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/misc/sg_path.hxx>
  40 #include <simgear/screen/extensions.hxx>
  41 #include <simgear/screen/texture.hxx>
  42 #include <simgear/structure/ssgSharedPtr.hxx>
  43
  44 #include "newcloud.hxx"
  45 #include "cloudfield.hxx"
  46 #include "cloud.hxx"
  47
  48 #if defined(__MINGW32__)
  49 #define isnan(x) _isnan(x)
  50 #endif
  51
  52 #if defined (__FreeBSD__)
  53 #  if __FreeBSD_version < 500000
  54      extern "C" {
  55        inline int isnan(double r) { return !(r <= 0 || r >= 0); }
  56      }
  57 #  endif
  58 #endif
  59
  60
  61 static ssgSharedPtr<ssgStateSelector> layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
  62 static bool state_initialized = false;
  63 static bool bump_mapping = false;
  64 static GLint nb_texture_unit = 0;
  65 static ssgSharedPtr<ssgTexture> normal_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  66 static ssgSharedPtr<ssgTexture> color_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  67 static GLuint normalization_cube_map;
  68
  69 static glActiveTextureProc glActiveTexturePtr = 0;
  70 static glClientActiveTextureProc glClientActiveTexturePtr = 0;
  71 static glBlendColorProc glBlendColorPtr = 0;
  72
  73 bool SGCloudLayer::enable_bump_mapping = false;
  74
  75 static void
  76 generateNormalizationCubeMap()
  77 {
  78     unsigned char data[ 32 * 32 * 3 ];
  79     const int size = 32;
  80     const float half_size = 16.0f,
  81                 offset = 0.5f;
  82     sgVec3 zero_normal;
  83     sgSetVec3( zero_normal, 0.5f, 0.5f, 0.5f );
  84     int i, j;
  85
  86     unsigned char *ptr = data;
  87     for ( j = 0; j < size; j++ ) {
  88         for ( i = 0; i < size; i++ ) {
  89             sgVec3 tmp;
  90             sgSetVec3( tmp, half_size,
  91                             -( j + offset - half_size ),
  92                             -( i + offset - half_size ) );
  93             sgNormalizeVec3( tmp );
  94             sgScaleVec3( tmp, 0.5f );
  95             sgAddVec3( tmp, zero_normal );
  96
  97             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
  98             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
  99             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 100         }
 101     }
 102     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
 103                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 104
 105     ptr = data;
 106     for ( j = 0; j < size; j++ ) {
 107         for ( i = 0; i < size; i++ ) {
 108             sgVec3 tmp;
 109             sgSetVec3( tmp, -half_size,
 110                             -( j + offset - half_size ),
 111                             ( i + offset - half_size ) );
 112             sgNormalizeVec3( tmp );
 113             sgScaleVec3( tmp, 0.5f );
 114             sgAddVec3( tmp, zero_normal );
 115
 116             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 117             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 118             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 119         }
 120     }
 121     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 122                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 123
 124     ptr = data;
 125     for ( j = 0; j < size; j++ ) {
 126         for ( i = 0; i < size; i++ ) {
 127             sgVec3 tmp;
 128             sgSetVec3( tmp, ( i + offset - half_size ),
 129                             half_size,
 130                             ( j + offset - half_size ) );
 131             sgNormalizeVec3( tmp );
 132             sgScaleVec3( tmp, 0.5f );
 133             sgAddVec3( tmp, zero_normal );
 134
 135             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 136             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 137             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 138         }
 139     }
 140     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 141                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 142
 143     ptr = data;
 144     for ( j = 0; j < size; j++ ) {
 145         for ( i = 0; i < size; i++ ) {
 146             sgVec3 tmp;
 147             sgSetVec3( tmp, ( i + offset - half_size ),
 148                             -half_size,
 149                             -( j + offset - half_size ) );
 150             sgNormalizeVec3( tmp );
 151             sgScaleVec3( tmp, 0.5f );
 152             sgAddVec3( tmp, zero_normal );
 153
 154             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 155             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 156             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 157         }
