simgear/scene/sky/cloud.cxx

   1 // cloud.cxx -- model a single cloud layer
   2 //
   3 // Written by Curtis Olson, started June 2000.
   4 //
   5 // Copyright (C) 2000  Curtis L. Olson  - http://www.flightgear.org/~curt
   6 //
   7 // This program is distributed in the hope that it will be useful, but
   8 // WITHOUT ANY WARRANTY; without even the implied warranty of
   9 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  10 // General Public License for more details.
  11 //
  12 // You should have received a copy of the GNU General Public License
  13 // along with this program; if not, write to the Free Software
  14 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  15 //
  16 // $Id$
  17
  18 #ifdef HAVE_CONFIG_H
  19 #  include <simgear_config.h>
  20 #endif
  21
  22 #include <simgear/compiler.h>
  23
  24 // #include <stdio.h>
  25 #include <math.h>
  26
  27 #include <plib/sg.h>
  28 #include <plib/ssg.h>
  29
  30 #include <simgear/math/point3d.hxx>
  31 #include <simgear/math/polar3d.hxx>
  32 #include <simgear/math/sg_random.h>
  33 #include <simgear/debug/logstream.hxx>
  34 #include <simgear/misc/sg_path.hxx>
  35 #include <simgear/screen/extensions.hxx>
  36 #include <simgear/screen/texture.hxx>
  37 #include <simgear/structure/ssgSharedPtr.hxx>
  38
  39 #include "newcloud.hxx"
  40 #include "cloudfield.hxx"
  41 #include "cloud.hxx"
  42
  43 #if defined(__MINGW32__)
  44 #define isnan(x) _isnan(x)
  45 #endif
  46
  47 #if defined (__FreeBSD__)
  48 #  if __FreeBSD_version < 500000
  49      extern "C" {
  50        inline int isnan(double r) { return !(r <= 0 || r >= 0); }
  51      }
  52 #  endif
  53 #endif
  54
  55
  56 static ssgSharedPtr<ssgStateSelector> layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
  57 static bool state_initialized = false;
  58 static bool bump_mapping = false;
  59 static GLint nb_texture_unit = 0;
  60 static ssgSharedPtr<ssgTexture> normal_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  61 static ssgSharedPtr<ssgTexture> color_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  62 static GLuint normalization_cube_map;
  63
  64 static glActiveTextureProc glActiveTexturePtr = 0;
  65 static glClientActiveTextureProc glClientActiveTexturePtr = 0;
  66 static glBlendColorProc glBlendColorPtr = 0;
  67
  68 bool SGCloudLayer::enable_bump_mapping = false;
  69
  70 static void
  71 generateNormalizationCubeMap()
  72 {
  73     unsigned char data[ 32 * 32 * 3 ];
  74     const int size = 32;
  75     const float half_size = 16.0f,
  76                 offset = 0.5f;
  77     sgVec3 zero_normal;
  78     sgSetVec3( zero_normal, 0.5f, 0.5f, 0.5f );
  79     int i, j;
  80
  81     unsigned char *ptr = data;
  82     for ( j = 0; j < size; j++ ) {
  83         for ( i = 0; i < size; i++ ) {
  84             sgVec3 tmp;
  85             sgSetVec3( tmp, half_size,
  86                             -( j + offset - half_size ),
  87                             -( i + offset - half_size ) );
  88             sgNormalizeVec3( tmp );
  89             sgScaleVec3( tmp, 0.5f );
  90             sgAddVec3( tmp, zero_normal );
  91
  92             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
  93             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
  94             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
  95         }
  96     }
  97     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
  98                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
  99
 100     ptr = data;
 101     for ( j = 0; j < size; j++ ) {
 102         for ( i = 0; i < size; i++ ) {
 103             sgVec3 tmp;
 104             sgSetVec3( tmp, -half_size,
 105                             -( j + offset - half_size ),
 106                             ( i + offset - half_size ) );
 107             sgNormalizeVec3( tmp );
 108             sgScaleVec3( tmp, 0.5f );
 109             sgAddVec3( tmp, zero_normal );
 110
 111             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 112             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 113             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 114         }
 115     }
 116     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 117                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 118
 119     ptr = data;
 120     for ( j = 0; j < size; j++ ) {
 121         for ( i = 0; i < size; i++ ) {
 122             sgVec3 tmp;
 123             sgSetVec3( tmp, ( i + offset - half_size ),
 124                             half_size,
 125                             ( j + offset - half_size ) );
 126             sgNormalizeVec3( tmp );
 127             sgScaleVec3( tmp, 0.5f );
 128             sgAddVec3( tmp, zero_normal );
 129
 130             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 131             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 132             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 133         }
 134     }
 135     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 136                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 137
 138     ptr = data;
