public Class TextureIO

Provides input and output facilities for both loading OpenGL textures from disk and streams as well as writing textures already in memory back to disk.

The TextureIO class supports an arbitrary number of plug-in readers and writers via TextureProviders and TextureWriters. TextureProviders know how to produce TextureData objects from files, InputStreams and URLs. TextureWriters know how to write TextureData objects to disk in various file formats. The TextureData class represents the raw data of the texture before it has been converted to an OpenGL texture object. The Texture class represents the OpenGL texture object and provides easy facilities for using the texture.

There are several built-in TextureProviders and TextureWriters supplied with the TextureIO implementation. The most basic provider uses the platform's Image I/O facilities to read in a BufferedImage and convert it to a texture. This is the baseline provider and is registered so that it is the last one consulted. All others are asked first to open a given file.

There are three other providers registered by default as of the time of this writing. One handles SGI RGB (".sgi", ".rgb") images from both files and streams. One handles DirectDraw Surface (".dds") images read from files, though can not read these images from streams. One handles Targa (".tga") images read from both files and streams. These providers are executed in an arbitrary order. Some of these providers require the file's suffix to either be specified via the newTextureData methods or for the file to be named with the appropriate suffix. In general a file suffix should be provided to the newTexture and newTextureData methods if at all possible.

Note that additional TextureProviders, if reading images from InputStreams, must use the mark()/reset() methods on InputStream when probing for e.g. magic numbers at the head of the file to make sure not to disturb the state of the InputStream for downstream TextureProviders.

There are analogous TextureWriters provided for writing textures back to disk if desired. As of this writing, there are four TextureWriters registered by default: one for Targa files, one for SGI RGB files, one for DirectDraw surface (.dds) files, and one for ImageIO-supplied formats such as .jpg and .png. Some of these writers have certain limitations such as only being able to write out textures stored in GL_RGB or GL_RGBA format. The DDS writer supports fetching and writing to disk of texture data in DXTn compressed format. Whether this will occur is dependent on whether the texture's internal format is one of the DXTn compressed formats and whether the target file is .dds format.