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 "newcloud.hxx"
  43 #include "cloudfield.hxx"
  44 #include "cloud.hxx"
  45
  46 #if defined(__MINGW32__)
  47 #define isnan(x) _isnan(x)
  48 #endif
  49
  50 #if defined (__FreeBSD__)
  51 #  if __FreeBSD_version < 500000
  52      extern "C" {
  53        inline int isnan(double r) { return !(r <= 0 || r >= 0); }
  54      }
  55 #  endif
  56 #endif
  57
  58
  59 static ssgStateSelector *layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
  60 static bool state_initialized = false;
  61 static bool bump_mapping = false;
  62 static GLint nb_texture_unit = 0;
  63 static ssgTexture *normal_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2] = { 0 };
  64 static ssgTexture *color_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2] = { 0 };
  65 static GLuint normalization_cube_map;
  66
  67 static glActiveTextureProc glActiveTexturePtr = 0;
  68 static glClientActiveTextureProc glClientActiveTexturePtr = 0;
  69 static glBlendColorProc glBlendColorPtr = 0;
  70
  71 bool SGCloudLayer::enable_bump_mapping = false;
  72
  73 static void
  74 generateNormalizationCubeMap()
  75 {
  76     unsigned char data[ 32 * 32 * 3 ];
  77     const int size = 32;
  78     const float half_size = 16.0f,
  79                 offset = 0.5f;
  80     sgVec3 zero_normal;
  81     sgSetVec3( zero_normal, 0.5f, 0.5f, 0.5f );
  82     int i, j;
  83
  84     unsigned char *ptr = data;
  85     for ( j = 0; j < size; j++ ) {
  86         for ( i = 0; i < size; i++ ) {
  87             sgVec3 tmp;
  88             sgSetVec3( tmp, half_size,
  89                             -( j + offset - half_size ),
  90                             -( i + offset - half_size ) );
  91             sgNormalizeVec3( tmp );
  92             sgScaleVec3( tmp, 0.5f );
  93             sgAddVec3( tmp, zero_normal );
  94
  95             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
  96             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
  97             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
  98         }
  99     }
 100     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
 101                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 102
 103     ptr = data;
 104     for ( j = 0; j < size; j++ ) {
 105         for ( i = 0; i < size; i++ ) {
 106             sgVec3 tmp;
 107             sgSetVec3( tmp, -half_size,
 108                             -( j + offset - half_size ),
 109                             ( i + offset - half_size ) );
 110             sgNormalizeVec3( tmp );
 111             sgScaleVec3( tmp, 0.5f );
 112             sgAddVec3( tmp, zero_normal );
 113
 114             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 115             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 116             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 117         }
 118     }
 119     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 120                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 121
 122     ptr = data;
 123     for ( j = 0; j < size; j++ ) {
 124         for ( i = 0; i < size; i++ ) {
 125             sgVec3 tmp;
 126             sgSetVec3( tmp, ( i + offset - half_size ),
 127                             half_size,
 128                             ( j + offset - half_size ) );
 129             sgNormalizeVec3( tmp );
 130             sgScaleVec3( tmp, 0.5f );
 131             sgAddVec3( tmp, zero_normal );
 132
 133             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 134             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 135             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 136         }
 137     }
 138     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 139                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 140
 141     ptr = data;
 142     for ( j = 0; j < size; j++ ) {
 143         for ( i = 0; i < size; i++ ) {
 144             sgVec3 tmp;
 145             sgSetVec3( tmp, ( i + offset - half_size ),
 146                             -half_size,
 147                             -( j + offset - half_size ) );
 148             sgNormalizeVec3( tmp );
 149             sgScaleVec3( tmp, 0.5f );
 150             sgAddVec3( tmp, zero_normal );
 151
 152             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 153             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 154             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 155         }
