109 lines
3.4 KiB
HTML
109 lines
3.4 KiB
HTML
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<!DOCTYPE html>
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<html>
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<!-- ahhh -->
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<body style="margin:0;">
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<canvas id="myCanvas" width="10" height="10"
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style="display: block;box-sizing: border-box;">
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Your browser does not support the HTML5 canvas tag.</canvas>
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<script>
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let c = document.getElementById("myCanvas");
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let ctx = c.getContext("2d");
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ctx.canvas.width = window.innerWidth;
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ctx.canvas.height = window.innerHeight;
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let deg_per_sec = 30;
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let time = 120;
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let fps = 60;
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centerX = ctx.canvas.width / 2;
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centerY = ctx.canvas.height / 2;
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rotation = 0; //was = j = angle
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currentFrame = 0; //was = i
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function render() {
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if (currentFrame < time / (1 / fps)) {
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setTimeout(() => {
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render();
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render_clear();
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DrawPolyTwist_width(3,400,-90,rotation,"red")
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// DrawSquareTwist_angle(3,400,0,rotation,"red")
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}, 1000 / fps);
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rotation += deg_per_sec / fps; // was = j = innerRotation, now = rotation
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currentFrame += 1; // was = i
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}
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}
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render();
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function DrawSquareTwist_angle(sides,width, rotation,innerRotation, colour){
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let out_angle = innerRotation;
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// let widthMultiplier = 169 / (239 * Math.sin(Math.PI / 180 * (135 - out_angle + 90 * Math.floor(out_angle / 90))))
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// let widthMultiplier = Math.sqrt(0.5) * 1/ (Math.sin(Math.PI / 180 * (135 - out_angle + 90 * Math.floor(out_angle / 90))))
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let widthMultiplier = Math.sqrt(0.5) * 1/ (Math.sin(Math.PI / 180 * (135 - out_angle + 90 * Math.floor(out_angle / 90))))
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for (let i = 0; i < 25; i++) {
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DrawPolygon(sides,width*widthMultiplier**i,innerRotation*i, colour)
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}
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function DrawPolyTwist_width(sides,width, rotation,innerRotation, colour){
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let out_angle = 0
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let innerAngle = 180 - ((sides-2) *180/sides);
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let scopeAngle = innerRotation - (innerAngle*Math.floor(innerRotation/innerAngle));
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if (scopeAngle < innerAngle/2) {
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out_angle = innerAngle / (2 * Math.cos((2*Math.PI*scopeAngle)/(3*innerAngle))) - innerAngle/2
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}
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else {
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out_angle = -innerAngle / (2 * Math.cos( ((2*Math.PI)/3) - ((2*Math.PI*scopeAngle)/(3*innerAngle))) ) + (innerAngle*3)/2
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}
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let minWidth = Math.sin(rad(innerAngle/2))*(0.5/Math.tan(rad(innerAngle/2)))*2;
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let widthMultiplier = minWidth / Math.sin(Math.PI / 180 * (90+innerAngle/2 - out_angle + innerAngle * Math.floor(out_angle / innerAngle)))
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for (let i = 0; i < 25; i++) {
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DrawPolygon(sides,width*widthMultiplier**i,out_angle*i+rotation, colour)
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}
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}
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function DrawPolygon(sides, width, rotation, colour) {
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ctx.beginPath();
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ctx.moveTo (centerX + width * Math.cos(rotation*Math.PI/180), centerY + width * Math.sin(rotation*Math.PI/180));
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for (var i = 1; i <= sides; i += 1) {
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ctx.lineTo(
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centerX + width * Math.cos(i * 2 * Math.PI / sides + (rotation*Math.PI/180)),
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centerY + width * Math.sin(i * 2 * Math.PI / sides + (rotation*Math.PI/180))
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);
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}
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ctx.strokeStyle = colour;
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ctx.lineWidth = 1;
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ctx.stroke();
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}
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function rad(degrees) {
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var pi = Math.PI;
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return degrees * (pi / 180);
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}
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function render_clear() {
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ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
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ctx.fillStyle = "black";
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ctx.fillRect(0, 0, ctx.canvas.width, ctx.canvas.height);
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}
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</script>
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</body>
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</html>
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