Re: [Stellarium-pubdevel] Converting coordinate to screen?

[Timothy R. <tr...@si...>]

On Dec 14, 2009, at 4:22 AM, Fabien Chéreau wrote:

> Hi, it is StelProjector::project(). You Vec3d has to be in the same
> reference frame as the StelProjector you use.
> Not that the result is given in a Vec3d, but only the 2 first
> components contain the x,y screen coordinates.
> Fabien
> 
> 
> On Mon, Dec 14, 2009 at 03:14, Timothy Reaves
> <tr...@si...> wrote:
>>        If I have a vec3d, how do I convert that to screen coordinates?  I thought it was unproject, but that doesn't seem to do it.


	Then I'm doing it wrong, I guess.  I'm using the following code to determine where a line from the center of the screen to the south pole intersects the viewport.

// Center of screen
Vec3d cS(prj->getViewportPosX()+prj->getViewportWidth()/2, 
    prj->getViewportPosY()+prj->getViewportHeight()/2+1, 
    0);
Vec3d cV;
prj->unProject(cS, cV);

Vec3d southPole = Vec3d(0.0, 0.0, -1.0);
Vec3d intersect;
if (prj->project(southPole, win) && prj->checkInViewport(win)) {
	southVector = southPole;
} else {
	Vec3d southScreen;
	prj->project(southPole, southScreen);
	southScreen = prj->viewPortIntersect(centerScreen, southScreen);
	prj->unProject(southScreen, southVector);
}

When I print out southScreen, the numbers do not represent the pixel coordinates on the screen.  What am I doing wrong?

	Thanks.