1 // moon.hxx -- model earth's moon
3 // Written by Durk Talsma. Originally started October 1997, for distribution
4 // with the FlightGear project. Version 2 was written in August and
5 // September 1998. This code is based upon algorithms and data kindly
6 // provided by Mr. Paul Schlyter. (pausch@saaf.se).
8 // Separated out rendering pieces and converted to ssg by Curt Olson,
10 // This library is free software; you can redistribute it and/or
11 // modify it under the terms of the GNU Library General Public
12 // License as published by the Free Software Foundation; either
13 // version 2 of the License, or (at your option) any later version.
15 // This library is distributed in the hope that it will be useful,
16 // but WITHOUT ANY WARRANTY; without even the implied warranty of
17 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 // Library General Public License for more details.
20 // You should have received a copy of the GNU Library General Public
21 // License along with this library; if not, write to the
22 // Free Software Foundation, Inc., 59 Temple Place - Suite 330,
23 // Boston, MA 02111-1307, USA.
28 #include <simgear/compiler.h>
36 #include <simgear/constants.h>
37 #include <simgear/screen/colors.hxx>
43 // Set up moon rendering call backs
44 static int sgMoonOrbPreDraw( ssgEntity *e ) {
45 /* cout << endl << "Moon orb pre draw" << endl << "----------------"
48 ssgLeaf *f = (ssgLeaf *)e;
49 if ( f -> hasState () ) f->getState()->apply() ;
51 glPushAttrib( GL_COLOR_BUFFER_BIT | GL_ENABLE_BIT );
52 // cout << "push error = " << glGetError() << endl;
54 glDisable( GL_DEPTH_TEST );
56 glBlendFunc ( GL_SRC_ALPHA, GL_ONE ) ;
62 static int sgMoonOrbPostDraw( ssgEntity *e ) {
63 /* cout << endl << "Moon orb post draw" << endl << "----------------"
65 // glEnable( GL_DEPTH_TEST );
66 // glEnable( GL_FOG );
68 // Some drivers don't properly reset glBendFunc with a
69 // glPopAttrib() so we reset it to the 'default' here.
70 glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
73 // cout << "pop error = " << glGetError() << endl;
76 glDisable( GL_LIGHTING );
77 glDisable( GL_CULL_FACE );
78 glEnable( GL_COLOR_MATERIAL );
79 glColorMaterial( GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE );
80 glEnable( GL_CULL_FACE );
81 glEnable( GL_LIGHTING ); */
88 static int sgMoonHaloPreDraw( ssgEntity *e ) {
89 /* cout << endl << "Moon halo pre draw" << endl << "----------------"
92 ssgLeaf *f = (ssgLeaf *)e;
93 if ( f -> hasState () ) f->getState()->apply() ;
95 glPushAttrib( GL_DEPTH_BUFFER_BIT | GL_FOG_BIT | GL_COLOR_BUFFER_BIT);
96 // cout << "push error = " << glGetError() << endl;
98 glDisable( GL_DEPTH_TEST );
100 glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
105 static int sgMoonHaloPostDraw( ssgEntity *e ) {
106 /* cout << endl << "Moon halo post draw" << endl << "----------------"
108 // glEnable( GL_DEPTH_TEST );
109 // glEnable( GL_FOG );
110 // glBlendFunc ( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA ) ;
113 // cout << "pop error = " << glGetError() << endl;
121 SGMoon::SGMoon( void ) {
126 SGMoon::~SGMoon( void ) {
130 // build the moon object
131 ssgBranch * SGMoon::build( SGPath path, double moon_size ) {
133 // set up the orb state
134 path.append( "moon.rgba" );
135 orb_state = new ssgSimpleState();
136 orb_state->setTexture( (char *)path.c_str() );
137 orb_state->setShadeModel( GL_SMOOTH );
138 orb_state->enable( GL_LIGHTING );
139 orb_state->enable( GL_CULL_FACE );
140 orb_state->enable( GL_TEXTURE_2D );
141 orb_state->enable( GL_COLOR_MATERIAL );
142 orb_state->setColourMaterial( GL_DIFFUSE );
143 orb_state->setMaterial( GL_AMBIENT, 0, 0, 0, 1.0 );
144 orb_state->setMaterial( GL_EMISSION, 0.1, 0.1, 0.1, 1 );
145 orb_state->setMaterial( GL_SPECULAR, 0, 0, 0, 1 );
146 orb_state->enable( GL_BLEND );
147 orb_state->enable( GL_ALPHA_TEST );
148 orb_state->setAlphaClamp( 0.01 );
150 cl = new ssgColourArray( 1 );
