Nicolas Butet

1616827200

Simple Third Person Camera Using Three.js/JavaScript

How to build out a simple third person camera in three.js and JavaScript, from scratch. The goal here is to understand the mechanics of a simple follow camera (or third person camera), what goes into designing one, what considerations are made, and how to code one up. We’ll step through various smoothing options and show you the effect of framerate differences and how to mitigate those problems.

Previously in videos, we covered three.js camera support and how to build out a simple third person character controller. This tutorial is a natural progression of the topic, covering 3rd person cameras. This is all part of a series of beginner tutorials on three.js, starting scratch and working up to the point of having moving animated characters in a small world.

The three.js library is available in JavaScript for cross-browser 3d graphics, wrapping webgl and making high level functionality available in the web browser. It’s an extremely mature and well maintained library that I use for many of these videos.

In the video, we cover:

  • Game camera systems, 1st person vs 3rd person cameras
  • Architecture considerations when building out the camera class, how to decouple things in a clean way for future reuse.
  • Smooth interpolation and how to combat framerate changes.

Github: https://github.com/simondevyoutube/​

Subscribe: https://www.youtube.com/channel/UCEwhtpXrg5MmwlH04ANpL8A

#javascript

What is GEEK

Buddha Community

Simple Third Person Camera Using Three.js/JavaScript

NBB: Ad-hoc CLJS Scripting on Node.js

Nbb

Not babashka. Node.js babashka!?

Ad-hoc CLJS scripting on Node.js.

Status

Experimental. Please report issues here.

Goals and features

Nbb's main goal is to make it easy to get started with ad hoc CLJS scripting on Node.js.

Additional goals and features are:

  • Fast startup without relying on a custom version of Node.js.
  • Small artifact (current size is around 1.2MB).
  • First class macros.
  • Support building small TUI apps using Reagent.
  • Complement babashka with libraries from the Node.js ecosystem.

Requirements

Nbb requires Node.js v12 or newer.

How does this tool work?

CLJS code is evaluated through SCI, the same interpreter that powers babashka. Because SCI works with advanced compilation, the bundle size, especially when combined with other dependencies, is smaller than what you get with self-hosted CLJS. That makes startup faster. The trade-off is that execution is less performant and that only a subset of CLJS is available (e.g. no deftype, yet).

Usage

Install nbb from NPM:

$ npm install nbb -g

Omit -g for a local install.

Try out an expression:

$ nbb -e '(+ 1 2 3)'
6

And then install some other NPM libraries to use in the script. E.g.:

$ npm install csv-parse shelljs zx

Create a script which uses the NPM libraries:

(ns script
  (:require ["csv-parse/lib/sync$default" :as csv-parse]
            ["fs" :as fs]
            ["path" :as path]
            ["shelljs$default" :as sh]
            ["term-size$default" :as term-size]
            ["zx$default" :as zx]
            ["zx$fs" :as zxfs]
            [nbb.core :refer [*file*]]))

(prn (path/resolve "."))

(prn (term-size))

(println (count (str (fs/readFileSync *file*))))

(prn (sh/ls "."))

(prn (csv-parse "foo,bar"))

(prn (zxfs/existsSync *file*))

(zx/$ #js ["ls"])

Call the script:

$ nbb script.cljs
"/private/tmp/test-script"
#js {:columns 216, :rows 47}
510
#js ["node_modules" "package-lock.json" "package.json" "script.cljs"]
#js [#js ["foo" "bar"]]
true
$ ls
node_modules
package-lock.json
package.json
script.cljs

Macros

Nbb has first class support for macros: you can define them right inside your .cljs file, like you are used to from JVM Clojure. Consider the plet macro to make working with promises more palatable:

(defmacro plet
  [bindings & body]
  (let [binding-pairs (reverse (partition 2 bindings))
        body (cons 'do body)]
    (reduce (fn [body [sym expr]]
              (let [expr (list '.resolve 'js/Promise expr)]
                (list '.then expr (list 'clojure.core/fn (vector sym)
                                        body))))
            body
            binding-pairs)))

Using this macro we can look async code more like sync code. Consider this puppeteer example:

(-> (.launch puppeteer)
      (.then (fn [browser]
               (-> (.newPage browser)
                   (.then (fn [page]
                            (-> (.goto page "https://clojure.org")
                                (.then #(.screenshot page #js{:path "screenshot.png"}))
                                (.catch #(js/console.log %))
                                (.then #(.close browser)))))))))

Using plet this becomes:

(plet [browser (.launch puppeteer)
       page (.newPage browser)
       _ (.goto page "https://clojure.org")
       _ (-> (.screenshot page #js{:path "screenshot.png"})
             (.catch #(js/console.log %)))]
      (.close browser))

See the puppeteer example for the full code.

