jcode/decoder.html at main · johanjomet/jcode · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>LumiLink v0.1 - Decoder (Aspect-Correct Auto-Align)</title>
    <style>
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background-color: #1e1e1e;
            color: #fff;
            display: flex;
            flex-direction: column;
            align-items: center;
            padding: 20px;
            margin: 0;
        }
        h1 { margin-bottom: 5px; font-size: 24px; }

        .container {
            position: relative;
            margin-top: 10px;
            width: 100%;
            max-width: 600px;
            display: flex;
            justify-content: center;
        }

        video {
            background: #000;
            border-radius: 12px;
            box-shadow: 0 10px 30px rgba(0,0,0,0.5);
            width: 100%;
            height: auto;
            max-height: 60vh;
        }

        /* Debug Overlay */
        #debug-canvas {
            position: absolute;
            top: 0; left: 0;
            width: 100%;
            height: 100%;
            pointer-events: none;
            object-fit: contain;
        }

        .output-box {
            margin-top: 20px;
            width: 100%;
            max-width: 600px;
            background: #2a2a2a;
            padding: 20px;
            border-radius: 12px;
            box-sizing: border-box;
        }

        h3 { margin-top: 0; color: #007bff; }
        #decoded-text {
            font-family: monospace;
            font-size: 16px;
            color: #00FF00;
            word-wrap: break-word;
            min-height: 50px;
        }

        .stats {
            margin-top: 15px;
            font-size: 12px;
            color: #aaa;
            display: flex;
            justify-content: space-between;
        }

        button {
            margin-top: 20px;
            padding: 12px 20px;
            background: #007bff;
            color: white;
            border: none;
            border-radius: 6px;
            cursor: pointer;
            font-weight: bold;
        }
    </style>
</head>
<body>

    <h1>LumiLink Decoder</h1>
    <p style="font-size: 14px; color: #ccc; margin-top:0; text-align:center;">Point at the Iris.<br>Green tracker means it has locked on.</p>

    <div class="container" id="video-container">
        <video id="video" autoplay playsinline></video>
        <canvas id="debug-canvas"></canvas>
        <canvas id="hidden-canvas" style="display:none;"></canvas>
    </div>

    <button id="btn-start">Start Camera</button>

    <div class="output-box">
        <h3>Decoded Payload</h3>
        <div id="decoded-text">Waiting for data...</div>
        <div class="stats">
            <span id="stat-packets">Packets: 0 / 0</span>
            <span id="stat-crc">CRC Fails: 0</span>
        </div>
    </div>

    <script>
        const video = document.getElementById('video');
        const hiddenCanvas = document.getElementById('hidden-canvas');
        const ctxHidden = hiddenCanvas.getContext('2d', { willReadFrequently: true });

        const debugCanvas = document.getElementById('debug-canvas');
        const ctxDebug = debugCanvas.getContext('2d');

        const RINGS = [16, 32, 48, 64, 96]; // 256 sectors

        let packetBuffer = {};
        let totalPacketsExpected = 0;
        let crcFails = 0;
        let lastSeqId = -1;
        let isDecoding = false;

        // CRC-32 Implementation
        const crcTable = (function() {
            let c;
            let crcTable = [];
            for(let n =0; n < 256; n++){
                c = n;
                for(let k =0; k < 8; k++){
                    c = ((c&1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1));
                }
                crcTable[n] = c;
            }
            return crcTable;
        })();

        function crc32(buffer) {
            let crc = 0 ^ (-1);
            for (let i = 0; i < buffer.length; i++) {
                crc = (crc >>> 8) ^ crcTable[(crc ^ buffer[i]) & 0xFF];
            }
            return (crc ^ (-1)) >>> 0;
        }

        // Extremely Robust Color Classifier
        function classifyColorRobust(r, g, b) {
            let max = Math.max(r, g, b);
            let min = Math.min(r, g, b);

            // If it's overall dark, or the color is very desaturated (gray glare), call it black
            if (max < 80 || (max - min) < 30) return 0; // Black

            // Otherwise, find the dominant channel
            if (r === max) return 1; // Red
            if (g === max) return 2; // Green
            return 3; // Blue
        }

        function sampleFrame() {
            if (!isDecoding) return;

            let vw = video.videoWidth;
            let vh = video.videoHeight;

            if (vw === 0 || vh === 0) {
                requestAnimationFrame(sampleFrame);
                return;
            }

