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    ./demo/canvas-001.js ./demo/canvas-002.js ./demo/canvas-003.js ./demo/canvas-004.js ./demo/canvas-005.js ./demo/canvas-006.js ./demo/canvas-007.js ./demo/canvas-008.js ./demo/canvas-009.js ./demo/canvas-010.js ./demo/canvas-011.js ./demo/canvas-012.js ./demo/canvas-013.js ./demo/canvas-014.js ./demo/canvas-015.js ./demo/canvas-016.js ./demo/canvas-017.js ./demo/canvas-018.js ./demo/canvas-019.js ./demo/canvas-020.js ./demo/canvas-021.js ./demo/canvas-022.js ./demo/canvas-023.js ./demo/canvas-024.js ./demo/canvas-025.js ./demo/canvas-026.js ./demo/canvas-027.js ./demo/canvas-028.js ./demo/canvas-029.js ./demo/canvas-030.js ./demo/canvas-031.js ./demo/canvas-032.js ./demo/canvas-033.js ./demo/canvas-034.js ./demo/canvas-035.js ./demo/canvas-036.js ./demo/canvas-037.js ./demo/canvas-038.js ./demo/canvas-039.js ./demo/canvas-040.js ./demo/canvas-041.js ./demo/canvas-042.js ./demo/canvas-043.js ./demo/canvas-044.js ./demo/canvas-045.js ./demo/canvas-046.js ./demo/canvas-047.js ./demo/canvas-048.js ./demo/canvas-049.js ./demo/canvas-050.js ./demo/canvas-051.js ./demo/canvas-052.js ./demo/canvas-053.js ./demo/canvas-054.js ./demo/canvas-055.js ./demo/canvas-056.js ./demo/canvas-057.js ./demo/canvas-058.js ./demo/canvas-059.js ./demo/canvas-060.js ./demo/canvas-061.js ./demo/canvas-062.js ./demo/canvas-063.js ./demo/canvas-064.js ./demo/canvas-065.js ./demo/canvas-066.js ./demo/canvas-067.js ./demo/canvas-068.js ./demo/canvas-069.js ./demo/canvas-070.js ./demo/canvas-071.js ./demo/canvas-072.js ./demo/canvas-073.js ./demo/canvas-201.js ./demo/canvas-202.js ./demo/canvas-203.js ./demo/canvas-204.js ./demo/canvas-205.js ./demo/canvas-206.js ./demo/canvas-207.js ./demo/canvas-208.js ./demo/canvas-209.js ./demo/canvas-210.js ./demo/canvas-211.js ./demo/canvas-212.js ./demo/delaunator-001.js ./demo/delaunator-002.js ./demo/dom-001.js ./demo/dom-002.js ./demo/dom-003.js ./demo/dom-004.js ./demo/dom-005.js ./demo/dom-006.js ./demo/dom-007.js ./demo/dom-008.js ./demo/dom-009.js ./demo/dom-010.js ./demo/dom-011.js ./demo/dom-012.js ./demo/dom-013.js ./demo/dom-015.js ./demo/dom-016.js ./demo/dom-017.js ./demo/dom-018.js ./demo/dom-019.js ./demo/dom-020.js ./demo/dom-021.js ./demo/filters-001.js ./demo/filters-002.js ./demo/filters-003.js ./demo/filters-004.js ./demo/filters-005.js ./demo/filters-006.js ./demo/filters-007.js ./demo/filters-008.js ./demo/filters-009.js ./demo/filters-010.js ./demo/filters-011.js ./demo/filters-012.js ./demo/filters-013.js ./demo/filters-014.js ./demo/filters-015.js ./demo/filters-016.js ./demo/filters-017.js ./demo/filters-018.js ./demo/filters-019.js ./demo/filters-020.js ./demo/filters-021.js ./demo/filters-022.js ./demo/filters-023.js ./demo/filters-024.js ./demo/filters-025.js ./demo/filters-026.js ./demo/filters-027.js ./demo/filters-028.js ./demo/filters-029.js ./demo/filters-030.js ./demo/filters-031.js ./demo/filters-032.js ./demo/filters-033.js ./demo/filters-034.js ./demo/filters-035.js ./demo/filters-036.js ./demo/filters-037.js ./demo/filters-101.js ./demo/filters-102.js ./demo/filters-103.js ./demo/filters-104.js ./demo/filters-105.js ./demo/filters-501.js ./demo/filters-502.js ./demo/filters-503.js ./demo/filters-504.js ./demo/filters-505.js ./demo/mediapipe-001.js ./demo/mediapipe-002.js ./demo/mediapipe-003.js ./demo/modules-001.js ./demo/modules-002.js ./demo/modules-003.js ./demo/modules-004.js ./demo/modules-005.js ./demo/modules-006.js ./demo/packets-001.js ./demo/packets-002.js ./demo/particles-001.js ./demo/particles-002.js ./demo/particles-003.js ./demo/particles-004.js ./demo/particles-005.js ./demo/particles-006.js ./demo/particles-007.js ./demo/particles-008.js ./demo/particles-009.js ./demo/particles-010.js ./demo/particles-011.js ./demo/particles-012.js ./demo/particles-013.js ./demo/particles-014.js ./demo/particles-015.js ./demo/particles-016.js ./demo/particles-017.js ./demo/snippets-001.js ./demo/snippets-002.js ./demo/snippets-003.js ./demo/snippets-004.js ./demo/snippets-005.js ./demo/snippets-006.js ./demo/temp-001.js ./demo/temp-shape-scale-investigation.js ./demo/tensorflow-001.js ./demo/tensorflow-002.js ./demo/utilities.js
  • §

