semi-functioning vbap panning, still not done

git-svn-id: svn://localhost/ardour2/branches/3.0@8074 d708f5d6-7413-0410-9779-e7cbd77b26cf

1 files changed, 17 insertions, 11 deletions

diff --git a/libs/pbd/cartesian.cc b/libs/pbd/cartesian.cc
index 0a84fa6bbc..fe7bf29acf 100644
--- a/libs/pbd/cartesian.cc
+++ b/libs/pbd/cartesian.cc
@@ -17,13 +17,18 @@
 */
 
 #include <iostream>
-#include <cmath>
+#include <math.h>
 #include "pbd/cartesian.h"
 
+using namespace std;
+
 void
 PBD::azi_ele_to_cart (double azi, double ele, double& x, double& y, double& z)
 {
+        /* convert from cylindrical coordinates in degrees to cartesian */
+
         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);
@@ -32,7 +37,8 @@ PBD::azi_ele_to_cart (double azi, double ele, double& x, double& y, double& z)
 void 
 PBD::cart_to_azi_ele (double x, double y, double z, double& azimuth, double& elevation)
 {
-        /* converts cartesian coordinates to angular */
+        /* converts cartesian coordinates to cylindrical in degrees*/
+
         const double atorad = 2.0 * M_PI / 360.0;
         double atan_y_per_x, atan_x_pl_y_per_z;
         double distance;
@@ -40,13 +46,15 @@ PBD::cart_to_azi_ele (double x, double y, double z, double& azimuth, double& ele
         if(x == 0.0) {
                 atan_y_per_x = M_PI / 2;
         } else {
-                atan_y_per_x = atan (y/x);
+                atan_y_per_x = atan2 (y,x);
         }
 
-        azimuth = atan_y_per_x / atorad;
-
-        if (x < 0.0) {
-                azimuth += 180.0;
+        if (y < 0.0) {
+                /* below x-axis: atan2 returns 0 .. -PI (negative) so convert to degrees and ADD to 180 */
+                azimuth = 180.0 + (atan_y_per_x / (M_PI/180.0) + 180.0);
+        } else {
+                /* above x-axis: atan2 returns 0 .. +PI so convert to degrees */
+                azimuth = atan_y_per_x / atorad;
         }
 
         distance = sqrt (x*x + y*y);
@@ -54,21 +62,19 @@ PBD::cart_to_azi_ele (double x, double y, double z, double& azimuth, double& ele
         if (z == 0.0) {
                 atan_x_pl_y_per_z = 0.0;
         } else {
-                atan_x_pl_y_per_z = atan (z/distance);
+                atan_x_pl_y_per_z = atan2 (z,distance);
         }
 
         if (distance == 0.0) {
                 if (z < 0.0) {
                         atan_x_pl_y_per_z = -M_PI/2.0;
-                } else {
+                } else if (z > 0.0) {
                         atan_x_pl_y_per_z = M_PI/2.0;
                 }
         }
 
         elevation = atan_x_pl_y_per_z / atorad;
 
-        std::cerr << x << ", " << y << ", " << z << " = " << azimuth << " /= " << elevation << std::endl;
-
         // distance = sqrtf (x*x + y*y + z*z);
 }