            // Dynamically resize internal canvases to match exact camera resolution to avoid aspect ratio squashing!
            if (hiddenCanvas.width !== vw) {
                hiddenCanvas.width = vw;
                hiddenCanvas.height = vh;
                debugCanvas.width = vw;
                debugCanvas.height = vh;
            }

            ctxHidden.drawImage(video, 0, 0, vw, vh);
            const imgData = ctxHidden.getImageData(0, 0, vw, vh);
            const pixels = imgData.data;

            // 1. Find the Magenta Center (immune to white glare)
            let wSumX = 0, wSumY = 0, wCount = 0;

            // Scan middle 80% of screen for speed
            let scanSizeX = vw * 0.8;
            let scanSizeY = vh * 0.8;
            let startX = Math.floor((vw - scanSizeX) / 2);
            let endX = Math.floor(startX + scanSizeX);
            let startY = Math.floor((vh - scanSizeY) / 2);
            let endY = Math.floor(startY + scanSizeY);

            // Sample every 4th pixel for speed
            for (let y = startY; y < endY; y += 4) {
                for (let x = startX; x < endX; x += 4) {
                    let idx = (y * vw + x) * 4;
                    let r = pixels[idx], g = pixels[idx+1], b = pixels[idx+2];

                    // Magenta: High Red, High Blue, Low Green
                    if (r > 150 && b > 150 && g < 100) {
                        wSumX += x; wSumY += y; wCount++;
                    }
                }
            }

            ctxDebug.clearRect(0, 0, vw, vh);

            if (wCount > 10) {
                let cx = wSumX / wCount;
                let cy = wSumY / wCount;

                // 2. Find the Cyan Orientation Dot
                let cSumX = 0, cSumY = 0, cCount = 0;

                // Search in a bounding box around the center (max 20% of screen size)
                let searchRad = Math.min(vw, vh) * 0.2;
                let cStartX = Math.max(0, Math.floor(cx - searchRad));
                let cEndX = Math.min(vw, Math.floor(cx + searchRad));
                let cStartY = Math.max(0, Math.floor(cy - searchRad));
                let cEndY = Math.min(vh, Math.floor(cy + searchRad));

                // Finer resolution search for the smaller dot
                for (let y = cStartY; y < cEndY; y += 2) {
                    for (let x = cStartX; x < cEndX; x += 2) {
                        let idx = (y * vw + x) * 4;
                        let r = pixels[idx], g = pixels[idx+1], b = pixels[idx+2];

                        // Cyan: High Green, High Blue, Low Red
                        if (g > 150 && b > 150 && r < 100) {
                            cSumX += x; cSumY += y; cCount++;
                        }
                    }
                }

                if (cCount > 2) {
                    let rx = cSumX / cCount;
                    let ry = cSumY / cCount;

                    let dx = rx - cx;
                    let dy = ry - cy;
                    let distance = Math.sqrt(dx*dx + dy*dy);

                    let scale = distance / 25.0; // The cyan dot is at radius 25 in the encoder
                    let angle = Math.atan2(dy, dx);

                    // Draw Debug Overlay
                    ctxDebug.strokeStyle = '#00FF00';
                    ctxDebug.lineWidth = 2;
                    ctxDebug.beginPath(); ctxDebug.arc(cx, cy, 35 * scale, 0, Math.PI*2); ctxDebug.stroke();
                    ctxDebug.beginPath(); ctxDebug.moveTo(cx, cy); ctxDebug.lineTo(rx, ry); ctxDebug.stroke();

                    // 3. Sample Sectors
                    const maxRadius = 190;
                    const ringThickness = (maxRadius - 40) / RINGS.length;

                    let colorIndices = [];

                    for (let ring = 0; ring < RINGS.length; ring++) {
                        let midRadius = (40 + ring * ringThickness + (ringThickness / 2)) * scale;
                        let sectors = RINGS[ring];

                        for (let s = 0; s < sectors; s++) {
                            let theta = (s * Math.PI * 2) / sectors + (Math.PI / sectors) + angle;

                            let px = Math.floor(cx + midRadius * Math.cos(theta));
                            let py = Math.floor(cy + midRadius * Math.sin(theta));