 139     for ( j = 0; j < size; j++ ) {
 140         for ( i = 0; i < size; i++ ) {
 141             sgVec3 tmp;
 142             sgSetVec3( tmp, ( i + offset - half_size ),
 143                             -half_size,
 144                             -( j + offset - half_size ) );
 145             sgNormalizeVec3( tmp );
 146             sgScaleVec3( tmp, 0.5f );
 147             sgAddVec3( tmp, zero_normal );
 148
 149             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 150             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 151             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 152         }
 153     }
 154     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 155                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 156
 157     ptr = data;
 158     for ( j = 0; j < size; j++ ) {
 159         for ( i = 0; i < size; i++ ) {
 160             sgVec3 tmp;
 161             sgSetVec3( tmp, ( i + offset - half_size ),
 162                             -( j + offset - half_size ),
 163                             half_size );
 164             sgNormalizeVec3( tmp );
 165             sgScaleVec3( tmp, 0.5f );
 166             sgAddVec3( tmp, zero_normal );
 167
 168             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 169             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 170             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 171         }
 172     }
 173     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 174                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 175
 176     ptr = data;
 177     for ( j = 0; j < size; j++ ) {
 178         for ( i = 0; i < size; i++ ) {
 179             sgVec3 tmp;
 180             sgSetVec3( tmp, -( i + offset - half_size ),
 181                             -( j + offset - half_size ),
 182                             -half_size );
 183             sgNormalizeVec3( tmp );
 184             sgScaleVec3( tmp, 0.5f );
 185             sgAddVec3( tmp, zero_normal );
 186
 187             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 188             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 189             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 190         }
 191     }
 192     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB,
 193                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 194 }
 195
 196
 197 // Constructor
 198 SGCloudLayer::SGCloudLayer( const string &tex_path ) :
 199     vertices(0),
 200     indices(0),
 201     layer_root(new ssgRoot),
 202     layer_transform(new ssgTransform),
 203     state_sel(0),
 204     cloud_alpha(1.0),
 205     texture_path(tex_path),
 206     layer_span(0.0),
 207     layer_asl(0.0),
 208     layer_thickness(0.0),
 209     layer_transition(0.0),
 210     layer_coverage(SG_CLOUD_CLEAR),
 211     scale(4000.0),
 212     speed(0.0),
 213     direction(0.0),
 214     last_lon(0.0),
 215     last_lat(0.0)
 216 {
 217     cl[0] = cl[1] = cl[2] = cl[3] = NULL;
 218     vl[0] = vl[1] = vl[2] = vl[3] = NULL;
 219     tl[0] = tl[1] = tl[2] = tl[3] = NULL;
 220     layer[0] = layer[1] = layer[2] = layer[3] = NULL;
 221
 222     layer_root->addKid(layer_transform);
 223         layer3D = new SGCloudField;
 224     rebuild();
 225 }
 226
 227 // Destructor
 228 SGCloudLayer::~SGCloudLayer()
 229 {
 230         delete layer3D;
 231     delete vertices;
 232     delete indices;
 233     delete layer_root;          // deletes layer_transform and layer as well
 234 }
 235
 236 float
 237 SGCloudLayer::getSpan_m () const
 238 {
 239     return layer_span;
 240 }
 241
 242 void
 243 SGCloudLayer::setSpan_m (float span_m)
 244 {
 245     if (span_m != layer_span) {
 246         layer_span = span_m;
 247         rebuild();
 248     }
 249 }
 250
 251 float
 252 SGCloudLayer::getElevation_m () const
 253 {
 254     return layer_asl;
 255 }
 256
 257 void
 258 SGCloudLayer::setElevation_m (float elevation_m, bool set_span)
 259 {
 260     layer_asl = elevation_m;
 261
 262     if (set_span) {
 263         if (elevation_m > 4000)
 264             setSpan_m(  elevation_m * 10 );
 265         else
 266             setSpan_m( 40000 );
 267     }
 268 }
 269
 270 float
 271 SGCloudLayer::getThickness_m () const
 272 {
 273     return layer_thickness;
 274 }
 275
 276 void
 277 SGCloudLayer::setThickness_m (float thickness_m)
 278 {
 279     layer_thickness = thickness_m;
 280 }
 281
 282 float
 283 SGCloudLayer::getTransition_m () const
 284 {
 285     return layer_transition;
 286 }
 287
 288 void
 289 SGCloudLayer::setTransition_m (float transition_m)
 290 {
 291     layer_transition = transition_m;
 292 }
 293
 294 SGCloudLayer::Coverage
 295 SGCloudLayer::getCoverage () const
 296 {
 297     return layer_coverage;
 298 }
 299
 300 void
 301 SGCloudLayer::setCoverage (Coverage coverage)
 302 {
 303     if (coverage != layer_coverage) {
 304         layer_coverage = coverage;
 305         rebuild();
 306     }
 307 }
 308
 309
 310 // build the cloud object
 311 void
 312 SGCloudLayer::rebuild()
 313 {
 314     // Initialize states and sizes if necessary.
