flightgear/src/Main/renderer.cxx

// renderer.cxx -- top level sim routines
//
// Written by Curtis Olson, started May 1997.
// This file contains parts of main.cxx prior to october 2004
//
// Copyright (C) 1997 - 2002  Curtis L. Olson  - curt@flightgear.org
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$


#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif

#include <simgear/compiler.h>

#ifdef HAVE_WINDOWS_H
#  include <windows.h>
#endif

#include <plib/ssg.h>
#include <plib/netSocket.h>

#include <simgear/screen/extensions.hxx>
#include <simgear/scene/material/matlib.hxx>
#include <simgear/props/props.hxx>
#include <simgear/timing/sg_time.hxx>
#include <simgear/scene/model/animation.hxx>
#include <simgear/ephemeris/ephemeris.hxx>
#include <simgear/scene/model/placement.hxx>
#include <simgear/math/sg_random.h>
#include <simgear/scene/model/modellib.hxx>
#include <simgear/scene/model/model.hxx>

#ifdef FG_USE_CLOUDS_3D
#  include <simgear/scene/sky/clouds3d/SkySceneLoader.hpp>
#  include <simgear/scene/sky/clouds3d/SkyUtil.hpp>
#endif

#include <Scenery/tileentry.hxx>
#include <Time/light.hxx>
#include <Time/light.hxx>
#include <Aircraft/aircraft.hxx>
#include <Cockpit/panel.hxx>
#include <Cockpit/cockpit.hxx>
#include <Cockpit/radiostack.hxx>
#include <Cockpit/hud.hxx>
#include <Model/panelnode.hxx>
#include <Model/modelmgr.hxx>
#include <Model/acmodel.hxx>
#include <Scenery/scenery.hxx>
#include <Scenery/tilemgr.hxx>
#include <ATC/ATCdisplay.hxx>
#include <Replay/replay.hxx>
#include <GUI/new_gui.hxx>

#include "splash.hxx"
#include "renderer.hxx"
#include "main.hxx"


float default_attenuation[3] = {1.0, 0.0, 0.0};

ssgSelector *lightpoints_brightness = new ssgSelector;
ssgTransform *lightpoints_transform = new ssgTransform;
FGTileEntry *dummy_tile;
sgVec3 rway_ols;

// Clip plane settings...
float scene_nearplane = 0.5f;
float scene_farplane = 120000.0f;

glPointParameterfProc glPointParameterfPtr = 0;
glPointParameterfvProc glPointParameterfvPtr = 0;
bool glPointParameterIsSupported = false;


// fog constants.  I'm a little nervous about putting actual code out
// here but it seems to work (?)
static const double m_log01 = -log( 0.01 );
static const double sqrt_m_log01 = sqrt( m_log01 );
static GLfloat fog_exp_density;
static GLfloat fog_exp2_density;
static GLfloat rwy_exp2_punch_through;
static GLfloat taxi_exp2_punch_through;
static GLfloat ground_exp2_punch_through;

// Sky structures
SGSky *thesky;

#ifdef FG_USE_CLOUDS_3D
  SkySceneLoader *sgClouds3d;
  bool _bcloud_orig = true;
#endif

// hack
sgMat4 copy_of_ssgOpenGLAxisSwapMatrix =
{
  {  1.0f,  0.0f,  0.0f,  0.0f },
  {  0.0f,  0.0f, -1.0f,  0.0f },
  {  0.0f,  1.0f,  0.0f,  0.0f },
  {  0.0f,  0.0f,  0.0f,  1.0f }
};

ssgSimpleState *cloud3d_imposter_state;
ssgSimpleState *default_state;
ssgSimpleState *hud_and_panel;
ssgSimpleState *menus;


void
FGRenderer::build_states( void ) {
    default_state = new ssgSimpleState;
    default_state->ref();
    default_state->disable( GL_TEXTURE_2D );
    default_state->enable( GL_CULL_FACE );
    default_state->enable( GL_COLOR_MATERIAL );
    default_state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
    default_state->setMaterial( GL_EMISSION, 0, 0, 0, 1 );
    default_state->setMaterial( GL_SPECULAR, 0, 0, 0, 1 );
    default_state->disable( GL_BLEND );
    default_state->disable( GL_ALPHA_TEST );
    default_state->disable( GL_LIGHTING );