 156     }
 157     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 158                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 159
 160     ptr = data;
 161     for ( j = 0; j < size; j++ ) {
 162         for ( i = 0; i < size; i++ ) {
 163             sgVec3 tmp;
 164             sgSetVec3( tmp, ( i + offset - half_size ),
 165                             -( j + offset - half_size ),
 166                             half_size );
 167             sgNormalizeVec3( tmp );
 168             sgScaleVec3( tmp, 0.5f );
 169             sgAddVec3( tmp, zero_normal );
 170
 171             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 172             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 173             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 174         }
 175     }
 176     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 177                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 178
 179     ptr = data;
 180     for ( j = 0; j < size; j++ ) {
 181         for ( i = 0; i < size; i++ ) {
 182             sgVec3 tmp;
 183             sgSetVec3( tmp, -( i + offset - half_size ),
 184                             -( j + offset - half_size ),
 185                             -half_size );
 186             sgNormalizeVec3( tmp );
 187             sgScaleVec3( tmp, 0.5f );
 188             sgAddVec3( tmp, zero_normal );
 189
 190             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 191             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 192             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 193         }
 194     }
 195     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB,
 196                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 197 }
 198
 199
 200 // Constructor
 201 SGCloudLayer::SGCloudLayer( const string &tex_path ) :
 202     vertices(0),
 203     indices(0),
 204     layer_root(new ssgRoot),
 205     layer_transform(new ssgTransform),
 206     state_sel(0),
 207     cloud_alpha(1.0),
 208     texture_path(tex_path),
 209     layer_span(0.0),
 210     layer_asl(0.0),
 211     layer_thickness(0.0),
 212     layer_transition(0.0),
 213     layer_coverage(SG_CLOUD_CLEAR),
 214     scale(4000.0),
 215     speed(0.0),
 216     direction(0.0),
 217     last_lon(0.0),
 218     last_lat(0.0)
 219 {
 220     cl[0] = cl[1] = cl[2] = cl[3] = NULL;
 221     vl[0] = vl[1] = vl[2] = vl[3] = NULL;
 222     tl[0] = tl[1] = tl[2] = tl[3] = NULL;
 223     layer[0] = layer[1] = layer[2] = layer[3] = NULL;
 224
 225     layer_root->addKid(layer_transform);
 226         layer3D = new SGCloudField;
 227     rebuild();
 228 }
 229
 230 // Destructor
 231 SGCloudLayer::~SGCloudLayer()
 232 {
 233         delete layer3D;
 234     delete vertices;
 235     delete indices;
 236     delete layer_root;          // deletes layer_transform and layer as well
 237 }
 238
 239 float
 240 SGCloudLayer::getSpan_m () const
 241 {
 242     return layer_span;
 243 }
 244
 245 void
 246 SGCloudLayer::setSpan_m (float span_m)
 247 {
 248     if (span_m != layer_span) {
 249         layer_span = span_m;
 250         rebuild();
 251     }
 252 }
 253
 254 float
 255 SGCloudLayer::getElevation_m () const
 256 {
 257     return layer_asl;
 258 }
 259
 260 void
 261 SGCloudLayer::setElevation_m (float elevation_m, bool set_span)
 262 {
 263     layer_asl = elevation_m;
 264
 265     if (set_span) {
 266         if (elevation_m > 4000)
 267             setSpan_m(  elevation_m * 10 );
 268         else
 269             setSpan_m( 40000 );
 270     }
 271 }
 272
 273 float
 274 SGCloudLayer::getThickness_m () const
 275 {
 276     return layer_thickness;
 277 }
 278
 279 void
 280 SGCloudLayer::setThickness_m (float thickness_m)
 281 {
 282     layer_thickness = thickness_m;
 283 }
 284
 285 float
 286 SGCloudLayer::getTransition_m () const
 287 {
 288     return layer_transition;
 289 }
 290
 291 void
 292 SGCloudLayer::setTransition_m (float transition_m)
 293 {
 294     layer_transition = transition_m;
 295 }
 296
 297 SGCloudLayer::Coverage
 298 SGCloudLayer::getCoverage () const
 299 {
 300     return layer_coverage;
 301 }
 302
 303 void
 304 SGCloudLayer::setCoverage (Coverage coverage)
 305 {
 306     if (coverage != layer_coverage) {
 307         layer_coverage = coverage;
 308         rebuild();
 309     }
 310 }
 311
 312
 313 // build the cloud object
 314 void
 315 SGCloudLayer::rebuild()
 316 {
 317     // Initialize states and sizes if necessary.
