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 library is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU Library General Public
   9 // License as published by the Free Software Foundation; either
  10 // version 2 of the License, or (at your option) any later version.
  11 //
  12 // This library is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20 //
  21 // $Id$
  22
  23 #ifdef HAVE_CONFIG_H
  24 #  include <simgear_config.h>
  25 #endif
  26
  27 #include <simgear/compiler.h>
  28
  29 // #include <stdio.h>
  30 #include <math.h>
  31
  32 #include <plib/sg.h>
  33 #include <plib/ssg.h>
  34
  35 #include <simgear/math/point3d.hxx>
  36 #include <simgear/math/polar3d.hxx>
  37 #include <simgear/math/sg_random.h>
  38 #include <simgear/debug/logstream.hxx>
  39 #include <simgear/screen/extensions.hxx>
  40 #include <simgear/screen/texture.hxx>
  41 #include <simgear/structure/ssgSharedPtr.hxx>
  42
  43 #include "newcloud.hxx"
  44 #include "cloudfield.hxx"
  45 #include "cloud.hxx"
  46
  47 #if defined(__MINGW32__)
  48 #define isnan(x) _isnan(x)
  49 #endif
  50
  51 #if defined (__FreeBSD__)
  52 #  if __FreeBSD_version < 500000
  53      extern "C" {
  54        inline int isnan(double r) { return !(r <= 0 || r >= 0); }
  55      }
  56 #  endif
  57 #endif
  58
  59
  60 static ssgSharedPtr<ssgStateSelector> layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
  61 static bool state_initialized = false;
  62 static bool bump_mapping = false;
  63 static GLint nb_texture_unit = 0;
  64 static ssgSharedPtr<ssgTexture> normal_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  65 static ssgSharedPtr<ssgTexture> color_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  66 static GLuint normalization_cube_map;
  67
  68 static glActiveTextureProc glActiveTexturePtr = 0;
  69 static glClientActiveTextureProc glClientActiveTexturePtr = 0;
  70 static glBlendColorProc glBlendColorPtr = 0;
  71
  72 bool SGCloudLayer::enable_bump_mapping = false;
  73
  74 static void
  75 generateNormalizationCubeMap()
  76 {
  77     unsigned char data[ 32 * 32 * 3 ];
  78     const int size = 32;
  79     const float half_size = 16.0f,
  80                 offset = 0.5f;
  81     sgVec3 zero_normal;
  82     sgSetVec3( zero_normal, 0.5f, 0.5f, 0.5f );
  83     int i, j;
  84
  85     unsigned char *ptr = data;
  86     for ( j = 0; j < size; j++ ) {
  87         for ( i = 0; i < size; i++ ) {
  88             sgVec3 tmp;
  89             sgSetVec3( tmp, half_size,
  90                             -( j + offset - half_size ),
  91                             -( i + offset - half_size ) );
  92             sgNormalizeVec3( tmp );
  93             sgScaleVec3( tmp, 0.5f );
  94             sgAddVec3( tmp, zero_normal );
  95
  96             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
  97             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
  98             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
  99         }
 100     }
 101     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
 102                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 103
 104     ptr = data;
 105     for ( j = 0; j < size; j++ ) {
 106         for ( i = 0; i < size; i++ ) {
 107             sgVec3 tmp;
 108             sgSetVec3( tmp, -half_size,
 109                             -( j + offset - half_size ),
 110                             ( i + offset - half_size ) );
 111             sgNormalizeVec3( tmp );
 112             sgScaleVec3( tmp, 0.5f );
 113             sgAddVec3( tmp, zero_normal );
 114
 115             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 116             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 117             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 118         }
 119     }
 120     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 121                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 122
 123     ptr = data;
 124     for ( j = 0; j < size; j++ ) {
 125         for ( i = 0; i < size; i++ ) {
 126             sgVec3 tmp;
 127             sgSetVec3( tmp, ( i + offset - half_size ),
 128                             half_size,
 129                             ( j + offset - half_size ) );
 130             sgNormalizeVec3( tmp );
 131             sgScaleVec3( tmp, 0.5f );
 132             sgAddVec3( tmp, zero_normal );
 133
 134             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 135             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 136             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 137         }
 138     }
 139     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 140                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 141
 142     ptr = data;
 143     for ( j = 0; j < size; j++ ) {
 144         for ( i = 0; i < size; i++ ) {
 145             sgVec3 tmp;
 146             sgSetVec3( tmp, ( i + offset - half_size ),
