cloudfield.cxx

// a layer of 3d clouds
//
// 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 <simgear_config.h>
#endif

#include <simgear/compiler.h>

#include <plib/sg.h>
#include <plib/ssg.h>
#include <simgear/math/sg_random.h>
#include <simgear/math/sg_geodesy.hxx>
#include <simgear/math/polar3d.hxx>

#include STL_ALGORITHM
#include <vector>

SG_USING_STD(vector);

#include <simgear/environment/visual_enviro.hxx>
#include "sky.hxx"
#include "newcloud.hxx"
#include "cloudfield.hxx"

#if defined(__MINGW32__)
#define isnan(x) _isnan(x)
#endif

#if defined (__FreeBSD__)
#  if __FreeBSD_version < 500000
     extern "C" {
       inline int isnan(double r) { return !(r <= 0 || r >= 0); }
     }
#  endif
#endif


#if defined (__CYGWIN__)
#include <ieeefp.h>
#endif

static list_of_culledCloud inViewClouds;

// visibility distance for clouds in meters
float SGCloudField::CloudVis = 25000.0f;
bool SGCloudField::enable3D = false;
// fieldSize must be > CloudVis or we can destroy the impostor cache
// a cloud must only be seen once or the impostor will be generated for each of his positions
double SGCloudField::fieldSize = 50000.0;
float SGCloudField::density = 100.0;
double SGCloudField::timer_dt = 0.0;
sgVec3 SGCloudField::view_vec, SGCloudField::view_X, SGCloudField::view_Y;

static int last_cache_size = 1*1024;
static int cacheResolution = 64;
static sgVec3 last_sunlight={0.0f, 0.0f, 0.0f};

int SGCloudField::get_CacheResolution(void) {
        return cacheResolution;
}

void SGCloudField::set_CacheResolution(int resolutionPixels) {
        if (resolutionPixels == 0)
            resolutionPixels = 64;
        if(cacheResolution == resolutionPixels)
                return;
        cacheResolution = resolutionPixels;
        if(enable3D) {
                int count = last_cache_size * 1024 / (cacheResolution * cacheResolution * 4);
                if(count == 0)
                        count = 1;
                SGNewCloud::cldCache->setCacheSize(count, cacheResolution);
        }
}

int SGCloudField::get_CacheSize(void) { 
        return SGNewCloud::cldCache->queryCacheSize(); 
}

void SGCloudField::set_CacheSize(int sizeKb) {
        // apply in rendering option dialog
        if (sizeKb == 0)
            sizeKb = 1024;
        if(last_cache_size == sizeKb)
                return;
        if(sizeKb)
                last_cache_size = sizeKb;
        if(enable3D) {
                int count = last_cache_size * 1024 / (cacheResolution * cacheResolution * 4);
                if(count == 0)
                        count = 1;
                SGNewCloud::cldCache->setCacheSize(count, cacheResolution);
        }
}
void SGCloudField::set_CloudVis(float distance) {
        if( distance <= fieldSize )
                SGCloudField::CloudVis = distance;
}
void SGCloudField::set_density(float density) {
        SGCloudField::density = density;
}
void SGCloudField::set_enable3dClouds(bool enable) {
        if(enable3D == enable)
                return;
        enable3D = enable;
        if(enable) {
                int count = last_cache_size * 1024 / (cacheResolution * cacheResolution * 4);
                if(count == 0)
                        count = 1;
                SGNewCloud::cldCache->setCacheSize(count, cacheResolution);
        } else {
                SGNewCloud::cldCache->setCacheSize(0);
        }
}

// reposition the cloud layer at the specified origin and orientation
void SGCloudField::reposition( sgVec3 p, sgVec3 up, double lon, double lat, double alt, double dt, float direction, float speed) {
    sgMat4 T1, LON, LAT;
    sgVec3 axis;

    sgMakeTransMat4( T1, p );

    sgSetVec3( axis, 0.0, 0.0, 1.0 );
    sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );

    sgSetVec3( axis, 0.0, 1.0, 0.0 );
    sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );

    sgMat4 TRANSFORM;

    sgCopyMat4( TRANSFORM, T1 );
    sgPreMultMat4( TRANSFORM, LON );
    sgPreMultMat4( TRANSFORM, LAT );

    sgCoord layerpos;
    sgSetCoord( &layerpos, TRANSFORM );

        sgMakeCoordMat4( transform, &layerpos );


        this->alt = alt;

