You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
277 lines
15 KiB
277 lines
15 KiB
3 years ago
|
<!DOCTYPE html><html lang="en"><head>
|
||
|
|
<meta charset="utf-8">
|
||
|
|
<title>Responsive Design</title>
|
||
|
|
<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
|
||
|
|
<meta name="twitter:card" content="summary_large_image">
|
||
|
|
<meta name="twitter:site" content="@threejs">
|
||
|
|
<meta name="twitter:title" content="Three.js – Responsive Design">
|
||
|
|
<meta property="og:image" content="https://threejs.org/files/share.png">
|
||
|
|
<link rel="shortcut icon" href="/files/favicon_white.ico" media="(prefers-color-scheme: dark)">
|
||
|
|
<link rel="shortcut icon" href="/files/favicon.ico" media="(prefers-color-scheme: light)">
|
||
|
|
|
||
|
|
<link rel="stylesheet" href="/manual/resources/lesson.css">
|
||
|
|
<link rel="stylesheet" href="/manual/resources/lang.css">
|
||
|
|
<!-- Import maps polyfill -->
|
||
|
|
<!-- Remove this when import maps will be widely supported -->
|
||
|
|
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>
|
||
|
|
|
||
|
|
<script type="importmap">
|
||
|
|
{
|
||
|
|
"imports": {
|
||
|
|
"three": "../../build/three.module.js"
|
||
|
|
}
|
||
|
|
}
|
||
|
|
</script>
|
||
|
|
</head>
|
||
|
|
<body>
|
||
|
|
<div class="container">
|
||
|
|
<div class="lesson-title">
|
||
|
|
<h1>Responsive Design</h1>
|
||
|
|
</div>
|
||
|
|
<div class="lesson">
|
||
|
|
<div class="lesson-main">
|
||
|
|
<p>This is the second article in a series of articles about three.js.
|
||
|
|
The first article was <a href="fundamentals.html">about fundamentals</a>.
|
||
|
|
If you haven't read that yet you might want to start there.</p>
|
||
|
|
<p>This article is about how to make your three.js app be responsive
|
||
|
|
to any situation. Making a webpage responsive generally refers
|
||
|
|
to the page displaying well on different sized displays from
|
||
|
|
desktops to tablets to phones.</p>
|
||
|
|
<p>For three.js there are even more situations to consider. For
|
||
|
|
example, a 3D editor with controls on the left, right, top, or
|
||
|
|
bottom is something we might want to handle. A live diagram
|
||
|
|
in the middle of a document is another example.</p>
|
||
|
|
<p>The last sample we had used a plain canvas with no CSS and
|
||
|
|
no size</p>
|
||
|
|
<pre class="prettyprint showlinemods notranslate lang-html" translate="no"><canvas id="c"></canvas>
|
||
|
|
</pre>
|
||
|
|
<p>That canvas defaults to 300x150 CSS pixels in size.</p>
|
||
|
|
<p>In the web platform the recommended way to set the size
|
||
|
|
of something is to use CSS.</p>
|
||
|
|
<p>Let's make the canvas fill the page by adding CSS</p>
|
||
|
|
<pre class="prettyprint showlinemods notranslate lang-html" translate="no"><style>
|
||
|
|
html, body {
|
||
|
|
margin: 0;
|
||
|
|
height: 100%;
|
||
|
|
}
|
||
|
|
#c {
|
||
|
|
width: 100%;
|
||
|
|
height: 100%;
|
||
|
|
display: block;
|
||
|
|
}
|
||
|
|
</style>
|
||
|
|
</pre>
|
||
|
|
<p>In HTML the body has a margin of 5 pixels by default so setting the
|
||
|
|
margin to 0 removes the margin. Setting the html and body height to 100%
|
||
|
|
makes them fill the window. Otherwise they are only as large
|
||
|
|
as the content that fills them.</p>
|
||
|
|
<p>Next we tell the <code class="notranslate" translate="no">id=c</code> element to be
|
||
|
|
100% the size of its container which in this case is the body of
|
||
|
|
the document.</p>
|
||
|
|
<p>Finally we set its <code class="notranslate" translate="no">display</code> mode to <code class="notranslate" translate="no">block</code>. A canvas's
|
||
|
|
default display mode is <code class="notranslate" translate="no">inline</code>. Inline
|
||
|
|
elements can end up adding whitespace to what is displayed. By
|
||
|
|
setting the canvas to <code class="notranslate" translate="no">block</code> that issue goes away.</p>
|
||
|
|
<p>Here's the result</p>
|
||
|
|
<p></p><div translate="no" class="threejs_example_container notranslate">
|
||
|
|
<div><iframe class="threejs_example notranslate" translate="no" style=" " src="/manual/examples/resources/editor.html?url=/manual/examples/responsive-no-resize.html"></iframe></div>
|
||
|
|
<a class="threejs_center" href="/manual/examples/responsive-no-resize.html" target="_blank">click here to open in a separate window</a>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<p></p>
|
||
|
|
<p>You can see the canvas is now filling the page but there are 2
|
||
