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<!DOCTYPE html>
<html>
<head>
<meta charset=utf-8 />
<title>Kurs i WebGL med THREE.js</title>
<script src=remark-0.5.7.min.js></script>
<script src=res/libs/three.min.js></script>
<link rel=stylesheet type=text/css href=res/css/style.css />
<link href='http://fonts.googleapis.com/css?family=Lato&subset=latin,latin-ext' rel='stylesheet' type='text/css'>
<style>
canvas {
border: 1px solid #000;
display: block;
margin: 0 auto;
}
</style>
</head>
<body>
<textarea id="source">
class: center, middle
# The THREE.js Musketeers
<span class=subtle>by Poëtene</span>
---
# This course
Short tasks that demonstrate basic THREE.js concepts.
Then: combine what you have learned to make your own cool effect!
Have some fun :)
???
Hver del skal de gjøre litt selv.
De må gjerne finne på og tweake selv.
---
<img src="res/img/DSC_0303.JPG" style="width:100%">
---
<img src="res/img/DSC_0304.JPG" style="width:100%">
---
# WebGL
Javascript API for GPU rendering
OpenGL in the browser
Works in modern browser (mobile and desktop)
???
WebGL er et JavaScript-API for 3D-grafikk i nettleseren.
Det er basert på OpenGL
Grafikken tegnes på et canvas-element (HTML5)
Støttes av Firefox, Chrome, Safari, Opera, IE11
Støttes også i iOS 8 og i nye Android-versjoner
---
### Coordinate system in WebGL
.float-left[x goes rightwards
y goes upwards
z goes outwards (from the screen)
]
.float-right[
]
???
Forklar at når man ser et 2-dimensjonalt koordinatsystem på skjermen er det veldig naturlig å ha Y-aksen oppover og X-aksen bortover.
WebGL er en utvidelse av dette, og har dermed Z-aksen som dybde.
---
# THREE.js
### Makes 3D easier
- Camera
- Scene
- 3D-objects (mesh)
- Lighting
???
THREE.js er et javascript-rammeverk som gjør det enkelt å jobbe med 3D i nettleseren.
---
class: tiny-font
```html
...
<canvas></canvas>
<div id="info"></div>
<script id="vs" type="x-shader/vertex">
attribute vec3 position;
void main() {
gl_Position = vec4( position, 1.0 );
}
</script>
<script id="fs" type="x-shader/fragment">
uniform float time;
uniform vec2 resolution;
void main( void ) {
vec2 position = - 1.0 + 2.0 * gl_FragCoord.xy / resolution.xy;
float red = abs( sin( position.x * position.y + time / 5.0 ) );
float green = abs( sin( position.x * position.y + time / 4.0 ) );
float blue = abs( sin( position.x * position.y + time / 3.0 ) );
gl_FragColor = vec4( red, green, blue, 1.0 );
}
</script>
<script>
/**
* Provides requestAnimationFrame in a cross browser way.
* paulirish.com/2011/requestanimationframe-for-smart-animating/
*/
window.requestAnimationFrame = window.requestAnimationFrame || ( function() {
return window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function( callback, element ) {
window.setTimeout( callback, 1000 / 60 );
};
})();
var canvas,
gl,
buffer,
vertex_shader, fragment_shader,
currentProgram,
vertex_position,
parameters = { start_time : new Date().getTime(),
time : 0,
screenWidth : 0,
screenHeight: 0 };
init();
animate();
function init() {
vertex_shader = document.getElementById('vs').textContent;
fragment_shader = document.getElementById('fs').textContent;
canvas = document.querySelector( 'canvas' );
// Initialise WebGL
try {
gl = canvas.getContext( 'experimental-webgl' );
} catch( error ) { }
if ( !gl ) {
throw "cannot create webgl context";
}
// Create Vertex buffer (2 triangles)
buffer = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, buffer );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( [ - 1.0, - 1.0, 1.0, - 1.0, - 1.0, 1.0, 1.0, - 1.0, 1.0, 1.0, - 1.0, 1.0 ] ), gl.STATIC_DRAW );
// Create Program
currentProgram = createProgram( vertex_shader, fragment_shader );
onWindowResize();
window.addEventListener( 'resize', onWindowResize, false );
}
function createProgram( vertex, fragment ) {
var program = gl.createProgram();
var vs = createShader( vertex, gl.VERTEX_SHADER );
var fs = createShader( '#ifdef GL_ES\nprecision highp float;\n#endif\n\n' + fragment, gl.FRAGMENT_SHADER );
if ( vs == null || fs == null ) return null;
gl.attachShader( program, vs );
