Mesh.svelte

<!--
`accessors:true` hast to be set per component because of the svelte-language-server bug, otherwise accessors would be falsely detected as missing and highlighted as errors.
svelthree uses svelte-accmod, where accessors are always `true`, regardless of `svelte:options`.  
-->
<svelte:options accessors />

<!--
@component
**svelthree** _Mesh_ Component.
[ tbd ]  Link to Docs.
-->
<script lang="ts">
	import type { Scene } from "three"

	import { beforeUpdate, onMount, afterUpdate, onDestroy, getContext, setContext, tick } from "svelte"
	import { get_current_component } from "svelte/internal"
	import { self as _self } from "svelte/internal"
	import { c_rs, c_lc, c_mau, c_dev, verbose_mode, get_comp_name } from "../utils/SvelthreeLogger"
	import type { LogLC, LogDEV } from "../utils/SvelthreeLogger"
	import type { SvelthreeShadowDOMElement } from "../types-extra"

	import type { OnlyWritableNonFunctionPropsPlus, PropBlackList } from "../types-extra"

	import type { Euler, Matrix4, Object3D, Quaternion, Vector3 } from "three"

	import { svelthreeStores } from "svelthree/stores"
	import { PropUtils, SvelthreeProps } from "../utils"

	import { SvelthreeAnimation } from "../ani"
	import type { SvelthreeAnimationFunction, SvelthreeAnimationFunctionReturn } from "../types-extra"

	import { SvelthreeInteraction } from "../components-internal"
	import type { RaycastArray } from "../utils/RaycastArray"
	import { createEventDispatcher } from "svelte"
	import type { Writable } from "svelte/store"

	import type { SvelthreeModifiersProp } from "../constants/Interaction"
	import type {
		SvelthreePointerEventHandler,
		SvelthreeFocusEventHandler,
		SvelthreeKeyboardEventHandler,
		SvelthreeWheelEventHandler
	} from "../constants/Interaction"

	import { BoxHelper } from "three"
	import { get_root_scene } from "../utils/SceneUtils"

	import type { BufferGeometry } from "three"

	import { Mesh } from "three"
	import type { OnlyWritableNonFunctionPropsOverwritten, RemoveFirst } from "../types-extra"
	import type { MeshProps } from "../types-comp-props"
	import type { ButtonProp, LinkProp } from "../types-comp-props"
	import type { Material, Color } from "three"

	/**
	 *  SVELTEKIT  SSR
	 * `browser` is needed for the SvelteKit setup (SSR / CSR / SPA).
	 * For non-SSR output in RollUp only and Vite only setups (CSR / SPA) we're just mimicing `$app/env` where `browser = true`,
	 * -> TS fix: `$app/env` mapped to `src/$app/env` via svelthree's `tsconfig.json`'s `path` property.
	 * -> RollUp only setup: replace `$app/env` with `../$app/env`
	 * The import below will work out-of-the-box in a SvelteKit setup.
	 */
	import { browser } from "$app/env"

	const self = get_current_component()
	const c_name = get_comp_name(self)

	const shadow_root: Writable<{ element: HTMLDivElement }> = getContext("shadow_root")
	let shadow_root_el: HTMLDivElement
	$: shadow_root_el = $shadow_root.element

	const verbose: boolean = verbose_mode()

	export let log_all: boolean = false
	export let log_dev: { [P in keyof LogDEV]: LogDEV[P] } = log_all ? { all: true } : undefined
	export let log_rs: boolean = log_all
	export let log_lc: { [P in keyof LogLC]: LogLC[P] } = log_all ? { all: true } : undefined
	export let log_mau: boolean = log_all

	const dispatch = createEventDispatcher()

	let scene: Scene = getContext("scene")
	const sti: number = getContext("store_index")

	/** [ **feature**: allow providing (_injection_) of (_already created_) threejs object instances ].
	 * `create` is an internal indicator for how the component's corresponding threejs object instance has to be / has been created.
	 * It's being set to `false` on initialization if an (_already created_) threejs object instance was provided,
	 * otherwise it's set to `true`, means a new threejs object instance will be created. */
	let create = false

	/** The (three) instance that was shared to this component as it's 'parent'. */
	let our_parent: Object3D = undefined

	/** Returns the `mesh` instance created by the component & allows providing (_injection_) of (_already created / premade_) `THREE.Mesh` instances. */
	export let mesh: Mesh = undefined
	let mesh_uuid: string = undefined

