osg/BezierCurves源码
时间: 2023-11-14 16:06:53 浏览: 44
以下是一份使用OpenSceneGraph实现Bezier曲线的示例代码:
```cpp
#include <osg/Geode>
#include <osg/Geometry>
#include <osgViewer/Viewer>
osg::Vec3Array* createBezierCurve(osg::Vec3Array* points, int numSteps)
{
osg::Vec3Array* curvePoints = new osg::Vec3Array;
for (int i = 0; i < numSteps; i++)
{
float t = (float)i / (float)(numSteps - 1);
// Calculate blending functions
float b0 = (1.0f - t) * (1.0f - t) * (1.0f - t);
float b1 = 3.0f * t * (1.0f - t) * (1.0f - t);
float b2 = 3.0f * t * t * (1.0f - t);
float b3 = t * t * t;
// Calculate point on curve
osg::Vec3 p = b0 * (*points)[0] +
b1 * (*points)[1] +
b2 * (*points)[2] +
b3 * (*points)[3];
curvePoints->push_back(p);
}
return curvePoints;
}
int main(int argc, char** argv)
{
// Set up points for Bezier curve
osg::Vec3Array* points = new osg::Vec3Array;
points->push_back(osg::Vec3(-1.0f, 0.0f, 0.0f));
points->push_back(osg::Vec3(-0.5f, 1.0f, 0.0f));
points->push_back(osg::Vec3(0.5f, -1.0f, 0.0f));
points->push_back(osg::Vec3(1.0f, 0.0f, 0.0f));
// Create geometry for curve
osg::Geometry* curveGeom = new osg::Geometry;
curveGeom->setVertexArray(createBezierCurve(points, 20));
// Set up color array for curve
osg::Vec4Array* colors = new osg::Vec4Array;
colors->push_back(osg::Vec4(1.0f, 1.0f, 0.0f, 1.0f));
curveGeom->setColorArray(colors);
curveGeom->setColorBinding(osg::Geometry::BIND_OVERALL);
// Create line primitive for curve
curveGeom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::LINE_STRIP, 0, 20));
// Create geode for curve geometry
osg::Geode* curveGeode = new osg::Geode;
curveGeode->addDrawable(curveGeom);
// Create viewer and add curve geode to scene
osgViewer::Viewer viewer;
viewer.setSceneData(curveGeode);
return viewer.run();
}
```
这个示例代码定义了一个名为createBezierCurve的函数,它接收一个osg::Vec3Array类型的点数组和一个整数,用于指定在曲线上生成多少个点。该函数返回一个osg::Vec3Array类型的数组,包含生成的曲线上的点。
主函数中,我们使用createBezierCurve函数创建了一个Bezier曲线,并将其添加到一个osg::Geometry对象中。我们还定义了一个osg::Vec4Array类型的颜色数组,用于指定曲线的颜色。最后,我们创建一个osg::Geode对象,并将曲线的osg::Geometry对象添加到其中。我们将osg::Geode对象作为场景数据传递给osgViewer::Viewer对象,这样就可以在窗口中显示曲线了。
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