    cloud3d_imposter_state = new ssgSimpleState;
    cloud3d_imposter_state->ref();
    cloud3d_imposter_state->enable( GL_TEXTURE_2D );
    cloud3d_imposter_state->enable( GL_CULL_FACE );
    cloud3d_imposter_state->enable( GL_COLOR_MATERIAL );
    cloud3d_imposter_state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
    cloud3d_imposter_state->setMaterial( GL_DIFFUSE, 1, 1, 1, 1 );
    cloud3d_imposter_state->setMaterial( GL_AMBIENT, 1, 1, 1, 1 );
    cloud3d_imposter_state->setMaterial( GL_EMISSION, 0, 0, 0, 1 );
    cloud3d_imposter_state->setMaterial( GL_SPECULAR, 0, 0, 0, 1 );
    cloud3d_imposter_state->enable( GL_BLEND );
    cloud3d_imposter_state->enable( GL_ALPHA_TEST );
    cloud3d_imposter_state->disable( GL_LIGHTING );

    hud_and_panel = new ssgSimpleState;
    hud_and_panel->ref();
    hud_and_panel->disable( GL_CULL_FACE );
    hud_and_panel->disable( GL_TEXTURE_2D );
    hud_and_panel->disable( GL_LIGHTING );
    hud_and_panel->enable( GL_BLEND );

    menus = new ssgSimpleState;
    menus->ref();
    menus->disable( GL_CULL_FACE );
    menus->disable( GL_TEXTURE_2D );
    menus->enable( GL_BLEND );
}


// Initialize various GL/view parameters
void
FGRenderer::init( void ) {

    FGLight *l = (FGLight *)(globals->get_subsystem("lighting"));

    // Go full screen if requested ...
    if ( fgGetBool("/sim/startup/fullscreen") ) {
        fgOSFullScreen();
    }

    // If enabled, normal vectors specified with glNormal are scaled
    // to unit length after transformation.  Enabling this has
    // performance implications.  See the docs for glNormal.
    // glEnable( GL_NORMALIZE );

    glEnable( GL_LIGHTING );
    glEnable( GL_LIGHT0 );
    // glLightfv( GL_LIGHT0, GL_POSITION, l->sun_vec );  // done later with ssg

    sgVec3 sunpos;
    sgSetVec3( sunpos, l->sun_vec()[0], l->sun_vec()[1], l->sun_vec()[2] );
    ssgGetLight( 0 ) -> setPosition( sunpos );

    glFogi (GL_FOG_MODE, GL_EXP2);
    if ( (!strcmp(fgGetString("/sim/rendering/fog"), "disabled")) || 
         (!fgGetBool("/sim/rendering/shading"))) {
        // if fastest fog requested, or if flat shading force fastest
        glHint ( GL_FOG_HINT, GL_FASTEST );
    } else if ( !strcmp(fgGetString("/sim/rendering/fog"), "nicest") ) {
        glHint ( GL_FOG_HINT, GL_NICEST );
    }
    if ( fgGetBool("/sim/rendering/wireframe") ) {
        // draw wire frame
        glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
    }

    // This is the default anyways, but it can't hurt
    glFrontFace ( GL_CCW );

    // Just testing ...
    // glEnable(GL_POINT_SMOOTH);
    // glEnable(GL_LINE_SMOOTH);
    // glEnable(GL_POLYGON_SMOOTH);      
}


// For HiRes screen Dumps using Brian Pauls TR Library
void
FGRenderer::screendump( void ) {
#ifdef FG_ENABLE_MULTIPASS_CLOUDS
    bool multi_pass_clouds = fgGetBool("/sim/rendering/multi-pass-clouds") &&
                            !SGCloudLayer::enable_bump_mapping; // ugly artefact now
#else
    bool multi_pass_clouds = false;
#endif
    bool draw_clouds = fgGetBool("/environment/clouds/status");

    if ( fgPanelVisible() ) {
        GLfloat height = fgGetInt("/sim/startup/ysize");
        GLfloat view_h =
            (globals->get_current_panel()->getViewHeight() - globals->get_current_panel()->getYOffset())
            * (height / 768.0) + 1;
        glTranslatef( 0.0, view_h, 0.0 );
    }

    static GLfloat black[4] = { 0.0, 0.0, 0.0, 1.0 };
    static GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };

    FGLight *l = (FGLight *)(globals->get_subsystem("lighting"));

    glClearColor(l->adj_fog_color()[0], l->adj_fog_color()[1], 
                 l->adj_fog_color()[2], l->adj_fog_color()[3]);

    glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );

    // set the opengl state to known default values
    default_state->force();

    glEnable( GL_FOG );
    glFogf  ( GL_FOG_DENSITY, fog_exp2_density);
    glFogi  ( GL_FOG_MODE,    GL_EXP2 );
    glFogfv ( GL_FOG_COLOR,   l->adj_fog_color() );

