fgclouds.cxx

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// Build a cloud layer based on metar
//
// Written by Harald JOHNSEN, started April 2005.
//
// Copyright (C) 2005  Harald JOHNSEN - hjohnsen@evc.net
//
// 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
//
//
 
#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif
 
#include "fgclouds.hxx"
 
#include <cstring>
#include <cstdio>
#include <Main/fg_props.hxx>
 
#include <simgear/constants.h>
#include <simgear/sound/soundmgr.hxx>
#include <simgear/scene/sky/sky.hxx>
//#include <simgear/environment/visual_enviro.hxx>
#include <simgear/scene/sky/cloudfield.hxx>
#include <simgear/scene/sky/newcloud.hxx>
#include <simgear/structure/commands.hxx>
#include <simgear/props/props_io.hxx>
 
#include <Main/globals.hxx>
#include <Main/util.hxx>
#include <Viewer/renderer.hxx>
#include <Airports/airport.hxx>
 
// RNG seed to ensure cloud synchronization across multi-process
// deployments
static mt seed;
 
FGClouds::FGClouds() :
    clouds_3d_enabled(false),
    index(0)
{
        update_event = 0;
}
 
FGClouds::~FGClouds()
{
    globals->get_commands()->removeCommand("add-cloud");
        globals->get_commands()->removeCommand("del-cloud");
        globals->get_commands()->removeCommand("move-cloud");
 
}
 
int FGClouds::get_update_event(void) const {
        return update_event;
}
 
void FGClouds::set_update_event(int count) {
        update_event = count;
        buildCloudLayers();
}
 
void FGClouds::Init(void)
{
        mt_init_time_10(&seed);
 
        globals->get_commands()->addCommand("add-cloud", this, &FGClouds::add3DCloud);
        globals->get_commands()->addCommand("del-cloud", this, &FGClouds::delete3DCloud);
        globals->get_commands()->addCommand("move-cloud", this, &FGClouds::move3DCloud);
}
 
// Build an invidual cloud. Returns the extents of the cloud for coverage calculations
double FGClouds::buildCloud(SGPropertyNode *cloud_def_root, SGPropertyNode *box_def_root,
                            const std::string& name, double grid_z_rand, SGCloudField *layer)
{
        SGPropertyNode *box_def=NULL;
        SGPropertyNode *cld_def=NULL;
        double extent = 0.0;
 
        SGPath texture_root = globals->get_fg_root();
        texture_root.append("Textures");
        texture_root.append("Sky");
 
        box_def = box_def_root->getChild(name.c_str());
 
        string base_name = name.substr(0,2);
        if( !box_def ) {
                if( name[2] == '-' ) {
                        box_def = box_def_root->getChild(base_name.c_str());
                }
                if( !box_def )
                        return 0.0;
        }
 
        double x = mt_rand(&seed) * SGCloudField::fieldSize - (SGCloudField::fieldSize / 2.0);
        double y = mt_rand(&seed) * SGCloudField::fieldSize - (SGCloudField::fieldSize / 2.0);
        double z = grid_z_rand * (mt_rand(&seed) - 0.5);
 
        float lon = fgGetNode("/position/longitude-deg", false)->getFloatValue();
        float lat = fgGetNode("/position/latitude-deg", false)->getFloatValue();
 
        SGVec3f pos(x,y,z);
 
        for(int i = 0; i < box_def->nChildren() ; i++) {
                SGPropertyNode *abox = box_def->getChild(i);
                if( abox->getNameString() == "box" ) {
 
                        string type = abox->getStringValue("type", "cu-small");
                        cld_def = cloud_def_root->getChild(type.c_str());
                        if ( !cld_def ) return 0.0;
 
                        double w = abox->getDoubleValue("width", 1000.0);
                        double h = abox->getDoubleValue("height", 1000.0);
                        int hdist = abox->getIntValue("hdist", 1);
                        int vdist = abox->getIntValue("vdist", 1);
 
                        double c = abox->getDoubleValue("count", 5);
                        int count = (int) (c + (mt_rand(&seed) - 0.5) * c);
 
                        extent = std::max(w*w, extent);
 
                        for (int j = 0; j < count; j++) {
 
                                // Locate the clouds randomly in the defined space. The hdist and
                                // vdist values control the horizontal and vertical distribution
                                // by simply summing random components.
                                double x = 0.0;
                                double y = 0.0;
                                double z = 0.0;
 
                                for (int k = 0; k < hdist; k++)
                                {
                                        x += (mt_rand(&seed) / hdist);
                                        y += (mt_rand(&seed) / hdist);
                                }
 
                                for (int k = 0; k < vdist; k++)
                                {
                                        z += (mt_rand(&seed) / vdist);
                                }
 
                                x = w * (x - 0.5) + pos[0]; // N/S
                                y = w * (y - 0.5) + pos[1]; // E/W
                                z = h * z + pos[2]; // Up/Down. pos[2] is the cloudbase
 
