vulbyteDotCom/waic.html at main · vulbyte/vulbyteDotCom · 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">
    <script type="module" src="client_management.js"></script>
    <title>Worms Armageddon Map Converter</title>
</head>
<body>

    <h1>Worms Armageddon Image Converter</h1>
    <p>Drag and drop your image file here to convert it into a Worms Armageddon compliant indexed PNG map (max 112 colors, black = index 0, dimensions padded to a multiple of 8).</p>

    <div id="dropzone" dropzone="copy" style="border:2px dashed #888;padding:40px;text-align:center;">
        <p><strong>[ DRAG AND DROP IMAGE HERE ]</strong></p>
    </div>

    <hr>

    <h2>Output Map</h2>
    <a id="download-link" download="wa_custom_map.png" hidden>Download WA Compliant PNG</a>
    <br><br>
    <img id="output-image" alt="Converted map will appear here">

    <script>
        const dropzone = document.getElementById('dropzone');
        const outputImage = document.getElementById('output-image');
        const downloadLink = document.getElementById('download-link');

        const MAX_COLORS = 112; // includes the forced black at index 0

        dropzone.addEventListener('dragover', (event) => event.preventDefault());

        dropzone.addEventListener('drop', (event) => {
            event.preventDefault();
            const file = event.dataTransfer.files[0];
            if (!file) return;

            const reader = new FileReader();
            reader.onload = (e) => {
                const img = new Image();
                img.onload = () => convertToWAMap(img).catch(err => {
                    console.error(err);
                    alert('Conversion failed: ' + err.message);
                });
                img.src = e.target.result;
            };
            reader.readAsDataURL(file);
        });

        async function convertToWAMap(img) {
            // --- 1. Pad dimensions to a multiple of 8 (required by W:A) ---
            const padTo8 = (n) => Math.ceil(n / 8) * 8;
            const width = padTo8(img.width);
            const height = padTo8(img.height);

            const canvas = document.createElement('canvas');
            canvas.width = width;
            canvas.height = height;
            const ctx = canvas.getContext('2d');

            // Fill with pure black first: this becomes the padding color AND
            // flattens any transparency (W:A maps have no alpha channel).
            ctx.fillStyle = '#000000';
            ctx.fillRect(0, 0, width, height);
            ctx.drawImage(img, 0, 0);

            const imageData = ctx.getImageData(0, 0, width, height);
            const data = imageData.data;

            // --- 2. Build a palette, forcing pure black into index 0 ---
            const colorCounts = new Map();
            for (let i = 0; i < data.length; i += 4) {
                const key = (data[i] << 16) | (data[i + 1] << 8) | data[i + 2];
                colorCounts.set(key, (colorCounts.get(key) || 0) + 1);
            }
            colorCounts.delete(0); // pure black handled separately, always index 0

            const sorted = [...colorCounts.entries()].sort((a, b) => b[1] - a[1]);
            const palette = [[0, 0, 0]]; // index 0 MUST be pure black
            for (const [key] of sorted) {
                if (palette.length >= MAX_COLORS) break;
                palette.push([(key >> 16) & 0xff, (key >> 8) & 0xff, key & 0xff]);
            }
            // Pad palette to at least 17 entries so encoders/tools treat this as
            // 8-bit indexed rather than collapsing it to 1/4-bit.
            while (palette.length < 17) palette.push([0, 0, 0]);

            // --- 3. Map every pixel to its nearest palette index ---
            const indices = new Uint8Array(width * height);
            for (let p = 0, i = 0; i < data.length; i += 4, p++) {
                const r = data[i], g = data[i + 1], b = data[i + 2];
                let best = 0, bestDist = Infinity;
                for (let j = 0; j < palette.length; j++) {
                    const [pr, pg, pb] = palette[j];
                    const d = (r - pr) ** 2 + (g - pg) ** 2 + (b - pb) ** 2;
                    if (d < bestDist) { bestDist = d; best = j; }
                }
                indices[p] = best;
            }

