simgear/scene/sky/cloud.cxx

   1 // cloud.cxx -- model a single cloud layer
   2 //
   3 // Written by Curtis Olson, started June 2000.
   4 //
   5 // Copyright (C) 2000  Curtis L. Olson  - http://www.flightgear.org/~curt
   6 //
   7 // This program is distributed in the hope that it will be useful, but
   8 // WITHOUT ANY WARRANTY; without even the implied warranty of
   9 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  10 // General Public License for more details.
  11 //
  12 // You should have received a copy of the GNU General Public License
  13 // along with this program; if not, write to the Free Software
  14 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  15 //
  16 // $Id$
  17
  18
  19 #include <simgear/compiler.h>
  20
  21 // #include <stdio.h>
  22 #include <math.h>
  23
  24 #if defined (__APPLE__)
  25 // any C++ header file undefines isinf and isnan
  26 // so this should be included before <iostream>
  27 inline int (isinf)(double r) { return isinf(r); }
  28 inline int (isnan)(double r) { return isnan(r); }
  29 #endif
  30
  31 #include <plib/sg.h>
  32 #include <plib/ssg.h>
  33
  34 #include <simgear/math/point3d.hxx>
  35 #include <simgear/math/polar3d.hxx>
  36 #include <simgear/math/sg_random.h>
  37 #include <simgear/debug/logstream.hxx>
  38 #include <simgear/misc/sg_path.hxx>
  39 #include <simgear/screen/extensions.hxx>
  40 #include <simgear/screen/texture.hxx>
  41
  42 #include "cloud.hxx"
  43
  44 #if defined(__MINGW32__)
  45 #define isnan(x) _isnan(x)
  46 #endif
  47
  48 #if defined (__FreeBSD__)
  49 #  if __FreeBSD_version < 500000
  50      extern "C" {
  51        inline int isnan(double r) { return !(r <= 0 || r >= 0); }
  52      }
  53 #  endif
  54 #endif
  55
  56
  57 static ssgStateSelector *layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
  58 static bool state_initialized = false;
  59 static bool bump_mapping = false;
  60 static int nb_texture_unit = 0;
  61 static ssgTexture *normal_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2] = { 0 };
  62 static ssgTexture *color_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2] = { 0 };
  63 static GLuint normalization_cube_map;
  64
  65 static glActiveTextureProc glActiveTexturePtr = 0;
  66 static glClientActiveTextureProc glClientActiveTexturePtr = 0;
  67 static glBlendColorProc glBlendColorPtr = 0;
  68
  69 bool SGCloudLayer::enable_bump_mapping = false;
  70
  71 static void
  72 generateNormalizationCubeMap()
  73 {
  74     unsigned char data[ 32 * 32 * 3 ];
  75     const int size = 32;
  76     const float half_size = 16.0f,
  77                 offset = 0.5f;
  78     sgVec3 zero_normal;
  79     sgSetVec3( zero_normal, 0.5f, 0.5f, 0.5f );
  80     int i, j;
  81
  82     unsigned char *ptr = data;
  83     for ( j = 0; j < size; j++ ) {
  84         for ( i = 0; i < size; i++ ) {
  85             sgVec3 tmp;
  86             sgSetVec3( tmp, half_size,
  87                             -( j + offset - half_size ),
  88                             -( i + offset - half_size ) );
  89             sgNormalizeVec3( tmp );
  90             sgScaleVec3( tmp, 0.5f );
  91             sgAddVec3( tmp, zero_normal );
  92
  93             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
  94             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
  95             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
  96         }
  97     }
  98     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
  99                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 100
 101     ptr = data;
 102     for ( j = 0; j < size; j++ ) {
 103         for ( i = 0; i < size; i++ ) {
 104             sgVec3 tmp;
 105             sgSetVec3( tmp, -half_size,
 106                             -( j + offset - half_size ),
 107                             ( i + offset - half_size ) );
 108             sgNormalizeVec3( tmp );
 109             sgScaleVec3( tmp, 0.5f );
 110             sgAddVec3( tmp, zero_normal );
 111
 112             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 113             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 114             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 115         }
 116     }
 117     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 118                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 119
 120     ptr = data;
 121     for ( j = 0; j < size; j++ ) {
 122         for ( i = 0; i < size; i++ ) {
 123             sgVec3 tmp;
 124             sgSetVec3( tmp, ( i + offset - half_size ),
 125                             half_size,
 126                             ( j + offset - half_size ) );
 127             sgNormalizeVec3( tmp );
 128             sgScaleVec3( tmp, 0.5f );
 129             sgAddVec3( tmp, zero_normal );
 130
 131             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 132             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 133             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 134         }