    // GL_LIGHT_MODEL_AMBIENT has a default non-zero value so if
    // we only update GL_AMBIENT for our lights we will never get
    // a completely dark scene.  So, we set GL_LIGHT_MODEL_AMBIENT
    // explicitely to black.
    glLightModelfv( GL_LIGHT_MODEL_AMBIENT, black );
    glLightModeli( GL_LIGHT_MODEL_LOCAL_VIEWER, GL_FALSE );

    ssgGetLight( 0 ) -> setColour( GL_AMBIENT, l->scene_ambient() );

    // texture parameters
    glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE ) ;
    glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST ) ;

    // we need a white diffuse light for the phase of the moon
    ssgGetLight( 0 ) -> setColour( GL_DIFFUSE, white );
    thesky->preDraw( cur_fdm_state->get_Altitude() * SG_FEET_TO_METER,
                     fog_exp2_density );

    // draw the ssg scene
    // return to the desired diffuse color
    ssgGetLight( 0 ) -> setColour( GL_DIFFUSE, l->scene_diffuse() );
    glEnable( GL_DEPTH_TEST );
    ssgSetNearFar( scene_nearplane, scene_farplane );
    if ( draw_clouds ) {
        // Draw the terrain
        FGTileMgr::set_tile_filter( true );
        sgSetModelFilter( false );
        globals->get_aircraft_model()->select( false );
        ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
        // Disable depth buffer update, draw the clouds
        glDepthMask( GL_FALSE );
        thesky->drawUpperClouds();
        if ( multi_pass_clouds ) {
            thesky->drawLowerClouds();
        }
        glDepthMask( GL_TRUE );
        if ( multi_pass_clouds ) {
            // Draw the objects except the aircraft
            //  and update the stencil buffer with 1
            glEnable( GL_STENCIL_TEST );
            glStencilFunc( GL_ALWAYS, 1, 1 );
            glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
        }
        FGTileMgr::set_tile_filter( false );
        sgSetModelFilter( true );
        ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
    } else {
        FGTileMgr::set_tile_filter( true );
        sgSetModelFilter( true );
        globals->get_aircraft_model()->select( false );
        ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
    }

    // draw the lights
    glFogf (GL_FOG_DENSITY, rwy_exp2_punch_through);
    ssgSetNearFar( scene_nearplane, scene_farplane );
    ssgCullAndDraw( globals->get_scenery()->get_vasi_lights_root() );
    ssgCullAndDraw( globals->get_scenery()->get_rwy_lights_root() );

    ssgCullAndDraw( globals->get_scenery()->get_gnd_lights_root() );

    if ( draw_clouds ) {
        if ( multi_pass_clouds ) {
            // Disable depth buffer update, draw the clouds where the
            //  objects overwrite the already drawn clouds, by testing
            //  the stencil buffer against 1
            glDepthMask( GL_FALSE );
            glStencilFunc( GL_EQUAL, 1, 1 );
            glStencilOp( GL_KEEP, GL_KEEP, GL_KEEP );
            thesky->drawUpperClouds();
            thesky->drawLowerClouds();
            glDepthMask( GL_TRUE );
            glDisable( GL_STENCIL_TEST );
        } else {
            glDepthMask( GL_FALSE );
            thesky->drawLowerClouds();
            glDepthMask( GL_TRUE );
        }
    }

    globals->get_aircraft_model()->select( true );
    globals->get_model_mgr()->draw();
    globals->get_aircraft_model()->draw();
}


// Update all Visuals (redraws anything graphics related)
void
FGRenderer::update() {
    bool scenery_loaded = fgGetBool("sim/sceneryloaded") || fgGetBool("sim/sceneryloaded-override");
    bool draw_otw = fgGetBool("/sim/rendering/draw-otw");
    bool skyblend = fgGetBool("/sim/rendering/skyblend");
    bool enhanced_lighting = fgGetBool("/sim/rendering/enhanced-lighting");
    bool distance_attenuation = fgGetBool("/sim/rendering/distance-attenuation");
#ifdef FG_ENABLE_MULTIPASS_CLOUDS
    bool multi_pass_clouds = fgGetBool("/sim/rendering/multi-pass-clouds") && 
                                !SGCloudLayer::enable_bump_mapping;  // ugly artefact now
#else
    bool multi_pass_clouds = false;
#endif
    bool draw_clouds = fgGetBool("/environment/clouds/status");