 147                             -half_size,
 148                             -( j + offset - half_size ) );
 149             sgNormalizeVec3( tmp );
 150             sgScaleVec3( tmp, 0.5f );
 151             sgAddVec3( tmp, zero_normal );
 152
 153             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 154             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 155             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 156         }
 157     }
 158     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 159                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 160
 161     ptr = data;
 162     for ( j = 0; j < size; j++ ) {
 163         for ( i = 0; i < size; i++ ) {
 164             sgVec3 tmp;
 165             sgSetVec3( tmp, ( i + offset - half_size ),
 166                             -( j + offset - half_size ),
 167                             half_size );
 168             sgNormalizeVec3( tmp );
 169             sgScaleVec3( tmp, 0.5f );
 170             sgAddVec3( tmp, zero_normal );
 171
 172             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 173             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 174             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 175         }
 176     }
 177     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 178                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 179
 180     ptr = data;
 181     for ( j = 0; j < size; j++ ) {
 182         for ( i = 0; i < size; i++ ) {
 183             sgVec3 tmp;
 184             sgSetVec3( tmp, -( i + offset - half_size ),
 185                             -( j + offset - half_size ),
 186                             -half_size );
 187             sgNormalizeVec3( tmp );
 188             sgScaleVec3( tmp, 0.5f );
 189             sgAddVec3( tmp, zero_normal );
 190
 191             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 192             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 193             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 194         }
 195     }
 196     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB,
 197                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 198 }
 199
 200
 201 // Constructor
 202 SGCloudLayer::SGCloudLayer( const string &tex_path ) :
 203     vertices(0),
 204     indices(0),
 205     layer_root(new ssgRoot),
 206     layer_transform(new ssgTransform),
 207     state_sel(0),
 208     cloud_alpha(1.0),
 209     texture_path(tex_path),
 210     layer_span(0.0),
 211     layer_asl(0.0),
 212     layer_thickness(0.0),
 213     layer_transition(0.0),
 214     layer_coverage(SG_CLOUD_CLEAR),
 215     scale(4000.0),
 216     speed(0.0),
 217     direction(0.0),
 218     last_lon(0.0),
 219     last_lat(0.0)
 220 {
 221     cl[0] = cl[1] = cl[2] = cl[3] = NULL;
 222     vl[0] = vl[1] = vl[2] = vl[3] = NULL;
 223     tl[0] = tl[1] = tl[2] = tl[3] = NULL;
 224     layer[0] = layer[1] = layer[2] = layer[3] = NULL;
 225
 226     layer_root->addKid(layer_transform);
 227         layer3D = new SGCloudField;
 228     rebuild();
 229 }
 230
 231 // Destructor
 232 SGCloudLayer::~SGCloudLayer()
 233 {
 234         delete layer3D;
 235     delete vertices;
 236     delete indices;
 237     delete layer_root;          // deletes layer_transform and layer as well
 238 }
 239
 240 float
 241 SGCloudLayer::getSpan_m () const
 242 {
 243     return layer_span;
 244 }
 245
 246 void
 247 SGCloudLayer::setSpan_m (float span_m)
 248 {
 249     if (span_m != layer_span) {
 250         layer_span = span_m;
 251         rebuild();
 252     }
 253 }
 254
 255 float
 256 SGCloudLayer::getElevation_m () const
 257 {
 258     return layer_asl;
 259 }
 260
 261 void
 262 SGCloudLayer::setElevation_m (float elevation_m, bool set_span)
 263 {
 264     layer_asl = elevation_m;
 265
 266     if (set_span) {
 267         if (elevation_m > 4000)
 268             setSpan_m(  elevation_m * 10 );
 269         else
 270             setSpan_m( 40000 );
 271     }
 272 }
 273
 274 float
 275 SGCloudLayer::getThickness_m () const
 276 {
 277     return layer_thickness;
 278 }
 279
 280 void
 281 SGCloudLayer::setThickness_m (float thickness_m)
 282 {
 283     layer_thickness = thickness_m;
 284 }
 285
 286 float
 287 SGCloudLayer::getTransition_m () const
 288 {
 289     return layer_transition;
 290 }
 291
 292 void
 293 SGCloudLayer::setTransition_m (float transition_m)
 294 {
 295     layer_transition = transition_m;
 296 }
 297
 298 SGCloudLayer::Coverage
 299 SGCloudLayer::getCoverage () const
 300 {
 301     return layer_coverage;
 302 }
 303
 304 void
 305 SGCloudLayer::setCoverage (Coverage coverage)
 306 {
 307     if (coverage != layer_coverage) {
 308         layer_coverage = coverage;
 309         rebuild();
 310     }
 311 }
 312
 313
 314 // build the cloud object
 315 void
 316 SGCloudLayer::rebuild()
 317 {
 318     // Initialize states and sizes if necessary.