	// Generic Material type and props
	// COOL!  This is possible now! see https://github.com/sveltejs/language-tools/issues/442#issuecomment-977803507
	// 'mat' shorthand attribute will give us proper intellisense (props list) for the assigned 'material'!
	// TODO  MULTIPLE MATERIALS: this works only with single Material atm, multiple Materials are not implemented yet.
	type AnyMaterial = $$Generic<Material | Material[]>
	type AnyMaterialProps = OnlyWritableNonFunctionPropsOverwritten<
		Omit<AnyMaterial, PropBlackList>,
		{ color: Color | string | number | [r: number, g: number, b: number] | number[] | Vector3 }
	>
	export let material: AnyMaterial = undefined
	export let geometry: BufferGeometry = undefined

	export const is_svelthree_component: boolean = true
	export const is_svelthree_mesh: boolean = true

	if (mesh) {
		create = false
		on_instance_provided()
	} else {
		create = true
	}

	/** IMPORTANT  Executed when / if an instance was provided **on initializiation** -> only once if at all! */
	function on_instance_provided(): void {
		// check if type of provided instance is correct and then do something with it...
		if (mesh.type === "Mesh") {
			if (mesh.geometry) {
				geometry = mesh.geometry
				if (verbose && log_dev) console.debug(...c_dev(c_name, "saved geometry:", { geometry }))
			} else {
				// this will most probably never happen ( TODO  when would it?)
				throw new Error("SVELTHREE > Mesh : 'mesh' provided, but has no geometry!")
			}

			if (mesh.material) {
				material = mesh.material as AnyMaterial
				if (verbose && log_dev) console.debug(...c_dev(c_name, "saved material:", { material }))
			} else {
				// this will most probably never happen ( TODO  when would it?)
				throw new Error("SVELTHREE > Mesh : 'mesh' provided, but has no material!")
			}

			mesh.userData.initScale = mesh.scale.x
			mesh.userData.svelthreeComponent = self
		} else {
			throw new Error(
				`SVELTHREE > Mesh Error: provided 'mesh' instance has wrong type '${mesh.type}', should be 'Mesh'!`
			)
		}
	}

	// Determining 'parent' on initialization if 'mesh' instance was provided ('create' is false).
	if (!create) {
		// get the instance that was shared to us as our 'parent'.
		our_parent = getContext("parent") || scene

		// share created object (three) instance to all children (slots) as 'parent'.
		setContext("parent", mesh)
	}

	// reactive creating / recreating mesh

	$: if (geometry && create) on_geometry_provided()
	$: if (material && create) on_material_provided()

	function on_geometry_provided() {
		if (verbose && log_dev) console.debug(...c_dev(c_name, "'geometry' provided!"))
		try_geometry_update()
	}

	function on_material_provided() {
		if (verbose && log_dev) console.debug(...c_dev(c_name, "'material' provided!"))
		try_material_update()
	}

	// change geometry and material on provided mesh

	// we know mesh has geometry if geometry is available and !create, it was referenced on_instance_provided()
	$: if (geometry && !create) {
		if (geometry !== mesh.geometry) try_geometry_update()
	}

	// we know mesh has material if material is available and !create, it was referenced on_instance_provided()
	$: if (material && !create) {
		if (material !== mesh.material) try_material_update()
	}

	function try_geometry_update(): void {
		if (mesh) {
			mesh.geometry = geometry as BufferGeometry

			// update BoxHelper if any
			if (mesh.userData.box) mesh.userData.box.update()

			if (verbose && log_dev) console.debug(...c_dev(c_name, "'geometry' updated!"))
		}
	}

	function try_material_update(): void {
		if (mesh) {
			mesh.material = material
			if (verbose && log_dev) console.debug(...c_dev(c_name, "'material' updated!"))
			force_material_update()
		}
	}

	function force_material_update(): void {
		// recreate 'sMat' in case sMat was created with / is bound to 'mesh.material'
		sMat = new SvelthreeProps(material)
		if (sMat && mat) sMat.update(mat)
	}

	// creation using provided geometry & material or constructor 'params' shorthand

	/** Initializes `Mesh` with provided constructor parameters.*/
	export let params: ConstructorParameters<typeof Mesh> = undefined

	$: if (!mesh && create) {
		if (geometry && material) {
			if (params?.length)
				console.error(
					`SVELTHREE Error > ${c_name} : You've set 'geometry', 'material' & 'params' -> specified 'params' will be ignored! Please use either 'geometry' & 'material' or 'params' for initialization.`
				)

