//! Draw the sky grid in the current frame
void SkyGrid::draw(const StelCore* core) const
{
const StelProjectorP prj = core->getProjection(frameType, frameType!=StelCore::FrameAltAz ? StelCore::RefractionAuto : StelCore::RefractionOff);
if (!fader.getInterstate())
return;
bool withDecimalDegree = StelApp::getInstance().getFlagShowDecimalDegrees();;
// Look for all meridians and parallels intersecting with the disk bounding the viewport
// Check whether the pole are in the viewport
bool northPoleInViewport = false;
bool southPoleInViewport = false;
Vec3f win;
if (prj->project(Vec3f(0,0,1), win) && prj->checkInViewport(win))
northPoleInViewport = true;
if (prj->project(Vec3f(0,0,-1), win) && prj->checkInViewport(win))
southPoleInViewport = true;
// Get the longitude and latitude resolution at the center of the viewport
Vec3d centerV;
prj->unProject(prj->getViewportPosX()+prj->getViewportWidth()/2., prj->getViewportPosY()+prj->getViewportHeight()/2.+1., centerV);
double lon2, lat2;
StelUtils::rectToSphe(&lon2, &lat2, centerV);
const double gridStepParallelRad = M_PI/180.*getClosestResolutionDMS(prj->getPixelPerRadAtCenter());
double gridStepMeridianRad;
if (northPoleInViewport || southPoleInViewport)
gridStepMeridianRad = (frameType==StelCore::FrameAltAz || frameType==StelCore::FrameGalactic) ? M_PI/180.* 10. : M_PI/180.* 15.;
else
{
const double closestResLon = (frameType==StelCore::FrameAltAz || frameType==StelCore::FrameGalactic) ? getClosestResolutionDMS(prj->getPixelPerRadAtCenter()*std::cos(lat2)) : getClosestResolutionHMS(prj->getPixelPerRadAtCenter()*std::cos(lat2));
gridStepMeridianRad = M_PI/180.* ((northPoleInViewport || southPoleInViewport) ? 15. : closestResLon);
}
// Get the bounding halfspace
const SphericalCap& viewPortSphericalCap = prj->getBoundingCap();
// Compute the first grid starting point. This point is close to the center of the screen
// and lies at the intersection of a meridian and a parallel
lon2 = gridStepMeridianRad*((int)(lon2/gridStepMeridianRad+0.5));
lat2 = gridStepParallelRad*((int)(lat2/gridStepParallelRad+0.5));
Vec3d firstPoint;
StelUtils::spheToRect(lon2, lat2, firstPoint);
firstPoint.normalize();
// Q_ASSERT(viewPortSphericalCap.contains(firstPoint));
// Initialize a painter and set OpenGL state
StelPainter sPainter(prj);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); // Normal transparency mode
// OpenGL ES 2.0 doesn't have GL_LINE_SMOOTH
#ifdef GL_LINE_SMOOTH
if (QOpenGLContext::currentContext()->format().renderableType()==QSurfaceFormat::OpenGL)
glEnable(GL_LINE_SMOOTH);
#endif
// make text colors just a bit brighter. (But if >1, QColor::setRgb fails and makes text invisible.)
Vec4f textColor(qMin(1.0f, 1.25f*color[0]), qMin(1.0f, 1.25f*color[1]), qMin(1.0f, 1.25f*color[2]), fader.getInterstate());
sPainter.setColor(color[0],color[1],color[2], fader.getInterstate());
sPainter.setFont(font);
ViewportEdgeIntersectCallbackData userData(&sPainter);
userData.textColor = textColor;
userData.frameType = frameType;
/////////////////////////////////////////////////
// Draw all the meridians (great circles)
SphericalCap meridianSphericalCap(Vec3d(1,0,0), 0);
Mat4d rotLon = Mat4d::zrotation(gridStepMeridianRad);
Vec3d fpt = firstPoint;
Vec3d p1, p2;
int maxNbIter = (int)(M_PI/gridStepMeridianRad);
int i;
for (i=0; i<maxNbIter; ++i)
{
StelUtils::rectToSphe(&lon2, &lat2, fpt);
userData.raAngle = lon2;
meridianSphericalCap.n = fpt^Vec3d(0,0,1);
meridianSphericalCap.n.normalize();
if (!SphericalCap::intersectionPoints(viewPortSphericalCap, meridianSphericalCap, p1, p2))
{
if (viewPortSphericalCap.d<meridianSphericalCap.d && viewPortSphericalCap.contains(meridianSphericalCap.n))
{
// The meridian is fully included in the viewport, draw it in 3 sub-arcs to avoid length > 180.