 319     if ( !state_initialized ) {
 320         state_initialized = true;
 321
 322         SG_LOG(SG_ASTRO, SG_INFO, "initializing cloud layers");
 323
 324         bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
 325                        SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
 326                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
 327                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") &&
 328                        SGIsOpenGLExtensionSupported("GL_ARB_imaging");
 329
 330         if ( bump_mapping ) {
 331             glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
 332             if ( nb_texture_unit < 2 ) {
 333                 bump_mapping = false;
 334             }
 335             //nb_texture_unit = 2; // Force the number of units for now
 336         }
 337
 338         if ( bump_mapping ) {
 339
 340             // This bump mapping code was inspired by the tutorial available at
 341             // http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
 342             // and a NVidia white paper
 343             //  http://developer.nvidia.com/object/bumpmappingwithregistercombiners.html
 344             // The normal map textures were generated by the normal map Gimp plugin :
 345             //  http://nifelheim.dyndns.org/~cocidius/normalmap/
 346             //
 347             SGPath cloud_path;
 348
 349             glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
 350             glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
 351             glBlendColorPtr = (glBlendColorProc)SGLookupFunction("glBlendColor");
 352
 353             cloud_path.set(texture_path.str());
 354             cloud_path.append("overcast.rgb");
 355             color_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 356             cloud_path.set(texture_path.str());
 357             cloud_path.append("overcast_n.rgb");
 358             normal_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 359
 360             cloud_path.set(texture_path.str());
 361             cloud_path.append("overcast_top.rgb");
 362             color_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 363             cloud_path.set(texture_path.str());
 364             cloud_path.append("overcast_top_n.rgb");
 365             normal_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 366
 367             cloud_path.set(texture_path.str());
 368             cloud_path.append("broken.rgba");
 369             color_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 370             cloud_path.set(texture_path.str());
 371             cloud_path.append("broken_n.rgb");
 372             normal_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 373
 374             cloud_path.set(texture_path.str());
 375             cloud_path.append("scattered.rgba");
 376             color_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 377             cloud_path.set(texture_path.str());
 378             cloud_path.append("scattered_n.rgb");
 379             normal_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 380
 381             cloud_path.set(texture_path.str());
 382             cloud_path.append("few.rgba");
 383             color_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 384             cloud_path.set(texture_path.str());
 385             cloud_path.append("few_n.rgb");
 386             normal_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 387
 388             cloud_path.set(texture_path.str());
 389             cloud_path.append("cirrus.rgba");
 390             color_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 391             cloud_path.set(texture_path.str());
 392             cloud_path.append("cirrus_n.rgb");
 393             normal_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 394
 395             glGenTextures( 1, &normalization_cube_map );
 396             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 397             generateNormalizationCubeMap();
 398             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 399             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 400             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 401             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 402             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE );
 403         } /* else */ {
 404             SGPath cloud_path;
 405             ssgStateSelector *state_sel;
 406             ssgSimpleState *state;
 407
 408             state_sel = new ssgStateSelector( 2 );
 409             cloud_path.set(texture_path.str());
 410             cloud_path.append("overcast.rgb");
 411             state_sel->setStep( 0, sgCloudMakeState(cloud_path.str()) );
 412             cloud_path.set(texture_path.str());
 413             cloud_path.append("overcast_top.rgb");
 414             state_sel->setStep( 1, sgCloudMakeState(cloud_path.str()) );
 415             layer_states[SG_CLOUD_OVERCAST] = state_sel;
 416
 417             state_sel = new ssgStateSelector( 2 );
 418             cloud_path.set(texture_path.str());
 419             cloud_path.append("broken.rgba");
 420             state = sgCloudMakeState(cloud_path.str());
 421             state_sel->setStep( 0, state );
 422             state_sel->setStep( 1, state );
 423             layer_states[SG_CLOUD_BROKEN] = state_sel;
 424
 425             state_sel = new ssgStateSelector( 2 );
 426             cloud_path.set(texture_path.str());
 427             cloud_path.append("scattered.rgba");
 428             state = sgCloudMakeState(cloud_path.str());