			// letting threejs throw errors if anything's wrong with 'geometry' or 'material'
			mesh = new Mesh(geometry, material)

			mesh_uuid = mesh.uuid

			mesh.userData.initScale = mesh.scale.x
			mesh.userData.svelthreeComponent = self

			if (verbose && log_dev) console.debug(...c_dev(c_name, `${geometry.type} created!`, { mesh }))
			if (verbose && log_dev) console.debug(...c_dev(c_name, "saved 'geometry' (created):", geometry))
			if (verbose && log_dev) console.debug(...c_dev(c_name, "saved 'material' (created):", material))
		} else {
			// create 'mesh' via params (can be an empty []) or if no 'params' set (undefined) via new Mesh()

			// create with params -> since 'geometry' & 'material' are optional, params can also be empty []!
			if (params) {
				// disallow 'params' with 'geometry' or 'material'
				if (geometry)
					throw new Error(
						`SVELTHREE Error > ${c_name} : You've set 'geometry' & 'params' -> specified 'geometry' will be ignored! Please use either 'geometry' & 'material' or 'params' for initialization.`
					)
				if (material)
					throw new Error(
						`SVELTHREE Error > ${c_name} : You've set 'material' & 'params' -> specified 'material' will be ignored! Please use either 'geometry' & 'material' or 'params' for initialization.`
					)

				if (params.length) {
					// letting threejs throw errors if anything's wrong with provided 'params'
					mesh = new Mesh(...params)
				} else {
					// will create a blank 'BufferGeometry' and a blank Material
					mesh = new Mesh()
				}
			} else {
				// no 'geometry', no 'material' and no 'params'
				// will create a blank 'BufferGeometry' or a blank Material or both.
				mesh = new Mesh(geometry, material)
			}

			mesh_uuid = mesh.uuid

			mesh.userData.initScale = mesh.scale.x
			mesh.userData.svelthreeComponent = self

			if (verbose && log_dev) console.debug(...c_dev(c_name, `${geometry.type} created!`, { mesh }))
		}
	}

	// Determining 'parent' if 'mesh' instance has to be created first / was not provided on initialization ('create' is true).
	$: if (mesh && create && !our_parent) set_parent()

	function set_parent() {
		// get the instance that was shared to us as our 'parent'.
		our_parent = getContext("parent") || scene

		// share created object (three) instance to all children (slots) as 'parent'.
		setContext("parent", mesh)
	}

	// this statement is being triggered on creation / recreation
	$: if (mesh && ((mesh_uuid && mesh_uuid !== mesh.uuid) || (mesh.parent !== our_parent && mesh !== our_parent)))
		add_instance_to()

	function add_instance_to(): void {
		//let replacing = false

		// if 'mesh' was already created or set via 'mesh' attribute before
		if (mesh_uuid && mesh.uuid !== mesh_uuid) {
			// remove old instance and update references where needed

			const old_instance: Object3D = scene.getObjectByProperty("uuid", mesh_uuid)

			// update 'index_in_x'

			if (old_instance.userData.helper?.parent) {
				old_instance.userData.helper.parent.remove(old_instance.userData.helper)
				old_instance.userData.helper = null
			}

			if (old_instance.userData.box?.parent) {
				old_instance.userData.helper.parent.remove(old_instance.userData.helper)
				old_instance.userData.box = null
			}

			if (old_instance.parent) old_instance.parent.remove(old_instance)

			// recreate 'SvelthreeProps'
			// - all initially set props will be applied to the new instance.
			// - 'props' attribute can be used directly after mesh reassignment.
			sProps = new SvelthreeProps(mesh)

			// helpers will be recreated automatically
			// (see corresponding reactive statement -> !mesh.userData.helper)
		}

		// add `mesh` to `our_parent`
		if (our_parent) {
			// TODO  UNDERSTAND completely why we need the `mesh !== our_parent` check (was added as quick-fix)
			// TODO  Update - we changed the approach, still needed?
			if (mesh.parent !== our_parent && mesh !== our_parent) {
				our_parent.add(mesh)
				mesh_uuid = mesh.uuid

				if (verbose && log_dev) {
					console.debug(
						...c_dev(c_name, `${geometry.type} was added to ${our_parent.type}!`, {
							mesh,
							scene,
							total: scene.children.length
						})
					)
				}
			} else {
				// TODO / TOFIX  why is this happening if `!replacing`?
				//if (!replacing) console.warn(`mesh was already added to the ${get_comp_name(our_parent)}`, {mesh, our_parent, scene})
			}
		} else {
			console.error("No 'our_parent' (or 'scene')! Nothing to add 'mesh' to!", { mesh, our_parent, scene })
		}
	}

