SPR file format

Contents 1 Introduction 2 File format and header 3 Image structure 4 Palette structure 5 Sources

Introduction

.SPR files are small archives containing images, typically animated monster sprites. The images in .SPR files can be compressed with RLE compression.

Note: as with all RO file formats, integers are in little endian.

File format and header

struct SprFile {                   // Offset
    unsigned char signature[2];    // 0
    uint8 compressed;              // 2
    uint8 unknown;                 // 3
    uint16 numberOfImages;         // 4
    Image images[numberOfImages];  // 6
    PaletteEntry palette[256];     // EOF - sizeof(PaletteEntry * 256) = EOF - 1024
}

Image structure

The layout of the Image structure depends on whether this .SPR file is compressed (indicated by the 'compressed' field in the header).

This is the layout for compressed .SPR files:

struct Image {                              // Offset
    uint16 width;                           // 0
    uint16 height;                          // 2
    uint16 compressedLength;                // 4
    unsigned char data[compressedLength];   // 6
} // Size: 6 + compressedLength  bytes

This is the layout for uncompressed .SPR files:

struct Image {                              // Offset
    uint16 width;                           // 0
    uint16 height;                          // 2
    unsigned char data[width*height];       // 4
} // Size: 4 + width * height  bytes

Palette structure

struct PaletteEntry {  // Offset
    uint8 red;         // 0
    uint8 green;       // 1
    uint8 blue         // 2
    uint8 alpha;       // 4
} // Size: 4 bytes

Sources

• deufeufeu's .SPR file format description