From 6e511de7db128d6eefca58f822a7b23deb405bfc Mon Sep 17 00:00:00 2001
From: curt <curt>
Date: Wed, 28 Apr 2004 20:37:49 +0000
Subject: [PATCH] Add support for specifying a positional offset relative to
 the listener. This allows us to "place" cockpit sounds.  For example, we can
 make left engine sound come out of the left speaker, right engine out the
 right speaker, etc.

---
 simgear/sound/sample_openal.cxx | 15 ++++++++++-----
 simgear/sound/sample_openal.hxx | 27 ++++++++++++++++++++++++++-
 simgear/sound/xmlsound.cxx      | 13 +++++++++++++
 3 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/simgear/sound/sample_openal.cxx b/simgear/sound/sample_openal.cxx
index d2242d3c..77f0737a 100644
--- a/simgear/sound/sample_openal.cxx
+++ b/simgear/sound/sample_openal.cxx
@@ -80,9 +80,8 @@ SGSoundSample::SGSoundSample( const char *path, const char *file,
     SG_LOG( SG_GENERAL, SG_DEBUG, "From file sounds sample = "
             << samplepath.str() );
 
-    ALuint error;
-
-    source_pos[0] = 0.0; source_pos[1] = 0.0; source_pos[2] = 0.0;
+   source_pos[0] = 0.0; source_pos[1] = 0.0; source_pos[2] = 0.0;
+    offset_pos[0] = 0.0; offset_pos[1] = 0.0; offset_pos[2] = 0.0;
     source_vel[0] = 0.0; source_vel[1] = 0.0; source_vel[2] = 0.0;
 
     // clear errors from elsewhere?
@@ -90,7 +89,7 @@ SGSoundSample::SGSoundSample( const char *path, const char *file,
 
     // create an OpenAL buffer handle
     alGenBuffers(1, &buffer);
-    error = alGetError();
+    ALuint error = alGetError();
     if ( error != AL_NO_ERROR ) {
         print_openal_error( error );
         throw sg_exception("Failed to gen OpenAL buffer.");
@@ -152,11 +151,17 @@ SGSoundSample::SGSoundSample( unsigned char *_data, int len, int _freq ) :
     sample_name = "unknown, generated from data";
 
     source_pos[0] = 0.0; source_pos[1] = 0.0; source_pos[2] = 0.0;
+    offset_pos[0] = 0.0; offset_pos[1] = 0.0; offset_pos[2] = 0.0;
     source_vel[0] = 0.0; source_vel[1] = 0.0; source_vel[2] = 0.0;
 
+    // clear errors from elsewhere?
+    alGetError();
+
     // Load wav data into a buffer.
     alGenBuffers(1, &buffer);
-    if (alGetError() != AL_NO_ERROR) {
+    ALuint error = alGetError();
+    if ( error != AL_NO_ERROR ) {
+        print_openal_error( error );
         throw sg_exception("Failed to gen buffer." );
         return;
     }
diff --git a/simgear/sound/sample_openal.hxx b/simgear/sound/sample_openal.hxx
index e0488979..a7bfe03f 100644
--- a/simgear/sound/sample_openal.hxx
+++ b/simgear/sound/sample_openal.hxx
@@ -46,6 +46,8 @@
 # include <AL/alut.h>
 #endif
 
+#include <plib/sg.h>
+
 #include <simgear/debug/logstream.hxx>
 
 SG_USING_STD(string);
@@ -70,6 +72,9 @@ private:
     // Position of the source sound.
     ALfloat source_pos[3];
 
+    // A constant offset to be applied to the final source_pos
+    ALfloat offset_pos[3];
+
     // Velocity of the source sound.
     ALfloat source_vel[3];
 
@@ -85,6 +90,7 @@ private:
     double max_dist;
     ALboolean loop;
 
+
 public:
 
     /**
@@ -199,7 +205,26 @@ public:
         source_pos[0] = pos[0];
         source_pos[1] = pos[1];
         source_pos[2] = pos[2];
-        alSourcefv( source, AL_POSITION, source_pos );
+
+        sgVec3 final_pos;
+        sgAddVec3( final_pos, source_pos, offset_pos );
+
+        alSourcefv( source, AL_POSITION, final_pos );
+    }
+
+    /**
+     * Set "constant" offset position of sound source (uses same
+     * coordinate system as opengl)
+     */
+    inline void set_offset_pos( ALfloat *pos ) {
+        offset_pos[0] = pos[0];
+        offset_pos[1] = pos[1];
+        offset_pos[2] = pos[2];
+
+        sgVec3 final_pos;
+        sgAddVec3( final_pos, source_pos, offset_pos );
+
+        alSourcefv( source, AL_POSITION, final_pos );
     }
 
     /**
diff --git a/simgear/sound/xmlsound.cxx b/simgear/sound/xmlsound.cxx
index 3899be7c..58be2356 100644
--- a/simgear/sound/xmlsound.cxx
+++ b/simgear/sound/xmlsound.cxx
@@ -235,6 +235,18 @@ SGXmlSound::init(SGPropertyNode *root, SGPropertyNode *node, SGSoundMgr *sndmgr,
       p += pitch.offset;
    }
 
+   //
+   // Relative position
+   //
+   sgVec3 offset_pos;
+   sgSetVec3( offset_pos, 0.0, 0.0, 0.0 );
+   SGPropertyNode_ptr pos = node->getChild("position");
+   if ( pos != NULL ) {
+       offset_pos[0] = pos->getDoubleValue("x", 0.0);
+       offset_pos[1] = pos->getDoubleValue("y", 0.0);
+       offset_pos[2] = pos->getDoubleValue("z", 0.0);
+   }
+
    //
    // Initialize the sample
    //
@@ -247,6 +259,7 @@ SGXmlSound::init(SGPropertyNode *root, SGPropertyNode *node, SGSoundMgr *sndmgr,
        _mgr->add( _sample, _name );
    }
 
+   _sample->set_offset_pos( offset_pos );
    _sample->set_volume(v);
    _sample->set_reference_dist( reference_dist );
    _sample->set_max_dist( max_dist );
-- 
2.39.5