        // simulate clouds movement from wind
    double sp_dist = speed*dt;
    if (sp_dist > 0) {
        double bx = cos((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
        double by = sin((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
                relative_position[SG_X] += bx;
                relative_position[SG_Y] += by;
    }

    if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
        Point3D start( last_lon, last_lat, 0.0 );
        Point3D dest( lon, lat, 0.0 );
        double course = 0.0, dist = 0.0;

        calc_gc_course_dist( dest, start, &course, &dist );
        // if start and dest are too close together,
        // calc_gc_course_dist() can return a course of "nan".  If
        // this happens, lets just use the last known good course.
        // This is a hack, and it would probably be better to make
        // calc_gc_course_dist() more robust.
        if ( isnan(course) ) {
            course = last_course;
        } else {
            last_course = course;
        }

        // calculate cloud movement due to external forces
        double ax = 0.0, ay = 0.0;

        if (dist > 0.0) {
            ax = cos(course) * dist;
            ay = sin(course) * dist;
        }

                deltax += ax;
                deltay += ay;

        last_lon = lon;
        last_lat = lat;
    }


        // correct the frustum with the right far plane
        ssgContext *context = ssgGetCurrentContext();
        frustum = *context->getFrustum();

        float w, h;
        sgEnviro.getFOV( w, h );
        frustum.setFOV( w, h );
        frustum.setNearFar(1.0, CloudVis);
        timer_dt = dt;
}

SGCloudField::SGCloudField() :
        deltax(0.0),
        deltay(0.0),
        last_course(0.0),
        last_density(0.0),
        draw_in_3d(true)
{
        sgSetVec3( relative_position, 0,0,0);
        theField.reserve(200);
        inViewClouds.reserve(200);
        sg_srandom_time_10();
}

SGCloudField::~SGCloudField() {
        list_of_Cloud::iterator iCloud;
        for( iCloud = theField.begin() ; iCloud != theField.end() ; iCloud++ ) {
                delete iCloud->aCloud;
        }
        theField.clear();
}


void SGCloudField::clear(void) {
        list_of_Cloud::iterator iCloud;
        for( iCloud = theField.begin() ; iCloud != theField.end() ; iCloud++ ) {
                delete iCloud->aCloud;
        }
        theField.clear();
        // force a recompute of density on first redraw
        last_density = 0.0;
        // true to come back in set density after layer is built
        draw_in_3d = true;
}

// use a table or else we see poping when moving the slider...
static int densTable[][10] = {
        {0,0,0,0,0,0,0,0,0,0},
        {1,0,0,0,0,0,0,0,0,0},
        {1,0,0,0,1,0,0,0,0,0},
        {1,0,0,0,1,0,0,1,0,0}, // 30%
        {1,0,1,0,1,0,0,1,0,0},
        {1,0,1,0,1,0,1,1,0,0}, // 50%
        {1,0,1,0,1,0,1,1,0,1},
        {1,0,1,1,1,0,1,1,0,1}, // 70%
        {1,1,1,1,1,0,1,1,0,1},
        {1,1,1,1,1,0,1,1,1,1}, // 90%
        {1,1,1,1,1,1,1,1,1,1}
};

// set the visible flag depending on density
void SGCloudField::applyDensity(void) {
        int row = (int) (density / 10.0);
        int col = 0;
    sgBox fieldBox;

        list_of_Cloud::iterator iCloud;
        for( iCloud = theField.begin() ; iCloud != theField.end() ; iCloud++ ) {
                if(++col > 9)
                        col = 0;
                if( densTable[row][col] ) {
                        iCloud->visible = true;
            fieldBox.extend( *iCloud->aCloud->getCenter() );
                } else
                        iCloud->visible = false;
        }
        last_density = density;
        draw_in_3d = ( theField.size() != 0);
    sgVec3 center;
    sgSubVec3( center, fieldBox.getMax(), fieldBox.getMin() );
    sgScaleVec3( center, 0.5f );
    center[1] = 0.0f;
    field_sphere.setCenter( center );
    field_sphere.setRadius( fieldSize * 0.5f * 1.414f );
}

