: string = '#ff0000';
   private selectedParticle: Particle = Particle.DUST;
   private selectedSize: number = 1;
+  private onlyIntersecting: boolean = false;
 
-  constructor(private rendererService: RendererService) {
+  private readonly rendererService = inject(RendererService);
+  private readonly intersectionPlaneService = inject(IntersectionPlaneService);
+
+  constructor() {
+    this.intersectionPlaneService.planeChanged$.subscribe(() => {
+      if (this.onlyIntersecting) {
+        this.clearParticleVisuals();
+        this.renderFrameParticles(this.currentFrame);
+      }
+    });
   }
 
   /**
@@ -88,7 +99,34 @@ export class ParticleManagerService {
   renderFrameParticles(frameId: string): void {
     if (!this.particleData.frames[frameId]) return;
 
+    const filter = this.onlyIntersecting;
+    const orientation = this.intersectionPlaneService.getCurrentOrientation();
+    const offset16 = this.intersectionPlaneService.getPlanePosition();
+    const planePos = offset16 / 16; // convert from 1/16th units to world units
+    const epsilon = 0.02; // tolerance for intersection
+
+    const isOnPlane = (p: ParticleInfo) => {
+      if (!filter) return true;
+      switch (orientation) {
+        case PlaneOrientation.VERTICAL_ABOVE:
+        case PlaneOrientation.VERTICAL_BELOW:
+          // Horizontal plane at y = 0.8 +/- planePos
+          return Math.abs(p.y - (0.8 + (orientation === PlaneOrientation.VERTICAL_BELOW ? planePos : -planePos))) <= epsilon;
+        case PlaneOrientation.HORIZONTAL_FRONT:
+          return Math.abs(p.z - planePos) <= epsilon;
+        case PlaneOrientation.HORIZONTAL_BEHIND:
+          return Math.abs(p.z + planePos) <= epsilon;
+        case PlaneOrientation.HORIZONTAL_RIGHT:
+          return Math.abs(p.x - planePos) <= epsilon;
+        case PlaneOrientation.HORIZONTAL_LEFT:
+          return Math.abs(p.x + planePos) <= epsilon;
+      }
+    };
+
     for (const particleInfo of this.particleData.frames[frameId]) {
+      if (!isOnPlane(particleInfo)) {
+        continue;
+      }
       const particleGeometry = new THREE.SphereGeometry(0.03 * (particleInfo.size ?? 1), 16, 16);
 
       const color = this.getColor(particleInfo);
@@ -245,4 +283,14 @@ export class ParticleManagerService {
   generateJson(): string {
     return JSON.stringify(this.particleData, null, 2);
   }
+
+  public get onlyIntersectingParticles(): boolean {
+    return this.onlyIntersecting;
+  }
+
+  public set onlyIntersectingParticles(value: boolean) {
+    this.onlyIntersecting = value;
+    this.clearParticleVisuals();
+    this.renderFrameParticles(this.currentFrame);
+  }
 }