simgear/scene/sky/cloud.cxx

   1 // cloud.cxx -- model a single cloud layer
   2 //
   3 // Written by Curtis Olson, started June 2000.
   4 //
   5 // Copyright (C) 2000  Curtis L. Olson  - curt@flightgear.org
   6 //
   7 // This program is distributed in the hope that it will be useful, but
   8 // WITHOUT ANY WARRANTY; without even the implied warranty of
   9 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  10 // General Public License for more details.
  11 //
  12 // You should have received a copy of the GNU General Public License
  13 // along with this program; if not, write to the Free Software
  14 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  15 //
  16 // $Id$
  17
  18
  19 #include <simgear/compiler.h>
  20
  21 // #include <stdio.h>
  22 #include <math.h>
  23
  24 // #if defined (__APPLE__)
  25 // // any C++ header file undefines isinf and isnan
  26 // // so this should be included before <iostream>
  27 // inline int (isinf)(double r) { return isinf(r); }
  28 // inline int (isnan)(double r) { return isnan(r); }
  29 // #endif
  30
  31 // #include STL_IOSTREAM
  32
  33 #include <plib/sg.h>
  34 #include <plib/ssg.h>
  35
  36 #include <simgear/math/point3d.hxx>
  37 #include <simgear/math/polar3d.hxx>
  38 #include <simgear/math/sg_random.h>
  39 #include <simgear/debug/logstream.hxx>
  40 #include <simgear/misc/sg_path.hxx>
  41 #include <simgear/screen/extensions.hxx>
  42 #include <simgear/screen/texture.hxx>
  43
  44 #include "cloud.hxx"
  45
  46
  47 static ssgStateSelector *layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
  48 static bool state_initialized = false;
  49 static bool bump_mapping = false;
  50 static int nb_texture_unit = 0;
  51 static ssgTexture *normal_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2] = { 0 };
  52 static ssgTexture *color_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2] = { 0 };
  53 static GLuint normalization_cube_map;
  54
  55 static glActiveTextureProc glActiveTexturePtr = 0;
  56 static glClientActiveTextureProc glClientActiveTexturePtr = 0;
  57
  58 bool SGCloudLayer::enable_bump_mapping = false;
  59
  60 static void
  61 generateNormalizationCubeMap()
  62 {
  63     unsigned char data[ 32 * 32 * 3 ];
  64     const int size = 32;
  65     const float half_size = 16.0f,
  66                 offset = 0.5f;
  67     sgVec3 zero_normal;
  68     sgSetVec3( zero_normal, 0.5f, 0.5f, 0.5f );
  69     int i, j;
  70
  71     unsigned char *ptr = data;
  72     for ( j = 0; j < size; j++ ) {
  73         for ( i = 0; i < size; i++ ) {
  74             sgVec3 tmp;
  75             sgSetVec3( tmp, half_size,
  76                             -( j + offset - half_size ),
  77                             -( i + offset - half_size ) );
  78             sgNormalizeVec3( tmp );
  79             sgScaleVec3( tmp, 0.5f );
  80             sgAddVec3( tmp, zero_normal );
  81
  82             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
  83             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
  84             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
  85         }
  86     }
  87     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
  88                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
  89
  90     ptr = data;
  91     for ( j = 0; j < size; j++ ) {
  92         for ( i = 0; i < size; i++ ) {
  93             sgVec3 tmp;
  94             sgSetVec3( tmp, -half_size,
  95                             -( j + offset - half_size ),
  96                             ( i + offset - half_size ) );
  97             sgNormalizeVec3( tmp );
  98             sgScaleVec3( tmp, 0.5f );
  99             sgAddVec3( tmp, zero_normal );
 100
 101             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 102             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 103             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 104         }
 105     }
 106     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 107                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 108
 109     ptr = data;
 110     for ( j = 0; j < size; j++ ) {
 111         for ( i = 0; i < size; i++ ) {
 112             sgVec3 tmp;
 113             sgSetVec3( tmp, ( i + offset - half_size ),
 114                             half_size,
 115                             ( j + offset - half_size ) );
 116             sgNormalizeVec3( tmp );
 117             sgScaleVec3( tmp, 0.5f );
 118             sgAddVec3( tmp, zero_normal );
 119
 120             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 121             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 122             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 123         }
 124     }
 125     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 126                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 127
 128     ptr = data;
 129     for ( j = 0; j < size; j++ ) {