 318     if ( !state_initialized ) {
 319         state_initialized = true;
 320
 321         SG_LOG(SG_ASTRO, SG_INFO, "initializing cloud layers");
 322
 323         bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
 324                        SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
 325                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
 326                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") &&
 327                        SGIsOpenGLExtensionSupported("GL_ARB_imaging");
 328
 329         if ( bump_mapping ) {
 330             glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
 331             if ( nb_texture_unit < 2 ) {
 332                 bump_mapping = false;
 333             }
 334             //nb_texture_unit = 2; // Force the number of units for now
 335         }
 336
 337         if ( bump_mapping ) {
 338
 339             // This bump mapping code was inspired by the tutorial available at
 340             // http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
 341             // and a NVidia white paper
 342             //  http://developer.nvidia.com/object/bumpmappingwithregistercombiners.html
 343             // The normal map textures were generated by the normal map Gimp plugin :
 344             //  http://nifelheim.dyndns.org/~cocidius/normalmap/
 345             //
 346             SGPath cloud_path;
 347
 348             glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
 349             glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
 350             glBlendColorPtr = (glBlendColorProc)SGLookupFunction("glBlendColor");
 351
 352             cloud_path.set(texture_path.str());
 353             cloud_path.append("overcast.rgb");
 354             color_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 355             color_map[ SG_CLOUD_OVERCAST ][ 0 ]->ref();
 356             cloud_path.set(texture_path.str());
 357             cloud_path.append("overcast_n.rgb");
 358             normal_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 359             normal_map[ SG_CLOUD_OVERCAST ][ 0 ]->ref();
 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             color_map[ SG_CLOUD_OVERCAST ][ 1 ]->ref();
 365             cloud_path.set(texture_path.str());
 366             cloud_path.append("overcast_top_n.rgb");
 367             normal_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 368             normal_map[ SG_CLOUD_OVERCAST ][ 1 ]->ref();
 369
 370             cloud_path.set(texture_path.str());
 371             cloud_path.append("broken.rgba");
 372             color_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 373             color_map[ SG_CLOUD_BROKEN ][ 0 ]->ref();
 374             cloud_path.set(texture_path.str());
 375             cloud_path.append("broken_n.rgb");
 376             normal_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 377             normal_map[ SG_CLOUD_BROKEN ][ 0 ]->ref();
 378
 379             cloud_path.set(texture_path.str());
 380             cloud_path.append("scattered.rgba");
 381             color_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 382             color_map[ SG_CLOUD_SCATTERED ][ 0 ]->ref();
 383             cloud_path.set(texture_path.str());
 384             cloud_path.append("scattered_n.rgb");
 385             normal_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 386             normal_map[ SG_CLOUD_SCATTERED ][ 0 ]->ref();
 387
 388             cloud_path.set(texture_path.str());
 389             cloud_path.append("few.rgba");
 390             color_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 391             color_map[ SG_CLOUD_FEW ][ 0 ]->ref();
 392             cloud_path.set(texture_path.str());
 393             cloud_path.append("few_n.rgb");
 394             normal_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 395             normal_map[ SG_CLOUD_FEW ][ 0 ]->ref();
 396
 397             cloud_path.set(texture_path.str());
 398             cloud_path.append("cirrus.rgba");
 399             color_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 400             color_map[ SG_CLOUD_CIRRUS ][ 0 ]->ref();
 401             cloud_path.set(texture_path.str());
 402             cloud_path.append("cirrus_n.rgb");
 403             normal_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 404             normal_map[ SG_CLOUD_CIRRUS ][ 0 ]->ref();
 405
 406             glGenTextures( 1, &normalization_cube_map );
 407             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 408             generateNormalizationCubeMap();
 409             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 410             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 411             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 412             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 413             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE );
 414         } /* else */ {
 415             SGPath cloud_path;
 416             ssgStateSelector *state_sel;
 417             ssgSimpleState *state;
 418
 419             state_sel = new ssgStateSelector( 2 );
 420             state_sel->ref();
 421             cloud_path.set(texture_path.str());
 422             cloud_path.append("overcast.rgb");
 423             state_sel->setStep( 0, sgCloudMakeState(cloud_path.str()) );
 424             cloud_path.set(texture_path.str());
 425             cloud_path.append("overcast_top.rgb");
 426             state_sel->setStep( 1, sgCloudMakeState(cloud_path.str()) );
 427             layer_states[SG_CLOUD_OVERCAST] = state_sel;
 428
 429             state_sel = new ssgStateSelector( 2 );
 430             state_sel->ref();
 431             cloud_path.set(texture_path.str());
 432             cloud_path.append("broken.rgba");
 433             state = sgCloudMakeState(cloud_path.str());
 434             state_sel->setStep( 0, state );
 435             state_sel->setStep( 1, state );
