Fix a terrain intersection calculating bug. The code wasn't quite handling

traingle strips right ... it was mixing up the vertex ordering slightly.
Oh what the heck, it was really screwing up tristrips.  Everything else looks
correct though. :-)  Hurray for the red book.

diff --git a/src/Scenery/hitlist.cxx b/src/Scenery/hitlist.cxx
index 630e6685eb8a56f7fb4e4f63165e7c6e0f62eb7d..4490675e972af6acbef96f8e1e74acf645b3ebc3 100644 (file)
--- a/src/Scenery/hitlist.cxx
+++ b/src/Scenery/hitlist.cxx
@@ -243,7 +243,11 @@ int FGHitList::IntersectLeaf( ssgLeaf *leaf, sgdMat4 m,
         switch ( primType )
         {
         case GL_POLYGON :
+            SG_LOG( SG_TERRAIN, SG_ALERT,
+                    "WARNING: dubiously handled GL_POLYGON" );
         case GL_TRIANGLE_FAN :
+            /* SG_LOG( SG_TERRAIN, SG_ALERT,
+               "IntersectLeaf: GL_TRIANGLE_FAN" ); */
             if ( !n ) {
                 sgdSetVec3( tri[0], leaf->getVertex( short(0) ) );
                 sgdSetVec3( tri[1], leaf->getVertex( short(1) ) );
@@ -254,35 +258,42 @@ int FGHitList::IntersectLeaf( ssgLeaf *leaf, sgdMat4 m,
             }
             break;
         case GL_TRIANGLES :
+            /* SG_LOG( SG_TERRAIN, SG_DEBUG,
+               "IntersectLeaf: GL_TRIANGLES" ); */
             sgdSetVec3( tri[0], leaf->getVertex( short(n*3) ) );
             sgdSetVec3( tri[1], leaf->getVertex( short(n*3+1) ) );
             sgdSetVec3( tri[2], leaf->getVertex( short(n*3+2) ) );
             break;
-        case GL_TRIANGLE_STRIP :
         case GL_QUAD_STRIP :
+            SG_LOG( SG_TERRAIN, SG_ALERT,
+                    "WARNING: dubiously handled GL_QUAD_STRIP" );
+        case GL_TRIANGLE_STRIP :
+            /* SG_LOG( SG_TERRAIN, SG_ALERT,
+               "IntersectLeaf: GL_TRIANGLE_STRIP" ); */
             if ( !n ) {
                 sgdSetVec3( tri[0], leaf->getVertex( short(0) ) );
                 sgdSetVec3( tri[1], leaf->getVertex( short(1) ) );
                 sgdSetVec3( tri[2], leaf->getVertex( short(2) ) );
             } else {
                 if ( n & 1 ) {
-                    sgdSetVec3( tri[0], leaf->getVertex( short(n+2) ) );
-                    sgdCopyVec3( tri[1], tri[2] );
-                    sgdCopyVec3( tri[2], tri[1] );
-
+                    sgdCopyVec3( tri[0], tri[2] );
+                    sgdSetVec3( tri[2], leaf->getVertex( short(n+2) ) );
                 } else {
-                    sgdCopyVec3( tri[0], tri[1] );
-                    sgdCopyVec3( tri[1], tri[2] );
+                    sgdCopyVec3( tri[2], tri[1] );
                     sgdSetVec3( tri[2], leaf->getVertex( short(n+2) ) );
                 }
             }
             break;
         case GL_QUADS :
+            SG_LOG( SG_TERRAIN, SG_ALERT,
+                    "WARNING: dubiously handled GL_QUADS" );
             sgdSetVec3( tri[0], leaf->getVertex( short(n*2) ) );
             sgdSetVec3( tri[1], leaf->getVertex( short(n*2+1) ) );
             sgdSetVec3( tri[2], leaf->getVertex( short(n*2 + 2 - (n&1)*4) ) );
             break;
         default:
+            SG_LOG( SG_TERRAIN, SG_ALERT,
+                    "WARNING: not-handled structure: " << primType );
             return IntersectLeaf( leaf, m, orig, dir);
         }
 
@@ -519,14 +530,15 @@ bool fgCurrentElev( sgdVec3 abs_view_pos, sgdVec3 scenery_center,
     double result = -9999;
     Point3D sc(scenery_center[0], scenery_center[1], scenery_center[2]) ;
 
-    // cout << "hits = ";
     int hitcount = hit_list->num_hits();
+    // cout << "hits = " << hitcount << endl;
     for ( int i = 0; i < hitcount; ++i ) {
         geoc = sgCartToPolar3d( sc + hit_list->get_point(i) );
         double lat_geod, alt, sea_level_r;
         sgGeocToGeod(geoc.lat(), geoc.radius(), &lat_geod,
                      &alt, &sea_level_r);
-        // cout << alt << " ";
+        // cout << "hit " << i << " lon = " << geoc.lon() << " lat = "
+        //      << lat_geod << " alt = " << alt << endl;
         if ( alt > result && alt < 10000 ) {
             result = alt;
             this_hit = i;