simgear/scene/sky/cloud.cxx

   1 // cloud.cxx -- model a single cloud layer
   2 //
   3 // Written by Curtis Olson, started June 2000.
   4 //
   5 // Copyright (C) 2000  Curtis L. Olson  - http://www.flightgear.org/~curt
   6 //
   7 // This library is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU Library General Public
   9 // License as published by the Free Software Foundation; either
  10 // version 2 of the License, or (at your option) any later version.
  11 //
  12 // This library is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  20 //
  21 // $Id$
  22
  23 #ifdef HAVE_CONFIG_H
  24 #  include <simgear_config.h>
  25 #endif
  26
  27 #include <simgear/compiler.h>
  28
  29 // #include <stdio.h>
  30 #include <math.h>
  31
  32 #include <plib/sg.h>
  33 #include <plib/ssg.h>
  34
  35 #include <simgear/math/point3d.hxx>
  36 #include <simgear/math/polar3d.hxx>
  37 #include <simgear/math/sg_random.h>
  38 #include <simgear/debug/logstream.hxx>
  39 #include <simgear/screen/extensions.hxx>
  40 #include <simgear/screen/texture.hxx>
  41 #include <simgear/structure/ssgSharedPtr.hxx>
  42
  43 #include "newcloud.hxx"
  44 #include "cloudfield.hxx"
  45 #include "cloud.hxx"
  46
  47 #if defined(__MINGW32__)
  48 #define isnan(x) _isnan(x)
  49 #endif
  50
  51 #if defined (__FreeBSD__)
  52 #  if __FreeBSD_version < 500000
  53      extern "C" {
  54        inline int isnan(double r) { return !(r <= 0 || r >= 0); }
  55      }
  56 #  endif
  57 #endif
  58
  59 #if defined (__CYGWIN__)
  60 #include <ieeefp.h>
  61 #endif
  62
  63 static ssgSharedPtr<ssgStateSelector> layer_states[SGCloudLayer::SG_MAX_CLOUD_COVERAGES];
  64 static bool state_initialized = false;
  65 static bool bump_mapping = false;
  66 static GLint nb_texture_unit = 0;
  67 static ssgSharedPtr<ssgTexture> normal_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  68 static ssgSharedPtr<ssgTexture> color_map[SGCloudLayer::SG_MAX_CLOUD_COVERAGES][2];
  69 static GLuint normalization_cube_map;
  70
  71 static glActiveTextureProc glActiveTexturePtr = 0;
  72 static glClientActiveTextureProc glClientActiveTexturePtr = 0;
  73 static glBlendColorProc glBlendColorPtr = 0;
  74
  75 bool SGCloudLayer::enable_bump_mapping = false;
  76
  77 static void
  78 generateNormalizationCubeMap()
  79 {
  80     unsigned char data[ 32 * 32 * 3 ];
  81     const int size = 32;
  82     const float half_size = 16.0f,
  83                 offset = 0.5f;
  84     sgVec3 zero_normal;
  85     sgSetVec3( zero_normal, 0.5f, 0.5f, 0.5f );
  86     int i, j;
  87
  88     unsigned char *ptr = data;
  89     for ( j = 0; j < size; j++ ) {
  90         for ( i = 0; i < size; i++ ) {
  91             sgVec3 tmp;
  92             sgSetVec3( tmp, half_size,
  93                             -( j + offset - half_size ),
  94                             -( i + offset - half_size ) );
  95             sgNormalizeVec3( tmp );
  96             sgScaleVec3( tmp, 0.5f );
  97             sgAddVec3( tmp, zero_normal );
  98
  99             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 100             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 101             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 102         }
 103     }
 104     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_X_ARB,
 105                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 106
 107     ptr = data;
 108     for ( j = 0; j < size; j++ ) {
 109         for ( i = 0; i < size; i++ ) {
 110             sgVec3 tmp;
 111             sgSetVec3( tmp, -half_size,
 112                             -( j + offset - half_size ),
 113                             ( i + offset - half_size ) );
 114             sgNormalizeVec3( tmp );
 115             sgScaleVec3( tmp, 0.5f );
 116             sgAddVec3( tmp, zero_normal );
 117
 118             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 119             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 120             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 121         }
 122     }
 123     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_X_ARB,
 124                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 125