 436             layer_states[SG_CLOUD_BROKEN] = state_sel;
 437
 438             state_sel = new ssgStateSelector( 2 );
 439             state_sel->ref();
 440             cloud_path.set(texture_path.str());
 441             cloud_path.append("scattered.rgba");
 442             state = sgCloudMakeState(cloud_path.str());
 443             state_sel->setStep( 0, state );
 444             state_sel->setStep( 1, state );
 445             layer_states[SG_CLOUD_SCATTERED] = state_sel;
 446
 447             state_sel = new ssgStateSelector( 2 );
 448             state_sel->ref();
 449             cloud_path.set(texture_path.str());
 450             cloud_path.append("few.rgba");
 451             state = sgCloudMakeState(cloud_path.str());
 452             state_sel->setStep( 0, state );
 453             state_sel->setStep( 1, state );
 454             layer_states[SG_CLOUD_FEW] = state_sel;
 455
 456             state_sel = new ssgStateSelector( 2 );
 457             state_sel->ref();
 458             cloud_path.set(texture_path.str());
 459             cloud_path.append("cirrus.rgba");
 460             state = sgCloudMakeState(cloud_path.str());
 461             state_sel->setStep( 0, state );
 462             state_sel->setStep( 1, state );
 463             layer_states[SG_CLOUD_CIRRUS] = state_sel;
 464
 465             layer_states[SG_CLOUD_CLEAR] = 0;
 466         }
 467                 SGNewCloud::loadTextures(texture_path.str());
 468                 layer3D->buildTestLayer();
 469     }
 470
 471     if ( bump_mapping ) {
 472
 473         if ( !vertices ) {
 474             vertices = new CloudVertex[ 25 ];
 475             indices = new unsigned int[ 40 ];
 476         }
 477
 478         sgVec2 base;
 479         sgSetVec2( base, sg_random(), sg_random() );
 480
 481         const float layer_scale = layer_span / scale;
 482         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 483         const float half_angle = 0.5 * layer_span / layer_to_core;
 484
 485         int i;
 486         for ( i = -2; i <= 2; i++ ) {
 487             for ( int j = -2; j <= 2; j++ ) {
 488                 CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 489                 sgSetVec3( v1.position,
 490                            0.5 * i * layer_span,
 491                            0.5 * j * layer_span,
 492                            -layer_to_core * ( 1 - cos( i * half_angle ) * cos( j * half_angle ) ) );
 493                 sgSetVec2( v1.texCoord,
 494                            base[0] + layer_scale * i * 0.25,
 495                            base[1] + layer_scale * j * 0.25 );
 496                 sgSetVec3( v1.sTangent,
 497                            cos( i * half_angle ),
 498                            0.f,
 499                            -sin( i * half_angle ) );
 500                 sgSetVec3( v1.tTangent,
 501                            0.f,
 502                            cos( j * half_angle ),
 503                            -sin( j * half_angle ) );
 504                 sgVectorProductVec3( v1.normal, v1.tTangent, v1.sTangent );
 505                 sgSetVec4( v1.color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : cloud_alpha * 0.15f );
 506             }
 507         }
 508         /*
 509          * 0 1 5 6 10 11 15 16 20 21
 510          * 1 2 6 7 11 12 16 17 21 22
 511          * 2 3 7 8 12 13 17 18 22 23
 512          * 3 4 8 9 13 14 18 19 23 24
 513          */
 514         for ( i = 0; i < 4; i++ ) {
 515             for ( int j = 0; j < 5; j++ ) {
 516                 indices[ i*10 + (j*2) ]     =     i + 5 * j;
 517                 indices[ i*10 + (j*2) + 1 ] = 1 + i + 5 * j;
 518             }
 519         }
 520
 521     } /* else */ {
 522
 523         scale = 4000.0;
 524         last_lon = last_lat = -999.0f;
 525
 526         sgVec2 base;
 527         sgSetVec2( base, sg_random(), sg_random() );
 528
 529         // build the cloud layer
 530         sgVec4 color;
 531         sgVec3 vertex;
 532         sgVec2 tc;
 533
 534         const float layer_scale = layer_span / scale;
 535         const float mpi = SG_PI/4;
 536
 537         // caclculate the difference between a flat-earth model and
 538         // a round earth model given the span and altutude ASL of
 539         // the cloud layer. This is the difference in altitude between
 540         // the top of the inverted bowl and the edge of the bowl.
 541         // const float alt_diff = layer_asl * 0.8;
 542         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 543         const float layer_angle = 0.5*layer_span / layer_to_core; // The angle is half the span
 544         const float border_to_core = layer_to_core * cos(layer_angle);
 545         const float alt_diff = layer_to_core - border_to_core;
 546
 547         for (int i = 0; i < 4; i++)
 548         {
 549             if ( layer[i] != NULL ) {
 550                 layer_transform->removeKid(layer[i]); // automatic delete
 551             }
 552
 553             vl[i] = new ssgVertexArray( 10 );
 554             cl[i] = new ssgColourArray( 10 );
 555             tl[i] = new ssgTexCoordArray( 10 );
 556
 557
 558             sgSetVec3( vertex, layer_span*(i-2)/2, -layer_span,
 559                             alt_diff * (sin(i*mpi) - 2) );
 560
 561             sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 562
 563             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 564
 565             cl[i]->add( color );
 566             vl[i]->add( vertex );
 567             tl[i]->add( tc );
 568
 569             for (int j = 0; j < 4; j++)
 570             {
 571                 sgSetVec3( vertex, layer_span*(i-1)/2, layer_span*(j-2)/2,
 572                                 alt_diff * (sin((i+1)*mpi) + sin(j*mpi) - 2) );
 573
 574                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 575                             base[1] + layer_scale * j/4 );
 576
 577                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 578                                 ( (j == 0) || (i == 3)) ?
