From: curt <curt>
Date: Fri, 21 Nov 2003 03:13:52 +0000 (+0000)
Subject: Fix a terrain intersection calculating bug.  The code wasn't quite handling
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=0f1c24bbed5a8aa1ca99cf039e093041e372a3eb;p=flightgear.git

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 630e6685e..4490675e9 100644
--- 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;