 126     ptr = data;
 127     for ( j = 0; j < size; j++ ) {
 128         for ( i = 0; i < size; i++ ) {
 129             sgVec3 tmp;
 130             sgSetVec3( tmp, ( i + offset - half_size ),
 131                             half_size,
 132                             ( j + offset - half_size ) );
 133             sgNormalizeVec3( tmp );
 134             sgScaleVec3( tmp, 0.5f );
 135             sgAddVec3( tmp, zero_normal );
 136
 137             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 138             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 139             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 140         }
 141     }
 142     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Y_ARB,
 143                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 144
 145     ptr = data;
 146     for ( j = 0; j < size; j++ ) {
 147         for ( i = 0; i < size; i++ ) {
 148             sgVec3 tmp;
 149             sgSetVec3( tmp, ( i + offset - half_size ),
 150                             -half_size,
 151                             -( j + offset - half_size ) );
 152             sgNormalizeVec3( tmp );
 153             sgScaleVec3( tmp, 0.5f );
 154             sgAddVec3( tmp, zero_normal );
 155
 156             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 157             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 158             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 159         }
 160     }
 161     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Y_ARB,
 162                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 163
 164     ptr = data;
 165     for ( j = 0; j < size; j++ ) {
 166         for ( i = 0; i < size; i++ ) {
 167             sgVec3 tmp;
 168             sgSetVec3( tmp, ( i + offset - half_size ),
 169                             -( j + offset - half_size ),
 170                             half_size );
 171             sgNormalizeVec3( tmp );
 172             sgScaleVec3( tmp, 0.5f );
 173             sgAddVec3( tmp, zero_normal );
 174
 175             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 176             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 177             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 178         }
 179     }
 180     glTexImage2D( GL_TEXTURE_CUBE_MAP_POSITIVE_Z_ARB,
 181                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 182
 183     ptr = data;
 184     for ( j = 0; j < size; j++ ) {
 185         for ( i = 0; i < size; i++ ) {
 186             sgVec3 tmp;
 187             sgSetVec3( tmp, -( i + offset - half_size ),
 188                             -( j + offset - half_size ),
 189                             -half_size );
 190             sgNormalizeVec3( tmp );
 191             sgScaleVec3( tmp, 0.5f );
 192             sgAddVec3( tmp, zero_normal );
 193
 194             *ptr++ = (unsigned char)( tmp[ 0 ] * 255 );
 195             *ptr++ = (unsigned char)( tmp[ 1 ] * 255 );
 196             *ptr++ = (unsigned char)( tmp[ 2 ] * 255 );
 197         }
 198     }
 199     glTexImage2D( GL_TEXTURE_CUBE_MAP_NEGATIVE_Z_ARB,
 200                   0, GL_RGBA8, 32, 32, 0, GL_RGB, GL_UNSIGNED_BYTE, data );
 201 }
 202
 203
 204 // Constructor
 205 SGCloudLayer::SGCloudLayer( const string &tex_path ) :
 206     vertices(0),
 207     indices(0),
 208     layer_root(new ssgRoot),
 209     layer_transform(new ssgTransform),
 210     state_sel(0),
 211     cloud_alpha(1.0),
 212     texture_path(tex_path),
 213     layer_span(0.0),
 214     layer_asl(0.0),
 215     layer_thickness(0.0),
 216     layer_transition(0.0),
 217     layer_coverage(SG_CLOUD_CLEAR),
 218     scale(4000.0),
 219     speed(0.0),
 220     direction(0.0),
 221     last_lon(0.0),
 222     last_lat(0.0)
 223 {
 224     cl[0] = cl[1] = cl[2] = cl[3] = NULL;
 225     vl[0] = vl[1] = vl[2] = vl[3] = NULL;
 226     tl[0] = tl[1] = tl[2] = tl[3] = NULL;
 227     layer[0] = layer[1] = layer[2] = layer[3] = NULL;
 228
 229     layer_root->addKid(layer_transform);
 230         layer3D = new SGCloudField;
 231     rebuild();
 232 }
 233
 234 // Destructor
 235 SGCloudLayer::~SGCloudLayer()
 236 {
 237         delete layer3D;