    Demo Canvas 026

    Tower of Hanoi

  • §

    Run code

    import * as scrawl from '../source/scrawl.js'
    
    import { reportSpeed } from './utilities.js';
  • §

    Scene setup

    Get a handle to the Canvas wrapper

    const canvas = scrawl.findCanvas('mycanvas');
  • §

    Namespacing boilerplate

    const namespace = canvas.name;
    const name = (n) => `${namespace}-${n}`;
    
    
    scrawl.makeBlock({
    
        name: name('peg-1'),
    
        width: '30%',
        height: '90%',
    
        startX: '17%',
        startY: 'center',
    
        handleX: 'center',
        handleY: 'center',
    
        fillStyle: 'rgb(220 220 220)',
        strokeStyle: 'red',
        lineWidth: 5,
    
        method: 'drawThenFill',
    
    }).clone({
    
        name: name('peg-2'),
        startX: '50%',
        strokeStyle: 'blue',
    
    }).clone({
    
        name: name('peg-3'),
        startX: '83%',
        strokeStyle: 'orange',
    });
    
    scrawl.makeWheel({
    
        name: name('disc-1'),
    
        order: 1,
    
        radius: '12%',
    
        handleX: 'center',
        handleY: 'center',
    
        pivot: name('peg-1'),
        lockTo: 'pivot',
    
        fillStyle: 'pink',
        strokeStyle: 'red',
        lineWidth: 6,
    
        method: 'drawAndFill',
    
        shadowColor: 'black',
    
    }).clone({
    
        name: name('disc-2'),
        order: 2,
        radius: '10%',
        fillStyle: 'lightblue',
        strokeStyle: 'blue',
    
    }).clone({
    
        name: name('disc-3'),
        order: 3,
        radius: '8%',
        fillStyle: 'yellow',
        strokeStyle: 'orange',
    });
    
    const discGroup = scrawl.makeGroup({
    
        name: name('discs'),
    });
    
    const dragActions = scrawl.makeDragZone({
    
        zone: canvas,
        collisionGroup: name('discs'),
        endOn: ['up', 'leave'],
        exposeCurrentArtefact: true,
    
        resetCoordsToZeroOnTouchEnd: false,
    
        updateOnStart: {
            shadowBlur: 10,
            shadowOffsetX: 3,
            shadowOffsetY: 3,
        },
    
        updateOnEnd: {
            shadowBlur: 0,
            shadowOffsetX: 0,
            shadowOffsetY: 0,
        },
    });
    
    const checkPeg = function () {
    
        let peg, disc;
    
        const pegGroup = scrawl.makeGroup({
    
            name: name('pegs'),
    
        }).addArtefacts(
            name('peg-1'),
            name('peg-2'),
            name('peg-3'),
        );
  • §

    Setup the game’s initial state

        const pegState = {
    
            [name('peg-1')]: [
                name('disc-1'),
                name('disc-2'),
                name('disc-3'),
            ],
            [name('peg-2')]: [],
            [name('peg-3')]: [],
        };
  • §

    Function to update the game’s state

    • mydisc will always be the last member of an array,
    • so we can pop it when found, then push it onto mypeg
        const updateState = function (mypeg, mydisc) {
    
            Object.values(pegState).forEach(pState => {
    
                if (pState.includes(mydisc.name)) pState.pop();
            });
    
            pegState[mypeg.name].push(mydisc.name);
        }
  • §

    Function to update the disc group’s membership

    • a disc can only be moved if it is a member of this group
        const updateDiscGroup = function () {
    
            discGroup.clearArtefacts();
    
            Object.values(pegState).forEach(pState => {
    
                if (pState.length) discGroup.addArtefacts(pState[pState.length - 1]);
            });
  • §

    Because this Group is outside the Display cycle

    • (we haven’t assigned it to a Cell object)
    • we need to manually invoke its sort routine
            discGroup.sortArtefacts();
        }
        updateDiscGroup();
  • §

    Enforce the game rules

    • a disc can only move to a peg if no smaller discs are already on that peg
        const entity = scrawl.library.entity;
    
        const checkForLegalMove = function (mypeg, mydisc) {
    
            if (!pegState[mypeg.name].length) return true;
    
            return pegState[mypeg.name].every(d => entity[d].get('order') < mydisc.get('order'));
        }
    
        return function () {
    
            const hit = pegGroup.getArtefactAt(canvas.here);
    
            if (typeof hit !== 'boolean' && hit) peg = hit.artefact;
            else peg = false;
    
            const checkDrag = dragActions();
    
            if (typeof checkDrag !== 'boolean' && checkDrag) disc = checkDrag.artefact;
    
            else if (disc) {
    
                if (peg) {
    
                    if (checkForLegalMove(peg, disc)) {
    
                        updateState(peg, disc);
                        updateDiscGroup();
    
                        disc.set({
                            pivot: peg,
                        });
                    }
                }
                disc = false;
            }
        }
    }();
  • §

    Scene animation

    Function to display frames-per-second data, and other information relevant to the demo

    const report = reportSpeed('#reportmessage');
  • §

    Create the Animation loop which will run the Display cycle

    scrawl.makeRender({
        name: name('render'),
        target: canvas,
        commence: checkPeg,
        afterShow: report,
    });
  • §

    Development and testing

    console.log(scrawl.library);