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<script language="javascript" type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.5.8/p5.js"></script>
body {margin:0px; padding:0px; overflow: hidden}
// Global variables to track frame initialization and the number of harmonic circles.
let prevInitFrame = 1;
let n = 1;
let baseRadius = 100; // Initial circle's radius
let plotData = []; // Data to be plotted on the graph
function setup() {
createCanvas(windowWidth, windowHeight);
}
function draw() {
clear();
background(224, 239, 243);
let x = 0, y = 0;
// Setting up the central circle and base coordinates
push();
translate(baseRadius + 20, height / 2);
fill(255); stroke(0); strokeWeight(1);
ellipse(x, y, baseRadius * 2, baseRadius * 2);
// Multiplier based on Fourier series coefficients for square waves
let m = 4 / PI;
// Drawing harmonic circles
for (let i = 0; i < n; i++) {
let d = 1 + i * 2;
let rad = radians(frameCount - 1) * 2 * d;
let radius = baseRadius / d * m;
let sine = sin(rad);
let cosine = cos(rad);
let nx = x + cosine * radius;
let ny = y - sine * radius;
line(x, y, nx, ny); // Line from one circle's perimeter to the next's
drawCircleMarker(createVector(nx, ny), 2); // Dot on the circle's perimeter
// Update x and y for the next circle
x = nx;
y = ny;
}
// Drawing the main line and markers
drawCircleMarker(createVector(0, 0), 2); // Center of the main circle
line(baseRadius + 20, y, -baseRadius - 20, y); // Horizontal line
drawCircleMarker(createVector(x, y), 4); // Dot on the main line
pop();
// Adjusting graph width based on canvas size and circle size
let graphW = width - (baseRadius + 20) * 2;
let graphX = (baseRadius + 20) * 2;
// Resetting data when reaching the end of the canvas
if (frameCount > prevInitFrame + graphW) {
plotData = [];
prevInitFrame += graphW;
}
plotData.push({ x: frameCount - prevInitFrame, y: -y });
// Increase harmonic circles every 90 frames, reset after reaching 40 circles
if (frameCount % 90 == 0) {
n++;
if (n > 40) {
n = 1;
}
}
// Plotting the resulting wave
plotGraph(plotData, graphX, height / 2, graphW, height - 64, 0, graphW, -height / 2 + 32, height / 2 - 32, "time", "y");
// Displaying the number of harmonic circles
drawLabel(8, height - 32, "n = " + n, LEFT);
}
function plotGraph(data, ox, oy, w, h, minX, maxX, minY, maxY, xLabel, yLabel) {
let left = ox - minX / (maxX - minX) * w;
let top = oy - maxY / (maxY - minY) * h;
let labelLeft = abs(left - ox) > abs(left + w - ox);
let labelTop = abs(top - oy) > abs(top + h - oy);
push();
// Drawing the graph axes
noFill(); stroke(0);
line(left, oy, left + w, oy); // X-axis
line(ox, top, ox, top + h); // Y-axis
// Plotting the wave data
beginShape();
for (let i = 0; i < data.length; i++) {
let x = ox + data[i].x / (maxX - minX) * w;
let y = oy - data[i].y / (maxY - minY) * h;
vertex(x, y);
}
endShape();
// Drawing graph labels
fill(0);
drawLabel(labelLeft ? left : left + w, oy + (labelTop ? 16 : -8), xLabel, labelLeft ? LEFT : RIGHT);
drawLabel(ox, labelTop ? top : top + h, yLabel, labelLeft ? RIGHT : LEFT);
pop();
}
function drawLabel(x, y, label, align = CENTER) {
push();
noStroke(); // Removes potential line strokes
textFont("monospace");
textSize(14);
textAlign(align);
// Adjusting position based on alignment for better visibility
if (align == LEFT) x += 6;
if (align == RIGHT) x -= 6;
text(label, x, y);
pop();
}
function drawCircleMarker(p, size) {
ellipse(p.x, p.y, size * 2, size * 2);
}
Also see: Tab Triggers