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  - http://www.flightgear.org/~curt
   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 #include <plib/sg.h>
  25 #include <plib/ssg.h>
  26
  27 #include <simgear/math/point3d.hxx>
  28 #include <simgear/math/polar3d.hxx>
  29 #include <simgear/math/sg_random.h>
  30 #include <simgear/debug/logstream.hxx>
  31 #include <simgear/misc/sg_path.hxx>
  32 #include <simgear/screen/extensions.hxx>
  33 #include <simgear/screen/texture.hxx>
  34 #include <simgear/structure/ssgSharedPtr.hxx>
  35
  36 #include "newcloud.hxx"
  37 #include "cloudfield.hxx"
  38 #include "cloud.hxx"
  39
  40 #if defined(__MINGW32__)
  41 #define isnan(x) _isnan(x)
  42 #endif
  43
  44 #if defined (__FreeBSD__)
  45 #  if __FreeBSD_version < 500000
  46      extern "C" {
  47        inline int isnan(double r) { return !(r <= 0 || r >= 0); }
  48      }
  49 #  endif
  50 #endif
  51
  52
  53 static ssgSharedPtr<ssgStateSelector> layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
  54 static bool state_initialized = false;
  55 static bool bump_mapping = false;
  56 static GLint nb_texture_unit = 0;
  57 static ssgSharedPtr<ssgTexture> normal_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  58 static ssgSharedPtr<ssgTexture> color_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  59 static GLuint normalization_cube_map;
  60
  61 static glActiveTextureProc glActiveTexturePtr = 0;
  62 static glClientActiveTextureProc glClientActiveTexturePtr = 0;
  63 static glBlendColorProc glBlendColorPtr = 0;
  64
  65 bool SGCloudLayer::enable_bump_mapping = false;
  66
  67 static void
  68 generateNormalizationCubeMap()
  69 {
  70     unsigned char data[ 32 * 32 * 3 ];
  71     const int size = 32;
  72     const float half_size = 16.0f,
  73                 offset = 0.5f;
  74     sgVec3 zero_normal;
  75     sgSetVec3( zero_normal, 0.5f, 0.5f, 0.5f );
  76     int i, j;
  77
  78     unsigned char *ptr = data;
  79     for ( j = 0; j < size; j++ ) {
  80         for ( i = 0; i < size; i++ ) {
  81             sgVec3 tmp;
  82             sgSetVec3( tmp, half_size,
  83                             -( j + offset - half_size ),
  84                             -( i + offset - half_size ) );
  85             sgNormalizeVec3( tmp );
  86             sgScaleVec3( tmp, 0.5f );
  87             sgAddVec3( tmp, zero_normal );
  88
  89             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
  90             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
  91             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
  92         }
  93     }
  94     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
  95                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
  96
  97     ptr = data;
  98     for ( j = 0; j < size; j++ ) {
  99         for ( i = 0; i < size; i++ ) {
 100             sgVec3 tmp;
 101             sgSetVec3( tmp, -half_size,
 102                             -( j + offset - half_size ),
 103                             ( i + offset - half_size ) );
 104             sgNormalizeVec3( tmp );
 105             sgScaleVec3( tmp, 0.5f );
 106             sgAddVec3( tmp, zero_normal );
 107
 108             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 109             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 110             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 111         }
 112     }
 113     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 114                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 115
 116     ptr = data;
 117     for ( j = 0; j < size; j++ ) {
 118         for ( i = 0; i < size; i++ ) {
 119             sgVec3 tmp;
 120             sgSetVec3( tmp, ( i + offset - half_size ),
 121                             half_size,
 122                             ( j + offset - half_size ) );
 123             sgNormalizeVec3( tmp );
 124             sgScaleVec3( tmp, 0.5f );
 125             sgAddVec3( tmp, zero_normal );
 126
 127             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 128             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 129             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 130         }
 131     }
 132     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 133                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 134
 135     ptr = data;
 136     for ( j = 0; j < size; j++ ) {
 137         for ( i = 0; i < size; i++ ) {
 138             sgVec3 tmp;
 139             sgSetVec3( tmp, ( i + offset - half_size ),
 140                             -half_size,
 141                             -( j + offset - half_size ) );
 142             sgNormalizeVec3( tmp );
 143             sgScaleVec3( tmp, 0.5f );