 429             state_sel->setStep( 0, state );
 430             state_sel->setStep( 1, state );
 431             layer_states[SG_CLOUD_SCATTERED] = state_sel;
 432
 433             state_sel = new ssgStateSelector( 2 );
 434             cloud_path.set(texture_path.str());
 435             cloud_path.append("few.rgba");
 436             state = sgCloudMakeState(cloud_path.str());
 437             state_sel->setStep( 0, state );
 438             state_sel->setStep( 1, state );
 439             layer_states[SG_CLOUD_FEW] = state_sel;
 440
 441             state_sel = new ssgStateSelector( 2 );
 442             cloud_path.set(texture_path.str());
 443             cloud_path.append("cirrus.rgba");
 444             state = sgCloudMakeState(cloud_path.str());
 445             state_sel->setStep( 0, state );
 446             state_sel->setStep( 1, state );
 447             layer_states[SG_CLOUD_CIRRUS] = state_sel;
 448
 449             layer_states[SG_CLOUD_CLEAR] = 0;
 450         }
 451                 SGNewCloud::loadTextures(texture_path.str());
 452                 layer3D->buildTestLayer();
 453     }
 454
 455     if ( bump_mapping ) {
 456
 457         if ( !vertices ) {
 458             vertices = new CloudVertex[ 25 ];
 459             indices = new unsigned int[ 40 ];
 460         }
 461
 462         sgVec2 base;
 463         sgSetVec2( base, sg_random(), sg_random() );
 464
 465         const float layer_scale = layer_span / scale;
 466         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 467         const float half_angle = 0.5 * layer_span / layer_to_core;
 468
 469         int i;
 470         for ( i = -2; i <= 2; i++ ) {
 471             for ( int j = -2; j <= 2; j++ ) {
 472                 CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 473                 sgSetVec3( v1.position,
 474                            0.5 * i * layer_span,
 475                            0.5 * j * layer_span,
 476                            -layer_to_core * ( 1 - cos( i * half_angle ) * cos( j * half_angle ) ) );
 477                 sgSetVec2( v1.texCoord,
 478                            base[0] + layer_scale * i * 0.25,
 479                            base[1] + layer_scale * j * 0.25 );
 480                 sgSetVec3( v1.sTangent,
 481                            cos( i * half_angle ),
 482                            0.f,
 483                            -sin( i * half_angle ) );
 484                 sgSetVec3( v1.tTangent,
 485                            0.f,
 486                            cos( j * half_angle ),
 487                            -sin( j * half_angle ) );
 488                 sgVectorProductVec3( v1.normal, v1.tTangent, v1.sTangent );
 489                 sgSetVec4( v1.color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : cloud_alpha * 0.15f );
 490             }
 491         }
 492         /*
 493          * 0 1 5 6 10 11 15 16 20 21
 494          * 1 2 6 7 11 12 16 17 21 22
 495          * 2 3 7 8 12 13 17 18 22 23
 496          * 3 4 8 9 13 14 18 19 23 24
 497          */
 498         for ( i = 0; i < 4; i++ ) {
 499             for ( int j = 0; j < 5; j++ ) {
 500                 indices[ i*10 + (j*2) ]     =     i + 5 * j;
 501                 indices[ i*10 + (j*2) + 1 ] = 1 + i + 5 * j;
 502             }
 503         }
 504
 505     } /* else */ {
 506
 507         scale = 4000.0;
 508         last_lon = last_lat = -999.0f;
 509
 510         sgVec2 base;
 511         sgSetVec2( base, sg_random(), sg_random() );
 512
 513         // build the cloud layer
 514         sgVec4 color;
 515         sgVec3 vertex;
 516         sgVec2 tc;
 517
 518         const float layer_scale = layer_span / scale;
 519         const float mpi = SG_PI/4;
 520
 521         // caclculate the difference between a flat-earth model and
 522         // a round earth model given the span and altutude ASL of
 523         // the cloud layer. This is the difference in altitude between
 524         // the top of the inverted bowl and the edge of the bowl.
 525         // const float alt_diff = layer_asl * 0.8;
 526         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 527         const float layer_angle = 0.5*layer_span / layer_to_core; // The angle is half the span
 528         const float border_to_core = layer_to_core * cos(layer_angle);
 529         const float alt_diff = layer_to_core - border_to_core;
 530
 531         for (int i = 0; i < 4; i++)
 532         {
 533             if ( layer[i] != NULL ) {
 534                 layer_transform->removeKid(layer[i]); // automatic delete
 535             }
 536
 537             vl[i] = new ssgVertexArray( 10 );
 538             cl[i] = new ssgColourArray( 10 );
 539             tl[i] = new ssgTexCoordArray( 10 );
 540
 541
 542             sgSetVec3( vertex, layer_span*(i-2)/2, -layer_span,
 543                             alt_diff * (sin(i*mpi) - 2) );
 544
 545             sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 546
 547             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 548
 549             cl[i]->add( color );
 550             vl[i]->add( vertex );
 551             tl[i]->add( tc );
 552
 553             for (int j = 0; j < 4; j++)
 554             {
 555                 sgSetVec3( vertex, layer_span*(i-1)/2, layer_span*(j-2)/2,
 556                                 alt_diff * (sin((i+1)*mpi) + sin(j*mpi) - 2) );
 557
 558                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 559                             base[1] + layer_scale * j/4 );
 560
 561                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 562                                 ( (j == 0) || (i == 3)) ?
