Files
simgear/simgear/sky/moon.cxx
T
2000-10-19 22:27:27 +00:00

312 lines
9.0 KiB
C++

// moon.hxx -- model earth's moon
//
// Written by Durk Talsma. Originally started October 1997, for distribution
// with the FlightGear project. Version 2 was written in August and
// September 1998. This code is based upon algorithms and data kindly
// provided by Mr. Paul Schlyter. (pausch@saaf.se).
//
// Separated out rendering pieces and converted to ssg by Curt Olson,
// March 2000
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Library General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public
// License along with this library; if not, write to the
// Free Software Foundation, Inc., 59 Temple Place - Suite 330,
// Boston, MA 02111-1307, USA.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <simgear/compiler.h>
#include <stdio.h>
#include <iostream>
#include <plib/sg.h>
#include <plib/ssg.h>
#include <simgear/constants.h>
#include "sphere.hxx"
#include "moon.hxx"
// Set up moon rendering call backs
static int sgMoonOrbPreDraw( ssgEntity *e ) {
/* cout << endl << "Moon orb pre draw" << endl << "----------------"
<< endl << endl; */
ssgLeaf *f = (ssgLeaf *)e;
if ( f -> hasState () ) f->getState()->apply() ;
glPushAttrib( GL_COLOR_BUFFER_BIT | GL_ENABLE_BIT );
// cout << "push error = " << glGetError() << endl;
glDisable( GL_DEPTH_TEST );
glDisable( GL_FOG );
glBlendFunc ( GL_SRC_ALPHA, GL_ONE ) ;
return true;
}
static int sgMoonOrbPostDraw( ssgEntity *e ) {
/* cout << endl << "Moon orb post draw" << endl << "----------------"
<< endl << endl; */
// glEnable( GL_DEPTH_TEST );
// glEnable( GL_FOG );
// glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
glPopAttrib();
// cout << "pop error = " << glGetError() << endl;
/* test
glDisable( GL_LIGHTING );
glDisable( GL_CULL_FACE );
glEnable( GL_COLOR_MATERIAL );
glColorMaterial( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE );
glEnable( GL_CULL_FACE );
glEnable( GL_LIGHTING ); */
return true;
}
static int sgMoonHaloPreDraw( ssgEntity *e ) {
/* cout << endl << "Moon halo pre draw" << endl << "----------------"
<< endl << endl; */
ssgLeaf *f = (ssgLeaf *)e;
if ( f -> hasState () ) f->getState()->apply() ;
glPushAttrib( GL_DEPTH_BUFFER_BIT | GL_FOG_BIT | GL_COLOR_BUFFER_BIT);
// cout << "push error = " << glGetError() << endl;
glDisable( GL_DEPTH_TEST );
glDisable( GL_FOG );
glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
return true;
}
static int sgMoonHaloPostDraw( ssgEntity *e ) {
/* cout << endl << "Moon halo post draw" << endl << "----------------"
<< endl << endl; */
// glEnable( GL_DEPTH_TEST );
// glEnable( GL_FOG );
// glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
glPopAttrib();
// cout << "pop error = " << glGetError() << endl;
return true;
}
// Constructor
SGMoon::SGMoon( void ) {
}
// Destructor
SGMoon::~SGMoon( void ) {
}
// build the moon object
ssgBranch * SGMoon::build( FGPath path, double moon_size ) {
// set up the orb state
path.append( "moon.rgba" );
orb_state = new ssgSimpleState();
orb_state->setTexture( (char *)path.c_str() );
orb_state->setShadeModel( GL_SMOOTH );
orb_state->enable( GL_LIGHTING );
orb_state->enable( GL_CULL_FACE );
orb_state->enable( GL_TEXTURE_2D );
orb_state->enable( GL_COLOR_MATERIAL );
orb_state->setColourMaterial( GL_DIFFUSE );
orb_state->setMaterial( GL_AMBIENT, 0, 0, 0, 1.0 );
orb_state->setMaterial( GL_EMISSION, 0, 0, 0, 1 );
orb_state->setMaterial( GL_SPECULAR, 0, 0, 0, 1 );
orb_state->enable( GL_BLEND );
orb_state->enable( GL_ALPHA_TEST );
orb_state->setAlphaClamp( 0.01 );
cl = new ssgColourArray( 1 );
sgVec4 color;
sgSetVec4( color, 1.0, 1.0, 1.0, 1.0 );
cl->add( color );
ssgBranch *orb = ssgMakeSphere( orb_state, cl, moon_size, 15, 15,
sgMoonOrbPreDraw, sgMoonOrbPostDraw );
// force a repaint of the moon colors with arbitrary defaults
repaint( 0.0 );
// build the halo
// moon_texbuf = new GLubyte[64*64*3];
// moon_texid = makeHalo( moon_texbuf, 64 );
// my_glWritePPMFile("moonhalo.ppm", moon_texbuf, 64, 64, RGB);
#if 0