    GLfloat black[4] = { 0.0, 0.0, 0.0, 1.0 };
    GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };

    // static const SGPropertyNode *longitude
    //     = fgGetNode("/position/longitude-deg");
    // static const SGPropertyNode *latitude
    //     = fgGetNode("/position/latitude-deg");
    // static const SGPropertyNode *altitude
    //     = fgGetNode("/position/altitude-ft");
    static const SGPropertyNode *groundlevel_nearplane
        = fgGetNode("/sim/current-view/ground-level-nearplane-m");

    FGLight *l = (FGLight *)(globals->get_subsystem("lighting"));
    static double last_visibility = -9999;

    // update fog params
    double actual_visibility;
    if (fgGetBool("/environment/clouds/status"))
        actual_visibility = thesky->get_visibility();
    else
        actual_visibility = fgGetDouble("/environment/visibility-m");
    if ( actual_visibility != last_visibility ) {
        last_visibility = actual_visibility;

        fog_exp_density = m_log01 / actual_visibility;
        fog_exp2_density = sqrt_m_log01 / actual_visibility;
        ground_exp2_punch_through = sqrt_m_log01 / (actual_visibility * 1.5);
        if ( actual_visibility < 8000 ) {
            rwy_exp2_punch_through = sqrt_m_log01 / (actual_visibility * 2.5);
            taxi_exp2_punch_through = sqrt_m_log01 / (actual_visibility * 1.5);
        } else {
            rwy_exp2_punch_through = sqrt_m_log01 / ( 8000 * 2.5 );
            taxi_exp2_punch_through = sqrt_m_log01 / ( 8000 * 1.5 );
        }
    }

    // double angle;
    // GLfloat black[4] = { 0.0, 0.0, 0.0, 1.0 };
    // GLfloat white[4] = { 1.0, 1.0, 1.0, 1.0 };
    // GLfloat terrain_color[4] = { 0.54, 0.44, 0.29, 1.0 };
    // GLfloat mat_shininess[] = { 10.0 };
    GLbitfield clear_mask;

    if ( idle_state != 1000 || !scenery_loaded ) {
        // still initializing, draw the splash screen
        if ( fgGetBool("/sim/startup/splash-screen") ) {
            fgSplashUpdate(0.0, 1.0);
        }
        // Keep resetting sim time while the sim is initializing
        globals->set_sim_time_sec( 0.0 );
        SGAnimation::set_sim_time_sec( 0.0 );
    } else {
        // idle_state is now 1000 meaning we've finished all our
        // initializations and are running the main loop, so this will
        // now work without seg faulting the system.

        FGViewer *current__view = globals->get_current_view();

        // calculate our current position in cartesian space
        globals->get_scenery()->set_center( globals->get_scenery()->get_next_center() );

        // update view port
        resize( fgGetInt("/sim/startup/xsize"),
                   fgGetInt("/sim/startup/ysize") );

        if ( fgGetBool("/sim/rendering/clouds3d") ) {
            glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT );
            cloud3d_imposter_state->force();
            glDisable( GL_FOG );
            glColor4f( 1.0, 1.0, 1.0, 1.0 );
            glEnable(GL_DEPTH_TEST);
            glEnable(GL_BLEND);
            glBlendFunc( GL_ONE, GL_ONE_MINUS_SRC_ALPHA ) ;

#ifdef FG_USE_CLOUDS_3D
            if ( _bcloud_orig ) {
                Point3D c = globals->get_scenery()->get_center();
                sgClouds3d->Set_Cloud_Orig( &c );
                _bcloud_orig = false;
            }
            sgClouds3d->Update( current__view->get_absolute_view_pos() );
#endif
            glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
            glDisable(GL_DEPTH_TEST);
        }

        clear_mask = GL_DEPTH_BUFFER_BIT;
        if ( fgGetBool("/sim/rendering/wireframe") ) {
            clear_mask |= GL_COLOR_BUFFER_BIT;
        }

        if ( skyblend ) {
            if ( fgGetBool("/sim/rendering/textures") ) {
            // glClearColor(black[0], black[1], black[2], black[3]);
            glClearColor(l->adj_fog_color()[0], l->adj_fog_color()[1],
                         l->adj_fog_color()[2], l->adj_fog_color()[3]);
            clear_mask |= GL_COLOR_BUFFER_BIT;
            }
        } else {
            glClearColor(l->sky_color()[0], l->sky_color()[1],
                         l->sky_color()[2], l->sky_color()[3]);
            clear_mask |= GL_COLOR_BUFFER_BIT;
        }
        if ( multi_pass_clouds && draw_clouds ) {
            glClearStencil( 0 );
            clear_mask |= GL_STENCIL_BUFFER_BIT;
        }
        glClear( clear_mask );