	// accessability -> shadow dom element

	/** Specify the component / three.js object instance to act as an HTML `<button>` element. */
	export let button: ButtonProp = undefined

	/** Specify the component / three.js object instance to act as an HTML `<a>` element. */
	export let link: LinkProp = undefined

	/**
	 *  IMPORTANT  TODO  TOFIX   \
	 * if we're combining components into a non-svelthree component, like e.g. a `Car`
	 * component, there will be no `shadow_dom_target` or `shadow_root_el!
	 */
	export let shadow_dom_target: SvelthreeShadowDOMElement = undefined

	$: if (shadow_root_el && mesh && !shadow_dom_target) {
		if (browser) {
			if (button) {
				shadow_dom_target = document.createElement("button")

				for (const key in button) {
					shadow_dom_target[key] = button[key]
				}
			} else if (link) {
				shadow_dom_target = document.createElement("a")

				for (const key in link) {
					shadow_dom_target[key] = link[key]
				}
			} else {
				shadow_dom_target = document.createElement("div")
			}

			shadow_dom_target.dataset.kind = "Mesh"
			if (name) shadow_dom_target.dataset.name = name

			const shadow_target: SvelthreeShadowDOMElement = our_parent
				? our_parent.userData.svelthreeComponent.shadow_dom_target
				: shadow_root_el

			// see  TODO  above
			if (shadow_target) shadow_target.appendChild(shadow_dom_target)
		}
	}

	// accessability -> shadow dom focusable
	export let tabindex: number = undefined

	$: if (shadow_dom_target && tabindex !== undefined) {
		shadow_dom_target.tabIndex = tabindex
	}

	// accessability -> shadow dom wai-aria
	export let aria: Partial<ARIAMixin> = undefined

	$: if (shadow_dom_target && aria !== undefined) {
		for (const key in aria) {
			if (key === "ariaLabel") {
				// add specified `ariaLabel` as text to shadow DOM `<div>` element ONLY (for better reader support / indexing (?))
				if (!link && !button) {
					//  TODO  RECONSIDER  needs to be tested more, may be obsolete (?).
					shadow_dom_target.innerText += `${aria[key]}`
				}
			}

			shadow_dom_target[key] = aria[key]
		}
	}

	/** Override object's `.matrixAutoUpdate` set (*on initialzation*) by scene's `.matrixAutoUpdate` (*default is `true`*). Also: `mau` can be changed on-the-fly.*/
	export let mau: boolean = undefined
	$: if (mesh) mesh.matrixAutoUpdate = scene.matrixAutoUpdate
	$: if (mesh && mau !== undefined) mesh.matrixAutoUpdate = mau

	export let name: string = undefined
	$: if (mesh && name) mesh.name = name

	let sMat: SvelthreeProps

	$: if (!sMat) {
		if (mesh.material) {
			sMat = new SvelthreeProps(mesh.material)
		}
	}

	// Generic Material props
	// COOL!  This works now! 'mat' shorthand attribute will give us proper intellisense (props list) for the assigned 'material'!
	// TODO  MULTIPLE MATERIALS: this works only with single Material atm, multiple Materials are not implemented yet.
	/** **shorthand** attribute for setting properties of a `Material` using key-value pairs in an `Object`. */
	export let mat: { [P in keyof AnyMaterialProps]: AnyMaterialProps[P] } = undefined
	$: if (mat && sMat) sMat.update(mat)

	/** ☝️ `matrix` **shorthand** attribute overrides ( *are ignored* ) `pos`, `rot`, `quat`, `scale` and `lookAt` 'shorthand' attributes! */
	export let matrix: Matrix4 | Parameters<Matrix4["set"]> = undefined

	const w_sh = PropUtils.getShortHandAttrWarnings(`SVELTHREE > ${c_name} >`)

	let sProps: SvelthreeProps

	// IMPORTANT  `props` will be overridden by 'shorthand' attributes!
	/** **shorthand** attribute for setting properties using key-value pairs in an `Object`. */
	export let props: { [P in keyof MeshProps]: MeshProps[P] } = undefined

	$: if (!sProps && mesh && props) sProps = new SvelthreeProps(mesh)
	$: if (props && sProps) update_props()
	function update_props() {
		if (verbose && log_rs) console.debug(...c_rs(c_name, "props", props))
		sProps.update(props)
	}

	// IMPORTANT  following 'shorthand' attributes will override `props` attribute!