 315     if ( !state_initialized ) {
 316         state_initialized = true;
 317
 318         SG_LOG(SG_ASTRO, SG_INFO, "initializing cloud layers");
 319
 320         bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
 321                        SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
 322                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
 323                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") &&
 324                        SGIsOpenGLExtensionSupported("GL_ARB_imaging");
 325
 326         if ( bump_mapping ) {
 327             glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
 328             if ( nb_texture_unit < 2 ) {
 329                 bump_mapping = false;
 330             }
 331             //nb_texture_unit = 2; // Force the number of units for now
 332         }
 333
 334         if ( bump_mapping ) {
 335
 336             // This bump mapping code was inspired by the tutorial available at
 337             // http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
 338             // and a NVidia white paper
 339             //  http://developer.nvidia.com/object/bumpmappingwithregistercombiners.html
 340             // The normal map textures were generated by the normal map Gimp plugin :
 341             //  http://nifelheim.dyndns.org/~cocidius/normalmap/
 342             //
 343             SGPath cloud_path;
 344
 345             glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
 346             glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
 347             glBlendColorPtr = (glBlendColorProc)SGLookupFunction("glBlendColor");
 348
 349             cloud_path.set(texture_path.str());
 350             cloud_path.append("overcast.rgb");
 351             color_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 352             cloud_path.set(texture_path.str());
 353             cloud_path.append("overcast_n.rgb");
 354             normal_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 355
 356             cloud_path.set(texture_path.str());
 357             cloud_path.append("overcast_top.rgb");
 358             color_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 359             cloud_path.set(texture_path.str());
 360             cloud_path.append("overcast_top_n.rgb");
 361             normal_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 362
 363             cloud_path.set(texture_path.str());
 364             cloud_path.append("broken.rgba");
 365             color_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 366             cloud_path.set(texture_path.str());
 367             cloud_path.append("broken_n.rgb");
 368             normal_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 369
 370             cloud_path.set(texture_path.str());
 371             cloud_path.append("scattered.rgba");
 372             color_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 373             cloud_path.set(texture_path.str());
 374             cloud_path.append("scattered_n.rgb");
 375             normal_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 376
 377             cloud_path.set(texture_path.str());
 378             cloud_path.append("few.rgba");
 379             color_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 380             cloud_path.set(texture_path.str());
 381             cloud_path.append("few_n.rgb");
 382             normal_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 383
 384             cloud_path.set(texture_path.str());
 385             cloud_path.append("cirrus.rgba");
 386             color_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 387             cloud_path.set(texture_path.str());
 388             cloud_path.append("cirrus_n.rgb");
 389             normal_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 390
 391             glGenTextures( 1, &normalization_cube_map );
 392             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 393             generateNormalizationCubeMap();
 394             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 395             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 396             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 397             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 398             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE );
 399         } /* else */ {
 400             SGPath cloud_path;
 401             ssgStateSelector *state_sel;
 402             ssgSimpleState *state;
 403
 404             state_sel = new ssgStateSelector( 2 );
 405             cloud_path.set(texture_path.str());
 406             cloud_path.append("overcast.rgb");
 407             state_sel->setStep( 0, sgCloudMakeState(cloud_path.str()) );
 408             cloud_path.set(texture_path.str());
 409             cloud_path.append("overcast_top.rgb");
 410             state_sel->setStep( 1, sgCloudMakeState(cloud_path.str()) );
 411             layer_states[SG_CLOUD_OVERCAST] = state_sel;
 412
 413             state_sel = new ssgStateSelector( 2 );
 414             cloud_path.set(texture_path.str());
 415             cloud_path.append("broken.rgba");
 416             state = sgCloudMakeState(cloud_path.str());
 417             state_sel->setStep( 0, state );
 418             state_sel->setStep( 1, state );
 419             layer_states[SG_CLOUD_BROKEN] = state_sel;
 420
 421             state_sel = new ssgStateSelector( 2 );
 422             cloud_path.set(texture_path.str());
 423             cloud_path.append("scattered.rgba");
 424             state = sgCloudMakeState(cloud_path.str());