gl.attachShader( program, fs );
gl.deleteShader( vs );
gl.deleteShader( fs );
gl.linkProgram( program );
if ( !gl.getProgramParameter( program, gl.LINK_STATUS ) ) {
alert( "ERROR:\n" +
"VALIDATE_STATUS: " + gl.getProgramParameter( program, gl.VALIDATE_STATUS ) + "\n" +
"ERROR: " + gl.getError() + "\n\n" +
"- Vertex Shader -\n" + vertex + "\n\n" +
"- Fragment Shader -\n" + fragment );
return null;
}
return program;
}
function createShader( src, type ) {
var shader = gl.createShader( type );
gl.shaderSource( shader, src );
gl.compileShader( shader );
if ( !gl.getShaderParameter( shader, gl.COMPILE_STATUS ) ) {
alert( ( type == gl.VERTEX_SHADER ? "VERTEX" : "FRAGMENT" ) + " SHADER:\n" + gl.getShaderInfoLog( shader ) );
return null;
}
return shader;
}
function onWindowResize( event ) {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
parameters.screenWidth = canvas.width;
parameters.screenHeight = canvas.height;
gl.viewport( 0, 0, canvas.width, canvas.height );
}
function animate() {
requestAnimationFrame( animate );
render();
}
function render() {
if ( !currentProgram ) return;
parameters.time = new Date().getTime() - parameters.start_time;
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
// Load program into GPU
gl.useProgram( currentProgram );
// Set values to program variables
gl.uniform1f( gl.getUniformLocation( currentProgram, 'time' ), parameters.time / 1000 );
gl.uniform2f( gl.getUniformLocation( currentProgram, 'resolution' ), parameters.screenWidth, parameters.screenHeight );
// Render geometry
gl.bindBuffer( gl.ARRAY_BUFFER, buffer );
gl.vertexAttribPointer( vertex_position, 2, gl.FLOAT, false, 0, 0 );
gl.enableVertexAttribArray( vertex_position );
gl.drawArrays( gl.TRIANGLES, 0, 6 );
gl.disableVertexAttribArray( vertex_position );
}
...
```
???
Eksempel på WebGL uten THREE.js
---
class: middle
```javascript
var renderer = new THREE.WebGLRenderer();
var scene = new THREE.Scene();
var view_angle = 45;
var aspect = width / height;
var near = 0.1;
var far = 10000;
var camera = new THREE.PerspectiveCamera(
view_angle,
aspect,
near,
far
);
renderer.setSize(width, height);
document.body.appendChild(renderer.domElement);
renderer.render(scene, camera);
```
???
Minimalt eksempel.
Dette er den minste versjonen av boilerplaten du trenger.
Forklar de viktigste konseptene godt, alle talla er ikke så interessante.
---
demo: show-sphere
<div id=show-sphere class=small-demo></div>
# Add an object
## Geometry
```javascript
var geometry = new THREE.SphereGeometry(
50, // radius
16, // segments
16 // rings
);
```
---
<div style="width:200px; height: 200px; background: red; float: right;"></div>
# Add an object
## Material
```javascript
var material = new THREE.MeshBasicMaterial(
{color: 0xff0000}
);
```
---
demo: show-sphere-mesh
<div id=show-sphere-mesh class=small-demo></div>
# add an object
## Mesh
```javascript
var sphere = new THREE.Mesh(
geometry,
material
);
scene.add(sphere);
```
---
# Animation
The canvas must be redrawn many times per second
```javascript
function animate() {
requestAnimationFrame(animate);
// do animation here
renderer.render(scene, camera);
}
animate();
```
???
Nettleseren bestemmer hvor ofte funksjonen kalles.
Vi kaller animate én gang for å starte den, resten går automatisk.
---
class: center, middle
# Time
## Date.now()
Millisekunder siden 1. januar 1970
---
class: middle
```javascript
var initial_t = Date.now() / 1000;
function animate() {
requestAnimationFrame(animate);
var t = Date.now() / 1000 - initial_t;
// do animation here
renderer.render(scene, camera);
}
animate();
```
???
Nå har vi en variabel som øker for hver frame i animasjonen.
Uansett hvor ofte skjermen oppdateres øker den med én hvert sekund.
Initial_t gjør at den starter på 0.
---
class: center middle
# Tasks
???
Nå kommer noen oppgaver som viser ulike ting som er kjekt å kunne.
Til slutt skal dere kunne sette sammen ting dere har lært til en demo.
Og så har vi konkurranse.
---
demo: rotate-cube
# Task 1
## Make a rotating cube
<div id=rotate-cube class=demo></div>
???