 158     }
 159     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 160                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 161
 162     ptr = data;
 163     for ( j = 0; j < size; j++ ) {
 164         for ( i = 0; i < size; i++ ) {
 165             sgVec3 tmp;
 166             sgSetVec3( tmp, ( i + offset - half_size ),
 167                             -( j + offset - half_size ),
 168                             half_size );
 169             sgNormalizeVec3( tmp );
 170             sgScaleVec3( tmp, 0.5f );
 171             sgAddVec3( tmp, zero_normal );
 172
 173             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 174             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 175             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 176         }
 177     }
 178     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 179                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 180
 181     ptr = data;
 182     for ( j = 0; j < size; j++ ) {
 183         for ( i = 0; i < size; i++ ) {
 184             sgVec3 tmp;
 185             sgSetVec3( tmp, -( i + offset - half_size ),
 186                             -( j + offset - half_size ),
 187                             -half_size );
 188             sgNormalizeVec3( tmp );
 189             sgScaleVec3( tmp, 0.5f );
 190             sgAddVec3( tmp, zero_normal );
 191
 192             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 193             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 194             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 195         }
 196     }
 197     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB,
 198                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 199 }
 200
 201
 202 // Constructor
 203 SGCloudLayer::SGCloudLayer( const string &tex_path ) :
 204     vertices(0),
 205     indices(0),
 206     layer_root(new ssgRoot),
 207     layer_transform(new ssgTransform),
 208     state_sel(0),
 209     cloud_alpha(1.0),
 210     texture_path(tex_path),
 211     layer_span(0.0),
 212     layer_asl(0.0),
 213     layer_thickness(0.0),
 214     layer_transition(0.0),
 215     layer_coverage(SG_CLOUD_CLEAR),
 216     scale(4000.0),
 217     speed(0.0),
 218     direction(0.0),
 219     last_lon(0.0),
 220     last_lat(0.0)
 221 {
 222     cl[0] = cl[1] = cl[2] = cl[3] = NULL;
 223     vl[0] = vl[1] = vl[2] = vl[3] = NULL;
 224     tl[0] = tl[1] = tl[2] = tl[3] = NULL;
 225     layer[0] = layer[1] = layer[2] = layer[3] = NULL;
 226
 227     layer_root->addKid(layer_transform);
 228         layer3D = new SGCloudField;
 229     rebuild();
 230 }
 231
 232 // Destructor
 233 SGCloudLayer::~SGCloudLayer()
 234 {
 235         delete layer3D;
 236     delete vertices;
 237     delete indices;
 238     delete layer_root;          // deletes layer_transform and layer as well
 239 }
 240
 241 float
 242 SGCloudLayer::getSpan_m () const
 243 {
 244     return layer_span;
 245 }
 246
 247 void
 248 SGCloudLayer::setSpan_m (float span_m)
 249 {
 250     if (span_m != layer_span) {
 251         layer_span = span_m;
 252         rebuild();
 253     }
 254 }
 255
 256 float
 257 SGCloudLayer::getElevation_m () const
 258 {
 259     return layer_asl;
 260 }
 261
 262 void
 263 SGCloudLayer::setElevation_m (float elevation_m, bool set_span)
 264 {
 265     layer_asl = elevation_m;
 266
 267     if (set_span) {
 268         if (elevation_m > 4000)
 269             setSpan_m(  elevation_m * 10 );
 270         else
 271             setSpan_m( 40000 );
 272     }
 273 }
 274
 275 float
 276 SGCloudLayer::getThickness_m () const
 277 {
 278     return layer_thickness;
 279 }
 280
 281 void
 282 SGCloudLayer::setThickness_m (float thickness_m)
 283 {
 284     layer_thickness = thickness_m;
 285 }
 286
 287 float
 288 SGCloudLayer::getTransition_m () const
 289 {
 290     return layer_transition;
 291 }
 292
 293 void
 294 SGCloudLayer::setTransition_m (float transition_m)
 295 {
 296     layer_transition = transition_m;
 297 }
 298
 299 SGCloudLayer::Coverage
 300 SGCloudLayer::getCoverage () const
 301 {
 302     return layer_coverage;
 303 }
 304
 305 void
 306 SGCloudLayer::setCoverage (Coverage coverage)
 307 {
 308     if (coverage != layer_coverage) {
 309         layer_coverage = coverage;
 310         rebuild();
 311     }
 312 }
 313
 314
 315 // build the cloud object
 316 void
 317 SGCloudLayer::rebuild()
 318 {
 319     // Initialize states and sizes if necessary.
