[Marble-commits] KDE/kdeedu/marble/src/lib/Projections

[Bernhard Beschow]

SVN commit 1170544 by beschow:

simplify SphericalProjection::geoCoordinates(), part 1

* multiply radius, centerX, and centerY by inverseRadius => radius becomes 1 and can be omitted
* multiply centerY by -1 => its square stays the same, qy == centerY

 M  +5 -6      SphericalProjection.cpp  


--- trunk/KDE/kdeedu/marble/src/lib/Projections/SphericalProjection.cpp #1170543:1170544
@@ -197,13 +197,12 @@
     const qreal  inverseRadius = 1.0 / (qreal)(viewport->radius());
     bool          noerr         = false;
 
-    qreal radius  = (qreal)( viewport->radius() );
-    qreal centerX = (qreal)( x - viewport->width() / 2 );
-    qreal centerY = (qreal)( y - viewport->height() / 2 );
+    qreal centerX = +(qreal)( x - viewport->width()  / 2 ) * inverseRadius;
+    qreal centerY = -(qreal)( y - viewport->height() / 2 ) * inverseRadius;
 
-    if ( radius * radius > centerX * centerX + centerY * centerY ) {
-        qreal qx = inverseRadius * +centerX;
-        qreal qy = inverseRadius * -centerY;
+    if ( 1 > centerX * centerX + centerY * centerY ) {
+        qreal qx = centerX;
+        qreal qy = centerY;
         qreal qr = 1.0 - qy * qy;
 
         qreal qr2z = qr - qx * qx;