 130         for ( i = 0; i < size; i++ ) {
 131             sgVec3 tmp;
 132             sgSetVec3( tmp, ( i + offset - half_size ),
 133                             -half_size,
 134                             -( j + offset - half_size ) );
 135             sgNormalizeVec3( tmp );
 136             sgScaleVec3( tmp, 0.5f );
 137             sgAddVec3( tmp, zero_normal );
 138
 139             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 140             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 141             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 142         }
 143     }
 144     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 145                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 146
 147     ptr = data;
 148     for ( j = 0; j < size; j++ ) {
 149         for ( i = 0; i < size; i++ ) {
 150             sgVec3 tmp;
 151             sgSetVec3( tmp, ( i + offset - half_size ),
 152                             -( j + offset - half_size ),
 153                             half_size );
 154             sgNormalizeVec3( tmp );
 155             sgScaleVec3( tmp, 0.5f );
 156             sgAddVec3( tmp, zero_normal );
 157
 158             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 159             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 160             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 161         }
 162     }
 163     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 164                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 165
 166     ptr = data;
 167     for ( j = 0; j < size; j++ ) {
 168         for ( i = 0; i < size; i++ ) {
 169             sgVec3 tmp;
 170             sgSetVec3( tmp, -( i + offset - half_size ),
 171                             -( j + offset - half_size ),
 172                             -half_size );
 173             sgNormalizeVec3( tmp );
 174             sgScaleVec3( tmp, 0.5f );
 175             sgAddVec3( tmp, zero_normal );
 176
 177             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 178             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 179             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 180         }
 181     }
 182     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB,
 183                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 184 }
 185
 186
 187 // Constructor
 188 SGCloudLayer::SGCloudLayer( const string &tex_path ) :
 189     layer_root(new ssgRoot),
 190     layer_transform(new ssgTransform),
 191     state_sel(0),
 192     texture_path(tex_path),
 193     layer_span(0.0),
 194     layer_asl(0.0),
 195     layer_thickness(0.0),
 196     layer_transition(0.0),
 197     layer_coverage(SG_CLOUD_CLEAR),
 198     scale(4000.0),
 199     speed(0.0),
 200     direction(0.0),
 201     last_lon(0.0),
 202     last_lat(0.0),
 203     vertices(0),
 204     indices(0)
 205 {
 206     cl[0] = cl[1] = cl[2] = cl[3] = NULL;
 207     vl[0] = vl[1] = vl[2] = vl[3] = NULL;
 208     tl[0] = tl[1] = tl[2] = tl[3] = NULL;
 209     layer[0] = layer[1] = layer[2] = layer[3] = NULL;
 210
 211     layer_root->addKid(layer_transform);
 212     rebuild();
 213 }
 214
 215 // Destructor
 216 SGCloudLayer::~SGCloudLayer()
 217 {
 218     delete vertices;
 219     delete indices;
 220     delete layer_root;          // deletes layer_transform and layer as well
 221 }
 222
 223 float
 224 SGCloudLayer::getSpan_m () const
 225 {
 226     return layer_span;
 227 }
 228
 229 void
 230 SGCloudLayer::setSpan_m (float span_m)
 231 {
 232     if (span_m != layer_span) {
 233         layer_span = span_m;
 234         rebuild();
 235     }
 236 }
 237
 238 float
 239 SGCloudLayer::getElevation_m () const
 240 {
 241     return layer_asl;
 242 }
 243
 244 void
 245 SGCloudLayer::setElevation_m (float elevation_m, bool set_span)
 246 {
 247     layer_asl = elevation_m;
 248
 249     if (set_span) {
 250         if (elevation_m > 4000)
 251             setSpan_m(  elevation_m * 10 );
 252         else
 253             setSpan_m( 40000 );
 254     }
 255 }
 256
 257 float
 258 SGCloudLayer::getThickness_m () const
 259 {
 260     return layer_thickness;
 261 }
 262
 263 void
 264 SGCloudLayer::setThickness_m (float thickness_m)
 265 {
 266     layer_thickness = thickness_m;
 267 }
 268
 269 float
 270 SGCloudLayer::getTransition_m () const
 271 {
 272     return layer_transition;
 273 }
 274
 275 void
 276 SGCloudLayer::setTransition_m (float transition_m)
 277 {
 278     layer_transition = transition_m;
 279 }
 280
 281 SGCloudLayer::Coverage
 282 SGCloudLayer::getCoverage () const
 283 {
 284     return layer_coverage;
 285 }
 286
 287 void
 288 SGCloudLayer::setCoverage (Coverage coverage)
 289 {
 290     if (coverage != layer_coverage) {
 291         layer_coverage = coverage;
 292         rebuild();
 293     }
 294 }
 295
 296
 297 // build the cloud object
 298 void
 299 SGCloudLayer::rebuild()
 300 {
 301     // Initialize states and sizes if necessary.