 135     }
 136     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 137                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 138
 139     ptr = data;
 140     for ( j = 0; j < size; j++ ) {
 141         for ( i = 0; i < size; i++ ) {
 142             sgVec3 tmp;
 143             sgSetVec3( tmp, ( i + offset - half_size ),
 144                             -half_size,
 145                             -( j + offset - half_size ) );
 146             sgNormalizeVec3( tmp );
 147             sgScaleVec3( tmp, 0.5f );
 148             sgAddVec3( tmp, zero_normal );
 149
 150             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 151             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 152             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 153         }
 154     }
 155     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 156                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 157
 158     ptr = data;
 159     for ( j = 0; j < size; j++ ) {
 160         for ( i = 0; i < size; i++ ) {
 161             sgVec3 tmp;
 162             sgSetVec3( tmp, ( i + offset - half_size ),
 163                             -( j + offset - half_size ),
 164                             half_size );
 165             sgNormalizeVec3( tmp );
 166             sgScaleVec3( tmp, 0.5f );
 167             sgAddVec3( tmp, zero_normal );
 168
 169             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 170             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 171             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 172         }
 173     }
 174     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 175                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 176
 177     ptr = data;
 178     for ( j = 0; j < size; j++ ) {
 179         for ( i = 0; i < size; i++ ) {
 180             sgVec3 tmp;
 181             sgSetVec3( tmp, -( i + offset - half_size ),
 182                             -( j + offset - half_size ),
 183                             -half_size );
 184             sgNormalizeVec3( tmp );
 185             sgScaleVec3( tmp, 0.5f );
 186             sgAddVec3( tmp, zero_normal );
 187
 188             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 189             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 190             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 191         }
 192     }
 193     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB,
 194                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 195 }
 196
 197
 198 // Constructor
 199 SGCloudLayer::SGCloudLayer( const string &tex_path ) :
 200     layer_root(new ssgRoot),
 201     layer_transform(new ssgTransform),
 202     state_sel(0),
 203     texture_path(tex_path),
 204     layer_span(0.0),
 205     layer_asl(0.0),
 206     layer_thickness(0.0),
 207     layer_transition(0.0),
 208     layer_coverage(SG_CLOUD_CLEAR),
 209     scale(4000.0),
 210     speed(0.0),
 211     direction(0.0),
 212     last_lon(0.0),
 213     last_lat(0.0),
 214     vertices(0),
 215     indices(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     rebuild();
 224 }
 225
 226 // Destructor
 227 SGCloudLayer::~SGCloudLayer()
 228 {
 229     delete vertices;
 230     delete indices;
 231     delete layer_root;          // deletes layer_transform and layer as well
 232 }
 233
 234 float
 235 SGCloudLayer::getSpan_m () const
 236 {
 237     return layer_span;
 238 }
 239
 240 void
 241 SGCloudLayer::setSpan_m (float span_m)
 242 {
 243     if (span_m != layer_span) {
 244         layer_span = span_m;
 245         rebuild();
 246     }
 247 }
 248
 249 float
 250 SGCloudLayer::getElevation_m () const
 251 {
 252     return layer_asl;
 253 }
 254
 255 void
 256 SGCloudLayer::setElevation_m (float elevation_m, bool set_span)
 257 {
 258     layer_asl = elevation_m;
 259
 260     if (set_span) {
 261         if (elevation_m > 4000)
 262             setSpan_m(  elevation_m * 10 );
 263         else
 264             setSpan_m( 40000 );
 265     }
 266 }
 267
 268 float
 269 SGCloudLayer::getThickness_m () const
 270 {
 271     return layer_thickness;
 272 }
 273
 274 void
 275 SGCloudLayer::setThickness_m (float thickness_m)
 276 {
 277     layer_thickness = thickness_m;
 278 }
 279
 280 float
 281 SGCloudLayer::getTransition_m () const
 282 {
 283     return layer_transition;
 284 }
 285
 286 void
 287 SGCloudLayer::setTransition_m (float transition_m)
 288 {
 289     layer_transition = transition_m;
 290 }
 291
 292 SGCloudLayer::Coverage
 293 SGCloudLayer::getCoverage () const
 294 {
 295     return layer_coverage;
 296 }
 297
 298 void
 299 SGCloudLayer::setCoverage (Coverage coverage)
 300 {
 301     if (coverage != layer_coverage) {
 302         layer_coverage = coverage;
 303         rebuild();
 304     }
 305 }
 306
 307
 308 // build the cloud object
 309 void
 310 SGCloudLayer::rebuild()
 311 {
 312     // Initialize states and sizes if necessary.
