Bring lights in in stages as it get's darker.

src/Scenery/newcache.cxx

@@ -133,7 +133,7 @@ static void print_refs( ssgSelector *sel, ssgTransform *trans,
 #endif
 
 
-static ssgLeaf *gen_lights( ssgVertexArray *lights ) {
+static ssgLeaf *gen_lights( ssgVertexArray *lights, float bright ) {
     // Allocate ssg structure
     ssgNormalArray   *nl = NULL;
     ssgTexCoordArray *tl = NULL;
@@ -141,7 +141,7 @@ static ssgLeaf *gen_lights( ssgVertexArray *lights ) {
 
     // default to slightly yellow lights for now
     sgVec4 color;
-    sgSetVec4( color, 1.0, 1.0, 0.7, 1.0 );
+    sgSetVec4( color, 1.0 * bright, 1.0 * bright, 0.7 * bright, 1.0 );
     cl->add( color );
 
     // create ssg leaf
@@ -250,12 +250,25 @@ void FGNewCache::fill_in( const FGBucket& b ) {
     terrain->addKid( e->terra_transform );
 
     e->lights_transform = NULL;
+    e->lights_range = NULL;
     /* uncomment this section for testing ground lights */
-    ssgLeaf *lights = gen_lights( light_pts );
+    if ( light_pts->getNum() ) {
-    if ( lights ) {
+	cout << "generating lights" << endl;
 	e->lights_transform = new ssgTransform;
 	e->lights_range = new ssgRangeSelector;
-	e->lights_range->addKid( lights );
+	e->lights_brightness = new ssgSelector;
+	ssgLeaf *lights;
+
+	lights = gen_lights( light_pts, 0.6 );
+	e->lights_brightness->addKid( lights );
+
+	lights = gen_lights( light_pts, 0.8 );
+	e->lights_brightness->addKid( lights );
+
+	lights = gen_lights( light_pts, 1.0 );
+	e->lights_brightness->addKid( lights );
+
+	e->lights_range->addKid( e->lights_brightness );
 	e->lights_transform->addKid( e->lights_range );
 	e->lights_transform->setTransform( &sgcoord );
 	ground->addKid( e->lights_transform );

src/Scenery/tileentry.cxx

@@ -36,6 +36,7 @@
 #include <Aircraft/aircraft.hxx>
 #include <Main/globals.hxx>
 #include <Scenery/scenery.hxx>
+#include <Time/light.hxx>
 
 #include "tileentry.hxx"
 
@@ -174,8 +175,10 @@ void FGTileEntry::prep_ssg_node( const Point3D& p, float vis) {
     ranges[0] = SG_ZERO;
     ranges[1] = vis + bounding_radius;
     terra_range->setRanges( ranges, 2 );
+    if ( lights_range ) {
 	ranges[1] = vis * 1.5 + bounding_radius;
 	lights_range->setRanges( ranges, 2 );
+    }
 #endif
     sgVec3 sgTrans;
     sgSetVec3( sgTrans, offset.x(), offset.y(), offset.z() );
@@ -207,5 +210,17 @@ void FGTileEntry::prep_ssg_node( const Point3D& p, float vis) {
 	sgScaleVec3( up, 10.0 + agl / 100.0 + dist / 10000 );
 	sgAddVec3( sgTrans, up );
 	lights_transform->setTransform( sgTrans );
+
+	// select which set of lights based on sun angle
+	float sun_angle = cur_light_params.sun_angle * RAD_TO_DEG;
+	if ( sun_angle > 100 ) {
+	    lights_brightness->select(0x04);
+	} else if ( sun_angle > 95.5 ) {
+	    lights_brightness->select(0x02);
+	} else if ( sun_angle > 91 ) {
+	    lights_brightness->select(0x01);
+	} else {
+	    lights_brightness->select(0x00);
+	}
     }
 }

src/Scenery/tileentry.hxx

@@ -109,6 +109,10 @@ public:
     ssgRangeSelector *terra_range;
     ssgRangeSelector *lights_range;
 
+    // we create several preset brightness and can choose which one we
+    // want based on lighting conditions.
+    ssgSelector *lights_brightness;
+
 public:
 
     // Constructor

src/Scenery/tilemgr.cxx

@@ -130,7 +130,7 @@ void FGTileMgr::load_tile( const FGBucket& b ) {
     if ( t == NULL ) {
 	FG_LOG( FG_TERRAIN, FG_DEBUG, "Loading tile " << b );
 	global_tile_cache.fill_in( b );
-	FGTileEntry *t = global_tile_cache.get_tile( b );
+	t = global_tile_cache.get_tile( b );
 	t->prep_ssg_node( scenery.center, vis);
     } else {
 	FG_LOG( FG_TERRAIN, FG_DEBUG, "Tile already in cache " << b );