Canvas Impulse Animation Effect - PullRequest
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Canvas Impulse Animation Effect

0 голосов
/ 09 сентября 2018

Я изучаю следующую анимацию холста Матей Копо. Может кто-нибудь объяснить, как работает «импульсный» / стреляющий эффект и как, скажем, я могу упростить код, чтобы иметь только 3 стационарные точки a, b и c (показывая импульсный эффект между a-> b и между b -> с)

var w = c.width = window.innerWidth,
		h = c.height = window.innerHeight,
		ctx = c.getContext( '2d' ),
		
		opts = {
			
			range: 180,
			baseConnections: 3,
			addedConnections: 5,
			baseSize: 5,
			minSize: 1,
			dataToConnectionSize: .4,
			sizeMultiplier: .7,
			allowedDist: 40,
			baseDist: 40,
			addedDist: 30,
			connectionAttempts: 100,
			
			dataToConnections: 1,
			baseSpeed: .04,
			addedSpeed: .05,
			baseGlowSpeed: .4,
			addedGlowSpeed: .4,
			
			rotVelX: .003,
			rotVelY: .002,
			
			repaintColor: '#111',
			connectionColor: 'hsla(200,60%,light%,alp)',
			rootColor: 'hsla(0,60%,light%,alp)',
			endColor: 'hsla(160,20%,light%,alp)',
			dataColor: 'hsla(40,80%,light%,alp)',
			
			wireframeWidth: .1,
			wireframeColor: '#88f',
			
			depth: 250,
			focalLength: 250,
			vanishPoint: {
				x: w / 2,
				y: h / 2
			}
		},
		
		squareRange = opts.range * opts.range,
		squareAllowed = opts.allowedDist * opts.allowedDist,
		mostDistant = opts.depth + opts.range,
		sinX = sinY = 0,
		cosX = cosY = 0,
		
		connections = [],
		toDevelop = [],
		data = [],
		all = [],
		tick = 0,
		totalProb = 0,
		
		animating = false,
		
		Tau = Math.PI * 2;

ctx.fillStyle = '#222';
ctx.fillRect( 0, 0, w, h );
ctx.fillStyle = '#ccc';
ctx.font = '50px Verdana';
ctx.fillText( 'Calculating Nodes', w / 2 - ctx.measureText( 'Calculating Nodes' ).width / 2, h / 2 - 15 );

window.setTimeout( init, 4 ); // to render the loading screen

function init(){
	
	connections.length = 0;
	data.length = 0;
	all.length = 0;
	toDevelop.length = 0;
	
	var connection = new Connection( 0, 0, 0, opts.baseSize );
	connection.step = Connection.rootStep;
	connections.push( connection );
	all.push( connection );
	connection.link();
	
	while( toDevelop.length > 0 ){
	
		toDevelop[ 0 ].link();
		toDevelop.shift();
	}
	
	if( !animating ){
		animating = true;
		anim();
	}
}
function Connection( x, y, z, size ){
	
	this.x = x;
	this.y = y;
	this.z = z;
	this.size = size;
	
	this.screen = {};
	
	this.links = [];
	this.probabilities = [];
	this.isEnd = false;
	
	this.glowSpeed = opts.baseGlowSpeed + opts.addedGlowSpeed * Math.random();
}
Connection.prototype.link = function(){
	
	if( this.size < opts.minSize )
		return this.isEnd = true;
	
	var links = [],
			connectionsNum = opts.baseConnections + Math.random() * opts.addedConnections |0,
			attempt = opts.connectionAttempts,
			
			alpha, beta, len,
			cosA, sinA, cosB, sinB,
			pos = {},
			passedExisting, passedBuffered;
	
	while( links.length < connectionsNum && --attempt > 0 ){
		
		alpha = Math.random() * Math.PI;
		beta = Math.random() * Tau;
		len = opts.baseDist + opts.addedDist * Math.random();
		
		cosA = Math.cos( alpha );
		sinA = Math.sin( alpha );
		cosB = Math.cos( beta );
		sinB = Math.sin( beta );
		