        // Tell GL we are switching to model view parameters

        // I really should create a derived ssg node or use a call
        // back or something so that I can draw the sky within the
        // ssgCullAndDraw() function, but for now I just mimic what
        // ssg does to set up the model view matrix
        glMatrixMode(GL_MODELVIEW);
        glLoadIdentity();
        ssgSetCamera( (sgVec4 *)current__view->get_VIEW() );

        // set the opengl state to known default values
        default_state->force();

        // update fog params if visibility has changed
        double visibility_meters = fgGetDouble("/environment/visibility-m");
        thesky->set_visibility(visibility_meters);

        thesky->modify_vis( cur_fdm_state->get_Altitude() * SG_FEET_TO_METER,
                            ( global_multi_loop * fgGetInt("/sim/speed-up") )
                            / (double)fgGetInt("/sim/model-hz") );

        // Set correct opengl fog density
        glFogf (GL_FOG_DENSITY, fog_exp2_density);

        // update the sky dome
        if ( skyblend ) {
            /*
             SG_LOG( SG_GENERAL, SG_BULK, "thesky->repaint() sky_color = "
             << l->sky_color()[0] << " "
             << l->sky_color()[1] << " "
             << l->sky_color()[2] << " "
             << l->sky_color()[3] );
            SG_LOG( SG_GENERAL, SG_BULK, "    fog = "
             << l->fog_color()[0] << " "
             << l->fog_color()[1] << " "
             << l->fog_color()[2] << " "
             << l->fog_color()[3] ); 
            SG_LOG( SG_GENERAL, SG_BULK,
                    "    sun_angle = " << l->sun_angle
             << "    moon_angle = " << l->moon_angle );
            */

            static SGSkyColor scolor;
            FGLight *l = (FGLight *)(globals->get_subsystem("lighting"));

            scolor.sky_color   = l->sky_color();
            scolor.fog_color   = l->adj_fog_color();
            scolor.cloud_color = l->cloud_color();
            scolor.sun_angle   = l->get_sun_angle();
            scolor.moon_angle  = l->get_moon_angle();
            scolor.nplanets    = globals->get_ephem()->getNumPlanets();
            scolor.nstars      = globals->get_ephem()->getNumStars();
            scolor.planet_data = globals->get_ephem()->getPlanets();
            scolor.star_data   = globals->get_ephem()->getStars();

            thesky->repaint( scolor );

            /*
            SG_LOG( SG_GENERAL, SG_BULK,
                    "thesky->reposition( view_pos = " << view_pos[0] << " "
             << view_pos[1] << " " << view_pos[2] );
            SG_LOG( SG_GENERAL, SG_BULK,
                    "    zero_elev = " << zero_elev[0] << " "
             << zero_elev[1] << " " << zero_elev[2]
             << " lon = " << cur_fdm_state->get_Longitude()
             << " lat = " << cur_fdm_state->get_Latitude() );
            SG_LOG( SG_GENERAL, SG_BULK,
                    "    sun_rot = " << l->get_sun_rotation
             << " gst = " << SGTime::cur_time_params->getGst() );
            SG_LOG( SG_GENERAL, SG_BULK,
                 "    sun ra = " << globals->get_ephem()->getSunRightAscension()
              << " sun dec = " << globals->get_ephem()->getSunDeclination()
              << " moon ra = " << globals->get_ephem()->getMoonRightAscension()
              << " moon dec = " << globals->get_ephem()->getMoonDeclination() );
            */

            // The sun and moon distances are scaled down versions
            // of the actual distance to get both the moon and the sun
            // within the range of the far clip plane.
            // Moon distance:    384,467 kilometers
            // Sun distance: 150,000,000 kilometers
            double sun_horiz_eff, moon_horiz_eff;
            if (fgGetBool("/sim/rendering/horizon-effect")) {
            sun_horiz_eff = 0.67+pow(0.5+cos(l->get_sun_angle())*2/2, 0.33)/3;
            moon_horiz_eff = 0.67+pow(0.5+cos(l->get_moon_angle())*2/2, 0.33)/3;
            } else {
               sun_horiz_eff = moon_horiz_eff = 1.0;
            }

            static SGSkyState sstate;