 579                                 ( (j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f );
 580
 581                 cl[i]->add( color );
 582                 vl[i]->add( vertex );
 583                 tl[i]->add( tc );
 584
 585
 586                 sgSetVec3( vertex, layer_span*(i-2)/2, layer_span*(j-1)/2,
 587                                 alt_diff * (sin(i*mpi) + sin((j+1)*mpi) - 2) );
 588
 589                 sgSetVec2( tc, base[0] + layer_scale * i/4,
 590                             base[1] + layer_scale * (j+1)/4 );
 591
 592                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 593                                 ((j == 3) || (i == 0)) ?
 594                                 ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f );
 595                 cl[i]->add( color );
 596                 vl[i]->add( vertex );
 597                 tl[i]->add( tc );
 598             }
 599
 600             sgSetVec3( vertex, layer_span*(i-1)/2, layer_span,
 601                             alt_diff * (sin((i+1)*mpi) - 2) );
 602
 603             sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 604                         base[1] + layer_scale );
 605
 606             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 3) ? 0.0f : 0.15f );
 607
 608             cl[i]->add( color );
 609             vl[i]->add( vertex );
 610             tl[i]->add( tc );
 611
 612             layer[i] = new ssgVtxTable(GL_TRIANGLE_STRIP, vl[i], NULL, tl[i], cl[i]);
 613             layer_transform->addKid( layer[i] );
 614
 615             if ( layer_states[layer_coverage] != NULL ) {
 616                 layer[i]->setState( layer_states[layer_coverage] );
 617             }
 618             state_sel = layer_states[layer_coverage];
 619         }
 620
 621         // force a repaint of the sky colors with arbitrary defaults
 622         repaint( color );
 623     }
 624 }
 625
 626
 627 // repaint the cloud layer colors
 628 bool SGCloudLayer::repaint( sgVec3 fog_color ) {
 629
 630     if ( bump_mapping && enable_bump_mapping ) {
 631
 632         for ( int i = 0; i < 25; i++ ) {
 633             sgCopyVec3( vertices[ i ].color, fog_color );
 634         }
 635
 636     } else {
 637         float *color;
 638
 639         for ( int i = 0; i < 4; i++ ) {
 640             color = cl[i]->get( 0 );
 641             sgCopyVec3( color, fog_color );
 642             color[3] = (i == 0) ? 0.0f : cloud_alpha * 0.15f;
 643
 644             for ( int j = 0; j < 4; ++j ) {
 645                 color = cl[i]->get( (2*j) + 1 );
 646                 sgCopyVec3( color, fog_color );
 647                 color[3] =
 648                     ((j == 0) || (i == 3)) ?
 649                     ((j == 0) && (i == 3)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 650
 651                 color = cl[i]->get( (2*j) + 2 );
 652                 sgCopyVec3( color, fog_color );
 653                 color[3] =
 654                     ((j == 3) || (i == 0)) ?
 655                     ((j == 3) && (i == 0)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 656             }
 657
 658             color = cl[i]->get( 9 );
 659             sgCopyVec3( color, fog_color );
 660             color[3] = (i == 3) ? 0.0f : cloud_alpha * 0.15f;
 661         }
 662     }
 663
 664     return true;
 665 }
 666
 667 // reposition the cloud layer at the specified origin and orientation
 668 // lon specifies a rotation about the Z axis
 669 // lat specifies a rotation about the new Y axis
 670 // spin specifies a rotation about the new Z axis (and orients the
 671 // sunrise/set effects
 672 bool SGCloudLayer::reposition( sgVec3 p, sgVec3 up, double lon, double lat,
 673                                double alt, double dt )
 674 {
 675     sgMat4 T1, LON, LAT;
 676     sgVec3 axis;
 677
 678     // combine p and asl (meters) to get translation offset
 679     sgVec3 asl_offset;
 680     sgCopyVec3( asl_offset, up );
 681     sgNormalizeVec3( asl_offset );
 682     if ( alt <= layer_asl ) {
 683         sgScaleVec3( asl_offset, layer_asl );
 684     } else {
 685         sgScaleVec3( asl_offset, layer_asl + layer_thickness );
 686     }
 687     // cout << "asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 688     //      << "," << asl_offset[2] << endl;
 689     sgAddVec3( asl_offset, p );
 690     // cout << "  asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 691     //      << "," << asl_offset[2] << endl;
 692
 693     // Translate to zero elevation
 694     // Point3D zero_elev = current_view.get_cur_zero_elev();
 695     sgMakeTransMat4( T1, asl_offset );
 696
 697     // printf("  Translated to %.2f %.2f %.2f\n",
 698     //        zero_elev.x, zero_elev.y, zero_elev.z );
 699
 700     // Rotate to proper orientation
 701     // printf("  lon = %.2f  lat = %.2f\n",
 702     //        lon * SGD_RADIANS_TO_DEGREES,
 703     //        lat * SGD_RADIANS_TO_DEGREES);
 704     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 705     sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );
 706
 707     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 708     sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );
 709
 710     sgMat4 TRANSFORM;
 711
 712     sgCopyMat4( TRANSFORM, T1 );
 713     sgPreMultMat4( TRANSFORM, LON );
 714     sgPreMultMat4( TRANSFORM, LAT );
 715
 716     sgCoord layerpos;
 717     sgSetCoord( &layerpos, TRANSFORM );
 718
 719     layer_transform->setTransform( &layerpos );
 720
 721     // now calculate update texture coordinates
 722     if ( last_lon < -900 ) {
 723         last_lon = lon;
 724         last_lat = lat;
 725     }
 726
 727     double sp_dist = speed*dt;
 728
 729     if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
 730         Point3D start( last_lon, last_lat, 0.0 );
 731         Point3D dest( lon, lat, 0.0 );
 732         double course = 0.0, dist = 0.0;
 733
 734         calc_gc_course_dist( dest, start, &course, &dist );
 735         // cout << "course = " << course << ", dist = " << dist << endl;
 736
 737         // if start and dest are too close together,
 738         // calc_gc_course_dist() can return a course of "nan".  If
 739         // this happens, lets just use the last known good course.