 144             sgAddVec3( tmp, zero_normal );
 145
 146             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 147             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 148             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 149         }
 150     }
 151     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 152                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 153
 154     ptr = data;
 155     for ( j = 0; j < size; j++ ) {
 156         for ( i = 0; i < size; i++ ) {
 157             sgVec3 tmp;
 158             sgSetVec3( tmp, ( i + offset - half_size ),
 159                             -( j + offset - half_size ),
 160                             half_size );
 161             sgNormalizeVec3( tmp );
 162             sgScaleVec3( tmp, 0.5f );
 163             sgAddVec3( tmp, zero_normal );
 164
 165             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 166             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 167             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 168         }
 169     }
 170     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 171                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 172
 173     ptr = data;
 174     for ( j = 0; j < size; j++ ) {
 175         for ( i = 0; i < size; i++ ) {
 176             sgVec3 tmp;
 177             sgSetVec3( tmp, -( i + offset - half_size ),
 178                             -( j + offset - half_size ),
 179                             -half_size );
 180             sgNormalizeVec3( tmp );
 181             sgScaleVec3( tmp, 0.5f );
 182             sgAddVec3( tmp, zero_normal );
 183
 184             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 185             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 186             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 187         }
 188     }
 189     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB,
 190                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 191 }
 192
 193
 194 // Constructor
 195 SGCloudLayer::SGCloudLayer( const string &tex_path ) :
 196     vertices(0),
 197     indices(0),
 198     layer_root(new ssgRoot),
 199     layer_transform(new ssgTransform),
 200     state_sel(0),
 201     cloud_alpha(1.0),
 202     texture_path(tex_path),
 203     layer_span(0.0),
 204     layer_asl(0.0),
 205     layer_thickness(0.0),
 206     layer_transition(0.0),
 207     layer_coverage(SG_CLOUD_CLEAR),
 208     scale(4000.0),
 209     speed(0.0),
 210     direction(0.0),
 211     last_lon(0.0),
 212     last_lat(0.0)
 213 {
 214     cl[0] = cl[1] = cl[2] = cl[3] = NULL;
 215     vl[0] = vl[1] = vl[2] = vl[3] = NULL;
 216     tl[0] = tl[1] = tl[2] = tl[3] = NULL;
 217     layer[0] = layer[1] = layer[2] = layer[3] = NULL;
 218
 219     layer_root->addKid(layer_transform);
 220         layer3D = new SGCloudField;
 221     rebuild();
 222 }
 223
 224 // Destructor
 225 SGCloudLayer::~SGCloudLayer()
 226 {
 227         delete layer3D;
 228     delete vertices;
 229     delete indices;
 230     delete layer_root;          // deletes layer_transform and layer as well
 231 }
 232
 233 float
 234 SGCloudLayer::getSpan_m () const
 235 {
 236     return layer_span;
 237 }
 238
 239 void
 240 SGCloudLayer::setSpan_m (float span_m)
 241 {
 242     if (span_m != layer_span) {
 243         layer_span = span_m;
 244         rebuild();
 245     }
 246 }
 247
 248 float
 249 SGCloudLayer::getElevation_m () const
 250 {
 251     return layer_asl;
 252 }
 253
 254 void
 255 SGCloudLayer::setElevation_m (float elevation_m, bool set_span)
 256 {
 257     layer_asl = elevation_m;
 258
 259     if (set_span) {
 260         if (elevation_m > 4000)
 261             setSpan_m(  elevation_m * 10 );
 262         else
 263             setSpan_m( 40000 );
 264     }
 265 }
 266
 267 float
 268 SGCloudLayer::getThickness_m () const
 269 {
 270     return layer_thickness;
 271 }
 272
 273 void
 274 SGCloudLayer::setThickness_m (float thickness_m)
 275 {
 276     layer_thickness = thickness_m;
 277 }
 278
 279 float
 280 SGCloudLayer::getTransition_m () const
 281 {
 282     return layer_transition;
 283 }
 284
 285 void
 286 SGCloudLayer::setTransition_m (float transition_m)
 287 {
 288     layer_transition = transition_m;
 289 }
 290
 291 SGCloudLayer::Coverage
 292 SGCloudLayer::getCoverage () const
 293 {
 294     return layer_coverage;
 295 }
 296
 297 void
 298 SGCloudLayer::setCoverage (Coverage coverage)
 299 {
 300     if (coverage != layer_coverage) {
 301         layer_coverage = coverage;
 302         rebuild();
 303     }
 304 }
 305
 306
 307 // build the cloud object
 308 void
 309 SGCloudLayer::rebuild()
 310 {
 311     // Initialize states and sizes if necessary.