 313     if ( !state_initialized ) {
 314         state_initialized = true;
 315
 316         SG_LOG(SG_ASTRO, SG_INFO, "initializing cloud layers");
 317
 318         bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
 319                        SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
 320                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
 321                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") &&
 322                        SGIsOpenGLExtensionSupported("GL_ARB_imaging");
 323
 324         if ( bump_mapping ) {
 325             glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
 326             if ( nb_texture_unit < 2 ) {
 327                 bump_mapping = false;
 328             }
 329             //nb_texture_unit = 2; // Force the number of units for now
 330         }
 331
 332         if ( bump_mapping ) {
 333
 334             // This bump mapping code was inspired by the tutorial available at
 335             // http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
 336             // and a NVidia white paper
 337             //  http://developer.nvidia.com/object/bumpmappingwithregistercombiners.html
 338             // The normal map textures were generated by the normal map Gimp plugin :
 339             //  http://nifelheim.dyndns.org/~cocidius/normalmap/
 340             //
 341             SGPath cloud_path;
 342
 343             glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
 344             glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
 345             glBlendColorPtr = (glBlendColorProc)SGLookupFunction("glBlendColor");
 346
 347             cloud_path.set(texture_path.str());
 348             cloud_path.append("overcast.rgb");
 349             color_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 350             color_map[ SG_CLOUD_OVERCAST ][ 0 ]->ref();
 351             cloud_path.set(texture_path.str());
 352             cloud_path.append("overcast_n.rgb");
 353             normal_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 354             normal_map[ SG_CLOUD_OVERCAST ][ 0 ]->ref();
 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             color_map[ SG_CLOUD_OVERCAST ][ 1 ]->ref();
 360             cloud_path.set(texture_path.str());
 361             cloud_path.append("overcast_top_n.rgb");
 362             normal_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 363             normal_map[ SG_CLOUD_OVERCAST ][ 1 ]->ref();
 364
 365             cloud_path.set(texture_path.str());
 366             cloud_path.append("broken.rgba");
 367             color_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 368             color_map[ SG_CLOUD_BROKEN ][ 0 ]->ref();
 369             cloud_path.set(texture_path.str());
 370             cloud_path.append("broken_n.rgb");
 371             normal_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 372             normal_map[ SG_CLOUD_BROKEN ][ 0 ]->ref();
 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             color_map[ SG_CLOUD_SCATTERED ][ 0 ]->ref();
 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             normal_map[ SG_CLOUD_SCATTERED ][ 0 ]->ref();
 382
 383             cloud_path.set(texture_path.str());
 384             cloud_path.append("few.rgba");
 385             color_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 386             color_map[ SG_CLOUD_FEW ][ 0 ]->ref();
 387             cloud_path.set(texture_path.str());
 388             cloud_path.append("few_n.rgb");
 389             normal_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 390             normal_map[ SG_CLOUD_FEW ][ 0 ]->ref();
 391
 392             cloud_path.set(texture_path.str());
 393             cloud_path.append("cirrus.rgba");
 394             color_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 395             color_map[ SG_CLOUD_CIRRUS ][ 0 ]->ref();
 396             cloud_path.set(texture_path.str());
 397             cloud_path.append("cirrus_n.rgb");
 398             normal_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 399             normal_map[ SG_CLOUD_CIRRUS ][ 0 ]->ref();
 400
 401             glGenTextures( 1, &normalization_cube_map );
 402             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 403             generateNormalizationCubeMap();
 404             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 405             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 406             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 407             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 408             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE );
 409         } /* else */ {
 410             SGPath cloud_path;
 411             ssgStateSelector *state_sel;
 412             ssgSimpleState *state;
 413
 414             state_sel = new ssgStateSelector( 2 );
 415             state_sel->ref();
 416             cloud_path.set(texture_path.str());
 417             cloud_path.append("overcast.rgb");
 418             state_sel->setStep( 0, sgCloudMakeState(cloud_path.str()) );
 419             cloud_path.set(texture_path.str());
 420             cloud_path.append("overcast_top.rgb");
 421             state_sel->setStep( 1, sgCloudMakeState(cloud_path.str()) );
 422             layer_states[SG_CLOUD_OVERCAST] = state_sel;
 423
 424             state_sel = new ssgStateSelector( 2 );
 425             state_sel->ref();
 426             cloud_path.set(texture_path.str());
 427             cloud_path.append("broken.rgba");
 428             state = sgCloudMakeState(cloud_path.str());
 429             state_sel->setStep( 0, state );
 430             state_sel->setStep( 1, state );
 431             layer_states[SG_CLOUD_BROKEN] = state_sel;
 432
 433             state_sel = new ssgStateSelector( 2 );