		pos.x = this.x + len * cosA * sinB;
		pos.y = this.y + len * sinA * sinB;
		pos.z = this.z + len *        cosB;
		
		if( pos.x*pos.x + pos.y*pos.y + pos.z*pos.z < squareRange ){
		
			passedExisting = true;
			passedBuffered = true;
			for( var i = 0; i < connections.length; ++i )
				if( squareDist( pos, connections[ i ] ) < squareAllowed )
					passedExisting = false;

			if( passedExisting )
				for( var i = 0; i < links.length; ++i )
					if( squareDist( pos, links[ i ] ) < squareAllowed )
						passedBuffered = false;

			if( passedExisting && passedBuffered )
				links.push( { x: pos.x, y: pos.y, z: pos.z } );
			
		}
		
	}
	
	if( links.length === 0 )
		this.isEnd = true;
	else {
		for( var i = 0; i < links.length; ++i ){
			
			var pos = links[ i ],
					connection = new Connection( pos.x, pos.y, pos.z, this.size * opts.sizeMultiplier );
			
			this.links[ i ] = connection;
			all.push( connection );
			connections.push( connection );
		}
		for( var i = 0; i < this.links.length; ++i )
			toDevelop.push( this.links[ i ] );
	}
}
Connection.prototype.step = function(){
	
	this.setScreen();
	this.screen.color = ( this.isEnd ? opts.endColor : opts.connectionColor ).replace( 'light', 30 + ( ( tick * this.glowSpeed ) % 30 ) ).replace( 'alp', .2 + ( 1 - this.screen.z / mostDistant ) * .8 );
	
	for( var i = 0; i < this.links.length; ++i ){
		ctx.moveTo( this.screen.x, this.screen.y );
		ctx.lineTo( this.links[ i ].screen.x, this.links[ i ].screen.y );
	}
}
Connection.rootStep = function(){
	this.setScreen();
	this.screen.color = opts.rootColor.replace( 'light', 30 + ( ( tick * this.glowSpeed ) % 30 ) ).replace( 'alp', ( 1 - this.screen.z / mostDistant ) * .8 );
	
	for( var i = 0; i < this.links.length; ++i ){
		ctx.moveTo( this.screen.x, this.screen.y );
		ctx.lineTo( this.links[ i ].screen.x, this.links[ i ].screen.y );
	}
}
Connection.prototype.draw = function(){
	ctx.fillStyle = this.screen.color;
	ctx.beginPath();
	ctx.arc( this.screen.x, this.screen.y, this.screen.scale * this.size, 0, Tau );
	ctx.fill();
}
function Data( connection ){
	
	this.glowSpeed = opts.baseGlowSpeed + opts.addedGlowSpeed * Math.random();
	this.speed = opts.baseSpeed + opts.addedSpeed * Math.random();
	
	this.screen = {};
	
	this.setConnection( connection );
}
Data.prototype.reset = function(){
	
	this.setConnection( connections[ 0 ] );
	this.ended = 2;
}
Data.prototype.step = function(){
	
	this.proportion += this.speed;
	
	if( this.proportion < 1 ){
		this.x = this.ox + this.dx * this.proportion;
		this.y = this.oy + this.dy * this.proportion;
		this.z = this.oz + this.dz * this.proportion;
		this.size = ( this.os + this.ds * this.proportion ) * opts.dataToConnectionSize;
	} else 
		this.setConnection( this.nextConnection );
	
	this.screen.lastX = this.screen.x;
	this.screen.lastY = this.screen.y;
	this.setScreen();
	this.screen.color = opts.dataColor.replace( 'light', 40 + ( ( tick * this.glowSpeed ) % 50 ) ).replace( 'alp', .2 + ( 1 - this.screen.z / mostDistant ) * .6 );
	
