merge projection fixes

7 files changed, 36 insertions, 12 deletions

diff --git a/NEWS b/NEWS
index f38cf52..f238bff 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,11 @@
 gipfel ChangeLog
 =================
 
+gipfel-0.2.3
+ - Fix a major shortcoming in the rectilinear projection
+   code. This improves accuracy quite a bit, mostly in
+   wideangle images.
+
 gipfel-0.2.2
  - Fix a segfault if exif tool is not installed.
  - Some optimizations.
diff --git a/configure.ac b/configure.ac
index 02c0479..b5b9208 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2,7 +2,7 @@
 # Process this file with autoconf to produce a configure script.
 
 AC_PREREQ(2.59)
-AC_INIT(gipfel, 0.2.2, Johannes.Hofmann@gmx.de)
+AC_INIT(gipfel, 0.2.3, Johannes.Hofmann@gmx.de)
 AM_INIT_AUTOMAKE
 AC_CONFIG_SRCDIR([src/Panorama.H])
 AC_CONFIG_HEADER(config.h)
diff --git a/src/GipfelWidget.cxx b/src/GipfelWidget.cxx
index 63e89d2..881eb27 100644
--- a/src/GipfelWidget.cxx
+++ b/src/GipfelWidget.cxx
@@ -677,6 +677,7 @@ GipfelWidget::handle(int event) {
 			break;
 		case FL_DRAG:
 			set_mountain(Fl::event_x()-x(), Fl::event_y()-y());
+			comp_params();
 			return 1;
 			break;
 		case FL_RELEASE:
diff --git a/src/Panorama.cxx b/src/Panorama.cxx
index 06754ae..5f59103 100644
--- a/src/Panorama.cxx
+++ b/src/Panorama.cxx
@@ -413,8 +413,11 @@ Panorama::update_coordinates() {
 
 double 
 Panorama::distance(double phi, double lam) {
-	return acos(sin(view_phi) * sin(phi) + 
-		cos(view_phi) * cos(phi) * cos(view_lam - lam));
+	double d_lam = view_lam - lam;
+
+	return atan2(sqrt(pow(cos(phi) * sin(d_lam), 2.0) +
+				pow(cos(view_phi) * sin(phi) - sin(view_phi) * cos(phi) * cos(d_lam), 2.0)),
+		sin(view_phi) * sin(phi) + cos(view_phi) * cos(phi) * cos(d_lam));
 }
 
 double 
@@ -438,7 +441,6 @@ Panorama::refraction(const Hill *m) {
 
 	return c * get_real_distance(m) / (2000.0 * (1.0 + a));
 }
-
 double
 Panorama::nick(const Hill *m) {
 	double b, c, theta = refraction(m);
diff --git a/src/ProjectionLSQ.H b/src/ProjectionLSQ.H
index 44cc91d..d937114 100644
--- a/src/ProjectionLSQ.H
+++ b/src/ProjectionLSQ.H
@@ -17,6 +17,7 @@ class ProjectionLSQ {
 		int lsq(const Hills *m, ViewParams *parms, int distortion_correct);
 
 	protected:
+		static double pi;
 		double sec(double a);
 
 	public:
diff --git a/src/ProjectionLSQ.cxx b/src/ProjectionLSQ.cxx
index cdf9f04..461f36e 100644
--- a/src/ProjectionLSQ.cxx
+++ b/src/ProjectionLSQ.cxx
@@ -17,7 +17,7 @@
 
 #include "ProjectionLSQ.H"
 
-static double pi_d = asin(1.0) * 2.0;
+double ProjectionLSQ::pi = asin(1.0) * 2.0;
 
 ProjectionLSQ::ProjectionLSQ() {
 }
@@ -238,10 +238,10 @@ ProjectionLSQ::get_coordinates(double alph, double a_nick,
 	const ViewParams *parms, double *x, double *y) {
 
 	// Normalize alph - parms->a_center to [-pi/2, pi/2]
-	if (alph - parms->a_center > pi_d) {
-		alph -= 2.0 * pi_d;
-	} else if (alph - parms->a_center < -pi_d) {
-		alph += 2.0 * pi_d;
+	if (alph - parms->a_center > pi) {
+		alph -= 2.0 * pi;
+	} else if (alph - parms->a_center < -pi) {
+		alph += 2.0 * pi;
 	}
 
 	*x = mac_x(parms->a_center, parms->a_nick, parms->a_tilt, parms->scale,
diff --git a/src/lsq_rectilinear.mac b/src/lsq_rectilinear.mac
index 5bd7ac9..377c24a 100644
--- a/src/lsq_rectilinear.mac
+++ b/src/lsq_rectilinear.mac
@@ -2,10 +2,25 @@
  * rectilinear (pinhole) projection model with distortion correction
  */
 
-x : tan(m_view - c_view)$
-y : tan(c_nick - m_nick)$ 
-x_rot : y * sin(c_tilt) + x * cos(c_tilt)+x0$
+/* switch to cartesian coordinates */
+c_x : cos(m_nick) * cos(m_view - c_view)$
+c_y : cos(m_nick) * sin(m_view - c_view)$
+c_z : sin(m_nick)$
+
+/* nick rotation */
+c_x_rot : cos(c_nick) * c_x + sin(c_nick) * c_z$
+c_y_rot : c_y$
+c_z_rot : -sin(c_nick) * c_x + cos(c_nick) * c_z$
+
+/* pinhole projection */
+x : c_y_rot / c_x_rot$
+y : -c_z_rot / c_x_rot$ 
+
+/* rotation around view axis */
+x_rot : y * sin(c_tilt) + x * cos(c_tilt) + x0$
 y_rot : y * cos(c_tilt) - x * sin(c_tilt)$
+
+/* distortion correction */
 d : x_rot ^ 2 + y_rot ^ 2$
 dist_fact : d ^ 2 * k1 + d * k0$
 x_dist : x_rot * (1 + dist_fact) * scale$