 320     if ( !state_initialized ) {
 321         state_initialized = true;
 322
 323         SG_LOG(SG_ASTRO, SG_INFO, "initializing cloud layers");
 324
 325         bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
 326                        SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
 327                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
 328                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") &&
 329                        SGIsOpenGLExtensionSupported("GL_ARB_imaging");
 330
 331         if ( bump_mapping ) {
 332             glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
 333             if ( nb_texture_unit < 2 ) {
 334                 bump_mapping = false;
 335             }
 336             //nb_texture_unit = 2; // Force the number of units for now
 337         }
 338
 339         if ( bump_mapping ) {
 340
 341             // This bump mapping code was inspired by the tutorial available at
 342             // http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
 343             // and a NVidia white paper
 344             //  http://developer.nvidia.com/object/bumpmappingwithregistercombiners.html
 345             // The normal map textures were generated by the normal map Gimp plugin :
 346             //  http://nifelheim.dyndns.org/~cocidius/normalmap/
 347             //
 348             SGPath cloud_path;
 349
 350             glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
 351             glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
 352             glBlendColorPtr = (glBlendColorProc)SGLookupFunction("glBlendColor");
 353
 354             cloud_path.set(texture_path.str());
 355             cloud_path.append("overcast.rgb");
 356             color_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 357             cloud_path.set(texture_path.str());
 358             cloud_path.append("overcast_n.rgb");
 359             normal_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 360
 361             cloud_path.set(texture_path.str());
 362             cloud_path.append("overcast_top.rgb");
 363             color_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 364             cloud_path.set(texture_path.str());
 365             cloud_path.append("overcast_top_n.rgb");
 366             normal_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 367
 368             cloud_path.set(texture_path.str());
 369             cloud_path.append("broken.rgba");
 370             color_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 371             cloud_path.set(texture_path.str());
 372             cloud_path.append("broken_n.rgb");
 373             normal_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 374
 375             cloud_path.set(texture_path.str());
 376             cloud_path.append("scattered.rgba");
 377             color_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 378             cloud_path.set(texture_path.str());
 379             cloud_path.append("scattered_n.rgb");
 380             normal_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 381
 382             cloud_path.set(texture_path.str());
 383             cloud_path.append("few.rgba");
 384             color_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 385             cloud_path.set(texture_path.str());
 386             cloud_path.append("few_n.rgb");
 387             normal_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 388
 389             cloud_path.set(texture_path.str());
 390             cloud_path.append("cirrus.rgba");
 391             color_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 392             cloud_path.set(texture_path.str());
 393             cloud_path.append("cirrus_n.rgb");
 394             normal_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 395
 396             glGenTextures( 1, &normalization_cube_map );
 397             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 398             generateNormalizationCubeMap();
 399             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 400             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 401             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 402             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 403             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE );
 404         } /* else */ {
 405             SGPath cloud_path;
 406             ssgStateSelector *state_sel;
 407             ssgSimpleState *state;
 408
 409             state_sel = new ssgStateSelector( 2 );
 410             cloud_path.set(texture_path.str());
 411             cloud_path.append("overcast.rgb");
 412             state_sel->setStep( 0, sgCloudMakeState(cloud_path.str()) );
 413             cloud_path.set(texture_path.str());
 414             cloud_path.append("overcast_top.rgb");
 415             state_sel->setStep( 1, sgCloudMakeState(cloud_path.str()) );
 416             layer_states[SG_CLOUD_OVERCAST] = state_sel;
 417
 418             state_sel = new ssgStateSelector( 2 );
 419             cloud_path.set(texture_path.str());
 420             cloud_path.append("broken.rgba");
 421             state = sgCloudMakeState(cloud_path.str());
 422             state_sel->setStep( 0, state );
 423             state_sel->setStep( 1, state );
 424             layer_states[SG_CLOUD_BROKEN] = state_sel;
 425
 426             state_sel = new ssgStateSelector( 2 );
 427             cloud_path.set(texture_path.str());
 428             cloud_path.append("scattered.rgba");
 429             state = sgCloudMakeState(cloud_path.str());
 430             state_sel->setStep( 0, state );
 431             state_sel->setStep( 1, state );
 432             layer_states[SG_CLOUD_SCATTERED] = state_sel;
 433
 434             state_sel = new ssgStateSelector( 2 );
 435             cloud_path.set(texture_path.str());
 436             cloud_path.append("few.rgba");