 740         // This is a hack, and it would probably be better to make
 741         // calc_gc_course_dist() more robust.
 742         if ( isnan(course) ) {
 743             course = last_course;
 744         } else {
 745             last_course = course;
 746         }
 747
 748         // calculate cloud movement due to external forces
 749         double ax = 0.0, ay = 0.0, bx = 0.0, by = 0.0;
 750
 751         if (dist > 0.0) {
 752             ax = cos(course) * dist;
 753             ay = sin(course) * dist;
 754         }
 755
 756         if (sp_dist > 0) {
 757             bx = cos((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 758             by = sin((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 759         }
 760
 761
 762         double xoff = (ax + bx) / (2 * scale);
 763         double yoff = (ay + by) / (2 * scale);
 764
 765         const float layer_scale = layer_span / scale;
 766
 767         // cout << "xoff = " << xoff << ", yoff = " << yoff << endl;
 768
 769         float *base;
 770         if ( bump_mapping && enable_bump_mapping ) {
 771             base = vertices[12].texCoord;
 772         } else {
 773             base = tl[0]->get( 0 );
 774         }
 775         base[0] += xoff;
 776
 777         // the while loops can lead to *long* pauses if base[0] comes
 778         // with a bogus value.
 779         // while ( base[0] > 1.0 ) { base[0] -= 1.0; }
 780         // while ( base[0] < 0.0 ) { base[0] += 1.0; }
 781         if ( base[0] > -10.0 && base[0] < 10.0 ) {
 782             base[0] -= (int)base[0];
 783         } else {
 784             SG_LOG(SG_ASTRO, SG_DEBUG,
 785                 "Error: base = " << base[0] << "," << base[1] <<
 786                 " course = " << course << " dist = " << dist );
 787             base[0] = 0.0;
 788         }
 789
 790         base[1] += yoff;
 791         // the while loops can lead to *long* pauses if base[0] comes
 792         // with a bogus value.
 793         // while ( base[1] > 1.0 ) { base[1] -= 1.0; }
 794         // while ( base[1] < 0.0 ) { base[1] += 1.0; }
 795         if ( base[1] > -10.0 && base[1] < 10.0 ) {
 796             base[1] -= (int)base[1];
 797         } else {
 798             SG_LOG(SG_ASTRO, SG_ALERT,
 799                     "Error: base = " << base[0] << "," << base[1] <<
 800                     " course = " << course << " dist = " << dist );
 801             base[1] = 0.0;
 802         }
 803
 804         if ( bump_mapping && enable_bump_mapping ) {
 805
 806             for ( int i = -2; i <= 2; i++ ) {
 807                 for ( int j = -2; j <= 2; j++ ) {
 808                     if ( i == 0 && j == 0 )
 809                         continue; // Already done on base
 810                     CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 811                     sgSetVec2( v1.texCoord,
 812                             base[0] + layer_scale * i * 0.25,
 813                             base[1] + layer_scale * j * 0.25 );
 814                 }
 815             }
 816
 817         } else {
 818                 // cout << "base = " << base[0] << "," << base[1] << endl;
 819
 820             float *tc;
 821             for (int i = 0; i < 4; i++) {
 822                 tc = tl[i]->get( 0 );
 823                 sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 824
 825                 for (int j = 0; j < 4; j++)
 826                 {
 827                     tc = tl[i]->get( j*2+1 );
 828                     sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 829                                 base[1] + layer_scale * j/4 );
 830
 831                     tc = tl[i]->get( (j+1)*2 );
 832                     sgSetVec2( tc, base[0] + layer_scale * i/4,
 833                                 base[1] + layer_scale * (j+1)/4 );
 834                 }
 835
 836                 tc = tl[i]->get( 9 );
 837                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 838                             base[1] + layer_scale );
 839             }
 840         }
 841
 842         last_lon = lon;
 843         last_lat = lat;
 844     }
 845
 846         layer3D->reposition( p, up, lon, lat, alt, dt, direction, speed);
 847     return true;
 848 }
 849
 850
 851 void SGCloudLayer::draw( bool top ) {
 852     if ( layer_coverage != SG_CLOUD_CLEAR ) {
 853
 854                 if ( SGCloudField::enable3D && layer3D->is3D())
 855                         layer3D->Render();
 856                 else
 857         if ( bump_mapping && enable_bump_mapping ) {
 858
 859             sgMat4 modelview,
 860                    tmp,
 861                    transform;
 862             ssgGetModelviewMatrix( modelview );
 863             layer_transform->getTransform( transform );
 864
 865             sgTransposeNegateMat4( tmp, transform );
 866
 867             sgPostMultMat4( transform, modelview );
 868             ssgLoadModelviewMatrix( transform );
 869
 870             sgVec3 lightVec;
 871             ssgGetLight( 0 )->getPosition( lightVec );
 872             sgNegateVec3( lightVec );
 873             sgXformVec3( lightVec, tmp );
 874
 875             for ( int i = 0; i < 25; i++ ) {
 876                 CloudVertex &v = vertices[ i ];
 877                 sgSetVec3( v.tangentSpLight,
 878                            sgScalarProductVec3( v.sTangent, lightVec ),
 879                            sgScalarProductVec3( v.tTangent, lightVec ),
 880                            sgScalarProductVec3( v.normal, lightVec ) );
 881             }
 882
 883             ssgTexture *decal = color_map[ layer_coverage ][ top ? 1 : 0 ];
 884             if ( top && decal == 0 ) {
 885                 decal = color_map[ layer_coverage ][ 0 ];
 886             }
