下面的代码来自一本书。当我尝试运行它时,它失败了
osg::ref_ptr geom = new osg::Geometry();
而且,输出窗口似乎没有包含太多关于它为什么崩溃的信息,只是告诉我它确实发生了。知道我在下面的代码中可能做错了什么吗?提前致谢。
这是我尝试在 Visual Studio 2010(windows 7 64)中运行时出现的 windows 错误弹出窗口
Windows 已在 OSGPracticeLab.exe 中触发断点。这可能是由于堆损坏,这表明 OSGPracticeLab.exe 或其已加载的任何 DLL 中存在错误。这也可能是由于用户在 OSGPracticeLab.exe 获得焦点时按 F12。输出窗口可能有更多诊断信息。
在尝试调试代码时,我能够将问题追溯到新的函数调用。在下面的代码中,似乎跳过了 while 循环,并且为 p(没有分配内存,因此我的 Geometry 对象在下面的代码中返回了一个空值,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();
}