OpenScenegraph示例代码问题

Question

下面的代码来自一本书。当我尝试运行它时，它会失败。

osg::ref_ptr geom =新osg：：几何()；

而且，除了告诉我它崩溃的原因之外，输出窗口似乎没有包含太多关于它崩溃的信息。知道我在下面的代码中做错了什么吗？提前谢谢。

下面是在Visual 2010(windows 7 64)中运行此操作时窗口出现的错误

窗口在OSGPracticeLab.exe中触发了一个断点。这可能是由于堆损坏所致，它表示OSGPracticeLab.exe或其加载的任何DLL中存在错误。这也可能是由于用户按下F12，而OSGPracticeLab.exe有焦点。输出窗口可能有更多的诊断信息。

在尝试调试代码时，我能够将问题跟踪到新函数调用。在下面的代码中，应该跳过while循环，并返回p的空值(没有分配内存，因此下面代码中的几何对象没有实例化)。

void *__CRTDECL operator new(size_t size) _THROW1(_STD bad_alloc)
        {       // try to allocate size bytes
        void *p;
        while ((p = malloc(size)) == 0)
                if (_callnewh(size) == 0)
                {       // report no memory
                static const std::bad_alloc nomem;
                _RAISE(nomem);
                }

        return (p);
        }

下面是我绘制一些形状和显示的程序。

#include <osg/ShapeDrawable>
#include <osg/Geode>
#include <osgViewer/Viewer> 


int main()
{
    //An octahedron is a polyhedron having eight triangle faces. 
    //It is really a nice example to show why primitive indexing is important
    // we will sketch the octahedron structure now 

    osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array(6);
    //octahedron has six vertices, each shaed by four triangles.  
    //withe the help of an index array and the osg::DrawElementsUInt class, we can allocate
    //a vertex array with only six elements
    (*vertices)[0].set( 0.0f, 0.0f, 1.0f);
    (*vertices)[1].set(-0.5f,-0.5f, 0.0f);
    (*vertices)[2].set( 0.5f,-0.5f, 0.0f);
    (*vertices)[3].set( 0.5f, 0.5f, 0.0f);
    (*vertices)[4].set(-0.5f, 0.5f, 0.0f);
    (*vertices)[5].set( 0.0f, 0.0f,-1.0f);
    //The osg::DrawElementsUInt accepts a size parameter besides the drawing mode parameter, too. 
    //After that, we will specify the indices of vertices to describe all eight triangle faces.
    osg::ref_ptr<osg::DrawElementsUInt> indices = new osg::DrawElementsUInt(GL_TRIANGLES, 24);
    (*indices)[0] = 0; (*indices)[1] = 1; (*indices)[2] = 2;
    (*indices)[3] = 0; (*indices)[4] = 2; (*indices)[5] = 3;
    (*indices)[6] = 0; (*indices)[7] = 3; (*indices)[8] = 4;
    (*indices)[9] = 0; (*indices)[10]= 4; (*indices)[11]= 1;
    (*indices)[12]= 5; (*indices)[13]= 2; (*indices)[14]= 1;
    (*indices)[15]= 5; (*indices)[16]= 3; (*indices)[17]= 2;
    (*indices)[18]= 5; (*indices)[19]= 4; (*indices)[20]= 3;
    (*indices)[21]= 5; (*indices)[22]= 1; (*indices)[23]= 4;

    //To create a geometry with a default white color, we only set the vertex array 
    //and the osg::DrawElementsUInt primitive set. The normal array is also required but is not easy
    //to compute manually. We will use a smoothed normal calculator to automatically obtain it. This calculator
    //will be described in the next section, Using polygonal techniques.
    osg::ref_ptr<osg::Geometry> geom = new osg::Geometry();
    geom->setVertexArray( vertices.get() );
    geom->addPrimitiveSet( indices.get() );
    //osgUtil::SmoothingVisitor::smooth( *geom );
    //Add the geometry to an osg::Geode object and make it the scene root
    osg::ref_ptr<osg::Geode> root = new osg::Geode;
    root->addDrawable( geom.get() );
    osgViewer::Viewer viewer;
    viewer.setSceneData( root.get() );
    return viewer.run();
}

int drawShapeUsingVertices()
{
    //Create the vertex array and push the four corner points to the back of the array by using vector like operations:
    osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
    vertices->push_back( osg::Vec3(0.0f, 0.0f, 0.0f) );
    vertices->push_back( osg::Vec3(1.0f, 0.0f, 0.0f) );
    vertices->push_back( osg::Vec3(1.0f, 0.0f, 1.0f) );
    vertices->push_back( osg::Vec3(0.0f, 0.0f, 1.0f) );
    //We have to indicate the normal of each vertex; otherwise OpenGL will use a default (0, 0, 1) normal vector
    //and the lighting equation calculation may be incorrect. The four vertices actually face the same direction,
    //so a single normal vector is enough. We will also set the setNormalBinding() method to BIND_OVERALL later.
    osg::ref_ptr<osg::Vec3Array> normals = new osg::Vec3Array; 
    normals->push_back( osg::Vec3(0.0f,-1.0f, 0.0f) );
    osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array;
    //here We will indicate a unique color value to each vertex and make them colored. By default, 
    //OpenGL will use smooth coloring and blend colors at each vertex together:
    colors->push_back( osg::Vec4(1.0f, 0.0f, 0.0f, 1.0f) );
    colors->push_back( osg::Vec4(0.0f, 1.0f, 0.0f, 1.0f) );
    colors->push_back( osg::Vec4(0.0f, 0.0f, 1.0f, 1.0f) );
    colors->push_back( osg::Vec4(1.0f, 1.0f, 1.0f, 1.0f) );
    //Next, we create the osg::Geometry object and set the prepared vertex, normal, and color arrays to it. 
    //We also indicate that the single normal should be bound to the entire geometry and that the colors
    //should be bound per vertex:
    osg::ref_ptr<osg::Geometry> quad = new osg::Geometry;
    quad->setVertexArray( vertices.get() );
    quad->setNormalArray( normals.get() );
    quad->setNormalBinding( osg::Geometry::BIND_OVERALL );
    quad->setColorArray( colors.get() );
    quad->setColorBinding( osg::Geometry::BIND_PER_VERTEX );