            sstate.view_pos  = current__view->get_view_pos();
            sstate.zero_elev = current__view->get_zero_elev();
            sstate.view_up   = current__view->get_world_up();
            sstate.lon       = current__view->getLongitude_deg()
                                * SGD_DEGREES_TO_RADIANS;
            sstate.lat       = current__view->getLatitude_deg()
                                * SGD_DEGREES_TO_RADIANS;
            sstate.alt       = current__view->getAltitudeASL_ft()
                                * SG_FEET_TO_METER;
            sstate.spin      = l->get_sun_rotation();
            sstate.gst       = globals->get_time_params()->getGst();
            sstate.sun_ra    = globals->get_ephem()->getSunRightAscension();
            sstate.sun_dec   = globals->get_ephem()->getSunDeclination();
            sstate.sun_dist  = 50000.0 * sun_horiz_eff;
            sstate.moon_ra   = globals->get_ephem()->getMoonRightAscension();
            sstate.moon_dec  = globals->get_ephem()->getMoonDeclination();
            sstate.moon_dist = 40000.0 * moon_horiz_eff;

            thesky->reposition( sstate, delta_time_sec );
        }

        glEnable( GL_DEPTH_TEST );
        if ( strcmp(fgGetString("/sim/rendering/fog"), "disabled") ) {
            glEnable( GL_FOG );
            glFogi( GL_FOG_MODE, GL_EXP2 );
            glFogfv( GL_FOG_COLOR, l->adj_fog_color() );
        }

        // set sun/lighting parameters
        ssgGetLight( 0 ) -> setPosition( l->sun_vec() );

        // GL_LIGHT_MODEL_AMBIENT has a default non-zero value so if
        // we only update GL_AMBIENT for our lights we will never get
        // a completely dark scene.  So, we set GL_LIGHT_MODEL_AMBIENT
        // explicitely to black.
        glLightModelfv( GL_LIGHT_MODEL_AMBIENT, black );

        ssgGetLight( 0 ) -> setColour( GL_AMBIENT, l->scene_ambient() );
        ssgGetLight( 0 ) -> setColour( GL_DIFFUSE, l->scene_diffuse() );
        ssgGetLight( 0 ) -> setColour( GL_SPECULAR, l->scene_specular() );

        // texture parameters
        // glEnable( GL_TEXTURE_2D );
        glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE ) ;
        glHint( GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST ) ;

        // glMatrixMode( GL_PROJECTION );
        // glLoadIdentity();
        ssgSetFOV( current__view->get_h_fov(),
                   current__view->get_v_fov() );

        double agl =
            current_aircraft.fdm_state->get_Altitude() * SG_FEET_TO_METER
            - globals->get_scenery()->get_cur_elev();

        if ( agl > 10.0 ) {
            scene_nearplane = 10.0f;
            scene_farplane = 120000.0f;
        } else {
            scene_nearplane = groundlevel_nearplane->getDoubleValue();
            scene_farplane = 120000.0f;
        }

        ssgSetNearFar( scene_nearplane, scene_farplane );

        if ( draw_otw && skyblend ) {
            // draw the sky backdrop

            // we need a white diffuse light for the phase of the moon
            ssgGetLight( 0 ) -> setColour( GL_DIFFUSE, white );
            thesky->preDraw( cur_fdm_state->get_Altitude() * SG_FEET_TO_METER,
                             fog_exp2_density );
            // return to the desired diffuse color
            ssgGetLight( 0 ) -> setColour( GL_DIFFUSE, l->scene_diffuse() );
        }

        // draw the ssg scene
        glEnable( GL_DEPTH_TEST );

        ssgSetNearFar( scene_nearplane, scene_farplane );

        if ( fgGetBool("/sim/rendering/wireframe") ) {
            // draw wire frame
            glPolygonMode( GL_FRONT_AND_BACK, GL_LINE );
        }
        if ( draw_otw ) {
            if ( draw_clouds ) {

                // Draw the terrain
                FGTileMgr::set_tile_filter( true );
                sgSetModelFilter( false );
                globals->get_aircraft_model()->select( false );
                ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );

                // Disable depth buffer update, draw the clouds
                glDepthMask( GL_FALSE );
                thesky->drawUpperClouds();
                if ( multi_pass_clouds ) {
                    thesky->drawLowerClouds();
                }
                glDepthMask( GL_TRUE );

                if ( multi_pass_clouds ) {
                    // Draw the objects except the aircraft
                    //  and update the stencil buffer with 1
                    glEnable( GL_STENCIL_TEST );
                    glStencilFunc( GL_ALWAYS, 1, 1 );
                    glStencilOp( GL_KEEP, GL_KEEP, GL_REPLACE );
                }
                FGTileMgr::set_tile_filter( false );
                sgSetModelFilter( true );
                ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
            } else {
                FGTileMgr::set_tile_filter( true );
                sgSetModelFilter( true );
                globals->get_aircraft_model()->select( false );
                ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
            }
        }