 563                                 ( (j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f );
 564
 565                 cl[i]->add( color );
 566                 vl[i]->add( vertex );
 567                 tl[i]->add( tc );
 568
 569
 570                 sgSetVec3( vertex, layer_span*(i-2)/2, layer_span*(j-1)/2,
 571                                 alt_diff * (sin(i*mpi) + sin((j+1)*mpi) - 2) );
 572
 573                 sgSetVec2( tc, base[0] + layer_scale * i/4,
 574                             base[1] + layer_scale * (j+1)/4 );
 575
 576                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 577                                 ((j == 3) || (i == 0)) ?
 578                                 ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f );
 579                 cl[i]->add( color );
 580                 vl[i]->add( vertex );
 581                 tl[i]->add( tc );
 582             }
 583
 584             sgSetVec3( vertex, layer_span*(i-1)/2, layer_span,
 585                             alt_diff * (sin((i+1)*mpi) - 2) );
 586
 587             sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 588                         base[1] + layer_scale );
 589
 590             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 3) ? 0.0f : 0.15f );
 591
 592             cl[i]->add( color );
 593             vl[i]->add( vertex );
 594             tl[i]->add( tc );
 595
 596             layer[i] = new ssgVtxTable(GL_TRIANGLE_STRIP, vl[i], NULL, tl[i], cl[i]);
 597             layer_transform->addKid( layer[i] );
 598
 599             if ( layer_states[layer_coverage] != NULL ) {
 600                 layer[i]->setState( layer_states[layer_coverage] );
 601             }
 602             state_sel = layer_states[layer_coverage];
 603         }
 604
 605         // force a repaint of the sky colors with arbitrary defaults
 606         repaint( color );
 607     }
 608 }
 609
 610
 611 // repaint the cloud layer colors
 612 bool SGCloudLayer::repaint( sgVec3 fog_color ) {
 613
 614     if ( bump_mapping && enable_bump_mapping ) {
 615
 616         for ( int i = 0; i < 25; i++ ) {
 617             sgCopyVec3( vertices[ i ].color, fog_color );
 618         }
 619
 620     } else {
 621         float *color;
 622
 623         for ( int i = 0; i < 4; i++ ) {
 624             color = cl[i]->get( 0 );
 625             sgCopyVec3( color, fog_color );
 626             color[3] = (i == 0) ? 0.0f : cloud_alpha * 0.15f;
 627
 628             for ( int j = 0; j < 4; ++j ) {
 629                 color = cl[i]->get( (2*j) + 1 );
 630                 sgCopyVec3( color, fog_color );
 631                 color[3] =
 632                     ((j == 0) || (i == 3)) ?
 633                     ((j == 0) && (i == 3)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 634
 635                 color = cl[i]->get( (2*j) + 2 );
 636                 sgCopyVec3( color, fog_color );
 637                 color[3] =
 638                     ((j == 3) || (i == 0)) ?
 639                     ((j == 3) && (i == 0)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 640             }
 641
 642             color = cl[i]->get( 9 );
 643             sgCopyVec3( color, fog_color );
 644             color[3] = (i == 3) ? 0.0f : cloud_alpha * 0.15f;
 645         }
 646     }
 647
 648     return true;
 649 }
 650
 651 // reposition the cloud layer at the specified origin and orientation
 652 // lon specifies a rotation about the Z axis
 653 // lat specifies a rotation about the new Y axis
 654 // spin specifies a rotation about the new Z axis (and orients the
 655 // sunrise/set effects
 656 bool SGCloudLayer::reposition( sgVec3 p, sgVec3 up, double lon, double lat,
 657                                double alt, double dt )
 658 {
 659     sgMat4 T1, LON, LAT;
 660     sgVec3 axis;
 661
 662     // combine p and asl (meters) to get translation offset
 663     sgVec3 asl_offset;
 664     sgCopyVec3( asl_offset, up );
 665     sgNormalizeVec3( asl_offset );
 666     if ( alt <= layer_asl ) {
 667         sgScaleVec3( asl_offset, layer_asl );
 668     } else {
 669         sgScaleVec3( asl_offset, layer_asl + layer_thickness );
 670     }
 671     // cout << "asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 672     //      << "," << asl_offset[2] << endl;
 673     sgAddVec3( asl_offset, p );
 674     // cout << "  asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 675     //      << "," << asl_offset[2] << endl;
 676
 677     // Translate to zero elevation
 678     // Point3D zero_elev = current_view.get_cur_zero_elev();
 679     sgMakeTransMat4( T1, asl_offset );
 680
 681     // printf("  Translated to %.2f %.2f %.2f\n",
 682     //        zero_elev.x, zero_elev.y, zero_elev.z );
 683
 684     // Rotate to proper orientation
 685     // printf("  lon = %.2f  lat = %.2f\n",
 686     //        lon * SGD_RADIANS_TO_DEGREES,
 687     //        lat * SGD_RADIANS_TO_DEGREES);
 688     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 689     sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );
 690
 691     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 692     sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );
 693
 694     sgMat4 TRANSFORM;
 695
 696     sgCopyMat4( TRANSFORM, T1 );
 697     sgPreMultMat4( TRANSFORM, LON );
 698     sgPreMultMat4( TRANSFORM, LAT );
 699
 700     sgCoord layerpos;
 701     sgSetCoord( &layerpos, TRANSFORM );
 702
 703     layer_transform->setTransform( &layerpos );
 704
 705     // now calculate update texture coordinates
 706     if ( last_lon < -900 ) {
 707         last_lon = lon;
 708         last_lat = lat;
 709     }
 710
 711     double sp_dist = speed*dt;
 712
 713     if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
 714         Point3D start( last_lon, last_lat, 0.0 );
 715         Point3D dest( lon, lat, 0.0 );
 716         double course = 0.0, dist = 0.0;
 717
 718         calc_gc_course_dist( dest, start, &course, &dist );
 719         // cout << "course = " << course << ", dist = " << dist << endl;
 720
 721         // if start and dest are too close together,
 722         // calc_gc_course_dist() can return a course of "nan".  If
 723         // this happens, lets just use the last known good course.