const Mat4d& rotLon120 = Mat4d::rotation(meridianSphericalCap.n, 120.*M_PI/180.);
Vec3d rotFpt=fpt;
rotFpt.transfo4d(rotLon120);
Vec3d rotFpt2=rotFpt;
rotFpt2.transfo4d(rotLon120);
sPainter.drawGreatCircleArc(fpt, rotFpt, NULL, viewportEdgeIntersectCallback, &userData);
sPainter.drawGreatCircleArc(rotFpt, rotFpt2, NULL, viewportEdgeIntersectCallback, &userData);
sPainter.drawGreatCircleArc(rotFpt2, fpt, NULL, viewportEdgeIntersectCallback, &userData);
fpt.transfo4d(rotLon);
continue;
}
else
break;
}
Vec3d middlePoint = p1+p2;
middlePoint.normalize();
if (!viewPortSphericalCap.contains(middlePoint))
middlePoint*=-1.;
// Draw the arc in 2 sub-arcs to avoid lengths > 180 deg
sPainter.drawGreatCircleArc(p1, middlePoint, NULL, viewportEdgeIntersectCallback, &userData);
sPainter.drawGreatCircleArc(p2, middlePoint, NULL, viewportEdgeIntersectCallback, &userData);
fpt.transfo4d(rotLon);
}
if (i!=maxNbIter)
{
rotLon = Mat4d::zrotation(-gridStepMeridianRad);
fpt = firstPoint;
fpt.transfo4d(rotLon);
for (int j=0; j<maxNbIter-i; ++j)
{
StelUtils::rectToSphe(&lon2, &lat2, fpt);
userData.raAngle = lon2;
meridianSphericalCap.n = fpt^Vec3d(0,0,1);
meridianSphericalCap.n.normalize();
if (!SphericalCap::intersectionPoints(viewPortSphericalCap, meridianSphericalCap, p1, p2))
break;
Vec3d middlePoint = p1+p2;
middlePoint.normalize();
if (!viewPortSphericalCap.contains(middlePoint))
middlePoint*=-1;
sPainter.drawGreatCircleArc(p1, middlePoint, NULL, viewportEdgeIntersectCallback, &userData);
sPainter.drawGreatCircleArc(p2, middlePoint, NULL, viewportEdgeIntersectCallback, &userData);
fpt.transfo4d(rotLon);
}
}
/////////////////////////////////////////////////
// Draw all the parallels (small circles)
SphericalCap parallelSphericalCap(Vec3d(0,0,1), 0);
rotLon = Mat4d::rotation(firstPoint^Vec3d(0,0,1), gridStepParallelRad);
fpt = firstPoint;
maxNbIter = (int)(M_PI/gridStepParallelRad)-1;
for (i=0; i<maxNbIter; ++i)
{
StelUtils::rectToSphe(&lon2, &lat2, fpt);
if (withDecimalDegree)
userData.text = StelUtils::radToDecDegStr(lat2);
else
userData.text = StelUtils::radToDmsStrAdapt(lat2);
parallelSphericalCap.d = fpt[2];
if (parallelSphericalCap.d>0.9999999)
break;
const Vec3d rotCenter(0,0,parallelSphericalCap.d);
if (!SphericalCap::intersectionPoints(viewPortSphericalCap, parallelSphericalCap, p1, p2))
{
if ((viewPortSphericalCap.d<parallelSphericalCap.d && viewPortSphericalCap.contains(parallelSphericalCap.n))
|| (viewPortSphericalCap.d<-parallelSphericalCap.d && viewPortSphericalCap.contains(-parallelSphericalCap.n)))
{
// The parallel is fully included in the viewport, draw it in 3 sub-arcs to avoid lengths >= 180 deg
static const Mat4d rotLon120 = Mat4d::zrotation(120.*M_PI/180.);
Vec3d rotFpt=fpt;
rotFpt.transfo4d(rotLon120);
Vec3d rotFpt2=rotFpt;
rotFpt2.transfo4d(rotLon120);
sPainter.drawSmallCircleArc(fpt, rotFpt, rotCenter, viewportEdgeIntersectCallback, &userData);