                            if (px >= 0 && px < vw && py >= 0 && py < vh) {
                                let idx = (py * vw + px) * 4;
                                let pr = pixels[idx], pg = pixels[idx+1], pb = pixels[idx+2];
                                colorIndices.push(classifyColorRobust(pr, pg, pb));

                                // Draw debug sample point
                                ctxDebug.fillStyle = 'rgba(255,255,255,0.7)';
                                ctxDebug.fillRect(px - 1, py - 1, 3, 3);
                            } else {
                                colorIndices.push(0);
                            }
                        }
                    }

                    processSampledColors(colorIndices);
                }
            }

            requestAnimationFrame(sampleFrame);
        }

        function processSampledColors(colorIndices) {
            if (colorIndices.length !== 256) return;

            // Try Normal Decode
            if (tryDecode(colorIndices)) return;

            // Try Mirrored Decode (in case front-camera or OS horizontally flips the video)
            let mirroredIndices = [];
            let ptr = 0;
            for (let ring = 0; ring < RINGS.length; ring++) {
                let sectors = RINGS[ring];
                let ringColors = colorIndices.slice(ptr, ptr + sectors);

                mirroredIndices.push(ringColors[0]);
                for (let i = sectors - 1; i > 0; i--) {
                    mirroredIndices.push(ringColors[i]);
                }
                ptr += sectors;
            }
            tryDecode(mirroredIndices);
        }

        function tryDecode(colorIndices) {
            let packet = new Uint8Array(64);
            for (let i = 0; i < 64; i++) {
                let c1 = colorIndices[i*4];
                let c2 = colorIndices[i*4 + 1];
                let c3 = colorIndices[i*4 + 2];
                let c4 = colorIndices[i*4 + 3];
                packet[i] = (c1 << 6) | (c2 << 4) | (c3 << 2) | c4;
            }

            let seqId = packet[0];
            if (seqId === lastSeqId) return true; // Already processed this frame, treat as success to stop mirror check

            // CRC
            let crcBuffer = new Uint8Array(60);
            crcBuffer.set(packet.slice(0, 7), 0);
            crcBuffer.set(packet.slice(11, 64), 7);

            let calculatedCrc = crc32(crcBuffer);
            let packetCrc = (packet[7] << 24) | (packet[8] << 16) | (packet[9] << 8) | packet[10];

            if ((calculatedCrc >>> 0) !== (packetCrc >>> 0)) {
                crcFails++;
                document.getElementById('stat-crc').innerText = `CRC Fails: ${crcFails}`;
                return false;
            }

            // CRC Passed!
            lastSeqId = seqId;
            let total = (packet[3] << 8) | packet[4];
            let current = (packet[5] << 8) | packet[6];

            if (total === 0) return true;

            totalPacketsExpected = total;
            packetBuffer[current] = packet.slice(11, 48); // 37 payload bytes

            let receivedCount = Object.keys(packetBuffer).length;
            document.getElementById('stat-packets').innerText = `Packets: ${receivedCount} / ${totalPacketsExpected}`;

            if (receivedCount === totalPacketsExpected) {
                assemblePayload();
            }

            return true;
        }

        function assemblePayload() {
            let totalBytes = totalPacketsExpected * 37;
            let fullBuffer = new Uint8Array(totalBytes);

            for (let i = 0; i < totalPacketsExpected; i++) {
                if (packetBuffer[i]) {
                    fullBuffer.set(packetBuffer[i], i * 37);
                }
            }

            let endIdx = fullBuffer.indexOf(0);
            if (endIdx === -1) endIdx = fullBuffer.length;

            let text = new TextDecoder().decode(fullBuffer.slice(0, endIdx));
            document.getElementById('decoded-text').innerText = text;

            packetBuffer = {};
        }

        document.getElementById('btn-start').addEventListener('click', async () => {
            try {
                // Remove environment facing mode constraint for easier desktop testing, but prefer rear camera
                const stream = await navigator.mediaDevices.getUserMedia({
                    video: { facingMode: 'environment', width: { ideal: 1920 }, height: { ideal: 1080 } }
                });
                video.srcObject = stream;
                document.getElementById('btn-start').style.display = 'none';

                video.onloadedmetadata = () => {
                    isDecoding = true;
                    requestAnimationFrame(sampleFrame);
                };
            } catch (err) {
                alert("Camera access denied or unavailable. " + err.message);
            }
        });
    </script>
</body>
</html>