 434             state_sel->ref();
 435             cloud_path.set(texture_path.str());
 436             cloud_path.append("scattered.rgba");
 437             state = sgCloudMakeState(cloud_path.str());
 438             state_sel->setStep( 0, state );
 439             state_sel->setStep( 1, state );
 440             layer_states[SG_CLOUD_SCATTERED] = state_sel;
 441
 442             state_sel = new ssgStateSelector( 2 );
 443             state_sel->ref();
 444             cloud_path.set(texture_path.str());
 445             cloud_path.append("few.rgba");
 446             state = sgCloudMakeState(cloud_path.str());
 447             state_sel->setStep( 0, state );
 448             state_sel->setStep( 1, state );
 449             layer_states[SG_CLOUD_FEW] = state_sel;
 450
 451             state_sel = new ssgStateSelector( 2 );
 452             state_sel->ref();
 453             cloud_path.set(texture_path.str());
 454             cloud_path.append("cirrus.rgba");
 455             state = sgCloudMakeState(cloud_path.str());
 456             state_sel->setStep( 0, state );
 457             state_sel->setStep( 1, state );
 458             layer_states[SG_CLOUD_CIRRUS] = state_sel;
 459
 460             layer_states[SG_CLOUD_CLEAR] = 0;
 461         }
 462     }
 463
 464     if ( bump_mapping ) {
 465
 466         if ( !vertices ) {
 467             vertices = new CloudVertex[ 25 ];
 468             indices = new unsigned int[ 40 ];
 469         }
 470
 471         sgVec2 base;
 472         sgSetVec2( base, sg_random(), sg_random() );
 473
 474         const float layer_scale = layer_span / scale;
 475         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 476         const float half_angle = 0.5 * layer_span / layer_to_core;
 477
 478         int i;
 479         for ( i = -2; i <= 2; i++ ) {
 480             for ( int j = -2; j <= 2; j++ ) {
 481                 CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 482                 sgSetVec3( v1.position,
 483                            0.5 * i * layer_span,
 484                            0.5 * j * layer_span,
 485                            -layer_to_core * ( 1 - cos( i * half_angle ) * cos( j * half_angle ) ) );
 486                 sgSetVec2( v1.texCoord,
 487                            base[0] + layer_scale * i * 0.25,
 488                            base[1] + layer_scale * j * 0.25 );
 489                 sgSetVec3( v1.sTangent,
 490                            cos( i * half_angle ),
 491                            0.f,
 492                            -sin( i * half_angle ) );
 493                 sgSetVec3( v1.tTangent,
 494                            0.f,
 495                            cos( j * half_angle ),
 496                            -sin( j * half_angle ) );
 497                 sgVectorProductVec3( v1.normal, v1.tTangent, v1.sTangent );
 498                 sgSetVec4( v1.color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 499             }
 500         }
 501         /*
 502          * 0 1 5 6 10 11 15 16 20 21
 503          * 1 2 6 7 11 12 16 17 21 22
 504          * 2 3 7 8 12 13 17 18 22 23
 505          * 3 4 8 9 13 14 18 19 23 24
 506          */
 507         for ( i = 0; i < 4; i++ ) {
 508             for ( int j = 0; j < 5; j++ ) {
 509                 indices[ i*10 + (j*2) ]     =     i + 5 * j;
 510                 indices[ i*10 + (j*2) + 1 ] = 1 + i + 5 * j;
 511             }
 512         }
 513
 514     } /* else */ {
 515
 516         scale = 4000.0;
 517         last_lon = last_lat = -999.0f;
 518
 519         sgVec2 base;
 520         sgSetVec2( base, sg_random(), sg_random() );
 521
 522         // build the cloud layer
 523         sgVec4 color;
 524         sgVec3 vertex;
 525         sgVec2 tc;
 526
 527         const float layer_scale = layer_span / scale;
 528         const float mpi = SG_PI/4;
 529
 530         // caclculate the difference between a flat-earth model and
 531         // a round earth model given the span and altutude ASL of
 532         // the cloud layer. This is the difference in altitude between
 533         // the top of the inverted bowl and the edge of the bowl.
 534         // const float alt_diff = layer_asl * 0.8;
 535         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 536         const float layer_angle = 0.5*layer_span / layer_to_core; // The angle is half the span
 537         const float border_to_core = layer_to_core * cos(layer_angle);
 538         const float alt_diff = layer_to_core - border_to_core;
 539
 540         for (int i = 0; i < 4; i++)
 541         {
 542             if ( layer[i] != NULL ) {
 543                 layer_transform->removeKid(layer[i]); // automatic delete
 544             }
 545
 546             vl[i] = new ssgVertexArray( 10 );
 547             cl[i] = new ssgColourArray( 10 );
 548             tl[i] = new ssgTexCoordArray( 10 );
 549
 550
 551             sgSetVec3( vertex, layer_span*(i-2)/2, -layer_span,
 552                             alt_diff * (sin(i*mpi) - 2) );
 553
 554             sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 555
 556             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 557
 558             cl[i]->add( color );
 559             vl[i]->add( vertex );
 560             tl[i]->add( tc );
 561
 562             for (int j = 0; j < 4; j++)
 563             {
 564                 sgSetVec3( vertex, layer_span*(i-1)/2, layer_span*(j-2)/2,
 565                                 alt_diff * (sin((i+1)*mpi) + sin(j*mpi) - 2) );
 566
 567                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 568                             base[1] + layer_scale * j/4 );
 569
 570                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 571                                 ( (j == 0) || (i == 3)) ?