                                //SGVec3f newpos = SGVec3f(x, y, z);
                                SGNewCloud cld(texture_root, cld_def, &seed);
 
                                //layer->addCloud(newpos, cld.genCloud());
                                layer->addCloud(lon, lat, z, x, y, index++, cld.genCloud());
                        }
                }
        }
 
        // Return the maximum extent of the cloud
        return extent;
}
 
void FGClouds::buildLayer(int iLayer, const string& name, double coverage) {
        struct {
                string name;
                double count;
        } tCloudVariety[20];
        int CloudVarietyCount = 0;
        double totalCount = 0.0;
 
    SGSky* thesky = globals->get_renderer()->getSky();
    
        SGPropertyNode *cloud_def_root = fgGetNode("/environment/cloudlayers/clouds", false);
        SGPropertyNode *box_def_root   = fgGetNode("/environment/cloudlayers/boxes", false);
        SGPropertyNode *layer_def_root = fgGetNode("/environment/cloudlayers/layers", false);
        SGCloudField *layer = thesky->get_cloud_layer(iLayer)->get_layer3D();
        layer->clear();
 
        // If we don't have the required properties, then render the cloud in 2D
        if ((! clouds_3d_enabled) || coverage == 0.0 ||
                layer_def_root == NULL || cloud_def_root == NULL || box_def_root == NULL) {
                        thesky->get_cloud_layer(iLayer)->set_enable3dClouds(false);
                        return;
        }
 
        // If we can't find a definition for this cloud type, then render the cloud in 2D
        SGPropertyNode *layer_def=NULL;
        layer_def = layer_def_root->getChild(name.c_str());
        if( !layer_def ) {
                if( name[2] == '-' ) {
                        string base_name = name.substr(0,2);
                        layer_def = layer_def_root->getChild(base_name.c_str());
                }
                if( !layer_def ) {
                        thesky->get_cloud_layer(iLayer)->set_enable3dClouds(false);
                        return;
                }
        }
 
        // At this point, we know we've got some 3D clouds to generate.
        thesky->get_cloud_layer(iLayer)->set_enable3dClouds(true);
 
        double grid_z_rand = layer_def->getDoubleValue("grid-z-rand");
 
        for(int i = 0; i < layer_def->nChildren() ; i++) {
                SGPropertyNode *acloud = layer_def->getChild(i);
                if( acloud->getNameString() == "cloud" ) {
                        string cloud_name = acloud->getStringValue("name");
                        tCloudVariety[CloudVarietyCount].name = cloud_name;
                        double count = acloud->getDoubleValue("count", 1.0);
                        tCloudVariety[CloudVarietyCount].count = count;
                        int variety = 0;
                        char variety_name[50];
                        do {
                                variety++;
                                snprintf(variety_name, sizeof(variety_name) - 1, "%s-%d", cloud_name.c_str(), variety);
                        } while( box_def_root->getChild(variety_name, 0, false) );
 
                        totalCount += count;
                        if( CloudVarietyCount < 20 )
                                CloudVarietyCount++;
                }
        }
        totalCount = 1.0 / totalCount;
 
        // Determine how much cloud coverage we need in m^2.
        double cov = coverage * SGCloudField::fieldSize * SGCloudField::fieldSize;
 
        while (cov > 0.0f) {
                double choice = mt_rand(&seed);
 
                for(int i = 0; i < CloudVarietyCount ; i ++) {
                        choice -= tCloudVariety[i].count * totalCount;
                        if( choice <= 0.0 ) {
                                cov -= buildCloud(cloud_def_root,
                                                box_def_root,
                                                tCloudVariety[i].name,
                                                grid_z_rand,
                                                layer);
                                break;
                        }
                }
        }
 
        // Now we've built any clouds, enable them and set the density (coverage)
        //layer->setCoverage(coverage);
        //layer->applyCoverage();
        thesky->get_cloud_layer(iLayer)->set_enable3dClouds(clouds_3d_enabled);
}
 
void FGClouds::buildCloudLayers(void) {
        SGPropertyNode *metar_root = fgGetNode("/environment", true);
 
        //double wind_speed_kt   = metar_root->getDoubleValue("wind-speed-kt");
        double temperature_degc  = metar_root->getDoubleValue("temperature-sea-level-degc");
        double dewpoint_degc     = metar_root->getDoubleValue("dewpoint-sea-level-degc");
        double pressure_mb       = metar_root->getDoubleValue("pressure-sea-level-inhg") * SG_INHG_TO_PA / 100.0;
        double rel_humidity      = metar_root->getDoubleValue("relative-humidity");
 
        // formule d'Epsy, base d'un cumulus
        double cumulus_base = 122.0 * (temperature_degc - dewpoint_degc);
        double stratus_base = 100.0 * (100.0 - rel_humidity) * SG_FEET_TO_METER;
 