        // This is a bit kludgy.  Every 200 frames, do an extra
        // traversal of the scene graph without drawing anything, but
        // with the field-of-view set to 360x360 degrees.  This
        // ensures that out-of-range random objects that are not in
        // the current view frustum will still be freed properly.
        static int counter = 0;
        counter++;
        if (counter == 200) {
            sgFrustum f;
            f.setFOV(360, 360);
                    // No need to put the near plane too close;
                    // this way, at least the aircraft can be
                    // culled.
            f.setNearFar(1000, 1000000);
            sgMat4 m;
            ssgGetModelviewMatrix(m);
            FGTileMgr::set_tile_filter( true );
            sgSetModelFilter( true );
            globals->get_scenery()->get_scene_graph()->cull(&f, m, true);
            counter = 0;
        }

        // change state for lighting here

        // draw runway lighting
        glFogf (GL_FOG_DENSITY, rwy_exp2_punch_through);
        ssgSetNearFar( scene_nearplane, scene_farplane );

        if ( enhanced_lighting ) {

            // Enable states for drawing points with GL_extension
            glEnable(GL_POINT_SMOOTH);

            if ( distance_attenuation && glPointParameterIsSupported )
            {
                // Enable states for drawing points with GL_extension
                glEnable(GL_POINT_SMOOTH);

                float quadratic[3] = {1.0, 0.001, 0.0000001};
                // makes the points fade as they move away
                glPointParameterfvPtr(GL_DISTANCE_ATTENUATION_EXT, quadratic);
                glPointParameterfPtr(GL_POINT_SIZE_MIN_EXT, 1.0); 
            }

            glPointSize(4.0);

            // blending function for runway lights
            glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA) ;
        }

        glTexGeni(GL_S, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
        glTexGeni(GL_T, GL_TEXTURE_GEN_MODE, GL_SPHERE_MAP);
        glEnable(GL_TEXTURE_GEN_S);
        glEnable(GL_TEXTURE_GEN_T);
        glPolygonMode(GL_FRONT, GL_POINT);

        // draw runway lighting
        if ( draw_otw ) {
            ssgCullAndDraw( globals->get_scenery()->get_vasi_lights_root() );
            ssgCullAndDraw( globals->get_scenery()->get_rwy_lights_root() );
        }

        // change punch through and then draw taxi lighting
        glFogf ( GL_FOG_DENSITY, fog_exp2_density );
        // sgVec3 taxi_fog;
        // sgSetVec3( taxi_fog, 0.0, 0.0, 0.0 );
        // glFogfv ( GL_FOG_COLOR, taxi_fog );
        if ( draw_otw ) {
            ssgCullAndDraw( globals->get_scenery()->get_taxi_lights_root() );
        }

        // clean up lighting
        glPolygonMode(GL_FRONT, GL_FILL);
        glDisable(GL_TEXTURE_GEN_S);
        glDisable(GL_TEXTURE_GEN_T);

        //static int _frame_count = 0;
        //if (_frame_count % 30 == 0) {
        //  printf("SSG: %s\n", ssgShowStats());
        //}
        //else {
        //  ssgShowStats();
        //}
        //_frame_count++;


        if ( enhanced_lighting ) {
            if ( distance_attenuation && glPointParameterIsSupported ) {
                glPointParameterfvPtr(GL_DISTANCE_ATTENUATION_EXT,
                                      default_attenuation);
            }

            glPointSize(1.0);
            glDisable(GL_POINT_SMOOTH);
        }

        // draw ground lighting
        glFogf (GL_FOG_DENSITY, ground_exp2_punch_through);
        if ( draw_otw ) {
            ssgCullAndDraw( globals->get_scenery()->get_gnd_lights_root() );
        }

        if ( draw_otw && fgGetBool("/sim/rendering/clouds3d") ) {
            glDisable( GL_FOG );
            glDisable( GL_LIGHTING );
            // cout << "drawing new clouds" << endl;

            glEnable(GL_DEPTH_TEST);
            glEnable(GL_BLEND);
            glBlendFunc( GL_ONE, GL_ONE_MINUS_SRC_ALPHA ) ;

            /*
            glEnable( GL_TEXTURE_2D );
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
            glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
            */