 312     if ( !state_initialized ) {
 313         state_initialized = true;
 314
 315         SG_LOG(SG_ASTRO, SG_INFO, "initializing cloud layers");
 316
 317         bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
 318                        SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
 319                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
 320                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") &&
 321                        SGIsOpenGLExtensionSupported("GL_ARB_imaging");
 322
 323         if ( bump_mapping ) {
 324             glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
 325             if ( nb_texture_unit < 2 ) {
 326                 bump_mapping = false;
 327             }
 328             //nb_texture_unit = 2; // Force the number of units for now
 329         }
 330
 331         if ( bump_mapping ) {
 332
 333             // This bump mapping code was inspired by the tutorial available at
 334             // http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
 335             // and a NVidia white paper
 336             //  http://developer.nvidia.com/object/bumpmappingwithregistercombiners.html
 337             // The normal map textures were generated by the normal map Gimp plugin :
 338             //  http://nifelheim.dyndns.org/~cocidius/normalmap/
 339             //
 340             SGPath cloud_path;
 341
 342             glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
 343             glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
 344             glBlendColorPtr = (glBlendColorProc)SGLookupFunction("glBlendColor");
 345
 346             cloud_path.set(texture_path.str());
 347             cloud_path.append("overcast.rgb");
 348             color_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 349             cloud_path.set(texture_path.str());
 350             cloud_path.append("overcast_n.rgb");
 351             normal_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 352
 353             cloud_path.set(texture_path.str());
 354             cloud_path.append("overcast_top.rgb");
 355             color_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 356             cloud_path.set(texture_path.str());
 357             cloud_path.append("overcast_top_n.rgb");
 358             normal_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 359
 360             cloud_path.set(texture_path.str());
 361             cloud_path.append("broken.rgba");
 362             color_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 363             cloud_path.set(texture_path.str());
 364             cloud_path.append("broken_n.rgb");
 365             normal_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 366
 367             cloud_path.set(texture_path.str());
 368             cloud_path.append("scattered.rgba");
 369             color_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 370             cloud_path.set(texture_path.str());
 371             cloud_path.append("scattered_n.rgb");
 372             normal_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 373
 374             cloud_path.set(texture_path.str());
 375             cloud_path.append("few.rgba");
 376             color_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 377             cloud_path.set(texture_path.str());
 378             cloud_path.append("few_n.rgb");
 379             normal_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 380
 381             cloud_path.set(texture_path.str());
 382             cloud_path.append("cirrus.rgba");
 383             color_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 384             cloud_path.set(texture_path.str());
 385             cloud_path.append("cirrus_n.rgb");
 386             normal_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 387
 388             glGenTextures( 1, &normalization_cube_map );
 389             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 390             generateNormalizationCubeMap();
 391             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 392             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 393             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 394             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 395             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE );
 396         } /* else */ {
 397             SGPath cloud_path;
 398             ssgStateSelector *state_sel;
 399             ssgSimpleState *state;
 400
 401             state_sel = new ssgStateSelector( 2 );
 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             cloud_path.set(texture_path.str());
 412             cloud_path.append("broken.rgba");
 413             state = sgCloudMakeState(cloud_path.str());
 414             state_sel->setStep( 0, state );
 415             state_sel->setStep( 1, state );
 416             layer_states[SG_CLOUD_BROKEN] = state_sel;
 417
 418             state_sel = new ssgStateSelector( 2 );
 419             cloud_path.set(texture_path.str());
 420             cloud_path.append("scattered.rgba");
 421             state = sgCloudMakeState(cloud_path.str());
 422             state_sel->setStep( 0, state );
 423             state_sel->setStep( 1, state );
 424             layer_states[SG_CLOUD_SCATTERED] = state_sel;
 425
 426             state_sel = new ssgStateSelector( 2 );
 427             cloud_path.set(texture_path.str());
 428             cloud_path.append("few.rgba");
 429             state = sgCloudMakeState(cloud_path.str());
 430             state_sel->setStep( 0, state );
 431             state_sel->setStep( 1, state );
 432             layer_states[SG_CLOUD_FEW] = state_sel;
 433
 434             state_sel = new ssgStateSelector( 2 );
