steps toward a working VBAP panner

[ardour.git] / libs / pbd / cartesian.cc

diff --git a/libs/pbd/cartesian.cc b/libs/pbd/cartesian.cc
new file mode 100644 (file)
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+++ b/libs/pbd/cartesian.cc
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+/*
+    Copyright (C) 2010 Paul Davis
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <cmath>
+#include "pbd/cartesian.h"
+
+void
+PBD::azi_ele_to_cart (double azi, double ele, double& x, double& y, double& z)
+{
+        static const double atorad = 2.0 * M_PI / 360.0 ;
+        x = cos (azi * atorad) * cos (ele * atorad);
+        y = sin (azi * atorad) * cos (ele * atorad);
+        z = sin (ele * atorad);
+}
+
+void 
+PBD::cart_to_azi_ele (double x, double y, double z, double& azimuth, double& elevation)
+{
+        /* converts cartesian coordinates to angular */
+        const double atorad = 2.0 * M_PI / 360.0;
+        double atan_y_per_x, atan_x_pl_y_per_z;
+        double distance;
+
+        if(x == 0.0) {
+                atan_y_per_x = M_PI / 2;
+        } else {
+                atan_y_per_x = atan(y / x);
+        }
+
+        azimuth = atan_y_per_x / atorad;
+
+        if (x < 0.0) {
+                azimuth +=180.0;
+        }
+
+        distance = sqrt (x*x + y*y);
+
+        if (z == 0.0) {
+                atan_x_pl_y_per_z = 0.0;
+        } else {
+                atan_x_pl_y_per_z = atan (z/distance);
+        }
+
+        if (distance == 0.0) {
+                if (z < 0.0) {
+                        atan_x_pl_y_per_z = -M_PI/2.0;
+                } else {
+                        atan_x_pl_y_per_z = M_PI/2.0;
+                }
+        }
+
+        elevation = atan_x_pl_y_per_z / atorad;
+
+        // distance = sqrtf (x*x + y*y + z*z);
+}
+