 238     delete vertices;
 239     delete indices;
 240     delete layer_root;          // deletes layer_transform and layer as well
 241 }
 242
 243 float
 244 SGCloudLayer::getSpan_m () const
 245 {
 246     return layer_span;
 247 }
 248
 249 void
 250 SGCloudLayer::setSpan_m (float span_m)
 251 {
 252     if (span_m != layer_span) {
 253         layer_span = span_m;
 254         rebuild();
 255     }
 256 }
 257
 258 float
 259 SGCloudLayer::getElevation_m () const
 260 {
 261     return layer_asl;
 262 }
 263
 264 void
 265 SGCloudLayer::setElevation_m (float elevation_m, bool set_span)
 266 {
 267     layer_asl = elevation_m;
 268
 269     if (set_span) {
 270         if (elevation_m > 4000)
 271             setSpan_m(  elevation_m * 10 );
 272         else
 273             setSpan_m( 40000 );
 274     }
 275 }
 276
 277 float
 278 SGCloudLayer::getThickness_m () const
 279 {
 280     return layer_thickness;
 281 }
 282
 283 void
 284 SGCloudLayer::setThickness_m (float thickness_m)
 285 {
 286     layer_thickness = thickness_m;
 287 }
 288
 289 float
 290 SGCloudLayer::getTransition_m () const
 291 {
 292     return layer_transition;
 293 }
 294
 295 void
 296 SGCloudLayer::setTransition_m (float transition_m)
 297 {
 298     layer_transition = transition_m;
 299 }
 300
 301 SGCloudLayer::Coverage
 302 SGCloudLayer::getCoverage () const
 303 {
 304     return layer_coverage;
 305 }
 306
 307 void
 308 SGCloudLayer::setCoverage (Coverage coverage)
 309 {
 310     if (coverage != layer_coverage) {
 311         layer_coverage = coverage;
 312         rebuild();
 313     }
 314 }
 315
 316
 317 // build the cloud object
 318 void
 319 SGCloudLayer::rebuild()
 320 {
 321     // Initialize states and sizes if necessary.
 322     if ( !state_initialized ) {
 323         state_initialized = true;
 324
 325         SG_LOG(SG_ASTRO, SG_INFO, "initializing cloud layers");
 326
 327         bump_mapping = SGIsOpenGLExtensionSupported("GL_ARB_multitexture") &&
 328                        SGIsOpenGLExtensionSupported("GL_ARB_texture_cube_map") &&
 329                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_combine") &&
 330                        SGIsOpenGLExtensionSupported("GL_ARB_texture_env_dot3") &&
 331                        SGIsOpenGLExtensionSupported("GL_ARB_imaging");
 332
 333         if ( bump_mapping ) {
 334             glGetIntegerv( GL_MAX_TEXTURE_UNITS_ARB, &nb_texture_unit );
 335             if ( nb_texture_unit < 2 ) {
 336                 bump_mapping = false;
 337             }
 338             //nb_texture_unit = 2; // Force the number of units for now
 339         }
 340
 341         if ( bump_mapping ) {
 342
 343             // This bump mapping code was inspired by the tutorial available at
 344             // http://www.paulsprojects.net/tutorials/simplebump/simplebump.html
 345             // and a NVidia white paper
 346             //  http://developer.nvidia.com/object/bumpmappingwithregistercombiners.html
 347             // The normal map textures were generated by the normal map Gimp plugin :
 348             //  http://nifelheim.dyndns.org/~cocidius/normalmap/
 349             //
 350             SGPath cloud_path;
 351
 352             glActiveTexturePtr = (glActiveTextureProc)SGLookupFunction("glActiveTextureARB");
 353             glClientActiveTexturePtr = (glClientActiveTextureProc)SGLookupFunction("glClientActiveTextureARB");
 354             glBlendColorPtr = (glBlendColorProc)SGLookupFunction("glBlendColor");
 355
 356             cloud_path.set(texture_path.str());
 357             cloud_path.append("overcast.rgb");
 358             color_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 359             cloud_path.set(texture_path.str());
 360             cloud_path.append("overcast_n.rgb");
 361             normal_map[ SG_CLOUD_OVERCAST ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 362
 363             cloud_path.set(texture_path.str());
 364             cloud_path.append("overcast_top.rgb");
 365             color_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 366             cloud_path.set(texture_path.str());
 367             cloud_path.append("overcast_top_n.rgb");