De fyller ut der det står kommentarer i koden på linken
---
# Task 1
```javascript
cube = new THREE.Mesh(geometry, material);
```
cube.rotation has three properties: x, y og z
```javascript
cube.rotation.x = 1;
```
---
# Task 1
## Make a rotating cube
### http://poetene.net/threejs/effect/4
---
# Solution Task 1
```javascript
function animate() {
requestAnimationFrame(animate);
var t = Date.now() / 1000 - initial_t;
cube.rotation.x = t * 5;
cube.rotation.z = t * 5;
renderer.render(scene, camera);
}
```
---
# Task 2
Animate the camera in a circle around the z-axis
---
# Task 2
Set camera.position.x og .y
<div style=background:white;text-align:center;height:45%>
<img style=height:70% src=res/img/unit_circle.svg>
</div>
---
# Task 2
Animate the camera in a circle around the z-axis
http://poetene.net/threejs/effect/13-camera/
---
# Solution Task 2
Move the camera
```javascript
camera.position.x = DISTANCE_FROM_Z_PLANE * Math.sin(t);
camera.position.y = DISTANCE_FROM_Z_PLANE * Math.cos(t);
```
---
# Task 3
## Animate multiple cubes in fun trajectories
You could go for instance a circular movement, a ∞ trajectory, or in a ☃ trajectory.
---
# Task 3
An array of cubes is available in ```cubes```.
Can e.g. by animated by:
```javascript
for (var i = 0; i < cubes.length; i++) {
var cube = cubes[i];
//manipulate every cube here
cube.position.x = 200 * Math.sin(t + 0.5 * i);
}
```
---
# Task 3
## Animate many cubes
### http://poetene.net/threejs/effect/12
---
# Task 4
## Skybox
<img src=res/img/Skybox_example.png>
---
class: skybox-code-slide middle
```javascript
var urlPrefix = "/static/res/skyboxes/TropicalSunnyDay_";
var directions = ["left", "right", "up", "down", "front", "back"];
var skyGeometry = new THREE.BoxGeometry(15000, 15000, 15000);
var materialArray = [];
for (var i = 0; i < 6; i++) {
var url = urlPrefix + directions[i] + ".jpg";
materialArray.push(new THREE.MeshBasicMaterial({
map: THREE.ImageUtils.loadTexture(url),
side: THREE.BackSide
}));
}
var skyMaterial = new THREE.MeshFaceMaterial(materialArray);
var skyBoxMesh = new THREE.Mesh(skyGeometry, skyMaterial);
scene.add(skyBoxMesh);
```
---
# Task 4
Example: http://poetene.net/threejs/effect/51
Skyboxes available at http://poetene.net/threejs/skyboxes/
Add a skybox in your demo
---
# Task 5
## Music ♫ ♪
```html
<audio id="music" loop>
<source src="my_music.mp3" type="audio/mpeg">
</audio>
```
```javascript
music.play();
function animate() {
console.log(music.currentTime); // antall sekunder
}
```
---
# Task 5
## Add music
http://poetene.net/threejs/effect/44-musikk-eksempel/
---
# Task 6
## Shaders
<img src=res/img/shader_example.png alt="Shader example" style="width: 100%;" >
---
# What are shaders?
Programs written in GLSL that are designed to operate on arrays (vertex) and render textures (fragment).
THREE.js supplies their own shaders that contain the actual drawing, coloring, lighting, ++ logic
Can also chained for post-processing fx
???
glsl er et språk som ligner litt på c
Vi skal ikke lære glsl i dag, men bruke en del ferdig skrevne shaders vi har lagd fra før
---
# Using post-processing shaders
http://poetene.net/threejs/shaders/
```javascript
var shaderPass = new THREE.ShaderPass(SHADERS.multiply);
// Skriv kun dette for den siste shaderen
shaderPass.renderToScreen = true;
composer.addPass(shaderPass);
```
???
Laster inn en av de ferdige shaderne våre
---
# Uniforms
Parameters that are sent to a shader
```javascript
shaderPass.uniforms.amount.value = 1;
```
???
Et objekt med ulike verdier som kan styres fra javascript.
Shaderen bruker disse verdiene i beregningene sine
---
# Shaders
## Play with shaders
http://poetene.net/threejs/effect/54-oppgave-6-shaders/
---
# Demo compo
Lag noe kult, og vinn premie!
Make some cool effects \p/
???
Sjekk eksemplene på nettsiden, og sett sammen noe eget
Etterpå viser vi frem det dere har laget.
Spør oss om hjelp
</textarea>
<script type="text/javascript">
var slideshow = remark.create();
</script>
<script src=script.js></script>
</body>
</html>