	/** **shorthand** attribute for setting the `position` property. */
	export let pos: Vector3 | Parameters<Vector3["set"]> = undefined
	$: !matrix && mesh && pos ? set_pos() : pos && mesh ? console.warn(w_sh.pos) : null
	function set_pos() {
		if (verbose && log_rs) console.debug(...c_rs(c_name, "pos", pos))
		PropUtils.setPositionFromValue(mesh, pos)
	}

	/** **shorthand** attribute for setting the `rotation` property. */
	export let rot:
		| Euler
		| Parameters<Euler["set"]>
		| Quaternion
		| Parameters<Quaternion["set"]>
		| Vector3
		| Parameters<Vector3["set"]> = undefined
	$: !matrix && !quat && mesh && rot ? set_rot() : rot && mesh ? console.warn(w_sh.rot) : null
	function set_rot() {
		if (verbose && log_rs) console.debug(...c_rs(c_name, "rot", rot))
		PropUtils.setRotationFromValue(mesh, rot)
	}

	/** **shorthand** attribute for setting the `quaternion` property. */
	export let quat: Quaternion | Parameters<Quaternion["set"]> = undefined
	$: !matrix && mesh && quat ? set_quat() : quat && mesh ? console.warn(w_sh.quat) : null
	function set_quat() {
		if (verbose && log_rs) console.debug(...c_rs(c_name, "quat", quat))
		PropUtils.setQuaternionFromValue(mesh, quat)
	}

	export let scale: Vector3 | Parameters<Vector3["set"]> = undefined
	$: !matrix && mesh && scale ? set_scale() : scale && mesh ? console.warn(w_sh.scale) : null
	function set_scale() {
		if (verbose && log_rs) console.debug(...c_rs(c_name, "scale", scale))
		PropUtils.setScaleFromValue(mesh, scale)
	}

	/** */
	export let lookAt: Vector3 | Parameters<Vector3["set"]> | Object3D = undefined
	$: !matrix && mesh && lookAt ? set_lookat() : lookAt && mesh ? console.warn(w_sh.lookAt) : null
	function set_lookat() {
		if (verbose && log_rs) console.debug(...c_rs(c_name, "lookAt", lookAt))
		PropUtils.setLookAtFromValue(mesh, lookAt)
	}

	// IMPORTANT  `matrix` 'shorthand' attribute will override all other transforms ('shorthand' attributes)!
	$: if (matrix && mesh) set_matrix()
	function set_matrix(): void {
		if (verbose && log_rs) console.debug(...c_rs(c_name, "matrix", matrix))
		PropUtils.setMatrixFromValue(mesh, matrix)
	}

	export let castShadow: boolean = undefined
	$: if (castShadow !== undefined && mesh) mesh.castShadow = castShadow

	export let receiveShadow: boolean = undefined
	$: if (receiveShadow !== undefined && mesh) mesh.receiveShadow = receiveShadow

	/** The root scene -> `scene.parent = null`. */
	let root_scene: Scene | null = undefined
	$: if (root_scene === undefined) root_scene = get_root_scene(getContext("scene"))

	$: if (mesh && root_scene) {
		mesh.userData.root_scene = root_scene
	}

	type BoxHelperParams = ConstructorParameters<typeof BoxHelper>
	export let boxParams: RemoveFirst<BoxHelperParams> = undefined
	/** Creates and adds a `BoxHelper`. */
	export let box: boolean = undefined

	/** Removes `WebGLRenderer` `"update_helpers"` event listener. */
	let remove_update_box_on_render_event: () => void = undefined

	$: if (box && mesh && !mesh.userData.box) add_box_helper()
	$: if (!box && mesh.userData.box) remove_box_helper()

	function add_box_helper() {
		if (boxParams) {
			mesh.userData.box = new BoxHelper(mesh, ...boxParams)
		} else {
			mesh.userData.box = new BoxHelper(mesh)
		}

		mesh.userData.box.visible = false
	}

	// update and show box on next frame
	$: if (box && mesh && mesh.userData.box && $svelthreeStores[sti].rendererComponent && root_scene) {
		apply_box()
	}

	function apply_box(): void {
		if (!mesh.userData.box.parent) {
			// add all boxes to the root scene!
			if (root_scene) {
				root_scene.add(mesh.userData.box)
			} else {
				console.error(`SVELTHREE > ${c_name} > Cannot add box to 'root_scene'!`, root_scene)
			}
		}

		// update box and make it visible
		mesh.userData.box.update()
		mesh.userData.box.visible = true