 302     if ( !state_initialized ) {
 303         state_initialized = true;
 304
 305         SG_LOG(SG_ASTRO, SG_INFO, "initializing cloud layers");
 306
 307         bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
 308                        SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
 309                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
 310                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") && true;
 311
 312         if ( bump_mapping ) {
 313             glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
 314             if ( nb_texture_unit < 2 ) {
 315                 bump_mapping = false;
 316             }
 317         }
 318
 319         if ( bump_mapping ) {
 320
 321             // This bump mapping code was inspired by the tutorial available at
 322             // http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
 323             // and a NVidia white paper
 324             //  http://developer.nvidia.com/object/bumpmappingwithregistercombiners.html
 325             // The normal map textures were generated by the normal map Gimp plugin :
 326             //  http://nifelheim.dyndns.org/~cocidius/normalmap/
 327             //
 328             SGPath cloud_path;
 329
 330             glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
 331             glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
 332
 333             cloud_path.set(texture_path.str());
 334             cloud_path.append("overcast.rgb");
 335             color_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 336             color_map[ SG_CLOUD_OVERCAST ][ 0 ]->ref();
 337             cloud_path.set(texture_path.str());
 338             cloud_path.append("overcast_n.rgb");
 339             normal_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 340             normal_map[ SG_CLOUD_OVERCAST ][ 0 ]->ref();
 341
 342             cloud_path.set(texture_path.str());
 343             cloud_path.append("overcast_top.rgb");
 344             color_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 345             color_map[ SG_CLOUD_OVERCAST ][ 1 ]->ref();
 346             cloud_path.set(texture_path.str());
 347             cloud_path.append("overcast_top_n.rgb");
 348             normal_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 349             normal_map[ SG_CLOUD_OVERCAST ][ 1 ]->ref();
 350
 351             cloud_path.set(texture_path.str());
 352             cloud_path.append("broken.rgba");
 353             color_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 354             color_map[ SG_CLOUD_BROKEN ][ 0 ]->ref();
 355             cloud_path.set(texture_path.str());
 356             cloud_path.append("broken_n.rgb");
 357             normal_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 358             normal_map[ SG_CLOUD_BROKEN ][ 0 ]->ref();
 359
 360             cloud_path.set(texture_path.str());
 361             cloud_path.append("scattered.rgba");
 362             color_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 363             color_map[ SG_CLOUD_SCATTERED ][ 0 ]->ref();
 364             cloud_path.set(texture_path.str());
 365             cloud_path.append("scattered_n.rgb");
 366             normal_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 367             normal_map[ SG_CLOUD_SCATTERED ][ 0 ]->ref();
 368
 369             cloud_path.set(texture_path.str());
 370             cloud_path.append("few.rgba");
 371             color_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 372             color_map[ SG_CLOUD_FEW ][ 0 ]->ref();
 373             cloud_path.set(texture_path.str());
 374             cloud_path.append("few_n.rgb");
 375             normal_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 376             normal_map[ SG_CLOUD_FEW ][ 0 ]->ref();
 377
 378             cloud_path.set(texture_path.str());
 379             cloud_path.append("cirrus.rgba");
 380             color_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 381             color_map[ SG_CLOUD_CIRRUS ][ 0 ]->ref();
 382             cloud_path.set(texture_path.str());
 383             cloud_path.append("cirrus_n.rgb");
 384             normal_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 385             normal_map[ SG_CLOUD_CIRRUS ][ 0 ]->ref();
 386
 387             glGenTextures( 1, &normalization_cube_map );
 388             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 389             generateNormalizationCubeMap();
 390             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 391             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 392             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 393             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 394             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE );
 395         } /* else */ {
 396             SGPath cloud_path;
 397             ssgStateSelector *state_sel;
 398             ssgSimpleState *state;
 399
 400             state_sel = new ssgStateSelector( 2 );
