Decomposition of 32 bpp into 16 bpp textures with alpha

Abstract

In 2D game graphics, textures are packed into a single texture called a sprite sheet in order to achieve efficient rendering. The sprite sheet can be compressed to save memory by using various compression methods such as block-based compressions and 16 bpp (bits per pixel) tone reduction. These methods are not without some problems, though. Block-based compressions are GPU-dependent, and high-quality compressions such as ASTC [Nystad et al. 2012] are often unavailable on mobile devices. 16 bpp tone reduction--often used with dithering--can create undesirable noise when it is scaled up (Figure 1c).