}
Data.prototype.draw = function(){
	
	if( this.ended )
		return --this.ended; // not sre why the thing lasts 2 frames, but it does
	
	ctx.beginPath();
	ctx.strokeStyle = this.screen.color;
	ctx.lineWidth = this.size * this.screen.scale;
	ctx.moveTo( this.screen.lastX, this.screen.lastY );
	ctx.lineTo( this.screen.x, this.screen.y );
	ctx.stroke();
}
Data.prototype.setConnection = function( connection ){
	
	if( connection.isEnd )
		this.reset();
	
	else {
		
		this.connection = connection;
		this.nextConnection = connection.links[ connection.links.length * Math.random() |0 ];
		
		this.ox = connection.x; // original coordinates
		this.oy = connection.y;
		this.oz = connection.z;
		this.os = connection.size; // base size
		
		this.nx = this.nextConnection.x; // new
		this.ny = this.nextConnection.y;
		this.nz = this.nextConnection.z;
		this.ns = this.nextConnection.size;
		
		this.dx = this.nx - this.ox; // delta
		this.dy = this.ny - this.oy;
		this.dz = this.nz - this.oz;
		this.ds = this.ns - this.os;
		
		this.proportion = 0;
	}
}
Connection.prototype.setScreen = Data.prototype.setScreen = function(){
	
	var x = this.x,
			y = this.y,
			z = this.z;
	
	// apply rotation on X axis
	var Y = y;
	y = y * cosX - z * sinX;
	z = z * cosX + Y * sinX;
	
	// rot on Y
	var Z = z;
	z = z * cosY - x * sinY;
	x = x * cosY + Z * sinY;
	
	this.screen.z = z;
	
	// translate on Z
	z += opts.depth;
	
	this.screen.scale = opts.focalLength / z;
	this.screen.x = opts.vanishPoint.x + x * this.screen.scale;
	this.screen.y = opts.vanishPoint.y + y * this.screen.scale;
	
}
function squareDist( a, b ){
	
	var x = b.x - a.x,
			y = b.y - a.y,
			z = b.z - a.z;
	
	return x*x + y*y + z*z;
}

function anim(){
	
	window.requestAnimationFrame( anim );
	
	ctx.globalCompositeOperation = 'source-over';
	ctx.fillStyle = opts.repaintColor;
	ctx.fillRect( 0, 0, w, h );
	
	++tick;
	
	var rotX = tick * opts.rotVelX,
			rotY = tick * opts.rotVelY;
	
	cosX = Math.cos( rotX );
	sinX = Math.sin( rotX );
	cosY = Math.cos( rotY );
	sinY = Math.sin( rotY );
	
	if( data.length < connections.length * opts.dataToConnections ){
		var datum = new Data( connections[ 0 ] );
		data.push( datum );
		all.push( datum );
	}
	
	ctx.globalCompositeOperation = 'lighter';
	ctx.beginPath();
	ctx.lineWidth = opts.wireframeWidth;
	ctx.strokeStyle = opts.wireframeColor;
	all.map( function( item ){ item.step(); } );
	ctx.stroke();
	ctx.globalCompositeOperation = 'source-over';
	all.sort( function( a, b ){ return b.screen.z - a.screen.z } );
	all.map( function( item ){ item.draw(); } );
	
	/*ctx.beginPath();
	ctx.strokeStyle = 'red';
	ctx.arc( opts.vanishPoint.x, opts.vanishPoint.y, opts.range * opts.focalLength / opts.depth, 0, Tau );
	ctx.stroke();*/
}

window.addEventListener( 'resize', function(){
	
	opts.vanishPoint.x = ( w = c.width = window.innerWidth ) / 2;
	opts.vanishPoint.y = ( h = c.height = window.innerHeight ) / 2;
	ctx.fillRect( 0, 0, w, h );
});
window.addEventListener( 'click', init );
canvas {
	position: absolute;
	top: 0;
	left: 0;
}
<canvas id=c></canvas>
<!--
ALGORITHM:

structure:
- gen( x,y,z ):
	- create node at x,y,z // blue
	- append some children to list:
		- within a certain distance to parent
		- outside a certain distance from any node
		- within a global distance
	- if no children
		- don't append any
		- set as end node // green-ish

- gen( 0,0,0 ) // red
- while list has items
	- gen( position of first item )
	- remove first item


impulse behaviour:
- pick( node ):
	- if node is end node
		- pick( original node )
	- else
		- pick( random node from node children )

- pick( original node)

-->
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