From GameBrew - a wiki dedicated to Video Game Homebrew.
|Author(s)||kvance (Kevin Vance)|
|Version||0.1 (30 Mar 2009)|
This is a python script that can generate compressed textures for the Nintendo DS. It takes any image as input, and can output the NDS formatted texture in a variety of ways.
It will optionally use Psyco if you have it.
Hardware texture compression on the NDS allows you to display very large textures for the device. You can store two compressed 1024x512 textures on a device with a total screen size of 256x384. There is no performance penalty, as the hardware can decompress them on the fly. Unfortunately, the tools to generate compressed textures are not available to the homebrew community.
Compressed textures have a slightly complicated format, and the hardware is not very forgiving about how they are stored. The texture is divided into three parts:
- Pixmap - The pixels of the texture, grouped into 4x4 blocks.
- Index - A map from each pixel block to a part of the palette.
- Palette - The list of colors, used in groups of 2 or 4.
The pixmap can be stored in texture slots 0 or 2. The index must be stored in slot 1. This prevents textures larger than 1024x512, since the index would be in the middle of them. Palettes are stored normally.