feat(soba): add preload

Author: nartc

Diff for: libs/soba/misc/src/index.ts

@@ -9,5 +9,6 @@ export * from './lib/fbo';
 export * from './lib/html/html';
 export * from './lib/html/html-content';
 export * from './lib/intersect';
+export * from './lib/preload';
 export * from './lib/sampler';
 export * from './lib/scale-factor';

Diff for: libs/soba/misc/src/lib/preload.ts

@@ -0,0 +1,58 @@
+import { afterNextRender, computed, Directive, ElementRef, model } from '@angular/core';
+import { injectStore, resolveRef } from 'angular-three';
+import { Camera, CubeCamera, Object3D, WebGLCubeRenderTarget } from 'three';
+
+@Directive({ selector: 'ngts-preload', standalone: true })
+export class NgtsPreload {
+	all = model<boolean>();
+	scene = model<Object3D | ElementRef<Object3D>>();
+	camera = model<Camera | ElementRef<Camera>>();
+
+	private store = injectStore();
+	private gl = this.store.select('gl');
+	private defaultScene = this.store.select('scene');
+	private defaultCamera = this.store.select('camera');
+
+	private trueScene = computed(() => {
+		const scene = this.scene();
+		if (scene) return resolveRef(scene);
+		return this.defaultScene();
+	});
+	private trueCamera = computed(() => {
+		const camera = this.camera();
+		if (camera) return resolveRef(camera);
+		return this.defaultCamera();
+	});
+
+	constructor() {
+		afterNextRender(() => {
+			const invisible: Object3D[] = [];
+
+			const [all, scene, camera, gl] = [this.all(), this.trueScene(), this.trueCamera(), this.gl()];
+
+			if (!scene || !camera) return;
+
+			if (all) {
+				// Find all invisible objects, store and then flip them
+				scene.traverse((object) => {
+					if (!object.visible) {
+						invisible.push(object);
+						object.visible = true;
+					}
+				});
+			}
+
+			// Now compile the scene
+			gl.compile(scene, camera);
+
+			// And for good measure, hit it with a cube camera
+			const cubeRenderTarget = new WebGLCubeRenderTarget(128);
+			const cubeCamera = new CubeCamera(0.01, 100000, cubeRenderTarget);
+			cubeCamera.update(gl, scene);
+			cubeRenderTarget.dispose();
+
+			// Flips these objects back
+			invisible.forEach((object) => (object.visible = false));
+		});
+	}
+}