 435             cloud_path.set(texture_path.str());
 436             cloud_path.append("cirrus.rgba");
 437             state = sgCloudMakeState(cloud_path.str());
 438             state_sel->setStep( 0, state );
 439             state_sel->setStep( 1, state );
 440             layer_states[SG_CLOUD_CIRRUS] = state_sel;
 441
 442             layer_states[SG_CLOUD_CLEAR] = 0;
 443         }
 444                 SGNewCloud::loadTextures(texture_path.str());
 445                 layer3D->buildTestLayer();
 446     }
 447
 448     if ( bump_mapping ) {
 449
 450         if ( !vertices ) {
 451             vertices = new CloudVertex[ 25 ];
 452             indices = new unsigned int[ 40 ];
 453         }
 454
 455         sgVec2 base;
 456         sgSetVec2( base, sg_random(), sg_random() );
 457
 458         const float layer_scale = layer_span / scale;
 459         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 460         const float half_angle = 0.5 * layer_span / layer_to_core;
 461
 462         int i;
 463         for ( i = -2; i <= 2; i++ ) {
 464             for ( int j = -2; j <= 2; j++ ) {
 465                 CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 466                 sgSetVec3( v1.position,
 467                            0.5 * i * layer_span,
 468                            0.5 * j * layer_span,
 469                            -layer_to_core * ( 1 - cos( i * half_angle ) * cos( j * half_angle ) ) );
 470                 sgSetVec2( v1.texCoord,
 471                            base[0] + layer_scale * i * 0.25,
 472                            base[1] + layer_scale * j * 0.25 );
 473                 sgSetVec3( v1.sTangent,
 474                            cos( i * half_angle ),
 475                            0.f,
 476                            -sin( i * half_angle ) );
 477                 sgSetVec3( v1.tTangent,
 478                            0.f,
 479                            cos( j * half_angle ),
 480                            -sin( j * half_angle ) );
 481                 sgVectorProductVec3( v1.normal, v1.tTangent, v1.sTangent );
 482                 sgSetVec4( v1.color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : cloud_alpha * 0.15f );
 483             }
 484         }
 485         /*
 486          * 0 1 5 6 10 11 15 16 20 21
 487          * 1 2 6 7 11 12 16 17 21 22
 488          * 2 3 7 8 12 13 17 18 22 23
 489          * 3 4 8 9 13 14 18 19 23 24
 490          */
 491         for ( i = 0; i < 4; i++ ) {
 492             for ( int j = 0; j < 5; j++ ) {
 493                 indices[ i*10 + (j*2) ]     =     i + 5 * j;
 494                 indices[ i*10 + (j*2) + 1 ] = 1 + i + 5 * j;
 495             }
 496         }
 497
 498     } /* else */ {
 499
 500         scale = 4000.0;
 501         last_lon = last_lat = -999.0f;
 502
 503         sgVec2 base;
 504         sgSetVec2( base, sg_random(), sg_random() );
 505
 506         // build the cloud layer
 507         sgVec4 color;
 508         sgVec3 vertex;
 509         sgVec2 tc;
 510
 511         const float layer_scale = layer_span / scale;
 512         const float mpi = SG_PI/4;
 513
 514         // caclculate the difference between a flat-earth model and
 515         // a round earth model given the span and altutude ASL of
 516         // the cloud layer. This is the difference in altitude between
 517         // the top of the inverted bowl and the edge of the bowl.
 518         // const float alt_diff = layer_asl * 0.8;
 519         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 520         const float layer_angle = 0.5*layer_span / layer_to_core; // The angle is half the span
 521         const float border_to_core = layer_to_core * cos(layer_angle);
 522         const float alt_diff = layer_to_core - border_to_core;
 523
 524         for (int i = 0; i < 4; i++)
 525         {
 526             if ( layer[i] != NULL ) {
 527                 layer_transform->removeKid(layer[i]); // automatic delete
 528             }
 529
 530             vl[i] = new ssgVertexArray( 10 );
 531             cl[i] = new ssgColourArray( 10 );
 532             tl[i] = new ssgTexCoordArray( 10 );
 533
 534
 535             sgSetVec3( vertex, layer_span*(i-2)/2, -layer_span,
 536                             alt_diff * (sin(i*mpi) - 2) );
 537
 538             sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 539
 540             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 541
 542             cl[i]->add( color );
 543             vl[i]->add( vertex );
 544             tl[i]->add( tc );
 545
 546             for (int j = 0; j < 4; j++)
 547             {
 548                 sgSetVec3( vertex, layer_span*(i-1)/2, layer_span*(j-2)/2,
 549                                 alt_diff * (sin((i+1)*mpi) + sin(j*mpi) - 2) );
 550
 551                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 552                             base[1] + layer_scale * j/4 );
 553
 554                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 555                                 ( (j == 0) || (i == 3)) ?
 556                                 ( (j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f );
 557
 558                 cl[i]->add( color );
 559                 vl[i]->add( vertex );
 560                 tl[i]->add( tc );
 561
 562
 563                 sgSetVec3( vertex, layer_span*(i-2)/2, layer_span*(j-1)/2,
 564                                 alt_diff * (sin(i*mpi) + sin((j+1)*mpi) - 2) );
 565
 566                 sgSetVec2( tc, base[0] + layer_scale * i/4,
 567                             base[1] + layer_scale * (j+1)/4 );
 568
 569                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 570                                 ((j == 3) || (i == 0)) ?