		// start updating
		if (!remove_update_box_on_render_event) {
			remove_update_box_on_render_event = $svelthreeStores[sti].rendererComponent.$on(
				"update_helpers",
				update_box
			)
		}
	}

	function update_box(): void {
		mesh.userData.box.update()
	}

	function remove_box_helper(): void {
		if (remove_update_box_on_render_event) {
			remove_update_box_on_render_event()
			remove_update_box_on_render_event = null
		}

		if (mesh.userData.box?.parent) {
			mesh.userData.box.parent.remove(mesh.userData.box)
			mesh.userData.box = null
		}
	}

	/** Make component's three.js object interactive -> enable raycasting, `on:<event_name>` directives and `on_<event_name>` internal actions. */
	export let interact: boolean = undefined

	/** Adds component's three.js object instance to the `raycast` array even if it's not set to `interact` ( _no interaction listeners_ ).
	 * This way the object acts as a pure _interaction occluder / blocker_ -> will be detected / intersected by `Raycaster`'s ray.
	 *
	 * Setting the `block` prop makes sense only if the `interact` prop is not set / set to `false`.
	 * In case `interact` prop is set / set to `true`, but no e.g. `on:<event_name>` directives or `on_<event_name>` internal actions are set,
	 * the object will automatically become an _interaction occluder / blocker_.
	 */
	export let block: boolean = false

	let interactive: boolean = undefined
	const canvas_interactivity: Writable<{ enabled: boolean }> = getContext("canvas_interactivity")

	$: interactive = $canvas_interactivity.enabled

	let interactionEnabled: boolean = undefined
	$: interactionEnabled = interactive && interact

	//  IMPORTANT  not reactive
	const raycast: RaycastArray = getContext("raycast")

	// reactively enable raycasting to the created three.js instance
	$: if (interactionEnabled && raycast && !block) {
		if (!raycast.includes(mesh)) {
			mesh.userData.block = false
			raycast.push(mesh)
		} else {
			mesh.userData.block = false
		}
	}

	// reactively enable raycasting to the created three.js instance if it's an 'interaction occluder / blocker'
	$: if (!interactionEnabled && raycast && block) {
		if (!raycast.includes(mesh)) {
			mesh.userData.block = true
			raycast.push(mesh)
		} else {
			mesh.userData.block = true
		}
	}

	// reactively disable raycasting to the created three.js instance
	$: if (!interactionEnabled && raycast && !block) {
		if (raycast.includes(mesh)) {
			raycast.splice(mesh.userData.index_in_raycast, 1)
			mesh.userData.block = false
		}
	}

	/** `SvelthreeInteraction` component reference used for reactive listener management only. */
	let interaction_comp = undefined

	/**
	 * **svelthree** replacement for [`$on`](https://svelte.dev/docs#run-time-client-side-component-api-$on), does basically the same,
	 * but it doesn't return a function for removal of the listener (_like Svelte native does_), instead use `.onx(type, callback)` syntax.
	 * Needed for **reactive** interaction listener management -> _internal svelthree functionality_.
	 *
	 * ☝️ _Can be used with **interactive components only** -> `interact` prop has to be `true`._
	 */
	export async function on(type: any, callback: any): Promise<void> {
		if (interact) {
			if (!interaction_comp) await tick()

			self.$on(type, callback)
			interaction_comp.update_listeners = true
		} else {
			console.error(
				"SVELTHREE > Mesh > on : You can call the '.on(...)' function with interactive components only! Component's 'interact' prop has to be 'true'."
			)
		}
	}

	/**
	 * **svelthree** replacement for the _event listener removal function_ returned by [`$on`](https://svelte.dev/docs#run-time-client-side-component-api-$on), does basically the same,
	 * needed for **reactive** interaction listener management -> _internal svelthree functionality_. It additionaly allows programmatic removal of all callbacks of a certain type and
	 * programmatic removal of 'forwarding' directives (no handlers) like `on:click`.
	 *
	 * ☝️ _Can be used with **interactive components only** -> `interact` prop has to be `true`._
	 */
	export async function onx(type: any, callback: any): Promise<void> {
		if (interact) {
			if (!interaction_comp) await tick()

			const cbacks = self.$$.callbacks[type]
			if (callback) {
				const index = cbacks.indexOf(callback)
				if (index !== -1) cbacks.splice(index, 1)
			} else {
				// allows e.g. onx("click") -> will remove all callbacks and the callback type itself
				// this way we can also programatically delete 'forwarding' directives (no handlers) like `on:click`
				self.$$.callbacks[type].length = 0
				delete self.$$.callbacks[type]
			}

			interaction_comp.update_listeners = true
		} else {
			console.error(
				"SVELTHREE > Mesh > onx : You can call the '.onx(...)' function with interactive components only! Component's 'interact' prop has to be 'true'!"
			)
		}
	}

