SWDiskStack Class Reference

/*
File: swDiskStack.js
Date: 2026-05-28
Author: klp + Copilot
Purpose: SWDiskStack class for SketchWaveJS

An SWDiskStack is a stack of interpolated SWDisk instances that transition
from a big endpoint disk to a small endpoint disk.

Dependencies:
- p5.js
- SWColor
- SWPoint
- SWDisk
*/

console.log("[swDiskStack.js] SWDiskStack class loaded.");

class SWDiskStack {
    /**
     * @param {SWDisk} bigDisk - Starting disk in the stack
     * @param {SWDisk} smallDisk - Ending disk in the stack
     * @param {number} [steps=12] - Number of disks in the blended stack
     */
    constructor(bigDisk, smallDisk, steps = 12) {
        this.bigDisk = SWDiskStack.copyDisk(bigDisk);
        this.smallDisk = SWDiskStack.copyDisk(smallDisk);
        this.steps = SWDiskStack.clampSteps(steps);
        this.layers = [];
        this.rebuildLayers();
    }//end constructor

    static clampSteps(n) {
        return Math.max(2, Math.round(Number(n) || 2));
    }//end clampSteps

    static copyDisk(disk) {
        if (!(disk instanceof SWDisk)) {
            throw new Error("SWDiskStack expects SWDisk endpoints.");
        }

        const centerCopy = SWPoint.copy(disk.center);
        const fillCopy = disk.fillColor ? SWColor.copy(disk.fillColor) : undefined;
        const strokeCopy = disk.strokeColor ? SWColor.copy(disk.strokeColor) : undefined;
        const copy = new SWDisk(centerCopy, disk.radius, disk.thickness, fillCopy, strokeCopy);
        copy.setShowCenter(!!disk.shouldShowCenter);
        return copy;
    }//end copyDisk

    static lerpNumber(a, b, t) {
        return a + (b - a) * t;
    }//end lerpNumber

    static lerpHue(h1, h2, t) {
        const d = ((h2 - h1 + 540) % 360) - 180;
        let out = h1 + d * t;
        out = ((out % 360) + 360) % 360;
        return out;
    }//end lerpHue

    static lerpColor(c1, c2, t, name = "orbColor") {
        if (!c1 && !c2) return undefined;
        if (!c1) return SWColor.copy(c2);
        if (!c2) return SWColor.copy(c1);

        const h = SWDiskStack.lerpHue(c1.h, c2.h, t);
        const s = SWDiskStack.lerpNumber(c1.s, c2.s, t);
        const b = SWDiskStack.lerpNumber(c1.b, c2.b, t);
        const a = SWDiskStack.lerpNumber(c1.a, c2.a, t);
        return new SWColor(h, s, b, a, name);
    }//end lerpColor

    setSteps(n) {
        this.steps = SWDiskStack.clampSteps(n);
        this.rebuildLayers();
    }//end setSteps

    setBigDisk(disk) {
        this.bigDisk = SWDiskStack.copyDisk(disk);
        this.rebuildLayers();
    }//end setBigDisk

    setSmallDisk(disk) {
        this.smallDisk = SWDiskStack.copyDisk(disk);
        this.rebuildLayers();
    }//end setSmallDisk

    setEndpoints(bigDisk, smallDisk) {
        this.bigDisk = SWDiskStack.copyDisk(bigDisk);
        this.smallDisk = SWDiskStack.copyDisk(smallDisk);
        this.rebuildLayers();
    }//end setEndpoints

    rebuildLayers() {
        this.layers = [];
        const n = this.steps;

        for (let i = 0; i < n; i++) {
            const t = (n === 1) ? 0 : i / (n - 1);

            const cx = SWDiskStack.lerpNumber(this.bigDisk.center.x, this.smallDisk.center.x, t);
            const cy = SWDiskStack.lerpNumber(this.bigDisk.center.y, this.smallDisk.center.y, t);
            const radius = SWDiskStack.lerpNumber(this.bigDisk.radius, this.smallDisk.radius, t);
            const thickness = SWDiskStack.lerpNumber(this.bigDisk.thickness, this.smallDisk.thickness, t);

            const fillColor = SWDiskStack.lerpColor(this.bigDisk.fillColor, this.smallDisk.fillColor, t, `diskStackFill_${i}`);
            const strokeColor = SWDiskStack.lerpColor(this.bigDisk.strokeColor, this.smallDisk.strokeColor, t, `diskStackStroke_${i}`);

            const center = new SWPoint(cx, cy, undefined, 1, strokeColor);
            const layerDisk = new SWDisk(center, radius, thickness, fillColor, strokeColor);
            layerDisk.setShowCenter(false);
            this.layers.push(layerDisk);
        }
    }//end rebuildLayers

    draw() {
        for (const layer of this.layers) {
            layer.draw();
        }
    }//end draw

    drawOnGrid(grid) {
        for (const layer of this.layers) {
            layer.drawOnGrid(grid);
        }
    }//end drawOnGrid

    getLayerCount() {
        return this.layers.length;
    }//end getLayerCount

    toString() {
        return `SWDiskStack(steps: ${this.steps}, bigRadius: ${this.bigDisk.radius}, smallRadius: ${this.smallDisk.radius}, layers: ${this.layers.length})`;
    }//end toString
}//end class SWDiskStack