|
|
problems. One our cubes are stretched. They are not cubes they
|
||
|
|
are more like boxes. Too tall or too wide. Open the
|
||
|
|
example in its own window and resize it. You'll see how
|
||
|
|
the cubes get stretched wide and tall.</p>
|
||
|
|
<p><img src="../resources/images/resize-incorrect-aspect.png" width="407" class="threejs_center nobg"></p>
|
||
|
|
<p>The second problem is they look low resolution or blocky and
|
||
|
|
blurry. Stretch the window really large and you'll really see
|
||
|
|
the issue.</p>
|
||
|
|
<p><img src="../resources/images/resize-low-res.png" class="threejs_center nobg"></p>
|
||
|
|
<p>Let's fix the stretchy problem first. To do that we need
|
||
|
|
to set the aspect of the camera to the aspect of the canvas's
|
||
|
|
display size. We can do that by looking at the canvas's
|
||
|
|
<code class="notranslate" translate="no">clientWidth</code> and <code class="notranslate" translate="no">clientHeight</code> properties.</p>
|
||
|
|
<p>We'll update our render loop like this</p>
|
||
|
|
<pre class="prettyprint showlinemods notranslate lang-js" translate="no">function render(time) {
|
||
|
|
time *= 0.001;
|
||
|
|
|
||
|
|
+ const canvas = renderer.domElement;
|
||
|
|
+ camera.aspect = canvas.clientWidth / canvas.clientHeight;
|
||
|
|
+ camera.updateProjectionMatrix();
|
||
|
|
|
||
|
|
...
|
||
|
|
</pre>
|
||
|
|
<p>Now the cubes should stop being distorted.</p>
|
||
|
|
<p></p><div translate="no" class="threejs_example_container notranslate">
|
||
|
|
<div><iframe class="threejs_example notranslate" translate="no" style=" " src="/manual/examples/resources/editor.html?url=/manual/examples/responsive-update-camera.html"></iframe></div>
|
||
|
|
<a class="threejs_center" href="/manual/examples/responsive-update-camera.html" target="_blank">click here to open in a separate window</a>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<p></p>
|
||
|
|
<p>Open the example in a separate window and resize the window
|
||
|
|
and you should see the cubes are no longer stretched tall or wide.
|
||
|
|
They stay the correct aspect regardless of window size.</p>
|
||
|
|
<p><img src="../resources/images/resize-correct-aspect.png" width="407" class="threejs_center nobg"></p>
|
||
|
|
<p>Now let's fix the blockiness.</p>
|
||
|
|
<p>Canvas elements have 2 sizes. One size is the size the canvas is displayed
|
||
|
|
on the page. That's what we set with CSS. The other size is the
|
||
|
|
number of pixels in the canvas itself. This is no different than an image.
|
||
|
|
For example we might have a 128x64 pixel image and using
|
||
|
|
CSS we might display as 400x200 pixels.</p>
|
||
|
|
<pre class="prettyprint showlinemods notranslate lang-html" translate="no"><img src="some128x64image.jpg" style="width:400px; height:200px">
|
||
|
|
</pre>
|
||
|
|
<p>A canvas's internal size, its resolution, is often called its drawingbuffer size.
|
||
|
|
In three.js we can set the canvas's drawingbuffer size by calling <code class="notranslate" translate="no">renderer.setSize</code>.
|
||
|
|
What size should we pick? The most obvious answer is "the same size the canvas is displayed".
|
||
|
|
Again, to do that we can look at the canvas's <code class="notranslate" translate="no">clientWidth</code> and <code class="notranslate" translate="no">clientHeight</code>
|
||
|
|
properties.</p>
|
||
|
|
<p>Let's write a function that checks if the renderer's canvas is not
|
||
|
|
already the size it is being displayed as and if so set its size.</p>
|
||
|
|
<pre class="prettyprint showlinemods notranslate lang-js" translate="no">function resizeRendererToDisplaySize(renderer) {
|
||
|
|
const canvas = renderer.domElement;
|
||
|
|
const width = canvas.clientWidth;
|
||
|
|
const height = canvas.clientHeight;
|
||
|
|
const needResize = canvas.width !== width || canvas.height !== height;
|
||
|
|
if (needResize) {
|
||
|
|
renderer.setSize(width, height, false);
|
||
|
|
}
|
||
|
|
return needResize;
|
||
|
|
}
|
||
|
|
</pre>
|
||
|
|
<p>Notice we check if the canvas actually needs to be resized. Resizing the canvas
|
||
|
|
is an interesting part of the canvas spec and it's best not to set the same
|
||
|
|
size if it's already the size we want.</p>
|
||
|
|
<p>Once we know if we need to resize or not we then call <code class="notranslate" translate="no">renderer.setSize</code> and
|
||
|
|
pass in the new width and height. It's important to pass <code class="notranslate" translate="no">false</code> at the end.