 368             normal_map[ SG_CLOUD_OVERCAST ][ 1 ] = new ssgTexture( cloud_path.str().c_str() );
 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             cloud_path.set(texture_path.str());
 374             cloud_path.append("broken_n.rgb");
 375             normal_map[ SG_CLOUD_BROKEN ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 376
 377             cloud_path.set(texture_path.str());
 378             cloud_path.append("scattered.rgba");
 379             color_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 380             cloud_path.set(texture_path.str());
 381             cloud_path.append("scattered_n.rgb");
 382             normal_map[ SG_CLOUD_SCATTERED ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 383
 384             cloud_path.set(texture_path.str());
 385             cloud_path.append("few.rgba");
 386             color_map[ SG_CLOUD_FEW ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 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
 391             cloud_path.set(texture_path.str());
 392             cloud_path.append("cirrus.rgba");
 393             color_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 394             cloud_path.set(texture_path.str());
 395             cloud_path.append("cirrus_n.rgb");
 396             normal_map[ SG_CLOUD_CIRRUS ][ 0 ] = new ssgTexture( cloud_path.str().c_str() );
 397
 398             glGenTextures( 1, &normalization_cube_map );
 399             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 400             generateNormalizationCubeMap();
 401             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
 402             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
 403             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
 404             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
 405             glTexParameteri( GL_TEXTURE_CUBE_MAP_ARB, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE );
 406         } /* else */ {
 407             SGPath cloud_path;
 408             ssgStateSelector *state_sel;
 409             ssgSimpleState *state;
 410
 411             state_sel = new ssgStateSelector( 2 );
 412             cloud_path.set(texture_path.str());
 413             cloud_path.append("overcast.rgb");
 414             state_sel->setStep( 0, sgCloudMakeState(cloud_path.str()) );
 415             cloud_path.set(texture_path.str());
 416             cloud_path.append("overcast_top.rgb");
 417             state_sel->setStep( 1, sgCloudMakeState(cloud_path.str()) );
 418             layer_states[SG_CLOUD_OVERCAST] = state_sel;
 419
 420             state_sel = new ssgStateSelector( 2 );
 421             cloud_path.set(texture_path.str());
 422             cloud_path.append("broken.rgba");
 423             state = sgCloudMakeState(cloud_path.str());
 424             state_sel->setStep( 0, state );
 425             state_sel->setStep( 1, state );
 426             layer_states[SG_CLOUD_BROKEN] = state_sel;
 427
 428             state_sel = new ssgStateSelector( 2 );
 429             cloud_path.set(texture_path.str());
 430             cloud_path.append("scattered.rgba");
 431             state = sgCloudMakeState(cloud_path.str());
 432             state_sel->setStep( 0, state );
 433             state_sel->setStep( 1, state );
 434             layer_states[SG_CLOUD_SCATTERED] = state_sel;
 435
 436             state_sel = new ssgStateSelector( 2 );
 437             cloud_path.set(texture_path.str());
 438             cloud_path.append("few.rgba");
 439             state = sgCloudMakeState(cloud_path.str());
 440             state_sel->setStep( 0, state );
 441             state_sel->setStep( 1, state );
 442             layer_states[SG_CLOUD_FEW] = state_sel;
 443
 444             state_sel = new ssgStateSelector( 2 );
 445             cloud_path.set(texture_path.str());
 446             cloud_path.append("cirrus.rgba");
 447             state = sgCloudMakeState(cloud_path.str());
 448             state_sel->setStep( 0, state );
 449             state_sel->setStep( 1, state );
 450             layer_states[SG_CLOUD_CIRRUS] = state_sel;
 451
 452             layer_states[SG_CLOUD_CLEAR] = 0;
 453         }