	/** Interaction modifiers. */
	export let modifiers: SvelthreeModifiersProp = undefined

	export let on_click: SvelthreePointerEventHandler = undefined
	$: if (on_click !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_pointerup: SvelthreePointerEventHandler = undefined
	$: if (on_pointerup !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_pointerdown: SvelthreePointerEventHandler = undefined
	$: if (on_pointerdown !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_pointerover: SvelthreePointerEventHandler = undefined
	$: if (on_pointerover !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_pointerout: SvelthreePointerEventHandler = undefined
	$: if (on_pointerout !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_pointermove: SvelthreePointerEventHandler = undefined
	$: if (on_pointermove !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_pointermoveover: SvelthreePointerEventHandler = undefined
	$: if (on_pointermoveover !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_keydown: SvelthreeKeyboardEventHandler = undefined
	$: if (on_keydown !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_keypress: SvelthreeKeyboardEventHandler = undefined
	$: if (on_keypress !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_keyup: SvelthreeKeyboardEventHandler = undefined
	$: if (on_keyup !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_focus: SvelthreeFocusEventHandler = undefined
	$: if (on_focus !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_blur: SvelthreeFocusEventHandler = undefined
	$: if (on_blur !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_focusin: SvelthreeFocusEventHandler = undefined
	$: if (on_focusin !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_focusout: SvelthreeFocusEventHandler = undefined
	$: if (on_focusout !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_wheel: SvelthreeWheelEventHandler = undefined // ->  TODO  implement
	$: if (on_wheel !== undefined && interaction_comp) interaction_comp.update_listeners = true

	export let on_wheelover: SvelthreeWheelEventHandler = undefined // -> TODO  implement
	$: if (on_wheelover !== undefined && interaction_comp) interaction_comp.update_listeners = true

	/** Animation logic to be performed with the (three) object instance created by the component. */
	export let animation: SvelthreeAnimationFunction = undefined

	let animationEnabled: boolean = false
	$: if (animation) animationEnabled = true

	/** Immediately start provided animation, default: `false`. Alternative: `<component_reference>.start_animation()` or shorter `.start_ani()`. */
	export let aniauto: boolean = undefined

	let ani: SvelthreeAnimation
	$: if (animation && animationEnabled) ani = new SvelthreeAnimation(scene, mesh, animation, aniauto)

	let currentSceneActive = undefined
	$: currentSceneActive = $svelthreeStores[sti].scenes[scene.userData.index_in_scenes]?.isActive
	$: if (ani && currentSceneActive !== undefined) ani.onCurrentSceneActiveChange(currentSceneActive)

	/** Removes the (three) instance of the object created by the component from it's parent. */
	export const remove_instance_from_parent = (): void => {
		if (mesh.parent) mesh.parent.remove(mesh)
	}
	/**
	 * Same as `remove_instance_from_parent()` just shorter syntax.
	 * Removes the (three) instance of the object created by the component from it's parent.
	 */
	export const remove = remove_instance_from_parent

	/** Returns the (three) instance of the object created by the component. */
	export const get_instance = (): Mesh => mesh

	/** Returns the `animation` object. */
	export const get_animation = (): any => ani.getAnimation()
	/** Same as `get_animation()` just shorter syntax. Returns the `animation` object. */
	export const get_ani = get_animation

	/** Starts the `animation` object. */
	export const start_animation = (): void => ani.startAni()
	/** Same as `start_animation()` just shorter syntax. Starts the `animation` object. */
	export const start_ani = start_animation

	/** Sets `focus()` on the component / it's shadow dom element. */
	export const focused = (): void => shadow_dom_target.focus()

	/** **Completely replace** `onMount` -> any `onMount_inject_before` & `onMount_inject_after` will be ignored.
	 * _default verbosity will be gone!_ */
	export let onMount_replace: (args?: any) => any = undefined

	onMount(
		onMount_replace
			? async () => onMount_replace(_self)
			: async () => {
					if (verbose && log_lc && (log_lc.all || log_lc.om)) {
						console.info(...c_lc(c_name, "onMount"))
					}

					if (verbose && log_mau) {
						console.debug(
							...c_mau(c_name, "onMount : mesh.", {
								matrixAutoUpdate: mesh.matrixAutoUpdate,
								matrixWorldNeedsUpdate: mesh.matrixWorldNeedsUpdate
							})
						)
					}
			  }
	)

	/** **Inject** functionality **before** component's existing `onDestroy` logic.
	 * _default verbosity not affected._ */
	export let onDestroy_inject_before: (args?: any) => any = undefined