 437             state = sgCloudMakeState(cloud_path.str());
 438             state_sel->setStep( 0, state );
 439             state_sel->setStep( 1, state );
 440             layer_states[SG_CLOUD_FEW] = state_sel;
 441
 442             state_sel = new ssgStateSelector( 2 );
 443             cloud_path.set(texture_path.str());
 444             cloud_path.append("cirrus.rgba");
 445             state = sgCloudMakeState(cloud_path.str());
 446             state_sel->setStep( 0, state );
 447             state_sel->setStep( 1, state );
 448             layer_states[SG_CLOUD_CIRRUS] = state_sel;
 449
 450             layer_states[SG_CLOUD_CLEAR] = 0;
 451         }
 452                 SGNewCloud::loadTextures(texture_path.str());
 453                 layer3D->buildTestLayer();
 454     }
 455
 456     if ( bump_mapping ) {
 457
 458         if ( !vertices ) {
 459             vertices = new CloudVertex[ 25 ];
 460             indices = new unsigned int[ 40 ];
 461         }
 462
 463         sgVec2 base;
 464         sgSetVec2( base, sg_random(), sg_random() );
 465
 466         const float layer_scale = layer_span / scale;
 467         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 468         const float half_angle = 0.5 * layer_span / layer_to_core;
 469
 470         int i;
 471         for ( i = -2; i <= 2; i++ ) {
 472             for ( int j = -2; j <= 2; j++ ) {
 473                 CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 474                 sgSetVec3( v1.position,
 475                            0.5 * i * layer_span,
 476                            0.5 * j * layer_span,
 477                            -layer_to_core * ( 1 - cos( i * half_angle ) * cos( j * half_angle ) ) );
 478                 sgSetVec2( v1.texCoord,
 479                            base[0] + layer_scale * i * 0.25,
 480                            base[1] + layer_scale * j * 0.25 );
 481                 sgSetVec3( v1.sTangent,
 482                            cos( i * half_angle ),
 483                            0.f,
 484                            -sin( i * half_angle ) );
 485                 sgSetVec3( v1.tTangent,
 486                            0.f,
 487                            cos( j * half_angle ),
 488                            -sin( j * half_angle ) );
 489                 sgVectorProductVec3( v1.normal, v1.tTangent, v1.sTangent );
 490                 sgSetVec4( v1.color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : cloud_alpha * 0.15f );
 491             }
 492         }
 493         /*
 494          * 0 1 5 6 10 11 15 16 20 21
 495          * 1 2 6 7 11 12 16 17 21 22
 496          * 2 3 7 8 12 13 17 18 22 23
 497          * 3 4 8 9 13 14 18 19 23 24
 498          */
 499         for ( i = 0; i < 4; i++ ) {
 500             for ( int j = 0; j < 5; j++ ) {
 501                 indices[ i*10 + (j*2) ]     =     i + 5 * j;
 502                 indices[ i*10 + (j*2) + 1 ] = 1 + i + 5 * j;
 503             }
 504         }
 505
 506     } /* else */ {
 507
 508         scale = 4000.0;
 509         last_lon = last_lat = -999.0f;
 510
 511         sgVec2 base;
 512         sgSetVec2( base, sg_random(), sg_random() );
 513
 514         // build the cloud layer
 515         sgVec4 color;
 516         sgVec3 vertex;
 517         sgVec2 tc;
 518
 519         const float layer_scale = layer_span / scale;
 520         const float mpi = SG_PI/4;
 521
 522         // caclculate the difference between a flat-earth model and
 523         // a round earth model given the span and altutude ASL of
 524         // the cloud layer. This is the difference in altitude between
 525         // the top of the inverted bowl and the edge of the bowl.
 526         // const float alt_diff = layer_asl * 0.8;
 527         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 528         const float layer_angle = 0.5*layer_span / layer_to_core; // The angle is half the span
 529         const float border_to_core = layer_to_core * cos(layer_angle);
 530         const float alt_diff = layer_to_core - border_to_core;
 531
 532         for (int i = 0; i < 4; i++)
 533         {
 534             if ( layer[i] != NULL ) {
 535                 layer_transform->removeKid(layer[i]); // automatic delete
 536             }
 537
 538             vl[i] = new ssgVertexArray( 10 );
 539             cl[i] = new ssgColourArray( 10 );
 540             tl[i] = new ssgTexCoordArray( 10 );
 541
 542
 543             sgSetVec3( vertex, layer_span*(i-2)/2, -layer_span,
 544                             alt_diff * (sin(i*mpi) - 2) );
 545
 546             sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 547
 548             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 549
 550             cl[i]->add( color );
 551             vl[i]->add( vertex );
 552             tl[i]->add( tc );
 553
 554             for (int j = 0; j < 4; j++)
 555             {
 556                 sgSetVec3( vertex, layer_span*(i-1)/2, layer_span*(j-2)/2,
 557                                 alt_diff * (sin((i+1)*mpi) + sin(j*mpi) - 2) );
 558
 559                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 560                             base[1] + layer_scale * j/4 );
 561
 562                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 563                                 ( (j == 0) || (i == 3)) ?
 564                                 ( (j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f );
 565
 566                 cl[i]->add( color );
 567                 vl[i]->add( vertex );
 568                 tl[i]->add( tc );
 569
 570
 571                 sgSetVec3( vertex, layer_span*(i-2)/2, layer_span*(j-1)/2,
 572                                 alt_diff * (sin(i*mpi) + sin((j+1)*mpi) - 2) );
 573
 574                 sgSetVec2( tc, base[0] + layer_scale * i/4,
 575                             base[1] + layer_scale * (j+1)/4 );
 576
 577                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 578                                 ((j == 3) || (i == 0)) ?