Since v0.0.36, nbb includes promesa which is a library to deal with promises. The above plet macro is similar to promesa.core/let.

Startup time

$ time nbb -e '(+ 1 2 3)'
6
nbb -e '(+ 1 2 3)'   0.17s  user 0.02s system 109% cpu 0.168 total

The baseline startup time for a script is about 170ms seconds on my laptop. When invoked via npx this adds another 300ms or so, so for faster startup, either use a globally installed nbb or use $(npm bin)/nbb script.cljs to bypass npx.

Dependencies

NPM dependencies

Nbb does not depend on any NPM dependencies. All NPM libraries loaded by a script are resolved relative to that script. When using the Reagent module, React is resolved in the same way as any other NPM library.

Classpath

To load .cljs files from local paths or dependencies, you can use the --classpath argument. The current dir is added to the classpath automatically. So if there is a file foo/bar.cljs relative to your current dir, then you can load it via (:require [foo.bar :as fb]). Note that nbb uses the same naming conventions for namespaces and directories as other Clojure tools: foo-bar in the namespace name becomes foo_bar in the directory name.

To load dependencies from the Clojure ecosystem, you can use the Clojure CLI or babashka to download them and produce a classpath:

$ classpath="$(clojure -A:nbb -Spath -Sdeps '{:aliases {:nbb {:replace-deps {com.github.seancorfield/honeysql {:git/tag "v2.0.0-rc5" :git/sha "01c3a55"}}}}}')"

and then feed it to the --classpath argument:

$ nbb --classpath "$classpath" -e "(require '[honey.sql :as sql]) (sql/format {:select :foo :from :bar :where [:= :baz 2]})"
["SELECT foo FROM bar WHERE baz = ?" 2]

Currently nbb only reads from directories, not jar files, so you are encouraged to use git libs. Support for .jar files will be added later.

Current file

The name of the file that is currently being executed is available via nbb.core/*file* or on the metadata of vars:

(ns foo
  (:require [nbb.core :refer [*file*]]))

(prn *file*) ;; "/private/tmp/foo.cljs"

(defn f [])
(prn (:file (meta #'f))) ;; "/private/tmp/foo.cljs"

Reagent

Nbb includes reagent.core which will be lazily loaded when required. You can use this together with ink to create a TUI application:

$ npm install ink

ink-demo.cljs:

(ns ink-demo
  (:require ["ink" :refer [render Text]]
            [reagent.core :as r]))

(defonce state (r/atom 0))

(doseq [n (range 1 11)]
  (js/setTimeout #(swap! state inc) (* n 500)))

(defn hello []
  [:> Text {:color "green"} "Hello, world! " @state])

(render (r/as-element [hello]))

Promesa

Working with callbacks and promises can become tedious. Since nbb v0.0.36 the promesa.core namespace is included with the let and do! macros. An example:

(ns prom
  (:require [promesa.core :as p]))

(defn sleep [ms]
  (js/Promise.
   (fn [resolve _]
     (js/setTimeout resolve ms))))

(defn do-stuff
  []
  (p/do!
   (println "Doing stuff which takes a while")
   (sleep 1000)
   1))

(p/let [a (do-stuff)
        b (inc a)
        c (do-stuff)
        d (+ b c)]
  (prn d))
$ nbb prom.cljs
Doing stuff which takes a while
Doing stuff which takes a while
3

Also see API docs.

Js-interop

Since nbb v0.0.75 applied-science/js-interop is available:

(ns example
  (:require [applied-science.js-interop :as j]))

(def o (j/lit {:a 1 :b 2 :c {:d 1}}))

(prn (j/select-keys o [:a :b])) ;; #js {:a 1, :b 2}
(prn (j/get-in o [:c :d])) ;; 1

Most of this library is supported in nbb, except the following:

  • destructuring using :syms
  • property access using .-x notation. In nbb, you must use keywords.

See the example of what is currently supported.

Examples

See the examples directory for small examples.

Also check out these projects built with nbb:

API

See API documentation.

Migrating to shadow-cljs

See this gist on how to convert an nbb script or project to shadow-cljs.

Build

Prequisites:

  • babashka >= 0.4.0
  • Clojure CLI >= 1.10.3.933
  • Node.js 16.5.0 (lower version may work, but this is the one I used to build)

To build:

  • Clone and cd into this repo
  • bb release

Run bb tasks for more project-related tasks.