 401             state_sel->ref();
 402             cloud_path.set(texture_path.str());
 403             cloud_path.append("overcast.rgb");
 404             state_sel->setStep( 0, sgCloudMakeState(cloud_path.str()) );
 405             cloud_path.set(texture_path.str());
 406             cloud_path.append("overcast_top.rgb");
 407             state_sel->setStep( 1, sgCloudMakeState(cloud_path.str()) );
 408             layer_states[SG_CLOUD_OVERCAST] = state_sel;
 409
 410             state_sel = new ssgStateSelector( 2 );
 411             state_sel->ref();
 412             cloud_path.set(texture_path.str());
 413             cloud_path.append("broken.rgba");
 414             state = sgCloudMakeState(cloud_path.str());
 415             state_sel->setStep( 0, state );
 416             state_sel->setStep( 1, state );
 417             layer_states[SG_CLOUD_BROKEN] = state_sel;
 418
 419             state_sel = new ssgStateSelector( 2 );
 420             state_sel->ref();
 421             cloud_path.set(texture_path.str());
 422             cloud_path.append("scattered.rgba");
 423             state = sgCloudMakeState(cloud_path.str());
 424             state_sel->setStep( 0, state );
 425             state_sel->setStep( 1, state );
 426             layer_states[SG_CLOUD_SCATTERED] = state_sel;
 427
 428             state_sel = new ssgStateSelector( 2 );
 429             state_sel->ref();
 430             cloud_path.set(texture_path.str());
 431             cloud_path.append("few.rgba");
 432             state = sgCloudMakeState(cloud_path.str());
 433             state_sel->setStep( 0, state );
 434             state_sel->setStep( 1, state );
 435             layer_states[SG_CLOUD_FEW] = state_sel;
 436
 437             state_sel = new ssgStateSelector( 2 );
 438             state_sel->ref();
 439             cloud_path.set(texture_path.str());
 440             cloud_path.append("cirrus.rgba");
 441             state = sgCloudMakeState(cloud_path.str());
 442             state_sel->setStep( 0, state );
 443             state_sel->setStep( 1, state );
 444             layer_states[SG_CLOUD_CIRRUS] = state_sel;
 445
 446             layer_states[SG_CLOUD_CLEAR] = 0;
 447         }
 448     }
 449
 450     if ( bump_mapping ) {
 451
 452         if ( !vertices ) {
 453             vertices = new CloudVertex[ 25 ];
 454             indices = new unsigned int[ 40 ];
 455         }
 456
 457         sgVec2 base;
 458         sgSetVec2( base, sg_random(), sg_random() );
 459
 460         const float layer_scale = layer_span / scale;
 461         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 462         const float half_angle = 0.5 * layer_span / layer_to_core;
 463
 464         int i;
 465         for ( i = -2; i <= 2; i++ ) {
 466             for ( int j = -2; j <= 2; j++ ) {
 467                 CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 468                 sgSetVec3( v1.position,
 469                            0.5 * i * layer_span,
 470                            0.5 * j * layer_span,
 471                            -layer_to_core * ( 1 - cos( i * half_angle ) * cos( j * half_angle ) ) );
 472                 sgSetVec2( v1.texCoord,
 473                            base[0] + layer_scale * i * 0.25,
 474                            base[1] + layer_scale * j * 0.25 );
 475                 sgSetVec3( v1.sTangent,
 476                            cos( i * half_angle ),
 477                            0.f,
 478                            -sin( i * half_angle ) );
 479                 sgSetVec3( v1.tTangent,
 480                            0.f,
 481                            cos( j * half_angle ),
 482                            -sin( j * half_angle ) );
 483                 sgVectorProductVec3( v1.normal, v1.tTangent, v1.sTangent );
 484                 sgSetVec4( v1.color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 485             }
 486         }
 487         /*
 488          * 0 1 5 6 10 11 15 16 20 21
 489          * 1 2 6 7 11 12 16 17 21 22
 490          * 2 3 7 8 12 13 17 18 22 23
 491          * 3 4 8 9 13 14 18 19 23 24
 492          */
 493         for ( i = 0; i < 4; i++ ) {
 494             for ( int j = 0; j < 5; j++ ) {
 495                 indices[ i*10 + (j*2) ]     =     i + 5 * j;
 496                 indices[ i*10 + (j*2) + 1 ] = 1 + i + 5 * j;
 497             }
 498         }
 499
 500     } /* else */ {
 501
 502         scale = 4000.0;
 503         last_lon = last_lat = -999.0f;
 504
 505         sgVec2 base;
 506         sgSetVec2( base, sg_random(), sg_random() );
 507
 508         // build the cloud layer
 509         sgVec4 color;
 510         sgVec3 vertex;
 511         sgVec2 tc;
 512
 513         const float layer_scale = layer_span / scale;
 514         const float mpi = SG_PI/4;
 515
 516         // caclculate the difference between a flat-earth model and
 517         // a round earth model given the span and altutude ASL of
 518         // the cloud layer. This is the difference in altitude between
 519         // the top of the inverted bowl and the edge of the bowl.