// add one cloud, data is not copied, ownership given
void SGCloudField::addCloud( sgVec3 pos, SGNewCloud *cloud) {
        Cloud cl;
        cl.aCloud = cloud;
        cl.visible = true;
        cloud->SetPos( pos );
        sgCopyVec3( cl.pos, *cloud->getCenter() );
        theField.push_back( cl );
}


static float Rnd(float n) {
        return n * (-0.5f + sg_random());
}

// for debug only
// build a field of cloud of size 25x25 km, its a grid of 11x11 clouds
void SGCloudField::buildTestLayer(void) {

        const float s = 2250.0f;

        for( int z = -5 ; z <= 5 ; z++) {
                for( int x = -5 ; x <= 5 ; x++ ) {
                        SGNewCloud *cloud = new SGNewCloud(SGNewCloud::CLFamilly_cu);
                        cloud->new_cu();
                        sgVec3 pos = {(x+Rnd(0.7)) * s, 750.0f, (z+Rnd(0.7)) * s};
            addCloud(pos, cloud);
                }
        }
        applyDensity();
}

// cull all clouds of a tiled field
void SGCloudField::cullClouds(sgVec3 eyePos, sgMat4 mat) {
        list_of_Cloud::iterator iCloud;

    sgSphere tile_sphere;
    tile_sphere.setRadius( field_sphere.getRadius() );
    sgVec3 tile_center;
    sgSubVec3( tile_center, field_sphere.getCenter(), eyePos );
    tile_sphere.setCenter( tile_center );
    tile_sphere.orthoXform(mat);
    if( frustum.contains( & tile_sphere ) == SG_OUTSIDE )
        return;

        for( iCloud = theField.begin() ; iCloud != theField.end() ; iCloud++ ) {
                sgVec3 dist;
                sgSphere sphere;
                if( ! iCloud->visible )
                        continue;
                sgSubVec3( dist, iCloud->pos, eyePos );
                sphere.setCenter(dist[0], dist[2], dist[1] + eyePos[1]);
                float radius = iCloud->aCloud->getRadius();
                sphere.setRadius(radius);
                sphere.orthoXform(mat);
                if( frustum.contains( & sphere ) != SG_OUTSIDE ) {
                        float squareDist = dist[0]*dist[0] + dist[1]*dist[1] + dist[2]*dist[2];
                        culledCloud tmp;
                        tmp.aCloud = iCloud->aCloud;
                        sgCopyVec3( tmp.eyePos, eyePos ); 
                        // save distance for later sort, opposite distance because we want back to front
                        tmp.dist   =  - squareDist;
                        tmp.heading = -SG_PI/2.0 - atan2( dist[0], dist[2] ); // + SG_PI;
                        tmp.alt         = iCloud->pos[1];
                        inViewClouds.push_back(tmp);
                        if( squareDist - radius*radius < 100*100 )
                                sgEnviro.set_view_in_cloud(true);
                }
        }

}


// Render a cloud field
// because no field can have an infinite size (and we don't want to reach his border)
// we draw this field and adjacent fields.
// adjacent fields are not real, its the same field displaced by some offset
void SGCloudField::Render( float *sun_color ) {
    sgVec3 eyePos;
        double relx, rely;

        if( ! enable3D )
                return;

        if( last_density != density ) {
                last_density = density;
                applyDensity();
        }

        if( ! draw_in_3d )
                return;

        if( ! SGNewCloud::cldCache->isRttAvailable() )
                return;

        inViewClouds.clear();

 
        glPushMatrix();
 
        sgMat4 modelview, tmp, invtrans;