152 sgSetVec4( color, 1.0, 1.0, 1.0, 1.0 );
155 ssgBranch *orb = ssgMakeSphere( orb_state, cl, moon_size, 15, 15,
156 sgMoonOrbPreDraw, sgMoonOrbPostDraw );
158 // force a repaint of the moon colors with arbitrary defaults
162 // moon_texbuf = new GLubyte[64*64*3];
163 // moon_texid = makeHalo( moon_texbuf, 64 );
164 // my_glWritePPMFile("moonhalo.ppm", moon_texbuf, 64, 64, RGB);
167 // set up the halo state
168 halo_state = new ssgSimpleState();
169 halo_state->setTexture( "halo.rgb" );
170 // halo_state->setTexture( moon_texid );
171 halo_state->enable( GL_TEXTURE_2D );
172 halo_state->disable( GL_LIGHTING );
173 halo_state->setShadeModel( GL_SMOOTH );
174 halo_state->disable( GL_CULL_FACE );
176 halo_state->disable( GL_COLOR_MATERIAL );
177 halo_state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
178 halo_state->setMaterial ( GL_AMBIENT_AND_DIFFUSE, 1, 1, 1, 1 ) ;
179 halo_state->setMaterial ( GL_EMISSION, 0, 0, 0, 1 ) ;
180 halo_state->setMaterial ( GL_SPECULAR, 0, 0, 0, 1 ) ;
181 // halo_state -> setShininess ( 0 ) ;
182 halo_state->enable( GL_ALPHA_TEST );
183 halo_state->setAlphaClamp(0.01);
184 halo_state->enable ( GL_BLEND ) ;
187 // Build ssg structure
188 double size = moon_size * 10.0;
190 halo_vl = new ssgVertexArray;
191 sgSetVec3( v3, -size, 0.0, -size );
193 sgSetVec3( v3, size, 0.0, -size );
195 sgSetVec3( v3, -size, 0.0, size );
197 sgSetVec3( v3, size, 0.0, size );
201 halo_tl = new ssgTexCoordArray;
202 sgSetVec2( v2, 0.0f, 0.0f );
204 sgSetVec2( v2, 1.0, 0.0 );
206 sgSetVec2( v2, 0.0, 1.0 );
208 sgSetVec2( v2, 1.0, 1.0 );
212 new ssgVtxTable ( GL_TRIANGLE_STRIP, halo_vl, NULL, halo_tl, cl );
213 halo->setState( halo_state );
216 // build the ssg scene graph sub tree for the sky and connected
217 // into the provide scene graph branch
218 moon_transform = new ssgTransform;
220 // moon_transform->addKid( halo );
221 moon_transform->addKid( orb );
223 return moon_transform;
227 // repaint the moon colors based on current value of moon_angle in
228 // degrees relative to verticle
229 // 0 degrees = high noon
230 // 90 degrees = moon rise/set
231 // 180 degrees = darkest midnight
232 bool SGMoon::repaint( double moon_angle ) {
234 if (prev_moon_angle != moon_angle) {
235 prev_moon_angle = moon_angle;
237 float moon_factor = 4*cos(moon_angle);
239 if (moon_factor > 1) moon_factor = 1.0;
240 if (moon_factor < -1) moon_factor = -1.0;
241 moon_factor = moon_factor/2 + 0.5;
244 color[1] = sqrt(moon_factor);
245 color[0] = sqrt(color[1]);
246 color[2] = moon_factor * moon_factor;
247 color[2] *= color[2];
250 gamma_correct_rgb( color );
252 // cout << "color = " << color[0] << " " << color[1] << " "
253 // << color[2] << endl;
257 sgCopyVec4( ptr, color );
264 // reposition the moon at the specified right ascension and
265 // declination, offset by our current position (p) so that it appears
266 // fixed at a great distance from the viewer. Also add in an optional
267 // rotation (i.e. for the current time of day.)
268 bool SGMoon::reposition( sgVec3 p, double angle,
269 double rightAscension, double declination,
272 sgMat4 T1, T2, GST, RA, DEC;
276 sgMakeTransMat4( T1, p );
278 sgSetVec3( axis, 0.0, 0.0, -1.0 );
279 sgMakeRotMat4( GST, angle, axis );
281 // xglRotatef( ((SGD_RADIANS_TO_DEGREES * rightAscension)- 90.0),
283 sgSetVec3( axis, 0.0, 0.0, 1.0 );
284 sgMakeRotMat4( RA, (rightAscension * SGD_RADIANS_TO_DEGREES) - 90.0, axis );
286 // xglRotatef((SGD_RADIANS_TO_DEGREES * declination), 1.0, 0.0, 0.0);
287 sgSetVec3( axis, 1.0, 0.0, 0.0 );
288 sgMakeRotMat4( DEC, declination * SGD_RADIANS_TO_DEGREES, axis );
290 // xglTranslatef(0,moon_dist);
291 sgSetVec3( v, 0.0, moon_dist, 0.0 );
292 sgMakeTransMat4( T2, v );
295 sgCopyMat4( TRANSFORM, T1 );
296 sgPreMultMat4( TRANSFORM, GST );
297 sgPreMultMat4( TRANSFORM, RA );
298 sgPreMultMat4( TRANSFORM, DEC );
299 sgPreMultMat4( TRANSFORM, T2 );
302 sgSetCoord( &skypos, TRANSFORM );
304 moon_transform->setTransform( &skypos );