 572                                 ( (j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f );
 573
 574                 cl[i]->add( color );
 575                 vl[i]->add( vertex );
 576                 tl[i]->add( tc );
 577
 578
 579                 sgSetVec3( vertex, layer_span*(i-2)/2, layer_span*(j-1)/2,
 580                                 alt_diff * (sin(i*mpi) + sin((j+1)*mpi) - 2) );
 581
 582                 sgSetVec2( tc, base[0] + layer_scale * i/4,
 583                             base[1] + layer_scale * (j+1)/4 );
 584
 585                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 586                                 ((j == 3) || (i == 0)) ?
 587                                 ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f );
 588                 cl[i]->add( color );
 589                 vl[i]->add( vertex );
 590                 tl[i]->add( tc );
 591             }
 592
 593             sgSetVec3( vertex, layer_span*(i-1)/2, layer_span,
 594                             alt_diff * (sin((i+1)*mpi) - 2) );
 595
 596             sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 597                         base[1] + layer_scale );
 598
 599             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 3) ? 0.0f : 0.15f );
 600
 601             cl[i]->add( color );
 602             vl[i]->add( vertex );
 603             tl[i]->add( tc );
 604
 605             layer[i] = new ssgVtxTable(GL_TRIANGLE_STRIP, vl[i], NULL, tl[i], cl[i]);
 606             layer_transform->addKid( layer[i] );
 607
 608             if ( layer_states[layer_coverage] != NULL ) {
 609                 layer[i]->setState( layer_states[layer_coverage] );
 610             }
 611             state_sel = layer_states[layer_coverage];
 612         }
 613
 614         // force a repaint of the sky colors with arbitrary defaults
 615         repaint( color );
 616     }
 617 }
 618
 619
 620 // repaint the cloud layer colors
 621 bool SGCloudLayer::repaint( sgVec3 fog_color ) {
 622
 623     if ( bump_mapping && enable_bump_mapping ) {
 624
 625         for ( int i = 0; i < 25; i++ ) {
 626             sgCopyVec3( vertices[ i ].color, fog_color );
 627         }
 628
 629     } else {
 630         float *color;
 631
 632         for ( int i = 0; i < 4; i++ ) {
 633             for ( int j = 0; j < 10; ++j ) {
 634                 color = cl[i]->get( j );
 635                 sgCopyVec3( color, fog_color );
 636             }
 637         }
 638     }
 639
 640     return true;
 641 }
 642
 643 // reposition the cloud layer at the specified origin and orientation
 644 // lon specifies a rotation about the Z axis
 645 // lat specifies a rotation about the new Y axis
 646 // spin specifies a rotation about the new Z axis (and orients the
 647 // sunrise/set effects
 648 bool SGCloudLayer::reposition( sgVec3 p, sgVec3 up, double lon, double lat,
 649                                double alt, double dt )
 650 {
 651     sgMat4 T1, LON, LAT;
 652     sgVec3 axis;
 653
 654     // combine p and asl (meters) to get translation offset
 655     sgVec3 asl_offset;
 656     sgCopyVec3( asl_offset, up );
 657     sgNormalizeVec3( asl_offset );
 658     if ( alt <= layer_asl ) {
 659         sgScaleVec3( asl_offset, layer_asl );
 660     } else {
 661         sgScaleVec3( asl_offset, layer_asl + layer_thickness );
 662     }
 663     // cout << "asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 664     //      << "," << asl_offset[2] << endl;
 665     sgAddVec3( asl_offset, p );
 666     // cout << "  asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 667     //      << "," << asl_offset[2] << endl;
 668
 669     // Translate to zero elevation
 670     // Point3D zero_elev = current_view.get_cur_zero_elev();
 671     sgMakeTransMat4( T1, asl_offset );
 672
 673     // printf("  Translated to %.2f %.2f %.2f\n",
 674     //        zero_elev.x, zero_elev.y, zero_elev.z );
 675
 676     // Rotate to proper orientation
 677     // printf("  lon = %.2f  lat = %.2f\n",
 678     //        lon * SGD_RADIANS_TO_DEGREES,
 679     //        lat * SGD_RADIANS_TO_DEGREES);
 680     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 681     sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );
 682
 683     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 684     sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );
 685
 686     sgMat4 TRANSFORM;
 687
 688     sgCopyMat4( TRANSFORM, T1 );
 689     sgPreMultMat4( TRANSFORM, LON );
 690     sgPreMultMat4( TRANSFORM, LAT );
 691
 692     sgCoord layerpos;
 693     sgSetCoord( &layerpos, TRANSFORM );
 694
 695     layer_transform->setTransform( &layerpos );
 696
 697     // now calculate update texture coordinates
 698     if ( last_lon < -900 ) {
 699         last_lon = lon;
 700         last_lat = lat;
 701     }
 702
 703     double sp_dist = speed*dt;
 704
 705     if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
 706         Point3D start( last_lon, last_lat, 0.0 );
 707         Point3D dest( lon, lat, 0.0 );
 708         double course = 0.0, dist = 0.0;
 709
 710         calc_gc_course_dist( dest, start, &course, &dist );
 711         // cout << "course = " << course << ", dist = " << dist << endl;
 712
 713         // if start and dest are too close together,
 714         // calc_gc_course_dist() can return a course of "nan".  If
 715         // this happens, lets just use the last known good course.