 520         // const float alt_diff = layer_asl * 0.8;
 521         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 522         const float layer_angle = 0.5*layer_span / layer_to_core; // The angle is half the span
 523         const float border_to_core = layer_to_core * cos(layer_angle);
 524         const float alt_diff = layer_to_core - border_to_core;
 525
 526         for (int i = 0; i < 4; i++)
 527         {
 528             if ( layer[i] != NULL ) {
 529                 layer_transform->removeKid(layer[i]); // automatic delete
 530             }
 531
 532             vl[i] = new ssgVertexArray( 10 );
 533             cl[i] = new ssgColourArray( 10 );
 534             tl[i] = new ssgTexCoordArray( 10 );
 535
 536
 537             sgSetVec3( vertex, layer_span*(i-2)/2, -layer_span,
 538                             alt_diff * (sin(i*mpi) - 2) );
 539
 540             sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 541
 542             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 543
 544             cl[i]->add( color );
 545             vl[i]->add( vertex );
 546             tl[i]->add( tc );
 547
 548             for (int j = 0; j < 4; j++)
 549             {
 550                 sgSetVec3( vertex, layer_span*(i-1)/2, layer_span*(j-2)/2,
 551                                 alt_diff * (sin((i+1)*mpi) + sin(j*mpi) - 2) );
 552
 553                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 554                             base[1] + layer_scale * j/4 );
 555
 556                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 557                                 ( (j == 0) || (i == 3)) ?
 558                                 ( (j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f );
 559
 560                 cl[i]->add( color );
 561                 vl[i]->add( vertex );
 562                 tl[i]->add( tc );
 563
 564
 565                 sgSetVec3( vertex, layer_span*(i-2)/2, layer_span*(j-1)/2,
 566                                 alt_diff * (sin(i*mpi) + sin((j+1)*mpi) - 2) );
 567
 568                 sgSetVec2( tc, base[0] + layer_scale * i/4,
 569                             base[1] + layer_scale * (j+1)/4 );
 570
 571                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 572                                 ((j == 3) || (i == 0)) ?
 573                                 ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f );
 574                 cl[i]->add( color );
 575                 vl[i]->add( vertex );
 576                 tl[i]->add( tc );
 577             }
 578
 579             sgSetVec3( vertex, layer_span*(i-1)/2, layer_span,
 580                             alt_diff * (sin((i+1)*mpi) - 2) );
 581
 582             sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 583                         base[1] + layer_scale );
 584
 585             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 3) ? 0.0f : 0.15f );
 586
 587             cl[i]->add( color );
 588             vl[i]->add( vertex );
 589             tl[i]->add( tc );
 590
 591             layer[i] = new ssgVtxTable(GL_TRIANGLE_STRIP, vl[i], NULL, tl[i], cl[i]);
 592             layer_transform->addKid( layer[i] );
 593
 594             if ( layer_states[layer_coverage] != NULL ) {
 595                 layer[i]->setState( layer_states[layer_coverage] );
 596             }
 597             state_sel = layer_states[layer_coverage];
 598         }
 599
 600         // force a repaint of the sky colors with arbitrary defaults
 601         repaint( color );
 602     }
 603 }
 604
 605
 606 // repaint the cloud layer colors
 607 bool SGCloudLayer::repaint( sgVec3 fog_color ) {
 608
 609     if ( bump_mapping && enable_bump_mapping ) {
 610
 611         for ( int i = 0; i < 25; i++ ) {
 612             sgCopyVec3( vertices[ i ].color, fog_color );
 613         }
 614
 615     } else {
 616         float *color;
 617
 618         for ( int i = 0; i < 4; i++ ) {
 619             for ( int j = 0; j < 10; ++j ) {
 620                 color = cl[i]->get( j );
 621                 sgCopyVec3( color, fog_color );
 622             }
 623         }
 624     }
 625
 626     return true;
 627 }
 628
 629
 630 // reposition the cloud layer at the specified origin and orientation
 631 // lon specifies a rotation about the Z axis
 632 // lat specifies a rotation about the new Y axis
 633 // spin specifies a rotation about the new Z axis (and orients the
 634 // sunrise/set effects
 635 bool SGCloudLayer::reposition( sgVec3 p, sgVec3 up, double lon, double lat,