	/** **Inject** functionality **after** component's existing `onDestroy` logic.
	 * _default verbosity not affected._ */
	export let onDestroy_inject_after: (args?: any) => any = undefined

	/** **Completely replace** `onDestroy` -> any `onDestroy_inject_before` & `onDestroy_inject_after` will be ignored.
	 * _default verbosity will be gone!_ */
	export let onDestroy_replace: (args?: any) => any = undefined

	onDestroy(
		onDestroy_replace
			? async () => onDestroy_replace(_self)
			: async () => {
					if (verbose && log_lc && (log_lc.all || log_lc.od)) {
						console.info(...c_lc(c_name, "onDestroy"))
					}

					if (verbose && log_mau) {
						console.debug(
							...c_mau(c_name, "onDestroy : mesh.", {
								matrixAutoUpdate: mesh.matrixAutoUpdate,
								matrixWorldNeedsUpdate: mesh.matrixWorldNeedsUpdate
							})
						)
					}

					if (onDestroy_inject_before) onDestroy_inject_before()

					remove_box_helper()
					if (ani) ani.destroyAnimation()

					if (onDestroy_inject_after) onDestroy_inject_after()
			  }
	)

	/** **Completely replace** `beforeUpdate` -> any `beforeUpdate_inject_before` & `beforeUpdate_inject_after` will be ignored.
	 * _default verbosity will be gone!_ */
	export let beforeUpdate_replace: (args?: any) => any = undefined

	beforeUpdate(
		beforeUpdate_replace
			? async () => beforeUpdate_replace(_self)
			: async () => {
					if (verbose && log_lc && (log_lc.all || log_lc.bu)) {
						console.info(...c_lc(c_name, "beforeUpdate"))
					}

					if (verbose && log_mau) {
						console.debug(
							...c_mau(c_name, "beforeUpdate : mesh.", {
								matrixAutoUpdate: mesh.matrixAutoUpdate,
								matrixWorldNeedsUpdate: mesh.matrixWorldNeedsUpdate
							})
						)
					}
			  }
	)

	/** **Inject** functionality **before** component's existing `afterUpdate` logic.
	 * _default verbosity not affected._ */
	export let afterUpdate_inject_before: (args?: any) => any = undefined

	/** **Inject** functionality **after** component's existing `afterUpdate` logic.
	 * _default verbosity not affected._ */
	export let afterUpdate_inject_after: (args?: any) => any = undefined

	/** **Completely replace** `afterUpdate` -> any `afterUpdate_inject_before` & `afterUpdate_inject_after` will be ignored.
	 * _default verbosity will be gone!_ */
	export let afterUpdate_replace: (args?: any) => any = undefined

	afterUpdate(
		afterUpdate_replace
			? async () => afterUpdate_replace(_self)
			: async () => {
					if (verbose && log_lc && (log_lc.all || log_lc.au)) {
						console.info(...c_lc(c_name, "afterUpdate"))
					}

					if (verbose && log_mau) {
						console.debug(
							...c_mau(c_name, "afterUpdate : mesh.", {
								matrixAutoUpdate: mesh.matrixAutoUpdate,
								matrixWorldNeedsUpdate: mesh.matrixWorldNeedsUpdate
							})
						)
					}

					if (afterUpdate_inject_before) afterUpdate_inject_before()

					// Update local matrix after all (props) changes (async microtasks) have been applied.
					if (!mesh.matrixAutoUpdate) mesh.updateMatrix()

					if (verbose && !mesh.matrixAutoUpdate && log_mau) {
						console.debug(
							...c_mau(c_name, "afterUpdate : mesh.", {
								matrixAutoUpdate: mesh.matrixAutoUpdate,
								matrixWorldNeedsUpdate: mesh.matrixWorldNeedsUpdate
							})
						)
					}

					if ($svelthreeStores[sti].rendererComponent?.mode === "auto") {
						root_scene.userData.dirty = true
						$svelthreeStores[sti].rendererComponent.schedule_render(root_scene)
					}

					if (afterUpdate_inject_after) afterUpdate_inject_after()
			  }
	)
</script>

<slot />

{#if $svelthreeStores[sti].renderer && $svelthreeStores[sti].renderer.xr.enabled === false && interact}
	<SvelthreeInteraction
		bind:this={interaction_comp}
		{shadow_dom_target}
		{modifiers}
		{dispatch}
		obj={mesh}
		parent={self}
		{interactionEnabled}
		{log_dev}
		{log_lc}
	/>
{/if}