 571                                 ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f );
 572                 cl[i]->add( color );
 573                 vl[i]->add( vertex );
 574                 tl[i]->add( tc );
 575             }
 576
 577             sgSetVec3( vertex, layer_span*(i-1)/2, layer_span,
 578                             alt_diff * (sin((i+1)*mpi) - 2) );
 579
 580             sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 581                         base[1] + layer_scale );
 582
 583             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 3) ? 0.0f : 0.15f );
 584
 585             cl[i]->add( color );
 586             vl[i]->add( vertex );
 587             tl[i]->add( tc );
 588
 589             layer[i] = new ssgVtxTable(GL_TRIANGLE_STRIP, vl[i], NULL, tl[i], cl[i]);
 590             layer_transform->addKid( layer[i] );
 591
 592             if ( layer_states[layer_coverage] != NULL ) {
 593                 layer[i]->setState( layer_states[layer_coverage] );
 594             }
 595             state_sel = layer_states[layer_coverage];
 596         }
 597
 598         // force a repaint of the sky colors with arbitrary defaults
 599         repaint( color );
 600     }
 601 }
 602
 603
 604 // repaint the cloud layer colors
 605 bool SGCloudLayer::repaint( sgVec3 fog_color ) {
 606
 607     if ( bump_mapping && enable_bump_mapping ) {
 608
 609         for ( int i = 0; i < 25; i++ ) {
 610             sgCopyVec3( vertices[ i ].color, fog_color );
 611         }
 612
 613     } else {
 614         float *color;
 615
 616         for ( int i = 0; i < 4; i++ ) {
 617             color = cl[i]->get( 0 );
 618             sgCopyVec3( color, fog_color );
 619             color[3] = (i == 0) ? 0.0f : cloud_alpha * 0.15f;
 620
 621             for ( int j = 0; j < 4; ++j ) {
 622                 color = cl[i]->get( (2*j) + 1 );
 623                 sgCopyVec3( color, fog_color );
 624                 color[3] =
 625                     ((j == 0) || (i == 3)) ?
 626                     ((j == 0) && (i == 3)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 627
 628                 color = cl[i]->get( (2*j) + 2 );
 629                 sgCopyVec3( color, fog_color );
 630                 color[3] =
 631                     ((j == 3) || (i == 0)) ?
 632                     ((j == 3) && (i == 0)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 633             }
 634
 635             color = cl[i]->get( 9 );
 636             sgCopyVec3( color, fog_color );
 637             color[3] = (i == 3) ? 0.0f : cloud_alpha * 0.15f;
 638         }
 639     }
 640
 641     return true;
 642 }
 643
 644 // reposition the cloud layer at the specified origin and orientation
 645 // lon specifies a rotation about the Z axis
 646 // lat specifies a rotation about the new Y axis
 647 // spin specifies a rotation about the new Z axis (and orients the
 648 // sunrise/set effects
 649 bool SGCloudLayer::reposition( sgVec3 p, sgVec3 up, double lon, double lat,
 650                                double alt, double dt )
 651 {
 652     sgMat4 T1, LON, LAT;
 653     sgVec3 axis;
 654
 655     // combine p and asl (meters) to get translation offset
 656     sgVec3 asl_offset;
 657     sgCopyVec3( asl_offset, up );
 658     sgNormalizeVec3( asl_offset );
 659     if ( alt <= layer_asl ) {
 660         sgScaleVec3( asl_offset, layer_asl );
 661     } else {
 662         sgScaleVec3( asl_offset, layer_asl + layer_thickness );
 663     }
 664     // cout << "asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 665     //      << "," << asl_offset[2] << endl;
 666     sgAddVec3( asl_offset, p );
 667     // cout << "  asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 668     //      << "," << asl_offset[2] << endl;
 669
 670     // Translate to zero elevation
 671     // Point3D zero_elev = current_view.get_cur_zero_elev();
 672     sgMakeTransMat4( T1, asl_offset );
 673
 674     // printf("  Translated to %.2f %.2f %.2f\n",
 675     //        zero_elev.x, zero_elev.y, zero_elev.z );
 676
 677     // Rotate to proper orientation
 678     // printf("  lon = %.2f  lat = %.2f\n",
 679     //        lon * SGD_RADIANS_TO_DEGREES,
 680     //        lat * SGD_RADIANS_TO_DEGREES);
 681     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 682     sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );
 683
 684     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 685     sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );
 686
 687     sgMat4 TRANSFORM;
 688
 689     sgCopyMat4( TRANSFORM, T1 );
 690     sgPreMultMat4( TRANSFORM, LON );
 691     sgPreMultMat4( TRANSFORM, LAT );
 692
 693     sgCoord layerpos;
 694     sgSetCoord( &layerpos, TRANSFORM );
 695
 696     layer_transform->setTransform( &layerpos );
 697
 698     // now calculate update texture coordinates
 699     if ( last_lon < -900 ) {
 700         last_lon = lon;
 701         last_lat = lat;
 702     }
 703
 704     double sp_dist = speed*dt;
 705
 706     if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
 707         Point3D start( last_lon, last_lat, 0.0 );
 708         Point3D dest( lon, lat, 0.0 );
 709         double course = 0.0, dist = 0.0;
 710
 711         calc_gc_course_dist( dest, start, &course, &dist );
 712         // cout << "course = " << course << ", dist = " << dist << endl;
 713
 714         // if start and dest are too close together,
 715         // calc_gc_course_dist() can return a course of "nan".  If
 716         // this happens, lets just use the last known good course.