|
||
|
|
<code class="notranslate" translate="no">render.setSize</code> by default sets the canvas's CSS size but doing so is not
|
||
|
|
what we want. We want the browser to continue to work how it does for all other
|
||
|
|
elements which is to use CSS to determine the display size of the element. We don't
|
||
|
|
want canvases used by three to be different than other elements.</p>
|
||
|
|
<p>Note that our function returns true if the canvas was resized. We can use
|
||
|
|
this to check if there are other things we should update. Let's modify
|
||
|
|
our render loop to use the new function</p>
|
||
|
|
<pre class="prettyprint showlinemods notranslate lang-js" translate="no">function render(time) {
|
||
|
|
time *= 0.001;
|
||
|
|
|
||
|
|
+ if (resizeRendererToDisplaySize(renderer)) {
|
||
|
|
+ const canvas = renderer.domElement;
|
||
|
|
+ camera.aspect = canvas.clientWidth / canvas.clientHeight;
|
||
|
|
+ camera.updateProjectionMatrix();
|
||
|
|
+ }
|
||
|
|
|
||
|
|
...
|
||
|
|
</pre>
|
||
|
|
<p>Since the aspect is only going to change if the canvas's display size
|
||
|
|
changed we only set the camera's aspect if <code class="notranslate" translate="no">resizeRendererToDisplaySize</code>
|
||
|
|
returns <code class="notranslate" translate="no">true</code>.</p>
|
||
|
|
<p></p><div translate="no" class="threejs_example_container notranslate">
|
||
|
|
<div><iframe class="threejs_example notranslate" translate="no" style=" " src="/manual/examples/resources/editor.html?url=/manual/examples/responsive.html"></iframe></div>
|
||
|
|
<a class="threejs_center" href="/manual/examples/responsive.html" target="_blank">click here to open in a separate window</a>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<p></p>
|
||
|
|
<p>It should now render with a resolution that matches the display
|
||
|
|
size of the canvas.</p>
|
||
|
|
<p>To make the point about letting CSS handle the resizing let's take
|
||
|
|
our code and put it in a <a href="../examples/threejs-responsive.js">separate <code class="notranslate" translate="no">.js</code> file</a>.
|
||
|
|
Here then are a few more examples where we let CSS choose the size and notice we had
|
||
|
|
to change zero code for them to work.</p>
|
||
|
|
<p>Let's put our cubes in the middle of a paragraph of text.</p>
|
||
|
|
<p></p><div translate="no" class="threejs_example_container notranslate">
|
||
|
|
<div><iframe class="threejs_example notranslate" translate="no" style=" " src="/manual/examples/resources/editor.html?url=/manual/examples/responsive-paragraph.html&startPane=html"></iframe></div>
|
||
|
|
<a class="threejs_center" href="/manual/examples/responsive-paragraph.html" target="_blank">click here to open in a separate window</a>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<p></p>
|
||
|
|
<p>and here's our same code used in an editor style layout
|
||
|
|
where the control area on the right can be resized.</p>
|
||
|
|
<p></p><div translate="no" class="threejs_example_container notranslate">
|
||
|
|
<div><iframe class="threejs_example notranslate" translate="no" style=" " src="/manual/examples/resources/editor.html?url=/manual/examples/responsive-editor.html&startPane=html"></iframe></div>
|
||
|
|
<a class="threejs_center" href="/manual/examples/responsive-editor.html" target="_blank">click here to open in a separate window</a>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<p></p>
|
||
|
|
<p>The important part to notice is no code changed. Only our HTML and CSS
|
||
|
|
changed.</p>
|
||
|
|
<h2 id="handling-hd-dpi-displays">Handling HD-DPI displays</h2>
|
||
|
|
<p>HD-DPI stands for high-density dot per inch displays.
|
||
|
|
That's most Macs nowadays and many Windows machines
|
||
|
|
as well as pretty much all smartphones.</p>
|
||
|
|
<p>The way this works in the browser is they use
|
||
|
|
CSS pixels to set the sizes which are supposed to be the same
|
||
|
|
regardless of how high res the display is. The browser
|
||
|
|
will just render text with more detail but the
|
||
|
|
same physical size.</p>
|
||
|
|
<p>There are various ways to handle HD-DPI with three.js.</p>
|
||
|
|
<p>The first one is just not to do anything special. This
|
||
|
|
is arguably the most common. Rendering 3D graphics
|
||
|
|
takes a lot of GPU processing power. Mobile GPUs have
|
||
|
|
less power than desktops, at least as of 2018, and yet
|
||
|
|
mobile phones often have very high resolution displays.