 579                                 ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f );
 580                 cl[i]->add( color );
 581                 vl[i]->add( vertex );
 582                 tl[i]->add( tc );
 583             }
 584
 585             sgSetVec3( vertex, layer_span*(i-1)/2, layer_span,
 586                             alt_diff * (sin((i+1)*mpi) - 2) );
 587
 588             sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 589                         base[1] + layer_scale );
 590
 591             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 3) ? 0.0f : 0.15f );
 592
 593             cl[i]->add( color );
 594             vl[i]->add( vertex );
 595             tl[i]->add( tc );
 596
 597             layer[i] = new ssgVtxTable(GL_TRIANGLE_STRIP, vl[i], NULL, tl[i], cl[i]);
 598             layer_transform->addKid( layer[i] );
 599
 600             if ( layer_states[layer_coverage] != NULL ) {
 601                 layer[i]->setState( layer_states[layer_coverage] );
 602             }
 603             state_sel = layer_states[layer_coverage];
 604         }
 605
 606         // force a repaint of the sky colors with arbitrary defaults
 607         repaint( color );
 608     }
 609 }
 610
 611
 612 // repaint the cloud layer colors
 613 bool SGCloudLayer::repaint( sgVec3 fog_color ) {
 614
 615     if ( bump_mapping && enable_bump_mapping ) {
 616
 617         for ( int i = 0; i < 25; i++ ) {
 618             sgCopyVec3( vertices[ i ].color, fog_color );
 619         }
 620
 621     } else {
 622         float *color;
 623
 624         for ( int i = 0; i < 4; i++ ) {
 625             color = cl[i]->get( 0 );
 626             sgCopyVec3( color, fog_color );
 627             color[3] = (i == 0) ? 0.0f : cloud_alpha * 0.15f;
 628
 629             for ( int j = 0; j < 4; ++j ) {
 630                 color = cl[i]->get( (2*j) + 1 );
 631                 sgCopyVec3( color, fog_color );
 632                 color[3] =
 633                     ((j == 0) || (i == 3)) ?
 634                     ((j == 0) && (i == 3)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 635
 636                 color = cl[i]->get( (2*j) + 2 );
 637                 sgCopyVec3( color, fog_color );
 638                 color[3] =
 639                     ((j == 3) || (i == 0)) ?
 640                     ((j == 3) && (i == 0)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 641             }
 642
 643             color = cl[i]->get( 9 );
 644             sgCopyVec3( color, fog_color );
 645             color[3] = (i == 3) ? 0.0f : cloud_alpha * 0.15f;
 646         }
 647     }
 648
 649     return true;
 650 }
 651
 652 // reposition the cloud layer at the specified origin and orientation
 653 // lon specifies a rotation about the Z axis
 654 // lat specifies a rotation about the new Y axis
 655 // spin specifies a rotation about the new Z axis (and orients the
 656 // sunrise/set effects
 657 bool SGCloudLayer::reposition( sgVec3 p, sgVec3 up, double lon, double lat,
 658                                double alt, double dt )
 659 {
 660     sgMat4 T1, LON, LAT;
 661     sgVec3 axis;
 662
 663     // combine p and asl (meters) to get translation offset
 664     sgVec3 asl_offset;
 665     sgCopyVec3( asl_offset, up );
 666     sgNormalizeVec3( asl_offset );
 667     if ( alt <= layer_asl ) {
 668         sgScaleVec3( asl_offset, layer_asl );
 669     } else {
 670         sgScaleVec3( asl_offset, layer_asl + layer_thickness );
 671     }
 672     // cout << "asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 673     //      << "," << asl_offset[2] << endl;
 674     sgAddVec3( asl_offset, p );
 675     // cout << "  asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 676     //      << "," << asl_offset[2] << endl;
 677
 678     // Translate to zero elevation
 679     // Point3D zero_elev = current_view.get_cur_zero_elev();
 680     sgMakeTransMat4( T1, asl_offset );
 681
 682     // printf("  Translated to %.2f %.2f %.2f\n",
 683     //        zero_elev.x, zero_elev.y, zero_elev.z );
 684
 685     // Rotate to proper orientation
 686     // printf("  lon = %.2f  lat = %.2f\n",
 687     //        lon * SGD_RADIANS_TO_DEGREES,
 688     //        lat * SGD_RADIANS_TO_DEGREES);
 689     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 690     sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );
 691
 692     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 693     sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );
 694
 695     sgMat4 TRANSFORM;
 696
 697     sgCopyMat4( TRANSFORM, T1 );
 698     sgPreMultMat4( TRANSFORM, LON );
 699     sgPreMultMat4( TRANSFORM, LAT );
 700
 701     sgCoord layerpos;
 702     sgSetCoord( &layerpos, TRANSFORM );
 703
 704     layer_transform->setTransform( &layerpos );
 705
 706     // now calculate update texture coordinates
 707     if ( last_lon < -900 ) {
 708         last_lon = lon;
 709         last_lat = lat;
 710     }
 711
 712     double sp_dist = speed*dt;
 713
 714     if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
 715         Point3D start( last_lon, last_lat, 0.0 );
 716         Point3D dest( lon, lat, 0.0 );
 717         double course = 0.0, dist = 0.0;
 718
 719         calc_gc_course_dist( dest, start, &course, &dist );
 720         // cout << "course = " << course << ", dist = " << dist << endl;
 721
 722         // if start and dest are too close together,
 723         // calc_gc_course_dist() can return a course of "nan".  If
 724         // this happens, lets just use the last known good course.