 724         // This is a hack, and it would probably be better to make
 725         // calc_gc_course_dist() more robust.
 726         if ( isnan(course) ) {
 727             course = last_course;
 728         } else {
 729             last_course = course;
 730         }
 731
 732         // calculate cloud movement due to external forces
 733         double ax = 0.0, ay = 0.0, bx = 0.0, by = 0.0;
 734
 735         if (dist > 0.0) {
 736             ax = cos(course) * dist;
 737             ay = sin(course) * dist;
 738         }
 739
 740         if (sp_dist > 0) {
 741             bx = cos((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 742             by = sin((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 743         }
 744
 745
 746         double xoff = (ax + bx) / (2 * scale);
 747         double yoff = (ay + by) / (2 * scale);
 748
 749         const float layer_scale = layer_span / scale;
 750
 751         // cout << "xoff = " << xoff << ", yoff = " << yoff << endl;
 752
 753         float *base;
 754         if ( bump_mapping && enable_bump_mapping ) {
 755             base = vertices[12].texCoord;
 756         } else {
 757             base = tl[0]->get( 0 );
 758         }
 759         base[0] += xoff;
 760
 761         // the while loops can lead to *long* pauses if base[0] comes
 762         // with a bogus value.
 763         // while ( base[0] > 1.0 ) { base[0] -= 1.0; }
 764         // while ( base[0] < 0.0 ) { base[0] += 1.0; }
 765         if ( base[0] > -10.0 && base[0] < 10.0 ) {
 766             base[0] -= (int)base[0];
 767         } else {
 768             SG_LOG(SG_ASTRO, SG_DEBUG,
 769                 "Error: base = " << base[0] << "," << base[1] <<
 770                 " course = " << course << " dist = " << dist );
 771             base[0] = 0.0;
 772         }
 773
 774         base[1] += yoff;
 775         // the while loops can lead to *long* pauses if base[0] comes
 776         // with a bogus value.
 777         // while ( base[1] > 1.0 ) { base[1] -= 1.0; }
 778         // while ( base[1] < 0.0 ) { base[1] += 1.0; }
 779         if ( base[1] > -10.0 && base[1] < 10.0 ) {
 780             base[1] -= (int)base[1];
 781         } else {
 782             SG_LOG(SG_ASTRO, SG_DEBUG,
 783                     "Error: base = " << base[0] << "," << base[1] <<
 784                     " course = " << course << " dist = " << dist );
 785             base[1] = 0.0;
 786         }
 787
 788         if ( bump_mapping && enable_bump_mapping ) {
 789
 790             for ( int i = -2; i <= 2; i++ ) {
 791                 for ( int j = -2; j <= 2; j++ ) {
 792                     if ( i == 0 && j == 0 )
 793                         continue; // Already done on base
 794                     CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 795                     sgSetVec2( v1.texCoord,
 796                             base[0] + layer_scale * i * 0.25,
 797                             base[1] + layer_scale * j * 0.25 );
 798                 }
 799             }
 800
 801         } else {
 802                 // cout << "base = " << base[0] << "," << base[1] << endl;
 803
 804             float *tc;
 805             for (int i = 0; i < 4; i++) {
 806                 tc = tl[i]->get( 0 );
 807                 sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 808
 809                 for (int j = 0; j < 4; j++)
 810                 {
 811                     tc = tl[i]->get( j*2+1 );
 812                     sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 813                                 base[1] + layer_scale * j/4 );
 814
 815                     tc = tl[i]->get( (j+1)*2 );
 816                     sgSetVec2( tc, base[0] + layer_scale * i/4,
 817                                 base[1] + layer_scale * (j+1)/4 );
 818                 }
 819
 820                 tc = tl[i]->get( 9 );
 821                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 822                             base[1] + layer_scale );
 823             }
 824         }
 825
 826         last_lon = lon;
 827         last_lat = lat;
 828     }
 829
 830         layer3D->reposition( p, up, lon, lat, alt, dt, direction, speed);
 831     return true;
 832 }
 833
 834
 835 void SGCloudLayer::draw( bool top ) {
 836     if ( layer_coverage != SG_CLOUD_CLEAR ) {
 837
 838                 if ( SGCloudField::enable3D && layer3D->is3D())
 839                         layer3D->Render();
 840                 else
 841         if ( bump_mapping && enable_bump_mapping ) {
 842
 843             sgMat4 modelview,
 844                    tmp,
 845                    transform;
 846             ssgGetModelviewMatrix( modelview );
 847             layer_transform->getTransform( transform );
 848
 849             sgTransposeNegateMat4( tmp, transform );
 850
 851             sgPostMultMat4( transform, modelview );
 852             ssgLoadModelviewMatrix( transform );
 853
 854             sgVec3 lightVec;
 855             ssgGetLight( 0 )->getPosition( lightVec );
 856             sgNegateVec3( lightVec );
 857             sgXformVec3( lightVec, tmp );
 858
 859             for ( int i = 0; i < 25; i++ ) {
 860                 CloudVertex &v = vertices[ i ];
 861                 sgSetVec3( v.tangentSpLight,
 862                            sgScalarProductVec3( v.sTangent, lightVec ),
 863                            sgScalarProductVec3( v.tTangent, lightVec ),
 864                            sgScalarProductVec3( v.normal, lightVec ) );
 865             }
 866
 867             ssgTexture *decal = color_map[ layer_coverage ][ top ? 1 : 0 ];
 868             if ( top && decal == 0 ) {
 869                 decal = color_map[ layer_coverage ][ 0 ];
 870             }