 716         // This is a hack, and it would probably be better to make
 717         // calc_gc_course_dist() more robust.
 718         if ( isnan(course) ) {
 719             course = last_course;
 720         } else {
 721             last_course = course;
 722         }
 723
 724         // calculate cloud movement due to external forces
 725         double ax = 0.0, ay = 0.0, bx = 0.0, by = 0.0;
 726
 727         if (dist > 0.0) {
 728             ax = cos(course) * dist;
 729             ay = sin(course) * dist;
 730         }
 731
 732         if (sp_dist > 0) {
 733             bx = cos((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 734             by = sin((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 735         }
 736
 737
 738         double xoff = (ax + bx) / (2 * scale);
 739         double yoff = (ay + by) / (2 * scale);
 740
 741         const float layer_scale = layer_span / scale;
 742
 743         // cout << "xoff = " << xoff << ", yoff = " << yoff << endl;
 744
 745         float *base;
 746         if ( bump_mapping && enable_bump_mapping ) {
 747             base = vertices[12].texCoord;
 748         } else {
 749             base = tl[0]->get( 0 );
 750         }
 751         base[0] += xoff;
 752
 753         // the while loops can lead to *long* pauses if base[0] comes
 754         // with a bogus value.
 755         // while ( base[0] > 1.0 ) { base[0] -= 1.0; }
 756         // while ( base[0] < 0.0 ) { base[0] += 1.0; }
 757         if ( base[0] > -10.0 && base[0] < 10.0 ) {
 758             base[0] -= (int)base[0];
 759         } else {
 760             SG_LOG(SG_ASTRO, SG_DEBUG,
 761                 "Error: base = " << base[0] << "," << base[1] <<
 762                 " course = " << course << " dist = " << dist );
 763             base[0] = 0.0;
 764         }
 765
 766         base[1] += yoff;
 767         // the while loops can lead to *long* pauses if base[0] comes
 768         // with a bogus value.
 769         // while ( base[1] > 1.0 ) { base[1] -= 1.0; }
 770         // while ( base[1] < 0.0 ) { base[1] += 1.0; }
 771         if ( base[1] > -10.0 && base[1] < 10.0 ) {
 772             base[1] -= (int)base[1];
 773         } else {
 774             SG_LOG(SG_ASTRO, SG_ALERT,
 775                     "Error: base = " << base[0] << "," << base[1] <<
 776                     " course = " << course << " dist = " << dist );
 777             base[1] = 0.0;
 778         }
 779
 780         if ( bump_mapping && enable_bump_mapping ) {
 781
 782             for ( int i = -2; i <= 2; i++ ) {
 783                 for ( int j = -2; j <= 2; j++ ) {
 784                     if ( i == 0 && j == 0 )
 785                         continue; // Already done on base
 786                     CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 787                     sgSetVec2( v1.texCoord,
 788                             base[0] + layer_scale * i * 0.25,
 789                             base[1] + layer_scale * j * 0.25 );
 790                 }
 791             }
 792
 793         } else {
 794                 // cout << "base = " << base[0] << "," << base[1] << endl;
 795
 796             float *tc;
 797             for (int i = 0; i < 4; i++) {
 798                 tc = tl[i]->get( 0 );
 799                 sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 800
 801                 for (int j = 0; j < 4; j++)
 802                 {
 803                     tc = tl[i]->get( j*2+1 );
 804                     sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 805                                 base[1] + layer_scale * j/4 );
 806
 807                     tc = tl[i]->get( (j+1)*2 );
 808                     sgSetVec2( tc, base[0] + layer_scale * i/4,
 809                                 base[1] + layer_scale * (j+1)/4 );
 810                 }
 811
 812                 tc = tl[i]->get( 9 );
 813                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 814                             base[1] + layer_scale );
 815             }
 816         }
 817
 818         last_lon = lon;
 819         last_lat = lat;
 820     }
 821
 822     return true;
 823 }
 824
 825
 826 void SGCloudLayer::draw( bool top ) {
 827     if ( layer_coverage != SG_CLOUD_CLEAR ) {
 828
 829         if ( bump_mapping && enable_bump_mapping ) {
 830
 831             sgMat4 modelview,
 832                    tmp,
 833                    transform;
 834             ssgGetModelviewMatrix( modelview );
 835             layer_transform->getTransform( transform );
 836
 837             sgTransposeNegateMat4( tmp, transform );
 838
 839             sgPostMultMat4( transform, modelview );
 840             ssgLoadModelviewMatrix( transform );
 841
 842             sgVec3 lightVec;
 843             ssgGetLight( 0 )->getPosition( lightVec );
 844             sgNegateVec3( lightVec );
 845             sgXformVec3( lightVec, tmp );
 846
 847             for ( int i = 0; i < 25; i++ ) {
 848                 CloudVertex &v = vertices[ i ];
 849                 sgSetVec3( v.tangentSpLight,
 850                            sgScalarProductVec3( v.sTangent, lightVec ),
 851                            sgScalarProductVec3( v.tTangent, lightVec ),
 852                            sgScalarProductVec3( v.normal, lightVec ) );
 853             }
 854
 855             ssgTexture *decal = color_map[ layer_coverage ][ top ? 1 : 0 ];
 856             if ( top && decal == 0 ) {
 857                 decal = color_map[ layer_coverage ][ 0 ];
 858             }
 859             ssgTexture *normal = normal_map[ layer_coverage ][ top ? 1 : 0 ];
 860             if ( top && normal == 0 ) {
