Coding

Creating 2-D Animations on Canvas - the solar system

In this tutorial you will learn:

How to make the planets turn around the Sun.
How to make the Moon turn around the Earth.
How to make the timing realistic while using the timer functions.
How to realistically update a calendar, depending the position of the Earth and the Moon.

Finding a good book to master HTML5 can be very challenging: there are so many around - most with eye-catching titles and very complex substance.
Therefore, Vivax Solutions strongly recommends Core HTML5 Canvas for those who really want to delve into HTML5.
Please click the image to access Amazon:

The Solar System

In this animation, three images of The Sun, Earth, and the rest of the planets, along with the Moon are used.

The Sun remains stationary; Earth orbits the sun in 365 days; The Moon orbits Earth in 28 days. Other planets orbits with a fairly realistic timings.

Using both sine and cosine functions of trigonometry, the positions of orbits are calculated.

When the animation progresses, the day, month and year are updated - giving them realistic values.

The Source Code for Interactive Solar System is as follows:

<script>
var canvas = document.getElementById('Canvas_Six');
var context_six = canvas.getContext('2d');
// x:angle; b:increment; m:months; d:day
var y = new Date();
var s = y.getSeconds();
var year = y.getFullYear(); x = 0; b = 1; m = 1; d = 1; angM = 0; angV = 0; angMa = 0; angJ = 270; angS = 20; angU = 180; angN = 120; angP = 300; angC = 0;
// variables for the sun, earth and moon
var imgSn = new Image();
var imgErth = new Image();
var imgMn = new Image();
var imgMerc = new Image();
var imgVenus = new Image();
var imgMars = new Image();
var imgJup = new Image();
var imgSat = new Image();
var imgUr = new Image();
var imgNep = new Image();
var imgPluto = new Image();
var imgComet = new Image();
//window.setInterval('orbit()', 180);
function orbit() {
x = x + b; d = d + 1;
var z;
// the earth makes the full circle; year updated;
if (x == 360) { x = 0; year = year + 1; m = 0; }
// days and months are updated
if (x % 30 == 0) { m = m + 1; d = 0; }
context_six.clearRect(0, 0, 500, 500);
// image of the sun
context_six.beginPath();
context_six.drawImage(imgSn, 220, 220);
imgSn.src = '../images/sun.png';
// image of the moving mercury
angM = angM + 0.2 * b;
if (angM >= 360) { angM = 0; }
var xm = 250 + 40 * Math.sin(angM * Math.PI / 180);
var ym = 250 + 40 * Math.cos(angM * Math.PI / 180);
context_six.drawImage(imgMerc, xm - 5, ym - 5);
imgMerc.src = '../images/mercury.png';
// image of the moving venus
angV = angV + 0.7 * b;
if (angV >= 360) { angV = 0; }
var xv = 250 + 60 * Math.sin(angV * Math.PI / 180);
var yv = 250 + 60 * Math.cos(angV * Math.PI / 180);
context_six.drawImage(imgVenus, xv - 10, yv - 10);
imgVenus.src = '../images/venus.png';
// image of the moving earth
var xe = 250 + 110 * Math.sin(x * Math.PI / 180);
var ye = 250 + 110 * Math.cos(x * Math.PI / 180);
context_six.drawImage(imgErth, xe - 10, ye - 10);
imgErth.src = '../images/earth.png';
// image of the moving moon
var x2 = xe + 20 * Math.sin(13 * x * Math.PI / 180);
var y2 = ye + 20 * Math.cos(13 * x * Math.PI / 180);
context_six.drawImage(imgMn, x2 - 4, y2 - 4);
imgMn.src = '../images/moon.png';
// image of the moving mars
angMa = angMa + 0.5 * b;