 636                                double alt, double dt )
 637 {
 638     sgMat4 T1, LON, LAT;
 639     sgVec3 axis;
 640
 641     // combine p and asl (meters) to get translation offset
 642     sgVec3 asl_offset;
 643     sgCopyVec3( asl_offset, up );
 644     sgNormalizeVec3( asl_offset );
 645     if ( alt <= layer_asl ) {
 646         sgScaleVec3( asl_offset, layer_asl );
 647     } else {
 648         sgScaleVec3( asl_offset, layer_asl + layer_thickness );
 649     }
 650     // cout << "asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 651     //      << "," << asl_offset[2] << endl;
 652     sgAddVec3( asl_offset, p );
 653     // cout << "  asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 654     //      << "," << asl_offset[2] << endl;
 655
 656     // Translate to zero elevation
 657     // Point3D zero_elev = current_view.get_cur_zero_elev();
 658     sgMakeTransMat4( T1, asl_offset );
 659
 660     // printf("  Translated to %.2f %.2f %.2f\n",
 661     //        zero_elev.x, zero_elev.y, zero_elev.z );
 662
 663     // Rotate to proper orientation
 664     // printf("  lon = %.2f  lat = %.2f\n",
 665     //        lon * SGD_RADIANS_TO_DEGREES,
 666     //        lat * SGD_RADIANS_TO_DEGREES);
 667     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 668     sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );
 669
 670     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 671     sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );
 672
 673     sgMat4 TRANSFORM;
 674
 675     sgCopyMat4( TRANSFORM, T1 );
 676     sgPreMultMat4( TRANSFORM, LON );
 677     sgPreMultMat4( TRANSFORM, LAT );
 678
 679     sgCoord layerpos;
 680     sgSetCoord( &layerpos, TRANSFORM );
 681
 682     layer_transform->setTransform( &layerpos );
 683
 684     // now calculate update texture coordinates
 685     if ( last_lon < -900 ) {
 686         last_lon = lon;
 687         last_lat = lat;
 688     }
 689
 690     double sp_dist = speed*dt;
 691
 692     if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
 693         Point3D start( last_lon, last_lat, 0.0 );
 694         Point3D dest( lon, lat, 0.0 );
 695         double course = 0.0, dist = 0.0;
 696
 697         calc_gc_course_dist( dest, start, &course, &dist );
 698         // cout << "course = " << course << ", dist = " << dist << endl;
 699
 700         // if start and dest are too close together,
 701         // calc_gc_course_dist() can return a course of "nan".  If
 702         // this happens, lets just use the last known good course.
 703         // This is a hack, and it would probably be better to make
 704         // calc_gc_course_dist() more robust.
 705         if ( isnan(course) ) {
 706             course = last_course;
 707         } else {
 708             last_course = course;
 709         }
 710
 711         // calculate cloud movement due to external forces
 712         double ax = 0.0, ay = 0.0, bx = 0.0, by = 0.0;
 713
 714         if (dist > 0.0) {
 715             ax = cos(course) * dist;
 716             ay = sin(course) * dist;
 717         }
 718
 719         if (sp_dist > 0) {
 720             bx = cos(-direction * SGD_DEGREES_TO_RADIANS) * sp_dist;
 721             by = sin(-direction * SGD_DEGREES_TO_RADIANS) * sp_dist;
 722         }
 723
 724
 725         double xoff = (ax + bx) / (2 * scale);
 726         double yoff = (ay + by) / (2 * scale);
 727
 728         const float layer_scale = layer_span / scale;
 729
 730         // cout << "xoff = " << xoff << ", yoff = " << yoff << endl;
 731
 732         float *base;
 733         if ( bump_mapping && enable_bump_mapping ) {
 734             base = vertices[12].texCoord;
 735         } else {
 736             base = tl[0]->get( 0 );
 737         }
 738         base[0] += xoff;
 739
 740         // the while loops can lead to *long* pauses if base[0] comes
 741         // with a bogus value.
 742         // while ( base[0] > 1.0 ) { base[0] -= 1.0; }
 743         // while ( base[0] < 0.0 ) { base[0] += 1.0; }
 744         if ( base[0] > -10.0 && base[0] < 10.0 ) {
 745             base[0] -= (int)base[0];
 746         } else {
 747             SG_LOG(SG_ASTRO, SG_DEBUG,
 748                 "Error: base = " << base[0] << "," << base[1] <<
 749                 " course = " << course << " dist = " << dist );
 750             base[0] = 0.0;
 751         }
 752
 753         base[1] += yoff;
 754         // the while loops can lead to *long* pauses if base[0] comes
 755         // with a bogus value.