 425             state_sel->setStep( 0, state );
 426             state_sel->setStep( 1, state );
 427             layer_states[SG_CLOUD_SCATTERED] = state_sel;
 428
 429             state_sel = new ssgStateSelector( 2 );
 430             cloud_path.set(texture_path.str());
 431             cloud_path.append("few.rgba");
 432             state = sgCloudMakeState(cloud_path.str());
 433             state_sel->setStep( 0, state );
 434             state_sel->setStep( 1, state );
 435             layer_states[SG_CLOUD_FEW] = state_sel;
 436
 437             state_sel = new ssgStateSelector( 2 );
 438             cloud_path.set(texture_path.str());
 439             cloud_path.append("cirrus.rgba");
 440             state = sgCloudMakeState(cloud_path.str());
 441             state_sel->setStep( 0, state );
 442             state_sel->setStep( 1, state );
 443             layer_states[SG_CLOUD_CIRRUS] = state_sel;
 444
 445             layer_states[SG_CLOUD_CLEAR] = 0;
 446         }
 447                 SGNewCloud::loadTextures(texture_path.str());
 448                 layer3D->buildTestLayer();
 449     }
 450
 451     if ( bump_mapping ) {
 452
 453         if ( !vertices ) {
 454             vertices = new CloudVertex[ 25 ];
 455             indices = new unsigned int[ 40 ];
 456         }
 457
 458         sgVec2 base;
 459         sgSetVec2( base, sg_random(), sg_random() );
 460
 461         const float layer_scale = layer_span / scale;
 462         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 463         const float half_angle = 0.5 * layer_span / layer_to_core;
 464
 465         int i;
 466         for ( i = -2; i <= 2; i++ ) {
 467             for ( int j = -2; j <= 2; j++ ) {
 468                 CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 469                 sgSetVec3( v1.position,
 470                            0.5 * i * layer_span,
 471                            0.5 * j * layer_span,
 472                            -layer_to_core * ( 1 - cos( i * half_angle ) * cos( j * half_angle ) ) );
 473                 sgSetVec2( v1.texCoord,
 474                            base[0] + layer_scale * i * 0.25,
 475                            base[1] + layer_scale * j * 0.25 );
 476                 sgSetVec3( v1.sTangent,
 477                            cos( i * half_angle ),
 478                            0.f,
 479                            -sin( i * half_angle ) );
 480                 sgSetVec3( v1.tTangent,
 481                            0.f,
 482                            cos( j * half_angle ),
 483                            -sin( j * half_angle ) );
 484                 sgVectorProductVec3( v1.normal, v1.tTangent, v1.sTangent );
 485                 sgSetVec4( v1.color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : cloud_alpha * 0.15f );
 486             }
 487         }
 488         /*
 489          * 0 1 5 6 10 11 15 16 20 21
 490          * 1 2 6 7 11 12 16 17 21 22
 491          * 2 3 7 8 12 13 17 18 22 23
 492          * 3 4 8 9 13 14 18 19 23 24
 493          */
 494         for ( i = 0; i < 4; i++ ) {
 495             for ( int j = 0; j < 5; j++ ) {
 496                 indices[ i*10 + (j*2) ]     =     i + 5 * j;
 497                 indices[ i*10 + (j*2) + 1 ] = 1 + i + 5 * j;
 498             }
 499         }
 500
 501     } /* else */ {
 502
 503         scale = 4000.0;
 504         last_lon = last_lat = -999.0f;
 505
 506         sgVec2 base;
 507         sgSetVec2( base, sg_random(), sg_random() );
 508
 509         // build the cloud layer
 510         sgVec4 color;
 511         sgVec3 vertex;
 512         sgVec2 tc;
 513
 514         const float layer_scale = layer_span / scale;
 515         const float mpi = SG_PI/4;
 516
 517         // caclculate the difference between a flat-earth model and
 518         // a round earth model given the span and altutude ASL of
 519         // the cloud layer. This is the difference in altitude between
 520         // the top of the inverted bowl and the edge of the bowl.
 521         // const float alt_diff = layer_asl * 0.8;
 522         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 523         const float layer_angle = 0.5*layer_span / layer_to_core; // The angle is half the span
 524         const float border_to_core = layer_to_core * cos(layer_angle);
 525         const float alt_diff = layer_to_core - border_to_core;
 526
 527         for (int i = 0; i < 4; i++)
 528         {
 529             if ( layer[i] != NULL ) {
 530                 layer_transform->removeKid(layer[i]); // automatic delete
 531             }
 532
 533             vl[i] = new ssgVertexArray( 10 );
 534             cl[i] = new ssgColourArray( 10 );
 535             tl[i] = new ssgTexCoordArray( 10 );
 536
 537
 538             sgSetVec3( vertex, layer_span*(i-2)/2, -layer_span,
 539                             alt_diff * (sin(i*mpi) - 2) );
 540
 541             sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 542
 543             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 544
 545             cl[i]->add( color );
 546             vl[i]->add( vertex );
 547             tl[i]->add( tc );
 548
 549             for (int j = 0; j < 4; j++)
 550             {
 551                 sgSetVec3( vertex, layer_span*(i-1)/2, layer_span*(j-2)/2,
 552                                 alt_diff * (sin((i+1)*mpi) + sin(j*mpi) - 2) );
 553
 554                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 555                             base[1] + layer_scale * j/4 );
 556
 557                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 558                                 ( (j == 0) || (i == 3)) ?
