osgPlugins相关

OSG提供了很多的插件用来读取常用的数据格式，包括图像和模型等等。下面对插件的使用进行简单的描述。

使用插件读取和保存数据

当使用osgDB读取文件时，会自动根据文件的扩展名来到插件目录中寻找相应的插件，来实现。

比如：

> osgviewer cow.osg

调用了osgdb_osg插件去读*.osg文件。 

> osgviewer model.flt

调用了osgdb_flt插件去读*.flt文件。 

如果使用代码我们是使用如下代码读取模型:

#include
osg::ref_ptr node = osgDB::readNodeFile("cow.osg");
osg::ref_ptr image = osgDB::readImageFile("lz.rgb");

下面是保存模型:

#include
osgDB::writeNodeFile(*node, "saved.osg");

使用OSG插件是用户无需过分关心的事情，机制已经建立，当读某文件时，它会自己去寻找相应的插件，当你需要读定特文件的时候，就要确认这个文件的插件是否存在，如果不存在如何编译。

列举一些OSG支持的模型类型

Plugin name	Description	Extensions	Read	Write	Notes
3dc	3DC point cloud reader	.3dc .asc	yes	no
3ds	3D Studio	.3ds	yes	yes
ac3d	AC3D modeler	.ac	yes	yes	http://www.inivis.com/
bsp	Quake3 BSP	.bsp	yes	no
dae	COLLADA 1.4.x	.dae	yes	yes	Requires Collada DOM library. See Collada plugin details
dw	Design Workshop Database	.dw	yes	no
dxf	Autodesk DXF Reader	.dxf	yes	no
fbx	Autodesk FBX	.fbx	yes	yes	Requires Autodesk's FBX SDK. If using OpenSceneGraph 2.8.x you'll need version 2010.2 of the SDK. Otherwise checkReaderWriterFBX.h to see which version of the SDK is required (currently 2012.1). If you have problems loading an FBX model please check that it works in Autodesk's FBX QuickTime Viewer first to see if the model was correctly exported.
geo	Geo	.gem .geo	yes	no
Inventor	Open Inventor format	.iv .wrl	yes	yes	.wrl Only VRML1.0
ive	Native osg binary	.ive	yes	yes	May also read/write (internal) images
logo	Logo database	.logo	yes	no
lwo	Lightwave Object	.lwo .lw .geo	yes	no
lws	Lightwave Scene	.lws	yes	no
md2	Quake MD2	.md2	yes	no
obj	Alias Wavefront	.obj	yes	yes	Also writes materials to .mtl
ogr		.ogr	yes	no
Openflight	Multigen Openflight	.flt	yes	yes	See OpenFlight plugin details
osg	Native osg ascii	.osg	yes	yes	Currently the writer supports OVERRIDE/PROTECTED flags in "StateSets" only for "Modes" and not for "StateAttributes".
pfb	Performer loader	All extensions supported by Performer loaders	yes	no	Requires Performer library
shp	ESRI Shapefile	.shp	yes	no
stl	Stereolithography file	.stl .sta	yes	no
vrml	VRML2	.wrl	yes	no	Requires OpenVRML library
x	DirectX 3D model	.x	yes	no

图片和视频

Plugin name	Description	Extensions	Read	Write	Notes
bmp	Window bitmap	.bmp	yes	yes
dds	DirectX image format	.dds	yes	yes
gdal	GDAL image loaders	All extensions supported by GDAL	yes	no
gif	GIF Image	.gif	yes	no
hdr	High Dynamic Range image	.hdr	yes	yes
jp2		.jps .jpc	yes	yes
jpeg	Jpeg image	.jpeg .jpg	yes	yes
Openflight	Image attribute files	.attr	yes	yes	Stores additional attributes that are not stored in .rgb files
pic	PIC image	.pic	yes	no
png	Portable Network Graphics	.png	yes	yes
pnm		.pnm. ppm .pgm .pbm	yes	yes
rgb		.rgb .sgi .rgba .int .inta .bw	yes	yes
tga	Targa image	.tga	yes	no
tiff	Tiff image	.tiff .tif	yes	yes
quicktime	Quicktime movie loader	.mov .mpg .mpv .mp4 .m4v .dc .avi .flv .swf	yes	yes
	Quicktime image loader	rgb. rgba .jpg .jpeg .tif .tiff .gif .png .pict .pct .tga .psd	yes	yes
xine	Xine image stream	.mpg .mpv .db .flv .mov .avi .wmv. xine	yes	no

压缩以及网络传输类型

Plugin name	Description	Extensions	Read	Write	Notes
curl	HTTP Protocol Model	.curl	yes	no
osga
txp	Terrapage file	.txp	yes	no	Produced by Terra Vista terrain building tools
net
zip
tgz
osgtgz

字体类型

Plugin name	Description	Extensions	Read	Write	Notes
freetype	Freetype font loader	.ttf .ttc .pfb .pfa .cid .cff .cef .fon .fnt	yes	no
txf	GLU texture font	.txf	yes	no

加载时可以显式加的矩阵操作

Plugin name	Description	Extensions	Read	Write	Notes
rot	Rotates to the loaded model	.rot
scale	Scales the loaded model	.scale
trans	Translates the loaded model	.trans
normals	Shows normals of the loaded model	.normals