Real-Time Normal Map DXT Compression

Using today's graphics hardware, normal maps can be stored in several compressed formats that are decompressed on the fly in hardware during rendering. Several object-space and tangent-space normal map compression techniques using existing texture compression formats are evaluated. While decompression from these formats happens in real-time in hardware during rendering, compression to these formats may take a considerable amount of time using existing compressors. Two highly optimized tangent-space normal map compression algorithms are presented that can be used to achieve real-time performance on both the CPU and GPU.