 861                 normal = normal_map[ layer_coverage ][ 0 ];
 862             }
 863
 864             glDisable( GL_LIGHTING );
 865             glDisable( GL_CULL_FACE );
 866 //            glDisable( GL_ALPHA_TEST );
 867             if ( layer_coverage == SG_CLOUD_FEW ) {
 868                 glEnable( GL_ALPHA_TEST );
 869                 glAlphaFunc ( GL_GREATER, 0.01 );
 870             }
 871             glEnable( GL_BLEND );
 872             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 873
 874             glShadeModel( GL_SMOOTH );
 875             glEnable( GL_COLOR_MATERIAL );
 876             sgVec4 color;
 877             float emis = 0.05;
 878             if ( 1 ) {
 879                 ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
 880                 emis = ( color[0]+color[1]+color[2] ) / 3.0;
 881                 if ( emis < 0.05 )
 882                     emis = 0.05;
 883             }
 884             sgSetVec4( color, emis, emis, emis, 0.0 );
 885             glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, color );
 886             sgSetVec4( color, 1.0f, 1.0f, 1.0f, 0.0 );
 887             glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, color );
 888             sgSetVec4( color, 1.0, 1.0, 1.0, 0.0 );
 889             glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, color );
 890             sgSetVec4( color, 0.0, 0.0, 0.0, 0.0 );
 891             glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, color );
 892
 893             glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
 894
 895             glActiveTexturePtr( GL_TEXTURE0_ARB );
 896             glBindTexture( GL_TEXTURE_2D, normal->getHandle() );
 897             glEnable( GL_TEXTURE_2D );
 898
 899             //Bind normalisation cube map to texture unit 1
 900             glActiveTexturePtr( GL_TEXTURE1_ARB );
 901             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 902             glEnable( GL_TEXTURE_CUBE_MAP_ARB );
 903             glActiveTexturePtr( GL_TEXTURE0_ARB );
 904
 905             //Set vertex arrays for cloud
 906             glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
 907             glEnableClientState( GL_VERTEX_ARRAY );
 908 /*
 909             if ( nb_texture_unit >= 3 ) {
 910                 glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
 911                 glEnableClientState( GL_COLOR_ARRAY );
 912             }
 913 */
 914             //Send texture coords for normal map to unit 0
 915             glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 916             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 917
 918             //Send tangent space light vectors for normalisation to unit 1
 919             glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 920             glTexCoordPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].tangentSpLight );
 921             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 922
 923             //Set up texture environment to do (tex0 dot tex1)*color
 924             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 925             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 926             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE );
 927             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE );
 928             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 929
 930             glActiveTexturePtr( GL_TEXTURE1_ARB );
 931
 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_DOT3_RGB_ARB );
 935             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 936             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB );
 937             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 938
 939             if ( nb_texture_unit >= 3 ) {
 940                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 941                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 942
 943                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 944                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 945                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 946
 947                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 948                 glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD );
 949                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 950                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 951
 952                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 953                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 954
 955                 //Draw cloud layer
 956                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 957                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 958                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 959                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 960
 961                 glDisable( GL_TEXTURE_2D );
 962                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 963                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 964                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 965                 glDisable( GL_TEXTURE_2D );
 966                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 967
 968                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 969                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 970                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 971                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 972                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 973                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 974
