DDS to PNG Converter

This texture converter decodes DirectDraw Surface (DDS) files — the standard GPU texture format used by game engines like Unreal, Unity, and Source — into universally viewable PNG images using pure client-side JavaScript with no library dependencies.

The tool validates the DDS magic number (0x20534444, ASCII "DDS ") and parses the 124-byte DDS header to extract image dimensions, pixel format flags, FourCC compression identifier, and bit masks for uncompressed formats. It then decodes the pixel data based on the detected format. For DXT1 (BC1) compressed textures, each 4×4 pixel block is encoded in 8 bytes — two 16-bit RGB565 reference colors generate a 4-color palette, and a 32-bit lookup table indexes each pixel to its palette entry. DXT1 supports 1-bit alpha for fully transparent pixels when the first reference color value is less than the second. DXT3 (BC2) adds explicit 4-bit-per-pixel alpha stored in 8 bytes preceding an identical color block, while DXT5 (BC3) uses interpolated alpha with two 8-bit reference values and a 48-bit index table providing smoother gradients.

For uncompressed DDS files, the tool reads raw pixel data using the header's RGBA bit masks and bit count, scaling each channel to 0-255 range. Decoded RGBA pixels are rendered onto an HTML5 Canvas via ImageData, then exported as a PNG blob using canvas.toBlob(). File size validation (50MB max) and dimension validation (16384×16384 max) prevent memory exhaustion.