 756         // while ( base[1] > 1.0 ) { base[1] -= 1.0; }
 757         // while ( base[1] < 0.0 ) { base[1] += 1.0; }
 758         if ( base[1] > -10.0 && base[1] < 10.0 ) {
 759             base[1] -= (int)base[1];
 760         } else {
 761             SG_LOG(SG_ASTRO, SG_ALERT,
 762                     "Error: base = " << base[0] << "," << base[1] <<
 763                     " course = " << course << " dist = " << dist );
 764             base[1] = 0.0;
 765         }
 766
 767         if ( bump_mapping && enable_bump_mapping ) {
 768
 769             for ( int i = -2; i <= 2; i++ ) {
 770                 for ( int j = -2; j <= 2; j++ ) {
 771                     if ( i == 0 && j == 0 )
 772                         continue; // Already done on base
 773                     CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 774                     sgSetVec2( v1.texCoord,
 775                             base[0] + layer_scale * i * 0.25,
 776                             base[1] + layer_scale * j * 0.25 );
 777                 }
 778             }
 779
 780         } else {
 781                 // cout << "base = " << base[0] << "," << base[1] << endl;
 782
 783             float *tc;
 784             for (int i = 0; i < 4; i++) {
 785                 tc = tl[i]->get( 0 );
 786                 sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 787
 788                 for (int j = 0; j < 4; j++)
 789                 {
 790                     tc = tl[i]->get( j*2+1 );
 791                     sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 792                                 base[1] + layer_scale * j/4 );
 793
 794                     tc = tl[i]->get( (j+1)*2 );
 795                     sgSetVec2( tc, base[0] + layer_scale * i/4,
 796                                 base[1] + layer_scale * (j+1)/4 );
 797                 }
 798
 799                 tc = tl[i]->get( 9 );
 800                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 801                             base[1] + layer_scale );
 802             }
 803         }
 804
 805         last_lon = lon;
 806         last_lat = lat;
 807     }
 808
 809     return true;
 810 }
 811
 812
 813 void SGCloudLayer::draw( bool top ) {
 814     if ( layer_coverage != SG_CLOUD_CLEAR ) {
 815
 816         if ( bump_mapping && enable_bump_mapping ) {
 817
 818             sgMat4 modelview,
 819                    tmp,
 820                    transform;
 821             ssgGetModelviewMatrix( modelview );
 822             layer_transform->getTransform( transform );
 823
 824             sgInvertMat4( tmp, transform );
 825
 826             sgPostMultMat4( transform, modelview );
 827             ssgLoadModelviewMatrix( transform );
 828
 829             sgVec3 lightVec;
 830             ssgGetLight( 0 )->getPosition( lightVec );
 831             sgNegateVec3( lightVec );
 832             sgXformVec3( lightVec, tmp );
 833
 834             for ( int i = 0; i < 25; i++ ) {
 835                 CloudVertex &v = vertices[ i ];
 836                 sgSetVec3( v.tangentSpLight,
 837                            sgScalarProductVec3( v.sTangent, lightVec ),
 838                            sgScalarProductVec3( v.tTangent, lightVec ),
 839                            sgScalarProductVec3( v.normal, lightVec ) );
 840             }
 841
 842             ssgTexture *decal = color_map[ layer_coverage ][ top ? 1 : 0 ];
 843             if ( top && decal == 0 ) {
 844                 decal = color_map[ layer_coverage ][ 0 ];
 845             }
 846             ssgTexture *normal = normal_map[ layer_coverage ][ top ? 1 : 0 ];
 847             if ( top && normal == 0 ) {
 848                 normal = normal_map[ layer_coverage ][ 0 ];
 849             }
 850
 851             glDisable( GL_LIGHTING );
 852             glDisable( GL_CULL_FACE );
 853             glEnable( GL_ALPHA_TEST );
 854             glAlphaFunc ( GL_GREATER, 0.1 ) ;
 855             glEnable( GL_BLEND );
 856             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 857
 858             glPolygonMode( GL_FILL, GL_FRONT_AND_BACK );
 859             glShadeModel( GL_SMOOTH );
 860             glEnable( GL_COLOR_MATERIAL );
 861             sgVec4 color;
 862             sgSetVec4( color, 0.05, 0.05, 0.05, 0.0 );
 863             glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, color );
 864             sgSetVec4( color, 0.8, 0.8, 0.8, 0.0 );
 865             glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, color );
 866             sgSetVec4( color, 0.5, 0.5, 0.5, 0.0 );
 867             glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, color );
 868             sgSetVec4( color, 1.0, 1.0, 1.0, 1.0 );
 869             glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, color );
 870
 871             glActiveTexturePtr( GL_TEXTURE0_ARB );
 872             glBindTexture( GL_TEXTURE_2D, normal->getHandle() );
 873             glEnable( GL_TEXTURE_2D );
 874
 875             //Bind normalisation cube map to texture unit 1
 876             glActiveTexturePtr( GL_TEXTURE1_ARB );
 877             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 878             glEnable( GL_TEXTURE_CUBE_MAP_ARB );
 879             glActiveTexturePtr( GL_TEXTURE0_ARB );
 880
 881             //Set vertex arrays for cloud
 882             glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
 883             glEnableClientState( GL_VERTEX_ARRAY );
 884
 885             if ( nb_texture_unit >= 3 ) {
 886                 glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
 887                 glEnableClientState( GL_COLOR_ARRAY );
 888             }
 889
 890             //Send texture coords for normal map to unit 0
 891             glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 892             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 893
 894             //Send tangent space light vectors for normalisation to unit 1
 895             glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 896             glTexCoordPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].tangentSpLight );
 897             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 898
 899             //Set up texture environment to do (tex0 dot tex1)*color
 900             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 901             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 902             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE );
 903             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE );
 904             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 905
 906             glActiveTexturePtr( GL_TEXTURE1_ARB );
 907
 908             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 909             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 910             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_DOT3_RGB_ARB );
 911             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 912
 913             if ( nb_texture_unit >= 3 ) {