// set up the halo state
halo_state = new ssgSimpleState();
halo_state->setTexture( "halo.rgb" );
// halo_state->setTexture( moon_texid );
halo_state->enable( GL_TEXTURE_2D );
halo_state->disable( GL_LIGHTING );
halo_state->setShadeModel( GL_SMOOTH );
halo_state->disable( GL_CULL_FACE );
halo_state->disable( GL_COLOR_MATERIAL );
halo_state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
halo_state->setMaterial ( GL_AMBIENT_AND_DIFFUSE, 1, 1, 1, 1 ) ;
halo_state->setMaterial ( GL_EMISSION, 0, 0, 0, 1 ) ;
halo_state->setMaterial ( GL_SPECULAR, 0, 0, 0, 1 ) ;
// halo_state -> setShininess ( 0 ) ;
halo_state->enable( GL_ALPHA_TEST );
halo_state->setAlphaClamp(0.01);
halo_state->enable ( GL_BLEND ) ;
// Build ssg structure
double size = moon_size * 10.0;
sgVec3 v3;
halo_vl = new ssgVertexArray;
sgSetVec3( v3, -size, 0.0, -size );
halo_vl->add( v3 );
sgSetVec3( v3, size, 0.0, -size );
halo_vl->add( v3 );
sgSetVec3( v3, -size, 0.0, size );
halo_vl->add( v3 );
sgSetVec3( v3, size, 0.0, size );
halo_vl->add( v3 );
sgVec2 v2;
halo_tl = new ssgTexCoordArray;
sgSetVec2( v2, 0.0f, 0.0f );
halo_tl->add( v2 );
sgSetVec2( v2, 1.0, 0.0 );
halo_tl->add( v2 );
sgSetVec2( v2, 0.0, 1.0 );
halo_tl->add( v2 );
sgSetVec2( v2, 1.0, 1.0 );
halo_tl->add( v2 );
ssgLeaf *halo =
new ssgVtxTable ( GL_TRIANGLE_STRIP, halo_vl, NULL, halo_tl, cl );
halo->setState( halo_state );
#endif
// build the ssg scene graph sub tree for the sky and connected
// into the provide scene graph branch
moon_transform = new ssgTransform;
// moon_transform->addKid( halo );
moon_transform->addKid( orb );
return moon_transform;
}
// repaint the moon colors based on current value of moon_angle in
// degrees relative to verticle
// 0 degrees = high noon
// 90 degrees = moon rise/set
// 180 degrees = darkest midnight
bool SGMoon::repaint( double moon_angle ) {
if ( moon_angle * SGD_RADIANS_TO_DEGREES < 100 ) {
// else moon is well below horizon (so no point in repainting it)
// x_10 = moon_angle^10
double x_10 = moon_angle * moon_angle * moon_angle * moon_angle
* moon_angle * moon_angle * moon_angle * moon_angle * moon_angle
* moon_angle;
float ambient = (float)(0.4 * pow (1.1, - x_10 / 30.0));
if (ambient < 0.3) { ambient = 0.3; }
if (ambient > 1.0) { ambient = 1.0; }
sgVec4 color;
sgSetVec4( color,
(ambient * 6.0) - 1.0, // minimum value = 0.8
(ambient * 11.0) - 3.0, // minimum value = 0.3
(ambient * 12.0) - 3.6, // minimum value = 0.0
0.5 );
// temp test, forces the color to always be white
// sgSetVec4( color, 1.0, 1.0, 1.0, 1.0 );
if (color[0] > 1.0) color[0] = 1.0;
if (color[1] > 1.0) color[1] = 1.0;
if (color[2] > 1.0) color[2] = 1.0;
// cout << "color = " << color[0] << " " << color[1] << " "
// << color[2] << endl;
float *ptr;
ptr = cl->get( 0 );
sgCopyVec4( ptr, color );
}
return true;
}
// reposition the moon at the specified right ascension and
// declination, offset by our current position (p) so that it appears
// fixed at a great distance from the viewer. Also add in an optional
// rotation (i.e. for the current time of day.)
bool SGMoon::reposition( sgVec3 p, double angle,
double rightAscension, double declination,
double moon_dist )
{
sgMat4 T1, T2, GST, RA, DEC;
sgVec3 axis;
sgVec3 v;
sgMakeTransMat4( T1, p );
sgSetVec3( axis, 0.0, 0.0, -1.0 );
sgMakeRotMat4( GST, angle, axis );
// xglRotatef( ((SGD_RADIANS_TO_DEGREES * rightAscension)- 90.0),
// 0.0, 0.0, 1.0);
sgSetVec3( axis, 0.0, 0.0, 1.0 );
sgMakeRotMat4( RA, (rightAscension * SGD_RADIANS_TO_DEGREES) - 90.0, axis );
// xglRotatef((SGD_RADIANS_TO_DEGREES * declination), 1.0, 0.0, 0.0);
sgSetVec3( axis, 1.0, 0.0, 0.0 );
sgMakeRotMat4( DEC, declination * SGD_RADIANS_TO_DEGREES, axis );
// xglTranslatef(0,moon_dist);
sgSetVec3( v, 0.0, moon_dist, 0.0 );
sgMakeTransMat4( T2, v );
sgMat4 TRANSFORM;
sgCopyMat4( TRANSFORM, T1 );
sgPreMultMat4( TRANSFORM, GST );
sgPreMultMat4( TRANSFORM, RA );
sgPreMultMat4( TRANSFORM, DEC );
sgPreMultMat4( TRANSFORM, T2 );
sgCoord skypos;
sgSetCoord( &skypos, TRANSFORM );
moon_transform->setTransform( &skypos );
return true;
}