 887             ssgTexture *normal = normal_map[ layer_coverage ][ top ? 1 : 0 ];
 888             if ( top && normal == 0 ) {
 889                 normal = normal_map[ layer_coverage ][ 0 ];
 890             }
 891
 892             glDisable( GL_LIGHTING );
 893             glDisable( GL_CULL_FACE );
 894 //            glDisable( GL_ALPHA_TEST );
 895             if ( layer_coverage == SG_CLOUD_FEW ) {
 896                 glEnable( GL_ALPHA_TEST );
 897                 glAlphaFunc ( GL_GREATER, 0.01 );
 898             }
 899             glEnable( GL_BLEND );
 900             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 901
 902             glShadeModel( GL_SMOOTH );
 903             glEnable( GL_COLOR_MATERIAL );
 904             sgVec4 color;
 905             float emis = 0.05;
 906             if ( 1 ) {
 907                 ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
 908                 emis = ( color[0]+color[1]+color[2] ) / 3.0;
 909                 if ( emis < 0.05 )
 910                     emis = 0.05;
 911             }
 912             sgSetVec4( color, emis, emis, emis, 0.0 );
 913             glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, color );
 914             sgSetVec4( color, 1.0f, 1.0f, 1.0f, 0.0 );
 915             glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, color );
 916             sgSetVec4( color, 1.0, 1.0, 1.0, 0.0 );
 917             glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, color );
 918             sgSetVec4( color, 0.0, 0.0, 0.0, 0.0 );
 919             glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, color );
 920
 921             glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
 922
 923             glActiveTexturePtr( GL_TEXTURE0_ARB );
 924             glBindTexture( GL_TEXTURE_2D, normal->getHandle() );
 925             glEnable( GL_TEXTURE_2D );
 926
 927             //Bind normalisation cube map to texture unit 1
 928             glActiveTexturePtr( GL_TEXTURE1_ARB );
 929             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 930             glEnable( GL_TEXTURE_CUBE_MAP_ARB );
 931             glActiveTexturePtr( GL_TEXTURE0_ARB );
 932
 933             //Set vertex arrays for cloud
 934             glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
 935             glEnableClientState( GL_VERTEX_ARRAY );
 936 /*
 937             if ( nb_texture_unit >= 3 ) {
 938                 glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
 939                 glEnableClientState( GL_COLOR_ARRAY );
 940             }
 941 */
 942             //Send texture coords for normal map to unit 0
 943             glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 944             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 945
 946             //Send tangent space light vectors for normalisation to unit 1
 947             glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 948             glTexCoordPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].tangentSpLight );
 949             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 950
 951             //Set up texture environment to do (tex0 dot tex1)*color
 952             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 953             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 954             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE );
 955             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE );
 956             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 957
 958             glActiveTexturePtr( GL_TEXTURE1_ARB );
 959
 960             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 961             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 962             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_DOT3_RGB_ARB );
 963             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 964             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB );
 965             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 966
 967             if ( nb_texture_unit >= 3 ) {
 968                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 969                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 970
 971                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 972                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 973                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 974
 975                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 976                 glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD );
 977                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 978                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 979
 980                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 981                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 982
 983                 //Draw cloud layer
 984                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 985                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 986                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 987                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 988
 989                 glDisable( GL_TEXTURE_2D );
 990                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 991                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 992                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 993                 glDisable( GL_TEXTURE_2D );
 994                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 995