 725         // This is a hack, and it would probably be better to make
 726         // calc_gc_course_dist() more robust.
 727         if ( isnan(course) ) {
 728             course = last_course;
 729         } else {
 730             last_course = course;
 731         }
 732
 733         // calculate cloud movement due to external forces
 734         double ax = 0.0, ay = 0.0, bx = 0.0, by = 0.0;
 735
 736         if (dist > 0.0) {
 737             ax = cos(course) * dist;
 738             ay = sin(course) * dist;
 739         }
 740
 741         if (sp_dist > 0) {
 742             bx = cos((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 743             by = sin((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 744         }
 745
 746
 747         double xoff = (ax + bx) / (2 * scale);
 748         double yoff = (ay + by) / (2 * scale);
 749
 750         const float layer_scale = layer_span / scale;
 751
 752         // cout << "xoff = " << xoff << ", yoff = " << yoff << endl;
 753
 754         float *base;
 755         if ( bump_mapping && enable_bump_mapping ) {
 756             base = vertices[12].texCoord;
 757         } else {
 758             base = tl[0]->get( 0 );
 759         }
 760         base[0] += xoff;
 761
 762         // the while loops can lead to *long* pauses if base[0] comes
 763         // with a bogus value.
 764         // while ( base[0] > 1.0 ) { base[0] -= 1.0; }
 765         // while ( base[0] < 0.0 ) { base[0] += 1.0; }
 766         if ( base[0] > -10.0 && base[0] < 10.0 ) {
 767             base[0] -= (int)base[0];
 768         } else {
 769             SG_LOG(SG_ASTRO, SG_DEBUG,
 770                 "Error: base = " << base[0] << "," << base[1] <<
 771                 " course = " << course << " dist = " << dist );
 772             base[0] = 0.0;
 773         }
 774
 775         base[1] += yoff;
 776         // the while loops can lead to *long* pauses if base[0] comes
 777         // with a bogus value.
 778         // while ( base[1] > 1.0 ) { base[1] -= 1.0; }
 779         // while ( base[1] < 0.0 ) { base[1] += 1.0; }
 780         if ( base[1] > -10.0 && base[1] < 10.0 ) {
 781             base[1] -= (int)base[1];
 782         } else {
 783             SG_LOG(SG_ASTRO, SG_ALERT,
 784                     "Error: base = " << base[0] << "," << base[1] <<
 785                     " course = " << course << " dist = " << dist );
 786             base[1] = 0.0;
 787         }
 788
 789         if ( bump_mapping && enable_bump_mapping ) {
 790
 791             for ( int i = -2; i <= 2; i++ ) {
 792                 for ( int j = -2; j <= 2; j++ ) {
 793                     if ( i == 0 && j == 0 )
 794                         continue; // Already done on base
 795                     CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 796                     sgSetVec2( v1.texCoord,
 797                             base[0] + layer_scale * i * 0.25,
 798                             base[1] + layer_scale * j * 0.25 );
 799                 }
 800             }
 801
 802         } else {
 803                 // cout << "base = " << base[0] << "," << base[1] << endl;
 804
 805             float *tc;
 806             for (int i = 0; i < 4; i++) {
 807                 tc = tl[i]->get( 0 );
 808                 sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 809
 810                 for (int j = 0; j < 4; j++)
 811                 {
 812                     tc = tl[i]->get( j*2+1 );
 813                     sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 814                                 base[1] + layer_scale * j/4 );
 815
 816                     tc = tl[i]->get( (j+1)*2 );
 817                     sgSetVec2( tc, base[0] + layer_scale * i/4,
 818                                 base[1] + layer_scale * (j+1)/4 );
 819                 }
 820
 821                 tc = tl[i]->get( 9 );
 822                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 823                             base[1] + layer_scale );
 824             }
 825         }
 826
 827         last_lon = lon;
 828         last_lat = lat;
 829     }
 830
 831         layer3D->reposition( p, up, lon, lat, alt, dt, direction, speed);
 832     return true;
 833 }
 834
 835
 836 void SGCloudLayer::draw( bool top ) {
 837     if ( layer_coverage != SG_CLOUD_CLEAR ) {
 838
 839                 if ( SGCloudField::enable3D && layer3D->is3D())
 840                         layer3D->Render();
 841                 else
 842         if ( bump_mapping && enable_bump_mapping ) {
 843
 844             sgMat4 modelview,
 845                    tmp,
 846                    transform;
 847             ssgGetModelviewMatrix( modelview );
 848             layer_transform->getTransform( transform );
 849
 850             sgTransposeNegateMat4( tmp, transform );
 851
 852             sgPostMultMat4( transform, modelview );
 853             ssgLoadModelviewMatrix( transform );
 854
 855             sgVec3 lightVec;
 856             ssgGetLight( 0 )->getPosition( lightVec );
 857             sgNegateVec3( lightVec );
 858             sgXformVec3( lightVec, tmp );
 859
 860             for ( int i = 0; i < 25; i++ ) {
 861                 CloudVertex &v = vertices[ i ];
 862                 sgSetVec3( v.tangentSpLight,
 863                            sgScalarProductVec3( v.sTangent, lightVec ),
 864                            sgScalarProductVec3( v.tTangent, lightVec ),
 865                            sgScalarProductVec3( v.normal, lightVec ) );
 866             }
 867
 868             ssgTexture *decal = color_map[ layer_coverage ][ top ? 1 : 0 ];
 869             if ( top && decal == 0 ) {
 870                 decal = color_map[ layer_coverage ][ 0 ];