 559                                 ( (j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f );
 560
 561                 cl[i]->add( color );
 562                 vl[i]->add( vertex );
 563                 tl[i]->add( tc );
 564
 565
 566                 sgSetVec3( vertex, layer_span*(i-2)/2, layer_span*(j-1)/2,
 567                                 alt_diff * (sin(i*mpi) + sin((j+1)*mpi) - 2) );
 568
 569                 sgSetVec2( tc, base[0] + layer_scale * i/4,
 570                             base[1] + layer_scale * (j+1)/4 );
 571
 572                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 573                                 ((j == 3) || (i == 0)) ?
 574                                 ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f );
 575                 cl[i]->add( color );
 576                 vl[i]->add( vertex );
 577                 tl[i]->add( tc );
 578             }
 579
 580             sgSetVec3( vertex, layer_span*(i-1)/2, layer_span,
 581                             alt_diff * (sin((i+1)*mpi) - 2) );
 582
 583             sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 584                         base[1] + layer_scale );
 585
 586             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 3) ? 0.0f : 0.15f );
 587
 588             cl[i]->add( color );
 589             vl[i]->add( vertex );
 590             tl[i]->add( tc );
 591
 592             layer[i] = new ssgVtxTable(GL_TRIANGLE_STRIP, vl[i], NULL, tl[i], cl[i]);
 593             layer_transform->addKid( layer[i] );
 594
 595             if ( layer_states[layer_coverage] != NULL ) {
 596                 layer[i]->setState( layer_states[layer_coverage] );
 597             }
 598             state_sel = layer_states[layer_coverage];
 599         }
 600
 601         // force a repaint of the sky colors with arbitrary defaults
 602         repaint( color );
 603     }
 604 }
 605
 606
 607 // repaint the cloud layer colors
 608 bool SGCloudLayer::repaint( sgVec3 fog_color ) {
 609
 610     if ( bump_mapping && enable_bump_mapping ) {
 611
 612         for ( int i = 0; i < 25; i++ ) {
 613             sgCopyVec3( vertices[ i ].color, fog_color );
 614         }
 615
 616     } else {
 617         float *color;
 618
 619         for ( int i = 0; i < 4; i++ ) {
 620             color = cl[i]->get( 0 );
 621             sgCopyVec3( color, fog_color );
 622             color[3] = (i == 0) ? 0.0f : cloud_alpha * 0.15f;
 623
 624             for ( int j = 0; j < 4; ++j ) {
 625                 color = cl[i]->get( (2*j) + 1 );
 626                 sgCopyVec3( color, fog_color );
 627                 color[3] =
 628                     ((j == 0) || (i == 3)) ?
 629                     ((j == 0) && (i == 3)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 630
 631                 color = cl[i]->get( (2*j) + 2 );
 632                 sgCopyVec3( color, fog_color );
 633                 color[3] =
 634                     ((j == 3) || (i == 0)) ?
 635                     ((j == 3) && (i == 0)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 636             }
 637
 638             color = cl[i]->get( 9 );
 639             sgCopyVec3( color, fog_color );
 640             color[3] = (i == 3) ? 0.0f : cloud_alpha * 0.15f;
 641         }
 642     }
 643
 644     return true;
 645 }
 646
 647 // reposition the cloud layer at the specified origin and orientation
 648 // lon specifies a rotation about the Z axis
 649 // lat specifies a rotation about the new Y axis
 650 // spin specifies a rotation about the new Z axis (and orients the
 651 // sunrise/set effects
 652 bool SGCloudLayer::reposition( sgVec3 p, sgVec3 up, double lon, double lat,
 653                                double alt, double dt )
 654 {
 655     sgMat4 T1, LON, LAT;
 656     sgVec3 axis;
 657
 658     // combine p and asl (meters) to get translation offset
 659     sgVec3 asl_offset;
 660     sgCopyVec3( asl_offset, up );
 661     sgNormalizeVec3( asl_offset );
 662     if ( alt <= layer_asl ) {
 663         sgScaleVec3( asl_offset, layer_asl );
 664     } else {
 665         sgScaleVec3( asl_offset, layer_asl + layer_thickness );
 666     }
 667     // cout << "asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 668     //      << "," << asl_offset[2] << endl;
 669     sgAddVec3( asl_offset, p );
 670     // cout << "  asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 671     //      << "," << asl_offset[2] << endl;
 672
 673     // Translate to zero elevation
 674     // Point3D zero_elev = current_view.get_cur_zero_elev();
 675     sgMakeTransMat4( T1, asl_offset );
 676
 677     // printf("  Translated to %.2f %.2f %.2f\n",
 678     //        zero_elev.x, zero_elev.y, zero_elev.z );
 679
 680     // Rotate to proper orientation
 681     // printf("  lon = %.2f  lat = %.2f\n",
 682     //        lon * SGD_RADIANS_TO_DEGREES,
 683     //        lat * SGD_RADIANS_TO_DEGREES);
 684     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 685     sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );
 686
 687     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 688     sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );
 689
 690     sgMat4 TRANSFORM;
 691
 692     sgCopyMat4( TRANSFORM, T1 );
 693     sgPreMultMat4( TRANSFORM, LON );
 694     sgPreMultMat4( TRANSFORM, LAT );
 695
 696     sgCoord layerpos;
 697     sgSetCoord( &layerpos, TRANSFORM );
 698
 699     layer_transform->setTransform( &layerpos );
 700
 701     // now calculate update texture coordinates
 702     if ( last_lon < -900 ) {
 703         last_lon = lon;
 704         last_lat = lat;
 705     }
 706
 707     double sp_dist = speed*dt;
 708
 709     if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
 710         Point3D start( last_lon, last_lat, 0.0 );
 711         Point3D dest( lon, lat, 0.0 );
 712         double course = 0.0, dist = 0.0;
 713
 714         calc_gc_course_dist( dest, start, &course, &dist );
 715         // cout << "course = " << course << ", dist = " << dist << endl;
 716
 717         // if start and dest are too close together,
 718         // calc_gc_course_dist() can return a course of "nan".  If
 719         // this happens, lets just use the last known good course.