if (angMa >= 360) { angMa = 0; }
var xMa = 250 + 150 * Math.sin(angMa * Math.PI / 180);
var yMa = 250 + 150 * Math.cos(angMa * Math.PI / 180);
context_six.drawImage(imgMars, xMa - 5, yMa - 5);
imgMars.src = '../images/mars.png';
// image of the moving jupiter
angJ = angJ + 0.03 * b;
if (angJ >= 360) { angJ = 0; }
var xj = 250 + 180 * Math.sin(angJ * Math.PI / 180);
var yj = 250 + 180 * Math.cos(angJ * Math.PI / 180);
context_six.drawImage(imgJup, xj - 15, yj - 15);
imgJup.src = '../images/jupiter.png';
// image of the moving saturn
angS = angS + 2 * 0.04 * b;
if (angS >= 360) { angS = 0; }
var xs = 250 + 205 * Math.sin(angS * Math.PI / 180);
var ys = 250 + 205 * Math.cos(angS * Math.PI / 180);
context_six.drawImage(imgSat, xs - 15, ys - 15);
imgSat.src = '../images/saturn.png';
// image of the moving uranus
angU = angU + 0.05 * b;
if (angU >= 360) { angU = 0; }
var xu = 250 + 235 * Math.sin(angU * Math.PI / 180);
var yu = 250 + 235 * Math.cos(angU * Math.PI / 180);
context_six.drawImage(imgUr, xu + 15, yu - 15);
imgUr.src = '../images/uranus.png';
// image of the moving neptune
angN = angN + 0.04 * b;
if (angN >= 360) { angN = 0; }
var xn = 250 + 265 * Math.sin(angN * Math.PI / 180);
var yn = 250 + 265 * Math.cos(angN * Math.PI / 180);
context_six.drawImage(imgNep, xn - 15, yn - 15);
imgNep.src = '../images/neptune.png';
// year, month and day updated
context_six.font = '12pt Calibri';
context_six.fillStyle = 'white'; context_six.fillText('Year: ' + year, 40, 20);
context_six.fillStyle = 'white';
context_six.fillText('Month: ' + m, 130, 20);
context_six.fillStyle = 'white';
context_six.fillText('Day: ' + d, 220, 20);
context_six.fillStyle = 'white';
z = x / 15;
if (x < 180)
{ context_six.fillText('Time - snap shot at: ' + Math.round(z) + ' .00 am', 300, 20); }
else if (x > 180) { context_six.fillText('Time - snap shot at: ' + (Math.round(z) - 12) + ' .00 pm', 300, 20); }
else { context_six.fillText('Time - snap shot at: ' + Math.round(z) + ' .00 noon', 300, 20); }
//colours of the sky
if (z >= 5 && z < 7) {
document.getElementById('Canvas_Six').style.backgroundImage = "";
document.getElementById('Canvas_Six').style.backgroundColor = "#98afc7";
}
else if (z >= 7 && z < 9) {
document.getElementById('Canvas_Six').style.backgroundImage = "";
document.getElementById('Canvas_Six').style.backgroundColor = "#4863a0"; ;
}
else if (z >= 9 && z < 16) {
document.getElementById('Canvas_Six').style.backgroundImage = "";
document.getElementById('Canvas_Six').style.backgroundColor = "#000080"; ;
}
else if (z >= 16 && z < 18) {
document.getElementById('Canvas_Six').style.backgroundImage = "";
document.getElementById('Canvas_Six').style.backgroundColor = "#4863a0";
}
else if (z >= 18 && z < 20) {
document.getElementById('Canvas_Six').style.backgroundImage = "";
document.getElementById('Canvas_Six').style.backgroundColor = "#000011";
}
else {
document.getElementById('Canvas_Six').style.backgroundImage = "url('../images/night.jpg')";
document.getElementById('Canvas_Six').style.backgroundColor = "#000000";
}
}
context_six.font = '10pt Calibri';
context_six.fillStyle = 'white';
context_six.fillText('Programmed by Vivax Solutions', 20, 490);
function orbitting() {
j = window.setInterval('orbit()', 180);
}
}
</script>

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