 717         // This is a hack, and it would probably be better to make
 718         // calc_gc_course_dist() more robust.
 719         if ( isnan(course) ) {
 720             course = last_course;
 721         } else {
 722             last_course = course;
 723         }
 724
 725         // calculate cloud movement due to external forces
 726         double ax = 0.0, ay = 0.0, bx = 0.0, by = 0.0;
 727
 728         if (dist > 0.0) {
 729             ax = cos(course) * dist;
 730             ay = sin(course) * dist;
 731         }
 732
 733         if (sp_dist > 0) {
 734             bx = cos((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 735             by = sin((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 736         }
 737
 738
 739         double xoff = (ax + bx) / (2 * scale);
 740         double yoff = (ay + by) / (2 * scale);
 741
 742         const float layer_scale = layer_span / scale;
 743
 744         // cout << "xoff = " << xoff << ", yoff = " << yoff << endl;
 745
 746         float *base;
 747         if ( bump_mapping && enable_bump_mapping ) {
 748             base = vertices[12].texCoord;
 749         } else {
 750             base = tl[0]->get( 0 );
 751         }
 752         base[0] += xoff;
 753
 754         // the while loops can lead to *long* pauses if base[0] comes
 755         // with a bogus value.
 756         // while ( base[0] > 1.0 ) { base[0] -= 1.0; }
 757         // while ( base[0] < 0.0 ) { base[0] += 1.0; }
 758         if ( base[0] > -10.0 && base[0] < 10.0 ) {
 759             base[0] -= (int)base[0];
 760         } else {
 761             SG_LOG(SG_ASTRO, SG_DEBUG,
 762                 "Error: base = " << base[0] << "," << base[1] <<
 763                 " course = " << course << " dist = " << dist );
 764             base[0] = 0.0;
 765         }
 766
 767         base[1] += yoff;
 768         // the while loops can lead to *long* pauses if base[0] comes
 769         // with a bogus value.
 770         // while ( base[1] > 1.0 ) { base[1] -= 1.0; }
 771         // while ( base[1] < 0.0 ) { base[1] += 1.0; }
 772         if ( base[1] > -10.0 && base[1] < 10.0 ) {
 773             base[1] -= (int)base[1];
 774         } else {
 775             SG_LOG(SG_ASTRO, SG_ALERT,
 776                     "Error: base = " << base[0] << "," << base[1] <<
 777                     " course = " << course << " dist = " << dist );
 778             base[1] = 0.0;
 779         }
 780
 781         if ( bump_mapping && enable_bump_mapping ) {
 782
 783             for ( int i = -2; i <= 2; i++ ) {
 784                 for ( int j = -2; j <= 2; j++ ) {
 785                     if ( i == 0 && j == 0 )
 786                         continue; // Already done on base
 787                     CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 788                     sgSetVec2( v1.texCoord,
 789                             base[0] + layer_scale * i * 0.25,
 790                             base[1] + layer_scale * j * 0.25 );
 791                 }
 792             }
 793
 794         } else {
 795                 // cout << "base = " << base[0] << "," << base[1] << endl;
 796
 797             float *tc;
 798             for (int i = 0; i < 4; i++) {
 799                 tc = tl[i]->get( 0 );
 800                 sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 801
 802                 for (int j = 0; j < 4; j++)
 803                 {
 804                     tc = tl[i]->get( j*2+1 );
 805                     sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 806                                 base[1] + layer_scale * j/4 );
 807
 808                     tc = tl[i]->get( (j+1)*2 );
 809                     sgSetVec2( tc, base[0] + layer_scale * i/4,
 810                                 base[1] + layer_scale * (j+1)/4 );
 811                 }
 812
 813                 tc = tl[i]->get( 9 );
 814                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 815                             base[1] + layer_scale );
 816             }
 817         }
 818
 819         last_lon = lon;
 820         last_lat = lat;
 821     }
 822
 823         layer3D->reposition( p, up, lon, lat, alt, dt, direction, speed);
 824     return true;
 825 }
 826
 827
 828 void SGCloudLayer::draw( bool top ) {
 829     if ( layer_coverage != SG_CLOUD_CLEAR ) {
 830
 831                 if ( SGCloudField::enable3D && layer3D->is3D())
 832                         layer3D->Render();
 833                 else
 834         if ( bump_mapping && enable_bump_mapping ) {
 835
 836             sgMat4 modelview,
 837                    tmp,
 838                    transform;
 839             ssgGetModelviewMatrix( modelview );
 840             layer_transform->getTransform( transform );
 841
 842             sgTransposeNegateMat4( tmp, transform );
 843
 844             sgPostMultMat4( transform, modelview );
 845             ssgLoadModelviewMatrix( transform );
 846
 847             sgVec3 lightVec;
 848             ssgGetLight( 0 )->getPosition( lightVec );
 849             sgNegateVec3( lightVec );
 850             sgXformVec3( lightVec, tmp );
 851
 852             for ( int i = 0; i < 25; i++ ) {
 853                 CloudVertex &v = vertices[ i ];
 854                 sgSetVec3( v.tangentSpLight,
 855                            sgScalarProductVec3( v.sTangent, lightVec ),
 856                            sgScalarProductVec3( v.tTangent, lightVec ),
 857                            sgScalarProductVec3( v.normal, lightVec ) );
 858             }
 859
 860             ssgTexture *decal = color_map[ layer_coverage ][ top ? 1 : 0 ];
 861             if ( top && decal == 0 ) {
 862                 decal = color_map[ layer_coverage ][ 0 ];
 863             }