 720         // This is a hack, and it would probably be better to make
 721         // calc_gc_course_dist() more robust.
 722         if ( isnan(course) ) {
 723             course = last_course;
 724         } else {
 725             last_course = course;
 726         }
 727
 728         // calculate cloud movement due to external forces
 729         double ax = 0.0, ay = 0.0, bx = 0.0, by = 0.0;
 730
 731         if (dist > 0.0) {
 732             ax = cos(course) * dist;
 733             ay = sin(course) * dist;
 734         }
 735
 736         if (sp_dist > 0) {
 737             bx = cos((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 738             by = sin((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 739         }
 740
 741
 742         double xoff = (ax + bx) / (2 * scale);
 743         double yoff = (ay + by) / (2 * scale);
 744
 745         const float layer_scale = layer_span / scale;
 746
 747         // cout << "xoff = " << xoff << ", yoff = " << yoff << endl;
 748
 749         float *base;
 750         if ( bump_mapping && enable_bump_mapping ) {
 751             base = vertices[12].texCoord;
 752         } else {
 753             base = tl[0]->get( 0 );
 754         }
 755         base[0] += xoff;
 756
 757         // the while loops can lead to *long* pauses if base[0] comes
 758         // with a bogus value.
 759         // while ( base[0] > 1.0 ) { base[0] -= 1.0; }
 760         // while ( base[0] < 0.0 ) { base[0] += 1.0; }
 761         if ( base[0] > -10.0 && base[0] < 10.0 ) {
 762             base[0] -= (int)base[0];
 763         } else {
 764             SG_LOG(SG_ASTRO, SG_DEBUG,
 765                 "Error: base = " << base[0] << "," << base[1] <<
 766                 " course = " << course << " dist = " << dist );
 767             base[0] = 0.0;
 768         }
 769
 770         base[1] += yoff;
 771         // the while loops can lead to *long* pauses if base[0] comes
 772         // with a bogus value.
 773         // while ( base[1] > 1.0 ) { base[1] -= 1.0; }
 774         // while ( base[1] < 0.0 ) { base[1] += 1.0; }
 775         if ( base[1] > -10.0 && base[1] < 10.0 ) {
 776             base[1] -= (int)base[1];
 777         } else {
 778             SG_LOG(SG_ASTRO, SG_ALERT,
 779                     "Error: base = " << base[0] << "," << base[1] <<
 780                     " course = " << course << " dist = " << dist );
 781             base[1] = 0.0;
 782         }
 783
 784         if ( bump_mapping && enable_bump_mapping ) {
 785
 786             for ( int i = -2; i <= 2; i++ ) {
 787                 for ( int j = -2; j <= 2; j++ ) {
 788                     if ( i == 0 && j == 0 )
 789                         continue; // Already done on base
 790                     CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 791                     sgSetVec2( v1.texCoord,
 792                             base[0] + layer_scale * i * 0.25,
 793                             base[1] + layer_scale * j * 0.25 );
 794                 }
 795             }
 796
 797         } else {
 798                 // cout << "base = " << base[0] << "," << base[1] << endl;
 799
 800             float *tc;
 801             for (int i = 0; i < 4; i++) {
 802                 tc = tl[i]->get( 0 );
 803                 sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 804
 805                 for (int j = 0; j < 4; j++)
 806                 {
 807                     tc = tl[i]->get( j*2+1 );
 808                     sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 809                                 base[1] + layer_scale * j/4 );
 810
 811                     tc = tl[i]->get( (j+1)*2 );
 812                     sgSetVec2( tc, base[0] + layer_scale * i/4,
 813                                 base[1] + layer_scale * (j+1)/4 );
 814                 }
 815
 816                 tc = tl[i]->get( 9 );
 817                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 818                             base[1] + layer_scale );
 819             }
 820         }
 821
 822         last_lon = lon;
 823         last_lat = lat;
 824     }
 825
 826         layer3D->reposition( p, up, lon, lat, alt, dt, direction, speed);
 827     return true;
 828 }
 829
 830
 831 void SGCloudLayer::draw( bool top ) {
 832     if ( layer_coverage != SG_CLOUD_CLEAR ) {
 833
 834                 if ( SGCloudField::enable3D && layer3D->is3D())
 835                         layer3D->Render();
 836                 else
 837         if ( bump_mapping && enable_bump_mapping ) {
 838
 839             sgMat4 modelview,
 840                    tmp,
 841                    transform;
 842             ssgGetModelviewMatrix( modelview );
 843             layer_transform->getTransform( transform );
 844
 845             sgTransposeNegateMat4( tmp, transform );
 846
 847             sgPostMultMat4( transform, modelview );
 848             ssgLoadModelviewMatrix( transform );
 849
 850             sgVec3 lightVec;
 851             ssgGetLight( 0 )->getPosition( lightVec );
 852             sgNegateVec3( lightVec );
 853             sgXformVec3( lightVec, tmp );
 854
 855             for ( int i = 0; i < 25; i++ ) {
 856                 CloudVertex &v = vertices[ i ];
 857                 sgSetVec3( v.tangentSpLight,
 858                            sgScalarProductVec3( v.sTangent, lightVec ),
 859                            sgScalarProductVec3( v.tTangent, lightVec ),
 860                            sgScalarProductVec3( v.normal, lightVec ) );
 861             }
 862
 863             ssgTexture *decal = color_map[ layer_coverage ][ top ? 1 : 0 ];
 864             if ( top && decal == 0 ) {
 865                 decal = color_map[ layer_coverage ][ 0 ];
 866             }
