355 lines
9.5 KiB
C++
355 lines
9.5 KiB
C++
// sky.cxx -- ssg based sky model
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//
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// Written by Curtis Olson, started December 1997.
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// SSG-ified by Curtis Olson, February 2000.
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//
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// Copyright (C) 1997-2000 Curtis L. Olson - curt@flightgear.org
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Library General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Library General Public License for more details.
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//
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// You should have received a copy of the GNU Library General Public
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// License along with this library; if not, write to the
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// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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// Boston, MA 02111-1307, USA.
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//
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// $Id$
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#include <plib/sg.h>
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#include <plib/ssg.h>
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#include <simgear/math/sg_random.h>
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#include "sky.hxx"
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// Constructor
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SGSky::SGSky( void ) {
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effective_visibility = visibility = 10000.0;
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// near cloud visibility state variables
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in_puff = false;
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puff_length = 0;
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puff_progression = 0;
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ramp_up = 0.15;
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ramp_down = 0.15;
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// ramp_up = 4.0;
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// ramp_down = 4.0;
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}
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// Destructor
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SGSky::~SGSky( void )
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{
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for (unsigned int i = 0; i < cloud_layers.size(); i++)
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delete cloud_layers[i];
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}
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// initialize the sky and connect the components to the scene graph at
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// the provided branch
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void SGSky::build( double sun_size, double moon_size,
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int nplanets, sgdVec3 *planet_data,
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double planet_dist,
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int nstars, sgdVec3 *star_data, double star_dist )
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{
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pre_root = new ssgRoot;
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post_root = new ssgRoot;
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pre_selector = new ssgSelector;
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post_selector = new ssgSelector;
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pre_transform = new ssgTransform;
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post_transform = new ssgTransform;
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dome = new SGSkyDome;
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pre_transform -> addKid( dome->build() );
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planets = new SGStars;
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pre_transform -> addKid( planets->build(nplanets, planet_data,
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planet_dist)
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);
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stars = new SGStars;
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pre_transform -> addKid( stars->build(nstars, star_data, star_dist) );
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moon = new SGMoon;
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pre_transform -> addKid( moon->build(tex_path, moon_size) );
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oursun = new SGSun;
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pre_transform -> addKid( oursun->build(tex_path, sun_size) );
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pre_selector->addKid( pre_transform );
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pre_selector->clrTraversalMaskBits( SSGTRAV_HOT );
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post_selector->addKid( post_transform );
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post_selector->clrTraversalMaskBits( SSGTRAV_HOT );
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pre_root->addKid( pre_selector );
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post_root->addKid( post_selector );
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}
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// repaint the sky components based on current value of sun_angle,
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// sky, and fog colors.
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//
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// sun angle in degrees relative to verticle
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// 0 degrees = high noon
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// 90 degrees = sun rise/set
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// 180 degrees = darkest midnight
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bool SGSky::repaint( sgVec4 sky_color, sgVec4 fog_color,
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double sun_angle, double moon_angle,
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int nplanets, sgdVec3 *planet_data,
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int nstars, sgdVec3 *star_data )
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{
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if ( effective_visibility > 1000.0 ) {
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enable();
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dome->repaint( sky_color, fog_color, sun_angle, effective_visibility );
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oursun->repaint( sun_angle );
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moon->repaint( moon_angle );
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planets->repaint( sun_angle, nplanets, planet_data );
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stars->repaint( sun_angle, nstars, star_data );
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for ( int i = 0; i < (int)cloud_layers.size(); ++i ) {
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cloud_layers[i]->repaint( fog_color );
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}
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} else {
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// turn off sky
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disable();
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}
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return true;
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}
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// reposition the sky at the specified origin and orientation
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//
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// lon specifies a rotation about the Z axis
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// lat specifies a rotation about the new Y axis
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// spin specifies a rotation about the new Z axis (this allows
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// additional orientation for the sunrise/set effects and is used by
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// the skydome and perhaps clouds.
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bool SGSky::reposition( sgVec3 view_pos, sgVec3 zero_elev, sgVec3 view_up,
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double lon, double lat, double alt, double spin,
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double gst,
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double sun_ra, double sun_dec, double sun_dist,
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double moon_ra, double moon_dec, double moon_dist )
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{
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double angle = gst * 15; // degrees
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dome->reposition( zero_elev, lon, lat, spin );
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oursun->reposition( view_pos, angle, sun_ra, sun_dec, sun_dist );
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moon->reposition( view_pos, angle, moon_ra, moon_dec, moon_dist );
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planets->reposition( view_pos, angle );
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stars->reposition( view_pos, angle );
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for ( int i = 0; i < (int)cloud_layers.size(); ++i ) {
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cloud_layers[i]->reposition( zero_elev, view_up, lon, lat, alt );
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}
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return true;
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}
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// draw background portions of the sky ... do this before you draw the
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// rest of your scene.
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void SGSky::preDraw() {
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ssgCullAndDraw( pre_root );
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}
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// draw translucent clouds ... do this after you've drawn all the
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// oapaque elements of your scene.
