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1、使用osg基本几何图形，用transform节点定位物体并改变它们的状态用osg:Shape 建立一场景，用osg:StateSet控制图形渲染Shape类是所以图形类的基类。Shapes被用于精选和碰撞检测，或者定义几何形状来生成几何体。以下的类由Shape类继承而来：TriangleMeshSphereInfinitePlaneHeightFieldCylinderConeCompositeShape如果要渲染这些内嵌形体，我们需要首先将其与Drawable类的实例相关联。我们可以使用ShapeDrawable类来完成这一功能。它派生自Drawable类，并提供了关联Shape实例的方法。
2、正因为ShapeDrawable是继承自Drawable的，它的实例因而可以被添加到Geode实例中。#include #include #include #include #include #include #include #include #include #include #include #include #include #include osg:Geode* createPyramid() osg:Geode* pyramidGeode = new osg:Geode(); osg:Geometry* pyramidGeometry = new osg:Geometry(); p
3、yramidGeode-addDrawable(pyramidGeometry); / 指定金字塔的五个顶点 osg:Vec3Array* pyramidVertices = new osg:Vec3Array; pyramidVertices-push_back( osg:Vec3(0, 0, 0) ); / 左前 pyramidVertices-push_back( osg:Vec3(2, 0, 0) ); / 右前 pyramidVertices-push_back( osg:Vec3(2, 2, 0) ); / 右后 pyramidVertices-push_back( osg:Vec
4、3( 0,2, 0) ); / 右前 pyramidVertices-push_back( osg:Vec3( 1, 1,2) ); / 尖顶 pyramidGeometry-setVertexArray( pyramidVertices ); / 定义金字塔五个面的顶点索引，底面为四边形，侧面为三角形 / 顶点的排列按照逆时针的顺序 osg:DrawElementsUInt* pyramidBase = new osg:DrawElementsUInt(osg:PrimitiveSet:QUADS, 0); pyramidBase-push_back(3); pyramidBase-push
5、_back(2); pyramidBase-push_back(1); pyramidBase-push_back(0); /将顶点数组关联给几何体 pyramidGeometry-addPrimitiveSet(pyramidBase); /以下是金字塔的四个面（三角形），push_back后为索引数字 osg:DrawElementsUInt* pyramidFaceOne = new osg:DrawElementsUInt(osg:PrimitiveSet:TRIANGLES, 0); pyramidFaceOne-push_back(0); pyramidFaceOne-push_b
6、ack(1); pyramidFaceOne-push_back(4); pyramidGeometry-addPrimitiveSet(pyramidFaceOne); osg:DrawElementsUInt* pyramidFaceTwo = new osg:DrawElementsUInt(osg:PrimitiveSet:TRIANGLES, 0); pyramidFaceTwo-push_back(1); pyramidFaceTwo-push_back(2); pyramidFaceTwo-push_back(4); pyramidGeometry-addPrimitiveSet
7、(pyramidFaceTwo); osg:DrawElementsUInt* pyramidFaceThree = new osg:DrawElementsUInt(osg:PrimitiveSet:TRIANGLES, 0); pyramidFaceThree-push_back(2); pyramidFaceThree-push_back(3); pyramidFaceThree-push_back(4); pyramidGeometry-addPrimitiveSet(pyramidFaceThree); osg:DrawElementsUInt* pyramidFaceFour =
8、new osg:DrawElementsUInt(osg:PrimitiveSet:TRIANGLES, 0); pyramidFaceFour-push_back(3); pyramidFaceFour-push_back(0); pyramidFaceFour-push_back(4); pyramidGeometry-addPrimitiveSet(pyramidFaceFour); /建立颜色数组，存储四种颜色 osg:Vec4Array* colors = new osg:Vec4Array; colors-push_back(osg:Vec4(1.0f, 0.0f, 0.0f, 1
9、.0f) ); / 红色索引 colors-push_back(osg:Vec4(0.0f, 1.0f, 0.0f, 1.0f) ); / 绿色索引 colors-push_back(osg:Vec4(0.0f, 0.0f, 1.0f, 1.0f) ); / 蓝色索引 colors-push_back(osg:Vec4(1.0f, 1.0f, 1.0f, 1.0f) ); / 白色索引 osg:TemplateIndexArray *colorIndexArray; colorIndexArray = new osg:TemplateIndexArray; colorIndexArray-pu
10、sh_back(0); / 顶点对应颜色元素 colorIndexArray-push_back(1); / 顶点对应颜色元素 colorIndexArray-push_back(2); / 顶点对应颜色元素 colorIndexArray-push_back(3); / 顶点对应颜色元素 colorIndexArray-push_back(0); / 顶点对应颜色元素 pyramidGeometry-setColorArray(colors); pyramidGeometry-setColorIndices(colorIndexArray); pyramidGeometry-setColor
11、Binding(osg:Geometry:BIND_PER_VERTEX);/*由于纹理坐标与顶点是一一对应的，因此不需要使用索引数组来进行映射。我们只需要直接使用setTexCoordArray方法即可. setTexCoordArray方法传递osg:Vec2的二维坐标数组作为参数，传递的二维坐标数与顶点数相同。数组中元素的位置与顶点数组中顶点的位置一一对应。*/ osg:Vec2Array* texcoords = new osg:Vec2Array(5); (*texcoords)0.set(0.00f,0.0f); / 顶点的纹理坐标 (*texcoords)1.set(0.25f,
12、0.0f); / 顶点的纹理坐标 (*texcoords)2.set(0.50f,0.0f); / 顶点的纹理坐标 (*texcoords)3.set(0.75f,0.0f); / 顶点的纹理坐标 (*texcoords)4.set(0.50f,1.0f); / 顶点的纹理坐标 pyramidGeometry-setTexCoordArray(0,texcoords); return pyramidGeode;int main() osgViewer:Viewer viewer; /创建场景的根节点 osg:Group* root = new osg:Group();/*声明Box类（派生自S
13、hape）的实例。构造函数的参数为：osg:Vec3的中心位置，以浮点数定义统一的高/宽/深度。也可以分别输入不同的高度、宽度、深度值.*/ osg:Box* unitCube = new osg:Box( osg:Vec3(0,0,0), 1.0f);/*声明ShapeDrawable类的实例，使用刚才创建的unitCube作为传递参数。这个类派生自Drawable类，因此可以直接添加到Geode实例中*/ osg:ShapeDrawable* unitCubeDrawable = new osg:ShapeDrawable(unitCube); / 声明Geode类的实例（立方体） osg:Geode* basicShapesGeode = new osg:Geode(); / 将Geode节点添加到场景中 root-addChild(basicShapesGeode); / 将单位立方体添加到Geode中 basicShapesGeode-addDrawable(unitCubeDrawable);