|
||
|
|
The current top of the line phones have an HD-DPI ratio
|
||
|
|
of 3x meaning for every one pixel from a non-HD-DPI display
|
||
|
|
those phones have 9 pixels. That means they have to do 9x
|
||
|
|
the rendering.</p>
|
||
|
|
<p>Computing 9x the pixels is a lot of work so if we just
|
||
|
|
leave the code as it is we'll compute 1x the pixels and the
|
||
|
|
browser will just draw it at 3x the size (3x by 3x = 9x pixels).</p>
|
||
|
|
<p>For any heavy three.js app that's probably what you want
|
||
|
|
otherwise you're likely to get a slow framerate.</p>
|
||
|
|
<p>That said if you actually do want to render at the resolution
|
||
|
|
of the device there are a couple of ways to do this in three.js.</p>
|
||
|
|
<p>One is to tell three.js a resolution multiplier using <code class="notranslate" translate="no">renderer.setPixelRatio</code>.
|
||
|
|
You ask the browser what the multiplier is from CSS pixels to device pixels
|
||
|
|
and pass that to three.js</p>
|
||
|
|
<pre class="prettyprint showlinemods notranslate notranslate" translate="no"> renderer.setPixelRatio(window.devicePixelRatio);
|
||
|
|
</pre><p>After that any calls to <code class="notranslate" translate="no">renderer.setSize</code> will magically
|
||
|
|
use the size you request multiplied by whatever pixel ratio
|
||
|
|
you passed in. <strong>This is strongly NOT RECOMMENDED</strong>. See below</p>
|
||
|
|
<p>The other way is to do it yourself when you resize the canvas.</p>
|
||
|
|
<pre class="prettyprint showlinemods notranslate lang-js" translate="no"> function resizeRendererToDisplaySize(renderer) {
|
||
|
|
const canvas = renderer.domElement;
|
||
|
|
const pixelRatio = window.devicePixelRatio;
|
||
|
|
const width = canvas.clientWidth * pixelRatio | 0;
|
||
|
|
const height = canvas.clientHeight * pixelRatio | 0;
|
||
|
|
const needResize = canvas.width !== width || canvas.height !== height;
|
||
|
|
if (needResize) {
|
||
|
|
renderer.setSize(width, height, false);
|
||
|
|
}
|
||
|
|
return needResize;
|
||
|
|
}
|
||
|
|
</pre>
|
||
|
|
<p>This second way is objectively better. Why? Because it means I get what I ask for.
|
||
|
|
There are many cases when using three.js where we need to know the actual
|
||
|
|
size of the canvas's drawingBuffer. For example when making a post processing filter,
|
||
|
|
or if we are making a shader that accesses <code class="notranslate" translate="no">gl_FragCoord</code>, if we are making
|
||
|
|
a screenshot, or reading pixels for GPU picking, for drawing into a 2D canvas,
|
||
|
|
etc... There are many cases where if we use <code class="notranslate" translate="no">setPixelRatio</code> then our actual size will be different
|
||
|
|
than the size we requested and we'll have to guess when to use the size
|
||
|
|
we asked for and when to use the size three.js is actually using.
|
||
|
|
By doing it ourselves we always know the size being used is the size we requested.
|
||
|
|
There is no special case where magic is happening behind the scenes.</p>
|
||
|
|
<p>Here's an example using the code above.</p>
|
||
|
|
<p></p><div translate="no" class="threejs_example_container notranslate">
|
||
|
|
<div><iframe class="threejs_example notranslate" translate="no" style=" " src="/manual/examples/resources/editor.html?url=/manual/examples/responsive-hd-dpi.html"></iframe></div>
|
||
|
|
<a class="threejs_center" href="/manual/examples/responsive-hd-dpi.html" target="_blank">click here to open in a separate window</a>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<p></p>
|
||
|
|
<p>It might be hard to see the difference but if you have an HD-DPI
|
||
|
|
display and you compare this sample to those above you should
|
||
|
|
notice the edges are more crisp.</p>
|
||
|
|
<p>This article covered a very basic but fundamental topic. Next up lets quickly
|
||
|
|
<a href="primitives.html">go over the basic primitives that three.js provides</a>.</p>
|
||
|
|
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
<script src="/manual/resources/prettify.js"></script>
|
||
|
|
<script src="/manual/resources/lesson.js"></script>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body></html>
|