        // try to find the sun position
        sgTransposeNegateMat4( invtrans, transform );
    sgVec3 lightVec;
    ssgGetLight( 0 )->getPosition( lightVec );
    sgXformVec3( lightVec, invtrans );

        sgSetVec3(  SGNewCloud::modelSunDir, lightVec[0], lightVec[2], lightVec[1]);
        // try to find the lighting data (not accurate)
        sgVec4 diffuse, ambient;
        ssgGetLight( 0 )->getColour( GL_DIFFUSE, diffuse );
        ssgGetLight( 0 )->getColour( GL_AMBIENT, ambient );
//      sgScaleVec3 ( SGNewCloud::sunlight, diffuse , 1.0f);
        sgScaleVec3 ( SGNewCloud::ambLight, ambient , 1.1f);
        // trying something else : clouds are more yellow/red at dawn/dusk
        // and added a bit of blue ambient
        sgScaleVec3 ( SGNewCloud::sunlight, sun_color , 0.4f);
        SGNewCloud::ambLight[2] += 0.1f;

        sgVec3 delta_light;
        sgSubVec3(delta_light, last_sunlight, SGNewCloud::sunlight);
        if( (fabs(delta_light[0]) + fabs(delta_light[1]) + fabs(delta_light[2])) > 0.05f ) {
                sgCopyVec3( last_sunlight, SGNewCloud::sunlight );
                // force the redraw of all the impostors
                SGNewCloud::cldCache->invalidateCache();
        }

        // voodoo things on the matrix stack
    ssgGetModelviewMatrix( modelview );
        sgCopyMat4( tmp, transform );
    sgPostMultMat4( tmp, modelview );

        // cloud fields are tiled on the flat earth
        // compute the position in the tile
        relx = fmod( deltax + relative_position[SG_X], fieldSize );
        rely = fmod( deltay + relative_position[SG_Y], fieldSize );

        relx = fmod( relx + fieldSize, fieldSize );
        rely = fmod( rely + fieldSize, fieldSize );
        sgSetVec3( eyePos, relx, alt, rely);

        sgSetVec3( view_X, tmp[0][0], tmp[1][0], tmp[2][0] );
        sgSetVec3( view_Y, tmp[0][1], tmp[1][1], tmp[2][1] );
        sgSetVec3( view_vec, tmp[0][2], tmp[1][2], tmp[2][2] );

    ssgLoadModelviewMatrix( tmp );
 
/* flat earth

        ^
        |
        |    FFF
        |    FoF
        |    FFF
        |
        O----------->
                o = we are here
                F = adjacent fields
*/

        for(int x = -1 ; x <= 1 ; x++)
                for(int y = -1 ; y <= 1 ; y++ ) {
                        sgVec3 fieldPos;
                        // pretend we are not where we are
                        sgSetVec3(fieldPos, eyePos[0] + x*fieldSize, eyePos[1], eyePos[2] + y*fieldSize);
                        cullClouds(fieldPos, tmp);
                }
        // sort all visible clouds back to front (because of transparency)
        std::sort( inViewClouds.begin(), inViewClouds.end() );
 
        // TODO:push states
        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
    glEnable(GL_ALPHA_TEST);
    glAlphaFunc(GL_GREATER, 0.0f);
        glDisable(GL_CULL_FACE);
        glEnable(GL_DEPTH_TEST);
        glDepthMask( GL_FALSE );
        glEnable(GL_SMOOTH);
    glEnable(GL_BLEND);
        glBlendFunc( GL_ONE, GL_ONE_MINUS_SRC_ALPHA );
        glEnable( GL_TEXTURE_2D );
        glDisable( GL_FOG );
    glDisable(GL_LIGHTING);

        // test data: field = 11x11 cloud, 9 fields
        // depending on position and view direction, perhaps 40 to 60 clouds not culled
        list_of_culledCloud::iterator iCloud;
        for( iCloud = inViewClouds.begin() ; iCloud != inViewClouds.end() ; iCloud++ ) {
//              iCloud->aCloud->drawContainers();
                iCloud->aCloud->Render(iCloud->eyePos);
                sgEnviro.callback_cloud(iCloud->heading, iCloud->alt, 
                        iCloud->aCloud->getRadius(), iCloud->aCloud->getFamilly(), - iCloud->dist, iCloud->aCloud->getId());
        }

        glBindTexture(GL_TEXTURE_2D, 0);
    glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
        glEnable( GL_FOG );
        glEnable(GL_CULL_FACE);
        glEnable(GL_DEPTH_TEST);

        ssgLoadModelviewMatrix( modelview );

        glPopMatrix();

}

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