animate/Catalogue/triangle.html

66 lines
1.9 KiB
HTML

<!DOCTYPE html>
<html>
<!-- ahhh -->
<body style="margin:0;overflow: hidden;">
<canvas id="myCanvas" width="10" height="10" style="display: block;box-sizing: border-box;">
Your browser does not support the HTML5 canvas tag.</canvas>
<script>
let c = document.getElementById("myCanvas");
let ctx = c.getContext("2d");
ctx.canvas.width = window.innerWidth;
ctx.canvas.height = window.innerHeight;
let deg_per_sec = 30;
let time = 120;
let fps = 60;
centerX = ctx.canvas.width / 2;
centerY = ctx.canvas.height / 2;
rotation = 0; //was = j = angle
currentFrame = 0; //was = i
function render() {
if (currentFrame < time / (1 / fps)) {
setTimeout(() => {
render();
render_clear();
draw_triangle(0, 200, "red");
}, 1000 / fps);
rotation += deg_per_sec / fps; // was = j = angle, now = rotation
currentFrame += 1; // was = i
}
}
render();
function draw_triangle(ang, radius, colour) {
ctx.beginPath();
ctx.moveTo(centerX + Math.cos(rad(90 + 120 * 1 + ang)) * radius, centerY + Math.sin(rad(90 + 120 * 1 + ang)) * radius);
ctx.lineTo(centerX + Math.cos(rad(90 + 120 * 2 + ang)) * radius, centerY + Math.sin(rad(90 + 120 * 2 + ang)) * radius);
ctx.lineTo(centerX + Math.cos(rad(90 + 120 * 3 + ang)) * radius, centerY + Math.sin(rad(90 + 120 * 3 + ang)) * radius);
ctx.lineTo(centerX + Math.cos(rad(90 + 120 * 1 + ang)) * radius, centerY + Math.sin(rad(90 + 120 * 1 + ang)) * radius);
ctx.strokeStyle = colour;
ctx.stroke();
}
function rad(degrees) {
var pi = Math.PI;
return degrees * (pi / 180);
}
function render_clear() {
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
ctx.fillStyle = "black";
ctx.fillRect(0, 0, ctx.canvas.width, ctx.canvas.height);
}
</script>
</body>
</html>