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void SGSky::postDraw( float alt ) {
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float slop = 5.0; // if we are closer than this to a cloud layer,
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// don't draw clouds
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int in_cloud = -1; // cloud we are in
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int i;
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// check where we are relative to the cloud layers
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for ( i = 0; i < (int)cloud_layers.size(); ++i ) {
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float asl = cloud_layers[i]->getElevation_m();
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float thickness = cloud_layers[i]->getThickness_m();
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if ( alt < asl - slop ) {
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// below cloud layer
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} else if ( alt < asl + thickness + slop ) {
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// in cloud layer
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// bail now and don't draw any clouds
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in_cloud = i;
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} else {
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// above cloud layer
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}
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}
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// determine rendering order
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int pos = 0;
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while ( pos < (int)cloud_layers.size() &&
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alt > cloud_layers[pos]->getElevation_m())
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{
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++pos;
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}
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if ( pos == 0 ) {
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// we are below all the cloud layers, draw top to bottom
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for ( i = cloud_layers.size() - 1; i >= 0; --i ) {
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if ( i != in_cloud ) {
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cloud_layers[i]->draw();
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}
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}
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} else if ( pos >= (int)cloud_layers.size() ) {
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// we are above all the cloud layers, draw bottom to top
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for ( i = 0; i < (int)cloud_layers.size(); ++i ) {
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if ( i != in_cloud ) {
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cloud_layers[i]->draw();
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}
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}
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} else {
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// we are between cloud layers, draw lower layers bottom to
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// top and upper layers top to bottom
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for ( i = 0; i < pos; ++i ) {
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if ( i != in_cloud ) {
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cloud_layers[i]->draw();
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}
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}
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for ( i = cloud_layers.size() - 1; i >= pos; --i ) {
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if ( i != in_cloud ) {
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cloud_layers[i]->draw();
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}
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}
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}
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}
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void
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SGSky::add_cloud_layer( SGCloudLayer * layer )
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{
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cloud_layers.push_back(layer);
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}
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const SGCloudLayer *
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SGSky::get_cloud_layer (int i) const
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{
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return cloud_layers[i];
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}
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SGCloudLayer *
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SGSky::get_cloud_layer (int i)
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{
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return cloud_layers[i];
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}
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int
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SGSky::get_cloud_layer_count () const
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{
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return cloud_layers.size();
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}
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// modify the current visibility based on cloud layers, thickness,
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// transition range, and simulated "puffs".
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void SGSky::modify_vis( float alt, float time_factor ) {
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float effvis = visibility;
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for ( int i = 0; i < (int)cloud_layers.size(); ++i ) {
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float asl = cloud_layers[i]->getElevation_m();
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float thickness = cloud_layers[i]->getThickness_m();
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float transition = cloud_layers[i]->getTransition_m();
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double ratio = 1.0;
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if ( alt < asl - transition ) {
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// below cloud layer
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ratio = 1.0;
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} else if ( alt < asl ) {
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// in lower transition
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ratio = (asl - alt) / transition;
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} else if ( alt < asl + thickness ) {
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// in cloud layer
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ratio = 0.0;
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} else if ( alt < asl + thickness + transition ) {
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// in upper transition
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ratio = (alt - (asl + thickness)) / transition;
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} else {
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// above cloud layer
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ratio = 1.0;
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}
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// accumulate effects from multiple cloud layers
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effvis *= ratio;
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if ( ratio < 1.0 ) {
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if ( ! in_puff ) {
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// calc chance of entering cloud puff
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double rnd = sg_random();
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double chance = rnd * rnd * rnd;
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if ( chance > 0.95 /* * (diff - 25) / 50.0 */ ) {
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in_puff = true;
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puff_length = sg_random() * 2.0; // up to 2 seconds
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puff_progression = 0.0;
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}
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}
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if ( in_puff ) {
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// modify actual_visibility based on puff envelope
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if ( puff_progression <= ramp_up ) {
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double x = 0.5 * SGD_PI * puff_progression / ramp_up;
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double factor = 1.0 - sin( x );
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// cout << "ramp up = " << puff_progression
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// << " factor = " << factor << endl;
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effvis = effvis * factor;
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} else if ( puff_progression >= ramp_up + puff_length ) {
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double x = 0.5 * SGD_PI *
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(puff_progression - (ramp_up + puff_length)) /
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ramp_down;
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double factor = sin( x );
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// cout << "ramp down = "
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// << puff_progression - (ramp_up + puff_length)
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// << " factor = " << factor << endl;
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effvis = effvis * factor;
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} else {
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effvis = 0.0;
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}
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/* cout << "len = " << puff_length
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<< " x = " << x
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<< " factor = " << factor
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<< " actual_visibility = " << actual_visibility
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<< endl; */
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// time_factor = ( global_multi_loop *
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// current_options.get_speed_up() ) /
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// (double)current_options.get_model_hz();
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puff_progression += time_factor;
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// cout << "time factor = " << time_factor << endl;
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/* cout << "gml = " << global_multi_loop
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<< " speed up = " << current_options.get_speed_up()
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<< " hz = " << current_options.get_model_hz() << endl;
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*/
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if ( puff_progression > puff_length + ramp_up + ramp_down) {
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in_puff = false;
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}
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}
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// never let visibility drop below 25 meters
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if ( effvis <= 25.0 ) {
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effvis = 25.0;
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}
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}
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} // for
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effective_visibility = effvis;
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}
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