 864             ssgTexture *normal = normal_map[ layer_coverage ][ top ? 1 : 0 ];
 865             if ( top && normal == 0 ) {
 866                 normal = normal_map[ layer_coverage ][ 0 ];
 867             }
 868
 869             glDisable( GL_LIGHTING );
 870             glDisable( GL_CULL_FACE );
 871 //            glDisable( GL_ALPHA_TEST );
 872             if ( layer_coverage == SG_CLOUD_FEW ) {
 873                 glEnable( GL_ALPHA_TEST );
 874                 glAlphaFunc ( GL_GREATER, 0.01 );
 875             }
 876             glEnable( GL_BLEND );
 877             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 878
 879             glShadeModel( GL_SMOOTH );
 880             glEnable( GL_COLOR_MATERIAL );
 881             sgVec4 color;
 882             float emis = 0.05;
 883             if ( 1 ) {
 884                 ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
 885                 emis = ( color[0]+color[1]+color[2] ) / 3.0;
 886                 if ( emis < 0.05 )
 887                     emis = 0.05;
 888             }
 889             sgSetVec4( color, emis, emis, emis, 0.0 );
 890             glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, color );
 891             sgSetVec4( color, 1.0f, 1.0f, 1.0f, 0.0 );
 892             glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, color );
 893             sgSetVec4( color, 1.0, 1.0, 1.0, 0.0 );
 894             glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, color );
 895             sgSetVec4( color, 0.0, 0.0, 0.0, 0.0 );
 896             glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, color );
 897
 898             glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
 899
 900             glActiveTexturePtr( GL_TEXTURE0_ARB );
 901             glBindTexture( GL_TEXTURE_2D, normal->getHandle() );
 902             glEnable( GL_TEXTURE_2D );
 903
 904             //Bind normalisation cube map to texture unit 1
 905             glActiveTexturePtr( GL_TEXTURE1_ARB );
 906             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 907             glEnable( GL_TEXTURE_CUBE_MAP_ARB );
 908             glActiveTexturePtr( GL_TEXTURE0_ARB );
 909
 910             //Set vertex arrays for cloud
 911             glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
 912             glEnableClientState( GL_VERTEX_ARRAY );
 913 /*
 914             if ( nb_texture_unit >= 3 ) {
 915                 glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
 916                 glEnableClientState( GL_COLOR_ARRAY );
 917             }
 918 */
 919             //Send texture coords for normal map to unit 0
 920             glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 921             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 922
 923             //Send tangent space light vectors for normalisation to unit 1
 924             glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 925             glTexCoordPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].tangentSpLight );
 926             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 927
 928             //Set up texture environment to do (tex0 dot tex1)*color
 929             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 930             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 931             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE );
 932             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE );
 933             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 934
 935             glActiveTexturePtr( GL_TEXTURE1_ARB );
 936
 937             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 938             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 939             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_DOT3_RGB_ARB );
 940             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 941             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB );
 942             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 943
 944             if ( nb_texture_unit >= 3 ) {
 945                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 946                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 947
 948                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 949                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 950                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 951
 952                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 953                 glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD );
 954                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 955                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 956
 957                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 958                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 959
 960                 //Draw cloud layer
 961                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 962                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 963                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 964                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 965
 966                 glDisable( GL_TEXTURE_2D );
 967                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 968                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 969                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 970                 glDisable( GL_TEXTURE_2D );
 971                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 972