    //The last step required to finish a geometry and add it to the scene graph is to specify the primitive set.
    //A newly allocated osg::DrawArrays instance with the drawing mode set to GL_QUADS is used here, in order to
    //render the four vertices as quad corners in a counter-clockwise order:
    quad->addPrimitiveSet( new osg::DrawArrays(GL_QUADS, 0, 4) );
    //Add the geometry to an osg::Geode object and render it in the scene viewer:
    osg::ref_ptr<osg::Geode> root = new osg::Geode;
    root->addDrawable( quad.get() );
    osgViewer::Viewer viewer;
    viewer.setSceneData( root.get() );
    return viewer.run();
}

Answer 1

我对密码没有任何问题。它是从初学者指南上学来的，效果很好：

#include <osg/Geometry>
#include <osg/Geode>
#include <osgViewer/Viewer>

int main()
{
    osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
    vertices->push_back( osg::Vec3(0.0f, 0.0f, 0.0f) );
    vertices->push_back( osg::Vec3(1.0f, 0.0f, 0.0f) );
    vertices->push_back( osg::Vec3(1.0f, 0.0f, 1.0f) );
    vertices->push_back( osg::Vec3(0.0f, 0.0f, 1.0f) );

    osg::ref_ptr<osg::Vec3Array> normals = new osg::Vec3Array;
    normals->push_back( osg::Vec3(0.0f,-1.0f, 0.0f) );

    osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array;
    colors->push_back( osg::Vec4(1.0f, 0.0f, 0.0f, 1.0f) );
    colors->push_back( osg::Vec4(0.0f, 1.0f, 0.0f, 1.0f) );
    colors->push_back( osg::Vec4(0.0f, 0.0f, 1.0f, 1.0f) );
    colors->push_back( osg::Vec4(1.0f, 1.0f, 1.0f, 1.0f) );

    osg::ref_ptr<osg::Geometry> quad = new osg::Geometry;
    quad->setVertexArray( vertices.get() );
    quad->setNormalArray( normals.get() );
    quad->setNormalBinding( osg::Geometry::BIND_OVERALL );
    quad->setColorArray( colors.get() );
    quad->setColorBinding( osg::Geometry::BIND_PER_VERTEX );

    quad->addPrimitiveSet( new osg::DrawArrays(GL_QUADS, 0, 4) );

    osg::ref_ptr<osg::Geode> root = new osg::Geode;
    root->addDrawable( quad.get() );
    osgViewer::Viewer viewer;
    viewer.setSceneData( root.get() );
    return viewer.run();
}  

我建议您检查项目属性。

您是否包括了其他包含目录：$(OSG_ROOT)\include;$(OSG_SOURCE)\include;$(OSG_ROOT)\include\osg;

如果您正处于调试模式，那么在您的预处理器定义中是否有此特性？_DEBUG;WIN32;

您是否指定了链接器附加目录：$(OSG_ROOT)\lib

您是否指定了链接器附加依赖项？：osgWidgetd.lib;osgVolumed.lib;osgViewerd.lib;osgUtild.lib;osgTextd.lib;osgTerraind.lib;osgSimd.lib;osgShadowd.lib;osgPresentationd.lib;osgParticled.lib;osgManipulatord.lib;osgGAd.lib;osgFXd.lib;osgDBd.lib;osgd.lib;osgAnimationd.lib;OpenThreadsd.lib;;;;;;kernel32.lib;user32.lib;gdi32.lib;winspool.lib;comdlg32.lib;advapi32.lib;shell32.lib;ole32.lib;oleaut32.lib;uuid.lib;odbc32.lib;odbccp32.lib;%(AdditionalDependencies)

是否将配置属性>调试>工作目录指定为：$(OSG_ROOT)\bin

如果是极端情况，可能是因为Visual安装已损坏。尝试重新安装Visual，如果OSG安装已损坏，则重新安装OSG (从源代码构建)。提到这一点是因为我的一个朋友在运行OSG时遇到了问题，因为他的Visual已经损坏了。重新安装它。

Answer 2

osg会建吗？你在OSG内部运行了“安装”项目吗？即使您这样做了，权限也可以在Win7中保存--您可能必须手动安装到程序文件中。

上面发布的示例在Win7 / VS 2008 /Win7 32发行版构建配置上为我完美地编译，构建于OSG的3.1.0版本。我刚刚用上面粘贴的代码替换了OSG解决方案中的一个示例项目中的main，它构建并运行时没有您列出的错误。

我正在使用OSG从主干-可能至少有一个小版本之前的任何预构建，但它应该工作从预构建，如果你有你的路径，等等，设置正确。当然，您也可以尝试从作者下载的示例开始：http://www.skew-matrix.com/OSGQSG/ --他们已经设置了正确的项目文件等等。

Answer 3

您没有在代码中定义osg::Geometry类，因此最可能的问题是没有正确链接到定义对象或库的对象或库。