 914                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 915                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 916
 917                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 918                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 919                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 920
 921                 sgVec4 factors;
 922                 if ( top || layer_coverage != SG_CLOUD_OVERCAST ) {
 923                     sgSetVec4( factors, 0.5f, 0.5f, 0.3f, 1.0f );
 924                 } else {
 925                     sgSetVec4( factors, 0.1f, 0.1f, 0.0f, 1.0f );
 926                 }
 927                 glTexEnvfv( GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR, factors );
 928
 929                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 930                 glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_INTERPOLATE_ARB );
 931                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 932                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 933                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB, GL_CONSTANT_ARB );
 934
 935                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 936                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 937
 938                 //Draw cloud layer
 939                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 940                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 941                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 942                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 943
 944                 glDisable( GL_TEXTURE_2D );
 945                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 946                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 947                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 948                 glDisable( GL_TEXTURE_2D );
 949                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 950
 951                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 952                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 953                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 954                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 955                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 956                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 957
 958                 glDisableClientState( GL_COLOR_ARRAY );
 959
 960             } else {
 961                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 962                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 963
 964                 //Draw cloud layer
 965                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 966                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 967                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 968                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 969
 970
 971                 //Disable textures
 972                 glDisable( GL_TEXTURE_2D );
 973
 974                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 975                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 976                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 977
 978                 //disable vertex arrays
 979                 glDisableClientState( GL_VERTEX_ARRAY );
 980
 981                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 982                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 983                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 984                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 985
 986                 //Return to standard modulate texenv
 987                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
 988
 989                 glDepthFunc(GL_LEQUAL);
 990                 //Enable multiplicative blending
 991                 glBlendFunc( GL_DST_COLOR, GL_ZERO );
 992
 993                 //Perform a second pass to color the torus
 994                 //Bind decal texture
 995                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 996                 glEnable(GL_TEXTURE_2D);
 997
 998                 //Set vertex arrays for torus
 999                 glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
1000                 glEnableClientState( GL_VERTEX_ARRAY );
1001
1002                 //glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
1003                 //glEnableClientState( GL_COLOR_ARRAY );
1004
1005                 glNormalPointer( GL_FLOAT, sizeof(CloudVertex), &vertices[0].normal );
1006                 glEnableClientState( GL_NORMAL_ARRAY );
1007
1008                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
1009                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
1010
1011                 //Draw cloud layer
1012                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1013                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1014                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1015                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1016
1017                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1018             }
1019             //Disable texture
1020             glDisable( GL_TEXTURE_2D );
1021
1022             glDisableClientState( GL_VERTEX_ARRAY );
1023             glDisableClientState( GL_NORMAL_ARRAY );
1024
1025             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1026
1027             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
1028             glEnable( GL_LIGHTING );
1029             glEnable( GL_CULL_FACE );
1030             glDepthFunc(GL_LESS);
1031
1032             ssgLoadModelviewMatrix( modelview );
1033
1034         } else {
1035             state_sel->selectStep( top ? 1 : 0 );
1036             ssgCullAndDraw( layer_root );
1037         }
1038     }
1039 }
1040
1041
1042 // make an ssgSimpleState for a cloud layer given the named texture
1043 ssgSimpleState *sgCloudMakeState( const string &path ) {
1044     ssgSimpleState *state = new ssgSimpleState();
1045
1046     SG_LOG(SG_ASTRO, SG_INFO, " texture = ");
1047
1048     state->setTexture( (char *)path.c_str() );
1049     state->setShadeModel( GL_SMOOTH );
1050     state->disable( GL_LIGHTING );
1051     state->disable( GL_CULL_FACE );
1052     state->enable( GL_TEXTURE_2D );
1053     state->enable( GL_COLOR_MATERIAL );
1054     state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
1055     state->setMaterial( GL_EMISSION, 0.05, 0.05, 0.05, 0.0 );
1056     state->setMaterial( GL_AMBIENT, 0.2, 0.2, 0.2, 0.0 );
1057     state->setMaterial( GL_DIFFUSE, 0.5, 0.5, 0.5, 0.0 );
1058     state->setMaterial( GL_SPECULAR, 0.0, 0.0, 0.0, 0.0 );
1059     state->enable( GL_BLEND );
1060     state->enable( GL_ALPHA_TEST );
1061     state->setAlphaClamp( 0.01 );
1062
1063     return state;
1064 }