#ifdef FG_USE_CLOUDS_3D
            sgClouds3d->Draw((sgVec4 *)current__view->get_VIEW());
#endif
            glEnable( GL_FOG );
            glEnable( GL_LIGHTING );
            glEnable( GL_DEPTH_TEST );
            glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
        }

        if ( draw_otw && draw_clouds ) {
            if ( multi_pass_clouds ) {
                // Disable depth buffer update, draw the clouds where the
                //  objects overwrite the already drawn clouds, by testing
                //  the stencil buffer against 1
                glDepthMask( GL_FALSE );
                glStencilFunc( GL_EQUAL, 1, 1 );
                glStencilOp( GL_KEEP, GL_KEEP, GL_KEEP );
                thesky->drawUpperClouds();
                thesky->drawLowerClouds();
                glDepthMask( GL_TRUE );
                glDisable( GL_STENCIL_TEST );
            } else {
                glDepthMask( GL_FALSE );
                thesky->drawLowerClouds();
                glDepthMask( GL_TRUE );
            }
        }

        if ( draw_otw ) {
            FGTileMgr::set_tile_filter( false );
            sgSetModelFilter( false );
            globals->get_aircraft_model()->select( true );
            globals->get_model_mgr()->draw();
            globals->get_aircraft_model()->draw();
            // If the view is internal, the previous line draw the 
            //  cockpit with modified near/far clip planes and deselect
            //  the aircraft in the global scenegraph
            // Otherwise, it just enables the aircraft: The scenegraph
            //  must be drawn again to see the plane.
            ssgCullAndDraw( globals->get_scenery()->get_scene_graph() );
            FGTileMgr::set_tile_filter( true );
            sgSetModelFilter( true );
            globals->get_aircraft_model()->select( true );
        }

        // display HUD && Panel
        glDisable( GL_FOG );
        glDisable( GL_DEPTH_TEST );
        // glDisable( GL_CULL_FACE );
        // glDisable( GL_TEXTURE_2D );

        // update the controls subsystem
        globals->get_controls()->update(delta_time_sec);

        hud_and_panel->apply();
        fgCockpitUpdate();

        // Use the hud_and_panel ssgSimpleState for rendering the ATC output
        // This only works properly if called before the panel call
        if((fgGetBool("/sim/ATC/enabled")) || (fgGetBool("/sim/ai-traffic/enabled")))
            globals->get_ATC_display()->update(delta_time_sec);

        // update the panel subsystem
        if ( globals->get_current_panel() != NULL ) {
            globals->get_current_panel()->update(delta_time_sec);
        }
        fgUpdate3DPanels();

        // We can do translucent menus, so why not. :-)
        menus->apply();
        glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
        puDisplay();
        // glDisable ( GL_BLEND ) ;

        glEnable( GL_DEPTH_TEST );
        glEnable( GL_FOG );

        // Fade out the splash screen over the first three seconds.
        double t = globals->get_sim_time_sec();
        if ( t <= 1.0 ) {
            fgSplashUpdate(0.0, 1.0);
        } else if ( t <= 3.0) {
            fgSplashUpdate(0.0, (3.0 - t) / 2.0);
        }
    }
}



// options.cxx needs to see this for toggle_panel()
// Handle new window size or exposure
void
FGRenderer::resize( int width, int height ) {
    int view_h;

    if ( (!fgGetBool("/sim/virtual-cockpit"))
         && fgPanelVisible() && idle_state == 1000 ) {
        view_h = (int)(height * (globals->get_current_panel()->getViewHeight() -
                             globals->get_current_panel()->getYOffset()) / 768.0);
    } else {
        view_h = height;
    }

    glViewport( 0, (GLint)(height - view_h), (GLint)(width), (GLint)(view_h) );

    fgSetInt("/sim/startup/xsize", width);
    fgSetInt("/sim/startup/ysize", height);
    guiInitMouse(width, height);

    // for all views
    FGViewMgr *viewmgr = globals->get_viewmgr();
    if (viewmgr) {
      for ( int i = 0; i < viewmgr->size(); ++i ) {
        viewmgr->get_view(i)->
          set_aspect_ratio((float)view_h / (float)width);
      }

      ssgSetFOV( viewmgr->get_current_view()->get_h_fov(),
                 viewmgr->get_current_view()->get_v_fov() );

#ifdef FG_USE_CLOUDS_3D
      sgClouds3d->Resize( viewmgr->get_current_view()->get_h_fov(),
                          viewmgr->get_current_view()->get_v_fov() );
#endif
    }

    fgHUDReshape();

}


// end of renderer.cxx