            // --- 4. Encode as a real indexed (color type 3) PNG ---
            const pngBytes = await encodeIndexedPNG(width, height, palette, indices);
            const blob = new Blob([pngBytes], { type: 'image/png' });
            const url = URL.createObjectURL(blob);

            outputImage.src = url;
            downloadLink.href = url;
            downloadLink.hidden = false;
        }

        // ---------- Minimal indexed-PNG encoder ----------

        async function encodeIndexedPNG(width, height, palette, indices) {
            const chunks = [];
            chunks.push(pngSignature());
            chunks.push(makeChunk('IHDR', buildIHDR(width, height)));
            chunks.push(makeChunk('PLTE', buildPLTE(palette)));

            const raw = buildRawScanlines(width, height, indices);
            const compressed = await deflateZlib(raw);
            chunks.push(makeChunk('IDAT', compressed));

            chunks.push(makeChunk('IEND', new Uint8Array(0)));
            return concatUint8Arrays(chunks);
        }

        function pngSignature() {
            return new Uint8Array([137, 80, 78, 71, 13, 10, 26, 10]);
        }

        function buildIHDR(width, height) {
            const buf = new Uint8Array(13);
            const view = new DataView(buf.buffer);
            view.setUint32(0, width);
            view.setUint32(4, height);
            buf[8] = 8;  // bit depth
            buf[9] = 3;  // color type 3 = indexed/palette
            buf[10] = 0; // compression
            buf[11] = 0; // filter
            buf[12] = 0; // interlace
            return buf;
        }

        function buildPLTE(palette) {
            const buf = new Uint8Array(palette.length * 3);
            palette.forEach(([r, g, b], i) => {
                buf[i * 3] = r; buf[i * 3 + 1] = g; buf[i * 3 + 2] = b;
            });
            return buf;
        }

        function buildRawScanlines(width, height, indices) {
            // Each row: 1 filter byte (0 = None) + width index bytes
            const raw = new Uint8Array(height * (width + 1));
            for (let y = 0; y < height; y++) {
                const rowStart = y * (width + 1);
                raw[rowStart] = 0; // filter type None
                raw.set(indices.subarray(y * width, (y + 1) * width), rowStart + 1);
            }
            return raw;
        }

        async function deflateZlib(data) {
            // 'deflate' (not 'deflate-raw') gives zlib-wrapped output, which is
            // exactly what PNG IDAT chunks require.
            const cs = new CompressionStream('deflate');
            const writer = cs.writable.getWriter();
            writer.write(data);
            writer.close();
            const compressedBuf = await new Response(cs.readable).arrayBuffer();
            return new Uint8Array(compressedBuf);
        }

        function makeChunk(type, data) {
            const typeBytes = new TextEncoder().encode(type);
            const chunk = new Uint8Array(4 + 4 + data.length + 4);
            const view = new DataView(chunk.buffer);
            view.setUint32(0, data.length);
            chunk.set(typeBytes, 4);
            chunk.set(data, 8);
            const crc = crc32(concatUint8Arrays([typeBytes, data]));
            view.setUint32(8 + data.length, crc >>> 0);
            return chunk;
        }

        function concatUint8Arrays(arrays) {
            const total = arrays.reduce((sum, a) => sum + a.length, 0);
            const out = new Uint8Array(total);
            let offset = 0;
            for (const a of arrays) { out.set(a, offset); offset += a.length; }
            return out;
        }

        // Standard CRC32 (used by PNG chunks)
        let crcTable = null;
        function crc32(buf) {
            if (!crcTable) {
                crcTable = new Uint32Array(256);
                for (let n = 0; n < 256; n++) {
                    let c = n;
                    for (let k = 0; k < 8; k++) {
                        c = (c & 1) ? (0xEDB88320 ^ (c >>> 1)) : (c >>> 1);
                    }
                    crcTable[n] = c;
                }
            }
            let crc = 0xFFFFFFFF;
            for (let i = 0; i < buf.length; i++) {
                crc = crcTable[(crc ^ buf[i]) & 0xFF] ^ (crc >>> 8);
            }
            return (crc ^ 0xFFFFFFFF);
        }
    </script>
</body>
</html>