import scrawl from '../source/scrawl.js'import scrawl from '../source/scrawl.js'let porthole = scrawl.library.artefact.porthole;
porthole.set({
backgroundColor: 'black',
css: {
borderRadius: '50%'
}
});We use this entity as a template for cloning new stars
let starling = scrawl.makeWheel({
name: 'starling',
radius: 3,
handleX: 'center',
handleY: 'center',
method: 'fill',
fillStyle: 'white',Adding in some flags to help speed up the Display cycle
noDeltaUpdates: true,
noPositionDependencies: true,
noFilters: true,
noUserInteraction: true,
purge: 'all',
});
let starCount = 0,
addNumber = 100;makeStar function
let makeStars = function (buildNumber) {We use a Vector for calculating the new star’s direction
let v = scrawl.requestVector(),
star, i, myRandom;
for (i = 0; i < buildNumber; i++) {
starCount++;Clone the entity template
star = starling.clone({
name: `star_${starCount}`,Additional flags for speeding up the Display cycle
noCanvasEngineUpdates: true,All cloned stars will share the template star’s State object - to save on memory
sharedState: true,
});
myRandom = Math.random();
v.setXY(1, 0).rotate(Math.random() * 360).scalarMultiply(300); scrawl.makeTween({
name: star.name,
targets: star,
duration: Math.round((myRandom * 3000) + 2000),
cycles: 0,We will animate the star’s start Coordinate (using startX and startY pseudo-attributes)
definitions: [{
attribute: 'startX',integer: true,
start: 300,
end: 300 + v.x
}, {
attribute: 'startY',integer: true,
start: 300,
end: 300 + v.y
}, {We will also animate the star’s scale value to make the animation look more 3D
attribute: 'scale',
start: 0.5,
end: Math.round((1 - myRandom) * 0.9) + 0.6,
}]We start the Tween running immediately after it has been created.
}).run();
}We need to release our Vector back to its vector pool
scrawl.releaseVector(v);Change the color of the stars each time the user clicks on the porthole
starling.set({
fillStyle: `rgb(${Math.floor(Math.random() * 55) + 200}, ${Math.floor(Math.random() * 55) + 200}, ${Math.floor(Math.random() * 55) + 200})`
});
};Generate the initial stars
makeStars(100);Function to display frames-per-second data, and other information relevant to the demo
let report = function () {
let testTicker = Date.now(),
testTime, testNow, dragging,
testMessage = document.querySelector('#reportmessage');
return function () {
testNow = Date.now();
testTime = testNow - testTicker;
testTicker = testNow;
testMessage.textContent = `Screen refresh: ${Math.ceil(testTime)}ms; fps: ${Math.floor(1000 / testTime)}
Stars: ${starCount}`;
};
}();Create the Display cycle animation
scrawl.makeRender({
name: 'demo-animation',
target: porthole,
afterShow: report,
});let addStars = (e) => {
e.preventDefault();
e.returnValue = false;
makeStars(addNumber);
};
scrawl.addNativeListener('click', addStars, porthole.domElement);