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List of file formats: Difference between revisions
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Robot: Cosmetic changes
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== *.rgb == | == *.rgb == | ||
These files are texture files in [http://en.wikipedia.org/wiki/Silicon_Graphics SGI] Image Format. This format supports multiple layers, transparency, compression, indexed colors, 8 bits and 16 bits per plane. Files of this format use different extensions, often to indicate the image properties, but in fact it's always the same format. The "official" extensions is <tt>*.sgi</tt>. Images with one layer are usually black/white (<tt>*.bw</tt>) or a mere alpha layer (<tt>*.a</tt>), with two layers black/white with alpha, with three layers red/green/blue (<tt>*.rgb</tt>), and with four layers red/green/blue/alpha (<tt>*.rgba</tt>). This, however, is only a convention and not mandated by the SGI image specification. SGI images can be uncompressed or | These files are texture files in [http://en.wikipedia.org/wiki/Silicon_Graphics SGI] Image Format. This format supports multiple layers, transparency, compression, indexed colors, 8 bits and 16 bits per plane. Files of this format use different extensions, often to indicate the image properties, but in fact it's always the same format. The "official" extensions is <tt>*.sgi</tt>. Images with one layer are usually black/white (<tt>*.bw</tt>) or a mere alpha layer (<tt>*.a</tt>), with two layers black/white with alpha, with three layers red/green/blue (<tt>*.rgb</tt>), and with four layers red/green/blue/alpha (<tt>*.rgba</tt>). This, however, is only a convention and not mandated by the SGI image specification. SGI images can be uncompressed or [http://en.wikipedia.org/wiki/Run-length_encoding RLE-compressed], which is a lossless compression method. | ||
FlightGear uses [http://plib.sourceforge.net/ plib] to read SGI images. They must not use 16 bits per plane and must have side lengths of 2<sup>n</sup>x2<sup>m</sup> (powers of 2), the size must be at least 4 pixels when using compressed textures (automatic feature in the osg branch). For example: 64x64, 256x256 or 128x2048 (but textures have '''square''' size inside the graphic card so a 16x1024 texture is really a 1024x1024 texture). Note that other sizes will '''not''' work, and FlightGear will use a red/white chequered texture instead! FlightGear textures ''shall'' be RLE-compressed, and as 'aggressively' as possible. | FlightGear uses [http://plib.sourceforge.net/ plib] to read SGI images. They must not use 16 bits per plane and must have side lengths of 2<sup>n</sup>x2<sup>m</sup> (powers of 2), the size must be at least 4 pixels when using compressed textures (automatic feature in the osg branch). For example: 64x64, 256x256 or 128x2048 (but textures have '''square''' size inside the graphic card so a 16x1024 texture is really a 1024x1024 texture). Note that other sizes will '''not''' work, and FlightGear will use a red/white chequered texture instead! FlightGear textures ''shall'' be RLE-compressed, and as 'aggressively' as possible. | ||
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=== OBJECT_BASE === | === OBJECT_BASE === | ||
specifies the terrain elevation data file. These files are generated by the [http://www.terragear.org/ TerraGear] using the [[BTG File Format|BTG file format]], and have file extension ".btg" ("binary terragear"; there used to be an "*.atg" file, too, where | specifies the terrain elevation data file. These files are generated by the [http://www.terragear.org/ TerraGear] using the [[BTG File Format|BTG file format]], and have file extension ".btg" ("binary terragear"; there used to be an "*.atg" file, too, where | ||
the 'a' stood for ASCII). | the 'a' stood for ASCII). | ||
Example: | Example: | ||