 871             ssgTexture *normal = normal_map[ layer_coverage ][ top ? 1 : 0 ];
 872             if ( top && normal == 0 ) {
 873                 normal = normal_map[ layer_coverage ][ 0 ];
 874             }
 875
 876             glDisable( GL_LIGHTING );
 877             glDisable( GL_CULL_FACE );
 878 //            glDisable( GL_ALPHA_TEST );
 879             if ( layer_coverage == SG_CLOUD_FEW ) {
 880                 glEnable( GL_ALPHA_TEST );
 881                 glAlphaFunc ( GL_GREATER, 0.01 );
 882             }
 883             glEnable( GL_BLEND );
 884             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 885
 886             glShadeModel( GL_SMOOTH );
 887             glEnable( GL_COLOR_MATERIAL );
 888             sgVec4 color;
 889             float emis = 0.05;
 890             if ( 1 ) {
 891                 ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
 892                 emis = ( color[0]+color[1]+color[2] ) / 3.0;
 893                 if ( emis < 0.05 )
 894                     emis = 0.05;
 895             }
 896             sgSetVec4( color, emis, emis, emis, 0.0 );
 897             glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, color );
 898             sgSetVec4( color, 1.0f, 1.0f, 1.0f, 0.0 );
 899             glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, color );
 900             sgSetVec4( color, 1.0, 1.0, 1.0, 0.0 );
 901             glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, color );
 902             sgSetVec4( color, 0.0, 0.0, 0.0, 0.0 );
 903             glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, color );
 904
 905             glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
 906
 907             glActiveTexturePtr( GL_TEXTURE0_ARB );
 908             glBindTexture( GL_TEXTURE_2D, normal->getHandle() );
 909             glEnable( GL_TEXTURE_2D );
 910
 911             //Bind normalisation cube map to texture unit 1
 912             glActiveTexturePtr( GL_TEXTURE1_ARB );
 913             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 914             glEnable( GL_TEXTURE_CUBE_MAP_ARB );
 915             glActiveTexturePtr( GL_TEXTURE0_ARB );
 916
 917             //Set vertex arrays for cloud
 918             glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
 919             glEnableClientState( GL_VERTEX_ARRAY );
 920 /*
 921             if ( nb_texture_unit >= 3 ) {
 922                 glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
 923                 glEnableClientState( GL_COLOR_ARRAY );
 924             }
 925 */
 926             //Send texture coords for normal map to unit 0
 927             glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 928             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 929
 930             //Send tangent space light vectors for normalisation to unit 1
 931             glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 932             glTexCoordPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].tangentSpLight );
 933             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 934
 935             //Set up texture environment to do (tex0 dot tex1)*color
 936             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 937             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 938             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE );
 939             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE );
 940             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 941
 942             glActiveTexturePtr( GL_TEXTURE1_ARB );
 943
 944             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 945             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 946             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_DOT3_RGB_ARB );
 947             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 948             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB );
 949             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 950
 951             if ( nb_texture_unit >= 3 ) {
 952                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 953                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 954
 955                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 956                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 957                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 958
 959                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 960                 glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD );
 961                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 962                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 963
 964                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 965                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 966
 967                 //Draw cloud layer
 968                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 969                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 970                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 971                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 972
 973                 glDisable( GL_TEXTURE_2D );
 974                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 975                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 976                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 977                 glDisable( GL_TEXTURE_2D );
 978                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 979