 996                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 997                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 998                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 999                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
1000                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1001                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1002
1003                 glDisableClientState( GL_COLOR_ARRAY );
1004                 glEnable( GL_LIGHTING );
1005
1006                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1007
1008             } else {
1009                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1010                 glActiveTexturePtr( GL_TEXTURE0_ARB );
1011
1012                 //Draw cloud layer
1013                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1014                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1015                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1016                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1017
1018                 //Disable textures
1019                 glDisable( GL_TEXTURE_2D );
1020
1021                 glActiveTexturePtr( GL_TEXTURE1_ARB );
1022                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
1023                 glActiveTexturePtr( GL_TEXTURE0_ARB );
1024
1025                 //disable vertex arrays
1026                 glDisableClientState( GL_VERTEX_ARRAY );
1027
1028                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1029                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
1030                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1031                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1032
1033                 //Return to standard modulate texenv
1034                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1035
1036                 if ( layer_coverage == SG_CLOUD_OVERCAST ) {
1037                     glDepthFunc(GL_LEQUAL);
1038
1039                     glEnable( GL_LIGHTING );
1040                     sgVec4 color;
1041                     ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
1042                     float average = ( color[0] + color[1] + color[2] ) / 3.0f;
1043                     average = 0.15 + average/10;
1044                     sgVec4 averageColor;
1045                     sgSetVec4( averageColor, average, average, average, 1.0f );
1046                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, averageColor );
1047
1048                     glBlendColorPtr( average, average, average, 1.0f );
1049                     glBlendFunc( GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_COLOR );
1050
1051                     //Perform a second pass to color the torus
1052                     //Bind decal texture
1053                     glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
1054                     glEnable(GL_TEXTURE_2D);
1055
1056                     //Set vertex arrays for torus
1057                     glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
1058                     glEnableClientState( GL_VERTEX_ARRAY );
1059
1060                     //glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
1061                     //glEnableClientState( GL_COLOR_ARRAY );
1062
1063                     glNormalPointer( GL_FLOAT, sizeof(CloudVertex), &vertices[0].normal );
1064                     glEnableClientState( GL_NORMAL_ARRAY );
1065
1066                     glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
1067                     glEnableClientState( GL_TEXTURE_COORD_ARRAY );
1068
1069                     //Draw cloud layer
1070                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1071                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1072                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1073                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1074
1075                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, color );
1076
1077                     glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1078                 }
1079             }
1080             //Disable texture
1081             glDisable( GL_TEXTURE_2D );
1082
1083             glDisableClientState( GL_VERTEX_ARRAY );
1084             glDisableClientState( GL_NORMAL_ARRAY );
1085
1086             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
1087             glEnable( GL_CULL_FACE );
1088             glDepthFunc(GL_LESS);
1089
1090             ssgLoadModelviewMatrix( modelview );
1091
1092         } else {
1093             state_sel->selectStep( top ? 1 : 0 );
1094             ssgCullAndDraw( layer_root );
1095         }
1096     }
1097 }
1098
1099
1100 // make an ssgSimpleState for a cloud layer given the named texture
1101 ssgSimpleState *sgCloudMakeState( const string &path ) {
1102     ssgSimpleState *state = new ssgSimpleState();
1103
1104     SG_LOG(SG_ASTRO, SG_INFO, " texture = ");
1105
1106     state->setTexture( (char *)path.c_str() );
1107     state->setShadeModel( GL_SMOOTH );
1108     state->disable( GL_LIGHTING );
1109     state->disable( GL_CULL_FACE );
1110     state->enable( GL_TEXTURE_2D );
1111     state->enable( GL_COLOR_MATERIAL );
1112     state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
1113     state->setMaterial( GL_EMISSION, 0.05, 0.05, 0.05, 0.0 );
1114     state->setMaterial( GL_AMBIENT, 0.2, 0.2, 0.2, 0.0 );
1115     state->setMaterial( GL_DIFFUSE, 0.5, 0.5, 0.5, 0.0 );
1116     state->setMaterial( GL_SPECULAR, 0.0, 0.0, 0.0, 0.0 );
1117     state->enable( GL_BLEND );
1118     state->enable( GL_ALPHA_TEST );
1119     state->setAlphaClamp( 0.01 );
1120
1121     return state;
1122 }