Download Details:
Author: borkdude
Download Link: Download The Source Code
Official Website: https://github.com/borkdude/nbb 
License: EPL-1.0

#node #javascript

CSS Boss

CSS Boss

1606912089

How to create a calculator using javascript - Pure JS tutorials |Web Tutorials

In this video I will tell you How to create a calculator using javascript very easily.

#how to build a simple calculator in javascript #how to create simple calculator using javascript #javascript calculator tutorial #javascript birthday calculator #calculator using javascript and html

Nicolas Butet

1616827200

Simple Third Person Camera Using Three.js/JavaScript

How to build out a simple third person camera in three.js and JavaScript, from scratch. The goal here is to understand the mechanics of a simple follow camera (or third person camera), what goes into designing one, what considerations are made, and how to code one up. We’ll step through various smoothing options and show you the effect of framerate differences and how to mitigate those problems.

Previously in videos, we covered three.js camera support and how to build out a simple third person character controller. This tutorial is a natural progression of the topic, covering 3rd person cameras. This is all part of a series of beginner tutorials on three.js, starting scratch and working up to the point of having moving animated characters in a small world.

The three.js library is available in JavaScript for cross-browser 3d graphics, wrapping webgl and making high level functionality available in the web browser. It’s an extremely mature and well maintained library that I use for many of these videos.

In the video, we cover:

  • Game camera systems, 1st person vs 3rd person cameras
  • Architecture considerations when building out the camera class, how to decouple things in a clean way for future reuse.
  • Smooth interpolation and how to combat framerate changes.

Github: https://github.com/simondevyoutube/​

Subscribe: https://www.youtube.com/channel/UCEwhtpXrg5MmwlH04ANpL8A

#javascript

sachin jaiswal

sachin jaiswal

1565073008

Best Tutorial To Become Master In JavaScript Closure - CodesQuery

#javascript #web-development #angular #node-js #reactjs #vue-js #angular-js #react-native #typescript #express #es6 #three-js

Samuel Tucker

Samuel Tucker

1548064012

Why my window resize event listener doesn't work? Using Three.js and Vuetify.js

I am putting a three.js renderer inside of a , using vuetify.js framework. What I would like my code to do is to change the div element dimensions whenever the window is resized.

This is part of my project and I omitted unnecessary code blocks, so don't mind the not used variables :)

<style scoped>
.map__three {
  position: absolute;
  bottom: 60px;
  left: 0px;
}
</style>

<template>
<div class=“flex fill-height wrap”>
<v-btn></v-btn>
<div id=“map” class=“flex fill-height wrap” v-on:dblclick=“addNewPoi3d”></div>
</div>
</template>

<script>

export default {
name: ‘ThreeTest’,
data() {
return {
scene: null,
renderer: null,
camera: null,
mouse: null,
mousePosition: new THREE.Vector2(),
canvasPosition: null,
rayCaster: new THREE.Raycaster(),
mapWidth: null,
mapHeight: null,
mapDimensions: null
};
},

methods: {
init() {
let map = document.getElementById(‘map’);
this.mapDimensions = map.getBoundingClientRect();
this.mapWidth = this.mapDimensions.width;
this.mapHeight = this.mapDimensions.height;
this.scene = new THREE.Scene();
this.scene.background = new THREE.Color( 0xf0f0f0 );

  this.camera = new THREE.PerspectiveCamera(
    75,
    this.mapWidth/this.mapHeight,
    0.1,
    1000,
  );
  this.camera.position.z = 3;


  this.renderer = new THREE.WebGLRenderer();
  this.renderer.setSize(this.mapWidth, this.mapHeight);
  map.appendChild(this.renderer.domElement);



  // EVENT LISTENERS:
  window.addEventListener('resize', this.onWindowResize, false);
},


onWindowResize()  {
    this.camera.aspect = this.mapWidth / this.mapHeight;
    this.camera.updateProjectionMatrix();
    this.renderer.setSize(this.mapWidth, this.mapHeight);
},



animate() {
  requestAnimationFrame(this.animate);
  this.render();
},
render() {
  this.renderer.render(this.scene, this.camera);
},

},

mounted() {
this.init();
this.animate();
}
};
</script>

EXPECTED: it should resize the dimensions of the scene and camera aspect ratio I’ve loaded in.

WHAT IT DOES: none of that :D It pertains the same size of the scene and camera.

#javascript #html #vue.js #three-js