Hi Yong,
The simple answer is you can't convert a NULL to Vec3, it simply is
wrong and compiler is right to bark about it.
The best way to write code like is would be to do:
bool lineintersection(const osg::Vec3f& p1, const osg::Vec3f& p2,
const osg::Vec3f &p3, const osg::Vec3f& p4, osg::Vec3f&
intersectionPoint)
{
float x1 = p1.x(), x2 = p2.x(), x3 = p3.x(), x4 = p4.x();
float y1 = p1.y(), y2 = p2.y(), y3 = p3. y(), y4 = p4.y();
float d = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
if(d==0) return false;
float p = (x1*y2 - y1*x2), post = (x3*y4 - y3*x4);
float x = ( p * (x3 - x4) - (x1 - x2) * post ) / d;
float y = ( p * (y3 - y4) - (y1 - y2) * post ) / d;
intersectionPoint.set(x, y, 0.0f);
return true;
}
Robert.
On 13 May 2013 05:10, Yong Chen <[email protected]> wrote:
> Hi,
>
> The following lines are used to calculate the intersection of two lines in a
> 2D plane. However, the NULL value cannot be returned because the Visual
> Studio tells me that "error C2664: cannot convert parameter 1 from 'int' to
> 'const osg::Vec3f &'". I don't know how to represent a Null value here. Very
> appreciate if you guys can help me out.
>
> osg::Vec3f lineintersection(osg::Vec3f p1, osg::Vec3f p2, osg::Vec3f p3,
> osg::Vec3f p4)
> {
> float x1 = p1.x(), x2 = p2.x(), x3 = p3.x(), x4 = p4.x();
> float y1 = p1.y(), y2 = p2.y(), y3 = p3. y(), y4 = p4.y();
>
> float d = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
> if(d==0) return NULL; // error occurs here
>
> float p = (x1*y2 - y1*x2), post = (x3*y4 - y3*x4);
> float x = ( p * (x3 - x4) - (x1 - x2) * post ) / d;
> float y = ( p * (y3 - y4) - (y1 - y2) * post ) / d;
>
> return osg::Vec3f(x, y, 0.0f);
> }
>
> Thank you!
>
> Cheers,
> Yong
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=53991#53991
>
>
>
>
>
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