BabylonJS/Babylon.js · error · Error

Wrong PIZ_COMPRESSION BITMAP_SIZE

Error message

Wrong PIZ_COMPRESSION BITMAP_SIZE

What it means

UncompressPIZ reads a bitmap used to reconstruct the 65536-entry luminance LUT of PIZ data. maxNonZero must be smaller than BITMAP_SIZE; a value >= BITMAP_SIZE means the bitmap section of the block is corrupt or misaligned, so the loader throws before overrunning the bitmap array.

Source

Thrown at packages/dev/core/src/Materials/Textures/Loaders/EXR/exrLoader.compression.ts:218

    let outBufferEnd = 0;
    const pizChannelData = new Array(decoder.channels);
    for (let i = 0; i < decoder.channels; i++) {
        pizChannelData[i] = {};
        pizChannelData[i]["start"] = outBufferEnd;
        pizChannelData[i]["end"] = pizChannelData[i]["start"];
        pizChannelData[i]["nx"] = decoder.width;
        pizChannelData[i]["ny"] = decoder.lines;
        pizChannelData[i]["size"] = decoder.type;

        outBufferEnd += pizChannelData[i].nx * pizChannelData[i].ny * pizChannelData[i].size;
    }

    // Read range compression data
    const minNonZero = ParseUint16(inDataView, inOffset);
    const maxNonZero = ParseUint16(inDataView, inOffset);

    if (maxNonZero >= BITMAP_SIZE) {
        throw new Error("Wrong PIZ_COMPRESSION BITMAP_SIZE");
    }

    if (minNonZero <= maxNonZero) {
        for (let i = 0; i < maxNonZero - minNonZero + 1; i++) {
            bitmap[i + minNonZero] = ParseUint8(inDataView, inOffset);
        }
    }

    // Reverse LUT
    const lut = new Uint16Array(USHORT_RANGE);
    const maxValue = ReverseLutFromBitmap(bitmap, lut);

    const length = ParseUint32(inDataView, inOffset);

    // Huffman decoding
    HufUncompress(decoder.array, inDataView, inOffset, length, outBuffer, outBufferEnd);

    // Wavelet decoding

View on GitHub (pinned to 0592b347b8)

Solutions

  1. Re-download/re-export the .exr and verify integrity
  2. Open the file in a reference EXR utility to confirm the PIZ block structure is valid
  3. Check the header/offset parsing upstream for drift that would misalign this read
  4. Re-export with ZIP compression instead of PIZ
Defensive patterns

Strategy: try-catch

Try / catch

try {
  await loader.loadAsync(file);
} catch (e) {
  if (/Wrong PIZ_COMPRESSION BITMAP_SIZE/.test(String(e))) {
    console.warn("PIZ bitmap corrupt; falling back to PNG");
    return loadPngFallback();
  }
  throw e;
}

Prevention

When it happens

Trigger: Raised in UncompressPIZ while reading the compressed-block preamble when ParseUint16 for maxNonZero returns a value >= BITMAP_SIZE — caused by wrong block offsets or corrupted compressed data.

Common situations: Malformed EXR files produced by broken writers, wrong chunk boundaries due to earlier parse drift, or corrupted downloads.

Related errors

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/97bd866889b1257e. Report an issue: GitHub.