 867             ssgTexture *normal = normal_map[ layer_coverage ][ top ? 1 : 0 ];
 868             if ( top && normal == 0 ) {
 869                 normal = normal_map[ layer_coverage ][ 0 ];
 870             }
 871
 872             glDisable( GL_LIGHTING );
 873             glDisable( GL_CULL_FACE );
 874 //            glDisable( GL_ALPHA_TEST );
 875             if ( layer_coverage == SG_CLOUD_FEW ) {
 876                 glEnable( GL_ALPHA_TEST );
 877                 glAlphaFunc ( GL_GREATER, 0.01 );
 878             }
 879             glEnable( GL_BLEND );
 880             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 881
 882             glShadeModel( GL_SMOOTH );
 883             glEnable( GL_COLOR_MATERIAL );
 884             sgVec4 color;
 885             float emis = 0.05;
 886             if ( 1 ) {
 887                 ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
 888                 emis = ( color[0]+color[1]+color[2] ) / 3.0;
 889                 if ( emis < 0.05 )
 890                     emis = 0.05;
 891             }
 892             sgSetVec4( color, emis, emis, emis, 0.0 );
 893             glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, color );
 894             sgSetVec4( color, 1.0f, 1.0f, 1.0f, 0.0 );
 895             glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, color );
 896             sgSetVec4( color, 1.0, 1.0, 1.0, 0.0 );
 897             glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, color );
 898             sgSetVec4( color, 0.0, 0.0, 0.0, 0.0 );
 899             glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, color );
 900
 901             glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
 902
 903             glActiveTexturePtr( GL_TEXTURE0_ARB );
 904             glBindTexture( GL_TEXTURE_2D, normal->getHandle() );
 905             glEnable( GL_TEXTURE_2D );
 906
 907             //Bind normalisation cube map to texture unit 1
 908             glActiveTexturePtr( GL_TEXTURE1_ARB );
 909             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 910             glEnable( GL_TEXTURE_CUBE_MAP_ARB );
 911             glActiveTexturePtr( GL_TEXTURE0_ARB );
 912
 913             //Set vertex arrays for cloud
 914             glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
 915             glEnableClientState( GL_VERTEX_ARRAY );
 916 /*
 917             if ( nb_texture_unit >= 3 ) {
 918                 glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
 919                 glEnableClientState( GL_COLOR_ARRAY );
 920             }
 921 */
 922             //Send texture coords for normal map to unit 0
 923             glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 924             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 925
 926             //Send tangent space light vectors for normalisation to unit 1
 927             glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 928             glTexCoordPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].tangentSpLight );
 929             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 930
 931             //Set up texture environment to do (tex0 dot tex1)*color
 932             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 933             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 934             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE );
 935             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE );
 936             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 937
 938             glActiveTexturePtr( GL_TEXTURE1_ARB );
 939
 940             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 941             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 942             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_DOT3_RGB_ARB );
 943             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 944             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB );
 945             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 946
 947             if ( nb_texture_unit >= 3 ) {
 948                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 949                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 950
 951                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 952                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 953                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 954
 955                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 956                 glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD );
 957                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 958                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 959
 960                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 961                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 962
 963                 //Draw cloud layer
 964                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 965                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 966                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 967                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 968
 969                 glDisable( GL_TEXTURE_2D );
 970                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 971                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 972                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 973                 glDisable( GL_TEXTURE_2D );
 974                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 975