    SGSky* thesky = globals->get_renderer()->getSky();
        for(int iLayer = 0 ; iLayer < thesky->get_cloud_layer_count(); iLayer++) {
                SGPropertyNode *cloud_root = fgGetNode("/environment/clouds/layer", iLayer, true);
 
                double alt_ft = cloud_root->getDoubleValue("elevation-ft");
                double alt_m = alt_ft * SG_FEET_TO_METER;
                string coverage = cloud_root->getStringValue("coverage");
 
                double coverage_norm = 0.0;
                if( coverage == "few" )
                        coverage_norm = 2.0/8.0;        // <1-2
                else if( coverage == "scattered" )
                        coverage_norm = 4.0/8.0;        // 3-4
                else if( coverage == "broken" )
                        coverage_norm = 6.0/8.0;        // 5-7
                else if( coverage == "overcast" )
                        coverage_norm = 8.0/8.0;        // 8
 
                string layer_type = "nn";
 
                if( coverage == "cirrus" ) {
                        layer_type = "ci";
                } else if( alt_ft > 16500 ) {
//                      layer_type = "ci|cs|cc";
                        layer_type = "ci";
                } else if( alt_ft > 6500 ) {
//                      layer_type = "as|ac|ns";
                        layer_type = "ac";
                        if( pressure_mb < 1005.0 && coverage_norm >= 0.5 )
                                layer_type = "ns";
                } else {
//                      layer_type = "st|cu|cb|sc";
                        if( cumulus_base * 0.80 < alt_m && cumulus_base * 1.20 > alt_m ) {
                                // +/- 20% from cumulus probable base
                                layer_type = "cu";
                        } else if( stratus_base * 0.80 < alt_m && stratus_base * 1.40 > alt_m ) {
                                // +/- 20% from stratus probable base
                                layer_type = "st";
                        } else {
                                // above formulae is far from perfect
                                if ( alt_ft < 2000 )
                                        layer_type = "st";
                                else if( alt_ft < 4500 )
                                        layer_type = "cu";
                                else
                                        layer_type = "sc";
                        }
                }
 
                cloud_root->setStringValue("layer-type",layer_type);
                buildLayer(iLayer, layer_type, coverage_norm);
        }
}
 
void FGClouds::set_3dClouds(bool enable)
{
        if (enable != clouds_3d_enabled) {
                clouds_3d_enabled = enable;
                buildCloudLayers();
        }
}
 
bool FGClouds::get_3dClouds() const
{
        return clouds_3d_enabled;
}

 bool FGClouds::add3DCloud(const SGPropertyNode *arg, SGPropertyNode * root)
 {
   int l = arg->getIntValue("layer", 0);
   int index = arg->getIntValue("index", 0);
 
   SGPath texture_root = globals->get_fg_root();
         texture_root.append("Textures");
         texture_root.append("Sky");
 
         float lon = arg->getFloatValue("lon-deg", 0.0f);
         float lat = arg->getFloatValue("lat-deg", 0.0f);
         float alt = arg->getFloatValue("alt-ft",  0.0f);
         float x   = arg->getFloatValue("x-offset-m",  0.0f);
         float y   = arg->getFloatValue("y-offset-m",  0.0f);
 
   SGSky* thesky = globals->get_renderer()->getSky();
   SGCloudField *layer = thesky->get_cloud_layer(l)->get_layer3D();
   SGNewCloud cld(texture_root, arg, &seed);
   bool success = layer->addCloud(lon, lat, alt, x, y, index, cld.genCloud());
 
   // Adding a 3D cloud immediately makes this layer 3D.
   thesky->get_cloud_layer(l)->set_enable3dClouds(true);
 
   return success;
 }

 bool FGClouds::delete3DCloud(const SGPropertyNode *arg, SGPropertyNode * root)
 {
   int l = arg->getIntValue("layer", 0);
   int i = arg->getIntValue("index", 0);
 
   SGSky* thesky = globals->get_renderer()->getSky();
   SGCloudField *layer = thesky->get_cloud_layer(l)->get_layer3D();
         return layer->deleteCloud(i);
 }

bool FGClouds::move3DCloud(const SGPropertyNode *arg, SGPropertyNode * root)
 {
   int l = arg->getIntValue("layer", 0);
   int i = arg->getIntValue("index", 0);
      SGSky* thesky = globals->get_renderer()->getSky();
     
         float lon = arg->getFloatValue("lon-deg", 0.0f);
         float lat = arg->getFloatValue("lat-deg", 0.0f);
         float alt = arg->getFloatValue("alt-ft",  0.0f);
         float x   = arg->getFloatValue("x-offset-m",  0.0f);
         float y   = arg->getFloatValue("y-offset-m",  0.0f);
 
   SGCloudField *layer = thesky->get_cloud_layer(l)->get_layer3D();
         return layer->repositionCloud(i, lon, lat, alt, x, y);
 }