sPainter.drawSmallCircleArc(rotFpt, rotFpt2, rotCenter, viewportEdgeIntersectCallback, &userData);
sPainter.drawSmallCircleArc(rotFpt2, fpt, rotCenter, viewportEdgeIntersectCallback, &userData);
fpt.transfo4d(rotLon);
continue;
}
else
break;
}
// Draw the arc in 2 sub-arcs to avoid lengths > 180 deg
Vec3d middlePoint = p1-rotCenter+p2-rotCenter;
middlePoint.normalize();
middlePoint*=(p1-rotCenter).length();
middlePoint+=rotCenter;
if (!viewPortSphericalCap.contains(middlePoint))
{
middlePoint-=rotCenter;
middlePoint*=-1.;
middlePoint+=rotCenter;
}
sPainter.drawSmallCircleArc(p1, middlePoint, rotCenter, viewportEdgeIntersectCallback, &userData);
sPainter.drawSmallCircleArc(p2, middlePoint, rotCenter, viewportEdgeIntersectCallback, &userData);
fpt.transfo4d(rotLon);
}
if (i!=maxNbIter)
{
rotLon = Mat4d::rotation(firstPoint^Vec3d(0,0,1), -gridStepParallelRad);
fpt = firstPoint;
fpt.transfo4d(rotLon);
for (int j=0; j<maxNbIter-i; ++j)
{
StelUtils::rectToSphe(&lon2, &lat2, fpt);
if (withDecimalDegree)
userData.text = StelUtils::radToDecDegStr(lat2);
else
userData.text = StelUtils::radToDmsStrAdapt(lat2);
parallelSphericalCap.d = fpt[2];
const Vec3d rotCenter(0,0,parallelSphericalCap.d);
if (!SphericalCap::intersectionPoints(viewPortSphericalCap, parallelSphericalCap, p1, p2))
{
if ((viewPortSphericalCap.d<parallelSphericalCap.d && viewPortSphericalCap.contains(parallelSphericalCap.n))
|| (viewPortSphericalCap.d<-parallelSphericalCap.d && viewPortSphericalCap.contains(-parallelSphericalCap.n)))
{
// The parallel is fully included in the viewport, draw it in 3 sub-arcs to avoid lengths >= 180 deg
static const Mat4d rotLon120 = Mat4d::zrotation(120.*M_PI/180.);
Vec3d rotFpt=fpt;
rotFpt.transfo4d(rotLon120);
Vec3d rotFpt2=rotFpt;
rotFpt2.transfo4d(rotLon120);
sPainter.drawSmallCircleArc(fpt, rotFpt, rotCenter, viewportEdgeIntersectCallback, &userData);
sPainter.drawSmallCircleArc(rotFpt, rotFpt2, rotCenter, viewportEdgeIntersectCallback, &userData);
sPainter.drawSmallCircleArc(rotFpt2, fpt, rotCenter, viewportEdgeIntersectCallback, &userData);
fpt.transfo4d(rotLon);
continue;
}
else
break;
}
// Draw the arc in 2 sub-arcs to avoid lengths > 180 deg
Vec3d middlePoint = p1-rotCenter+p2-rotCenter;
middlePoint.normalize();
middlePoint*=(p1-rotCenter).length();
middlePoint+=rotCenter;
if (!viewPortSphericalCap.contains(middlePoint))
{
middlePoint-=rotCenter;
middlePoint*=-1.;
middlePoint+=rotCenter;
}
sPainter.drawSmallCircleArc(p1, middlePoint, rotCenter, viewportEdgeIntersectCallback, &userData);
sPainter.drawSmallCircleArc(p2, middlePoint, rotCenter, viewportEdgeIntersectCallback, &userData);
fpt.transfo4d(rotLon);
}
}
// OpenGL ES 2.0 doesn't have GL_LINE_SMOOTH
#ifdef GL_LINE_SMOOTH
if (QOpenGLContext::currentContext()->format().renderableType()==QSurfaceFormat::OpenGL)
glDisable(GL_LINE_SMOOTH);
#endif
}