 976                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 977                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 978                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 979                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 980                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 981                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 982
 983                 glDisableClientState( GL_COLOR_ARRAY );
 984                 glEnable( GL_LIGHTING );
 985
 986                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
 987
 988             } else {
 989                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 990                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 991
 992                 //Draw cloud layer
 993                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 994                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 995                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 996                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 997
 998                 //Disable textures
 999                 glDisable( GL_TEXTURE_2D );
1000
1001                 glActiveTexturePtr( GL_TEXTURE1_ARB );
1002                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
1003                 glActiveTexturePtr( GL_TEXTURE0_ARB );
1004
1005                 //disable vertex arrays
1006                 glDisableClientState( GL_VERTEX_ARRAY );
1007
1008                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1009                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
1010                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1011                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1012
1013                 //Return to standard modulate texenv
1014                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1015
1016                 if ( layer_coverage == SG_CLOUD_OVERCAST ) {
1017                     glDepthFunc(GL_LEQUAL);
1018
1019                     glEnable( GL_LIGHTING );
1020                     sgVec4 color;
1021                     ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
1022                     float average = ( color[0] + color[1] + color[2] ) / 3.0f;
1023                     average = 0.15 + average/10;
1024                     sgVec4 averageColor;
1025                     sgSetVec4( averageColor, average, average, average, 1.0f );
1026                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, averageColor );
1027
1028                     glBlendColorPtr( average, average, average, 1.0f );
1029                     glBlendFunc( GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_COLOR );
1030
1031                     //Perform a second pass to color the torus
1032                     //Bind decal texture
1033                     glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
1034                     glEnable(GL_TEXTURE_2D);
1035
1036                     //Set vertex arrays for torus
1037                     glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
1038                     glEnableClientState( GL_VERTEX_ARRAY );
1039
1040                     //glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
1041                     //glEnableClientState( GL_COLOR_ARRAY );
1042
1043                     glNormalPointer( GL_FLOAT, sizeof(CloudVertex), &vertices[0].normal );
1044                     glEnableClientState( GL_NORMAL_ARRAY );
1045
1046                     glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
1047                     glEnableClientState( GL_TEXTURE_COORD_ARRAY );
1048
1049                     //Draw cloud layer
1050                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1051                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1052                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1053                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1054
1055                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, color );
1056
1057                     glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1058                 }
1059             }
1060             //Disable texture
1061             glDisable( GL_TEXTURE_2D );
1062
1063             glDisableClientState( GL_VERTEX_ARRAY );
1064             glDisableClientState( GL_NORMAL_ARRAY );
1065
1066             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
1067             glEnable( GL_CULL_FACE );
1068             glDepthFunc(GL_LESS);
1069
1070             ssgLoadModelviewMatrix( modelview );
1071
1072         } else {
1073             state_sel->selectStep( top ? 1 : 0 );
1074             ssgCullAndDraw( layer_root );
1075         }
1076     }
1077 }
1078
1079
1080 // make an ssgSimpleState for a cloud layer given the named texture
1081 ssgSimpleState *sgCloudMakeState( const string &path ) {
1082     ssgSimpleState *state = new ssgSimpleState();
1083
1084     SG_LOG(SG_ASTRO, SG_INFO, " texture = ");
1085
1086     state->setTexture( (char *)path.c_str() );
1087     state->setShadeModel( GL_SMOOTH );
1088     state->disable( GL_LIGHTING );
1089     state->disable( GL_CULL_FACE );
1090     state->enable( GL_TEXTURE_2D );
1091     state->enable( GL_COLOR_MATERIAL );
1092     state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
1093     state->setMaterial( GL_EMISSION, 0.05, 0.05, 0.05, 0.0 );
1094     state->setMaterial( GL_AMBIENT, 0.2, 0.2, 0.2, 0.0 );
1095     state->setMaterial( GL_DIFFUSE, 0.5, 0.5, 0.5, 0.0 );
1096     state->setMaterial( GL_SPECULAR, 0.0, 0.0, 0.0, 0.0 );
1097     state->enable( GL_BLEND );
1098     state->enable( GL_ALPHA_TEST );
1099     state->setAlphaClamp( 0.01 );
1100
1101     return state;
1102 }