 973                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 974                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 975                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 976                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 977                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 978                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 979
 980                 glDisableClientState( GL_COLOR_ARRAY );
 981                 glEnable( GL_LIGHTING );
 982
 983                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
 984
 985             } else {
 986                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 987                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 988
 989                 //Draw cloud layer
 990                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 991                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 992                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 993                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 994
 995                 //Disable textures
 996                 glDisable( GL_TEXTURE_2D );
 997
 998                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 999                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
1000                 glActiveTexturePtr( GL_TEXTURE0_ARB );
1001
1002                 //disable vertex arrays
1003                 glDisableClientState( GL_VERTEX_ARRAY );
1004
1005                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1006                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
1007                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1008                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1009
1010                 //Return to standard modulate texenv
1011                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1012
1013                 if ( layer_coverage == SG_CLOUD_OVERCAST ) {
1014                     glDepthFunc(GL_LEQUAL);
1015
1016                     glEnable( GL_LIGHTING );
1017                     sgVec4 color;
1018                     ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
1019                     float average = ( color[0] + color[1] + color[2] ) / 3.0f;
1020                     average = 0.15 + average/10;
1021                     sgVec4 averageColor;
1022                     sgSetVec4( averageColor, average, average, average, 1.0f );
1023                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, averageColor );
1024
1025                     glBlendColorPtr( average, average, average, 1.0f );
1026                     glBlendFunc( GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_COLOR );
1027
1028                     //Perform a second pass to color the torus
1029                     //Bind decal texture
1030                     glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
1031                     glEnable(GL_TEXTURE_2D);
1032
1033                     //Set vertex arrays for torus
1034                     glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
1035                     glEnableClientState( GL_VERTEX_ARRAY );
1036
1037                     //glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
1038                     //glEnableClientState( GL_COLOR_ARRAY );
1039
1040                     glNormalPointer( GL_FLOAT, sizeof(CloudVertex), &vertices[0].normal );
1041                     glEnableClientState( GL_NORMAL_ARRAY );
1042
1043                     glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
1044                     glEnableClientState( GL_TEXTURE_COORD_ARRAY );
1045
1046                     //Draw cloud layer
1047                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1048                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1049                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1050                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1051
1052                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, color );
1053
1054                     glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1055                 }
1056             }
1057             //Disable texture
1058             glDisable( GL_TEXTURE_2D );
1059
1060             glDisableClientState( GL_VERTEX_ARRAY );
1061             glDisableClientState( GL_NORMAL_ARRAY );
1062
1063             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
1064             glEnable( GL_CULL_FACE );
1065             glDepthFunc(GL_LESS);
1066
1067             ssgLoadModelviewMatrix( modelview );
1068
1069         } else {
1070             state_sel->selectStep( top ? 1 : 0 );
1071             ssgCullAndDraw( layer_root );
1072         }
1073     }
1074 }
1075
1076
1077 // make an ssgSimpleState for a cloud layer given the named texture
1078 ssgSimpleState *sgCloudMakeState( const string &path ) {
1079     ssgSimpleState *state = new ssgSimpleState();
1080
1081     SG_LOG(SG_ASTRO, SG_INFO, " texture = ");
1082
1083     state->setTexture( (char *)path.c_str() );
1084     state->setShadeModel( GL_SMOOTH );
1085     state->disable( GL_LIGHTING );
1086     state->disable( GL_CULL_FACE );
1087     state->enable( GL_TEXTURE_2D );
1088     state->enable( GL_COLOR_MATERIAL );
1089     state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
1090     state->setMaterial( GL_EMISSION, 0.05, 0.05, 0.05, 0.0 );
1091     state->setMaterial( GL_AMBIENT, 0.2, 0.2, 0.2, 0.0 );
1092     state->setMaterial( GL_DIFFUSE, 0.5, 0.5, 0.5, 0.0 );
1093     state->setMaterial( GL_SPECULAR, 0.0, 0.0, 0.0, 0.0 );
1094     state->enable( GL_BLEND );
1095     state->enable( GL_ALPHA_TEST );
1096     state->setAlphaClamp( 0.01 );
1097
1098     return state;
1099 }