 975                 glDisableClientState( GL_COLOR_ARRAY );
 976                 glEnable( GL_LIGHTING );
 977
 978                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
 979
 980             } else {
 981                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 982                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 983
 984                 //Draw cloud layer
 985                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 986                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 987                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 988                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 989
 990                 //Disable textures
 991                 glDisable( GL_TEXTURE_2D );
 992
 993                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 994                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 995                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 996
 997                 //disable vertex arrays
 998                 glDisableClientState( GL_VERTEX_ARRAY );
 999
1000                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1001                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
1002                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1003                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1004
1005                 //Return to standard modulate texenv
1006                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1007
1008                 if ( layer_coverage == SG_CLOUD_OVERCAST ) {
1009                     glDepthFunc(GL_LEQUAL);
1010
1011                     glEnable( GL_LIGHTING );
1012                     sgVec4 color;
1013                     ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
1014                     float average = ( color[0] + color[1] + color[2] ) / 3.0f;
1015                     average = 0.15 + average/10;
1016                     sgVec4 averageColor;
1017                     sgSetVec4( averageColor, average, average, average, 1.0f );
1018                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, averageColor );
1019
1020                     glBlendColorPtr( average, average, average, 1.0f );
1021                     glBlendFunc( GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_COLOR );
1022
1023                     //Perform a second pass to color the torus
1024                     //Bind decal texture
1025                     glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
1026                     glEnable(GL_TEXTURE_2D);
1027
1028                     //Set vertex arrays for torus
1029                     glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
1030                     glEnableClientState( GL_VERTEX_ARRAY );
1031
1032                     //glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
1033                     //glEnableClientState( GL_COLOR_ARRAY );
1034
1035                     glNormalPointer( GL_FLOAT, sizeof(CloudVertex), &vertices[0].normal );
1036                     glEnableClientState( GL_NORMAL_ARRAY );
1037
1038                     glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
1039                     glEnableClientState( GL_TEXTURE_COORD_ARRAY );
1040
1041                     //Draw cloud layer
1042                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1043                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1044                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1045                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1046
1047                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, color );
1048
1049                     glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1050                 }
1051             }
1052             //Disable texture
1053             glDisable( GL_TEXTURE_2D );
1054
1055             glDisableClientState( GL_VERTEX_ARRAY );
1056             glDisableClientState( GL_NORMAL_ARRAY );
1057
1058             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
1059             glEnable( GL_CULL_FACE );
1060             glDepthFunc(GL_LESS);
1061
1062             ssgLoadModelviewMatrix( modelview );
1063
1064         } else {
1065             state_sel->selectStep( top ? 1 : 0 );
1066             ssgCullAndDraw( layer_root );
1067         }
1068     }
1069 }
1070
1071
1072 // make an ssgSimpleState for a cloud layer given the named texture
1073 ssgSimpleState *sgCloudMakeState( const string &path ) {
1074     ssgSimpleState *state = new ssgSimpleState();
1075
1076     SG_LOG(SG_ASTRO, SG_INFO, " texture = ");
1077
1078     state->setTexture( (char *)path.c_str() );
1079     state->setShadeModel( GL_SMOOTH );
1080     state->disable( GL_LIGHTING );
1081     state->disable( GL_CULL_FACE );
1082     state->enable( GL_TEXTURE_2D );
1083     state->enable( GL_COLOR_MATERIAL );
1084     state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
1085     state->setMaterial( GL_EMISSION, 0.05, 0.05, 0.05, 0.0 );
1086     state->setMaterial( GL_AMBIENT, 0.2, 0.2, 0.2, 0.0 );
1087     state->setMaterial( GL_DIFFUSE, 0.5, 0.5, 0.5, 0.0 );
1088     state->setMaterial( GL_SPECULAR, 0.0, 0.0, 0.0, 0.0 );
1089     state->enable( GL_BLEND );
1090     state->enable( GL_ALPHA_TEST );
1091     state->setAlphaClamp( 0.01 );
1092
1093     return state;
1094 }