 871             }
 872             ssgTexture *normal = normal_map[ layer_coverage ][ top ? 1 : 0 ];
 873             if ( top && normal == 0 ) {
 874                 normal = normal_map[ layer_coverage ][ 0 ];
 875             }
 876
 877             glDisable( GL_LIGHTING );
 878             glDisable( GL_CULL_FACE );
 879 //            glDisable( GL_ALPHA_TEST );
 880             if ( layer_coverage == SG_CLOUD_FEW ) {
 881                 glEnable( GL_ALPHA_TEST );
 882                 glAlphaFunc ( GL_GREATER, 0.01 );
 883             }
 884             glEnable( GL_BLEND );
 885             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 886
 887             glShadeModel( GL_SMOOTH );
 888             glEnable( GL_COLOR_MATERIAL );
 889             sgVec4 color;
 890             float emis = 0.05;
 891             if ( 1 ) {
 892                 ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
 893                 emis = ( color[0]+color[1]+color[2] ) / 3.0;
 894                 if ( emis < 0.05 )
 895                     emis = 0.05;
 896             }
 897             sgSetVec4( color, emis, emis, emis, 0.0 );
 898             glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, color );
 899             sgSetVec4( color, 1.0f, 1.0f, 1.0f, 0.0 );
 900             glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, color );
 901             sgSetVec4( color, 1.0, 1.0, 1.0, 0.0 );
 902             glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, color );
 903             sgSetVec4( color, 0.0, 0.0, 0.0, 0.0 );
 904             glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, color );
 905
 906             glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
 907
 908             glActiveTexturePtr( GL_TEXTURE0_ARB );
 909             glBindTexture( GL_TEXTURE_2D, normal->getHandle() );
 910             glEnable( GL_TEXTURE_2D );
 911
 912             //Bind normalisation cube map to texture unit 1
 913             glActiveTexturePtr( GL_TEXTURE1_ARB );
 914             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 915             glEnable( GL_TEXTURE_CUBE_MAP_ARB );
 916             glActiveTexturePtr( GL_TEXTURE0_ARB );
 917
 918             //Set vertex arrays for cloud
 919             glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
 920             glEnableClientState( GL_VERTEX_ARRAY );
 921 /*
 922             if ( nb_texture_unit >= 3 ) {
 923                 glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
 924                 glEnableClientState( GL_COLOR_ARRAY );
 925             }
 926 */
 927             //Send texture coords for normal map to unit 0
 928             glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 929             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 930
 931             //Send tangent space light vectors for normalisation to unit 1
 932             glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 933             glTexCoordPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].tangentSpLight );
 934             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 935
 936             //Set up texture environment to do (tex0 dot tex1)*color
 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_REPLACE );
 940             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE );
 941             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 942
 943             glActiveTexturePtr( GL_TEXTURE1_ARB );
 944
 945             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 946             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 947             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_DOT3_RGB_ARB );
 948             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 949             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB );
 950             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 951
 952             if ( nb_texture_unit >= 3 ) {
 953                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 954                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 955
 956                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 957                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 958                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 959
 960                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 961                 glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD );
 962                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 963                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 964
 965                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 966                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 967
 968                 //Draw cloud layer
 969                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 970                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 971                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 972                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 973
 974                 glDisable( GL_TEXTURE_2D );
 975                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 976                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 977                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 978                 glDisable( GL_TEXTURE_2D );
 979                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 980