 980                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 981                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 982                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 983                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 984                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 985                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 986
 987                 glDisableClientState( GL_COLOR_ARRAY );
 988                 glEnable( GL_LIGHTING );
 989
 990                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
 991
 992             } else {
 993                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 994                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 995
 996                 //Draw cloud layer
 997                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 998                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 999                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1000                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1001
1002                 //Disable textures
1003                 glDisable( GL_TEXTURE_2D );
1004
1005                 glActiveTexturePtr( GL_TEXTURE1_ARB );
1006                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
1007                 glActiveTexturePtr( GL_TEXTURE0_ARB );
1008
1009                 //disable vertex arrays
1010                 glDisableClientState( GL_VERTEX_ARRAY );
1011
1012                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1013                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
1014                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1015                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1016
1017                 //Return to standard modulate texenv
1018                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1019
1020                 if ( layer_coverage == SG_CLOUD_OVERCAST ) {
1021                     glDepthFunc(GL_LEQUAL);
1022
1023                     glEnable( GL_LIGHTING );
1024                     sgVec4 color;
1025                     ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
1026                     float average = ( color[0] + color[1] + color[2] ) / 3.0f;
1027                     average = 0.15 + average/10;
1028                     sgVec4 averageColor;
1029                     sgSetVec4( averageColor, average, average, average, 1.0f );
1030                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, averageColor );
1031
1032                     glBlendColorPtr( average, average, average, 1.0f );
1033                     glBlendFunc( GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_COLOR );
1034
1035                     //Perform a second pass to color the torus
1036                     //Bind decal texture
1037                     glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
1038                     glEnable(GL_TEXTURE_2D);
1039
1040                     //Set vertex arrays for torus
1041                     glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
1042                     glEnableClientState( GL_VERTEX_ARRAY );
1043
1044                     //glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
1045                     //glEnableClientState( GL_COLOR_ARRAY );
1046
1047                     glNormalPointer( GL_FLOAT, sizeof(CloudVertex), &vertices[0].normal );
1048                     glEnableClientState( GL_NORMAL_ARRAY );
1049
1050                     glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
1051                     glEnableClientState( GL_TEXTURE_COORD_ARRAY );
1052
1053                     //Draw cloud layer
1054                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1055                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1056                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1057                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1058
1059                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, color );
1060
1061                     glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1062                 }
1063             }
1064             //Disable texture
1065             glDisable( GL_TEXTURE_2D );
1066
1067             glDisableClientState( GL_VERTEX_ARRAY );
1068             glDisableClientState( GL_NORMAL_ARRAY );
1069
1070             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
1071             glEnable( GL_CULL_FACE );
1072             glDepthFunc(GL_LESS);
1073
1074             ssgLoadModelviewMatrix( modelview );
1075
1076         } else {
1077             state_sel->selectStep( top ? 1 : 0 );
1078             ssgCullAndDraw( layer_root );
1079         }
1080     }
1081 }
1082
1083
1084 // make an ssgSimpleState for a cloud layer given the named texture
1085 ssgSimpleState *sgCloudMakeState( const string &path ) {
1086     ssgSimpleState *state = new ssgSimpleState();
1087
1088     SG_LOG(SG_ASTRO, SG_INFO, " texture = ");
1089
1090     state->setTexture( (char *)path.c_str() );
1091     state->setShadeModel( GL_SMOOTH );
1092     state->disable( GL_LIGHTING );
1093     state->disable( GL_CULL_FACE );
1094     state->enable( GL_TEXTURE_2D );
1095     state->enable( GL_COLOR_MATERIAL );
1096     state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
1097     state->setMaterial( GL_EMISSION, 0.05, 0.05, 0.05, 0.0 );
1098     state->setMaterial( GL_AMBIENT, 0.2, 0.2, 0.2, 0.0 );
1099     state->setMaterial( GL_DIFFUSE, 0.5, 0.5, 0.5, 0.0 );
1100     state->setMaterial( GL_SPECULAR, 0.0, 0.0, 0.0, 0.0 );
1101     state->enable( GL_BLEND );
1102     state->enable( GL_ALPHA_TEST );
1103     state->setAlphaClamp( 0.01 );
1104
1105     return state;
1106 }