 981                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 982                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 983                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 984                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 985                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 986                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 987
 988                 glDisableClientState( GL_COLOR_ARRAY );
 989                 glEnable( GL_LIGHTING );
 990
 991                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
 992
 993             } else {
 994                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 995                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 996
 997                 //Draw cloud layer
 998                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 999                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1000                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1001                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1002
1003                 //Disable textures
1004                 glDisable( GL_TEXTURE_2D );
1005
1006                 glActiveTexturePtr( GL_TEXTURE1_ARB );
1007                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
1008                 glActiveTexturePtr( GL_TEXTURE0_ARB );
1009
1010                 //disable vertex arrays
1011                 glDisableClientState( GL_VERTEX_ARRAY );
1012
1013                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1014                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
1015                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1016                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1017
1018                 //Return to standard modulate texenv
1019                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1020
1021                 if ( layer_coverage == SG_CLOUD_OVERCAST ) {
1022                     glDepthFunc(GL_LEQUAL);
1023
1024                     glEnable( GL_LIGHTING );
1025                     sgVec4 color;
1026                     ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
1027                     float average = ( color[0] + color[1] + color[2] ) / 3.0f;
1028                     average = 0.15 + average/10;
1029                     sgVec4 averageColor;
1030                     sgSetVec4( averageColor, average, average, average, 1.0f );
1031                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, averageColor );
1032
1033                     glBlendColorPtr( average, average, average, 1.0f );
1034                     glBlendFunc( GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_COLOR );
1035
1036                     //Perform a second pass to color the torus
1037                     //Bind decal texture
1038                     glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
1039                     glEnable(GL_TEXTURE_2D);
1040
1041                     //Set vertex arrays for torus
1042                     glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
1043                     glEnableClientState( GL_VERTEX_ARRAY );
1044
1045                     //glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
1046                     //glEnableClientState( GL_COLOR_ARRAY );
1047
1048                     glNormalPointer( GL_FLOAT, sizeof(CloudVertex), &vertices[0].normal );
1049                     glEnableClientState( GL_NORMAL_ARRAY );
1050
1051                     glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
1052                     glEnableClientState( GL_TEXTURE_COORD_ARRAY );
1053
1054                     //Draw cloud layer
1055                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1056                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1057                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1058                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1059
1060                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, color );
1061
1062                     glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1063                 }
1064             }
1065             //Disable texture
1066             glDisable( GL_TEXTURE_2D );
1067
1068             glDisableClientState( GL_VERTEX_ARRAY );
1069             glDisableClientState( GL_NORMAL_ARRAY );
1070
1071             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
1072             glEnable( GL_CULL_FACE );
1073             glDepthFunc(GL_LESS);
1074
1075             ssgLoadModelviewMatrix( modelview );
1076
1077         } else {
1078             state_sel->selectStep( top ? 1 : 0 );
1079             ssgCullAndDraw( layer_root );
1080         }
1081     }
1082 }
1083
1084
1085 // make an ssgSimpleState for a cloud layer given the named texture
1086 ssgSimpleState *sgCloudMakeState( const string &path ) {
1087     ssgSimpleState *state = new ssgSimpleState();
1088
1089     SG_LOG(SG_ASTRO, SG_INFO, " texture = ");
1090
1091     state->setTexture( (char *)path.c_str() );
1092     state->setShadeModel( GL_SMOOTH );
1093     state->disable( GL_LIGHTING );
1094     state->disable( GL_CULL_FACE );
1095     state->enable( GL_TEXTURE_2D );
1096     state->enable( GL_COLOR_MATERIAL );
1097     state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
1098     state->setMaterial( GL_EMISSION, 0.05, 0.05, 0.05, 0.0 );
1099     state->setMaterial( GL_AMBIENT, 0.2, 0.2, 0.2, 0.0 );
1100     state->setMaterial( GL_DIFFUSE, 0.5, 0.5, 0.5, 0.0 );
1101     state->setMaterial( GL_SPECULAR, 0.0, 0.0, 0.0, 0.0 );
1102     state->enable( GL_BLEND );
1103     state->enable( GL_ALPHA_TEST );
1104     state->setAlphaClamp( 0.01 );
1105
1106     return state;
1107 }