 454                 SGNewCloud::loadTextures(texture_path.str());
 455                 layer3D->buildTestLayer();
 456     }
 457
 458     if ( bump_mapping ) {
 459
 460         if ( !vertices ) {
 461             vertices = new CloudVertex[ 25 ];
 462             indices = new unsigned int[ 40 ];
 463         }
 464
 465         sgVec2 base;
 466         sgSetVec2( base, sg_random(), sg_random() );
 467
 468         const float layer_scale = layer_span / scale;
 469         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 470         const float half_angle = 0.5 * layer_span / layer_to_core;
 471
 472         int i;
 473         for ( i = -2; i <= 2; i++ ) {
 474             for ( int j = -2; j <= 2; j++ ) {
 475                 CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 476                 sgSetVec3( v1.position,
 477                            0.5 * i * layer_span,
 478                            0.5 * j * layer_span,
 479                            -layer_to_core * ( 1 - cos( i * half_angle ) * cos( j * half_angle ) ) );
 480                 sgSetVec2( v1.texCoord,
 481                            base[0] + layer_scale * i * 0.25,
 482                            base[1] + layer_scale * j * 0.25 );
 483                 sgSetVec3( v1.sTangent,
 484                            cos( i * half_angle ),
 485                            0.f,
 486                            -sin( i * half_angle ) );
 487                 sgSetVec3( v1.tTangent,
 488                            0.f,
 489                            cos( j * half_angle ),
 490                            -sin( j * half_angle ) );
 491                 sgVectorProductVec3( v1.normal, v1.tTangent, v1.sTangent );
 492                 sgSetVec4( v1.color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : cloud_alpha * 0.15f );
 493             }
 494         }
 495         /*
 496          * 0 1 5 6 10 11 15 16 20 21
 497          * 1 2 6 7 11 12 16 17 21 22
 498          * 2 3 7 8 12 13 17 18 22 23
 499          * 3 4 8 9 13 14 18 19 23 24
 500          */
 501         for ( i = 0; i < 4; i++ ) {
 502             for ( int j = 0; j < 5; j++ ) {
 503                 indices[ i*10 + (j*2) ]     =     i + 5 * j;
 504                 indices[ i*10 + (j*2) + 1 ] = 1 + i + 5 * j;
 505             }
 506         }
 507
 508     } /* else */ {
 509
 510         scale = 4000.0;
 511         last_lon = last_lat = -999.0f;
 512
 513         sgVec2 base;
 514         sgSetVec2( base, sg_random(), sg_random() );
 515
 516         // build the cloud layer
 517         sgVec4 color;
 518         sgVec3 vertex;
 519         sgVec2 tc;
 520
 521         const float layer_scale = layer_span / scale;
 522         const float mpi = SG_PI/4;
 523
 524         // caclculate the difference between a flat-earth model and
 525         // a round earth model given the span and altutude ASL of
 526         // the cloud layer. This is the difference in altitude between
 527         // the top of the inverted bowl and the edge of the bowl.
 528         // const float alt_diff = layer_asl * 0.8;
 529         const float layer_to_core = (SG_EARTH_RAD * 1000 + layer_asl);
 530         const float layer_angle = 0.5*layer_span / layer_to_core; // The angle is half the span
 531         const float border_to_core = layer_to_core * cos(layer_angle);
 532         const float alt_diff = layer_to_core - border_to_core;
 533
 534         for (int i = 0; i < 4; i++)
 535         {
 536             if ( layer[i] != NULL ) {
 537                 layer_transform->removeKid(layer[i]); // automatic delete
 538             }
 539
 540             vl[i] = new ssgVertexArray( 10 );
 541             cl[i] = new ssgColourArray( 10 );
 542             tl[i] = new ssgTexCoordArray( 10 );
 543
 544
 545             sgSetVec3( vertex, layer_span*(i-2)/2, -layer_span,
 546                             alt_diff * (sin(i*mpi) - 2) );
 547
 548             sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 549
 550             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 0) ? 0.0f : 0.15f );
 551
 552             cl[i]->add( color );
 553             vl[i]->add( vertex );
 554             tl[i]->add( tc );
 555
 556             for (int j = 0; j < 4; j++)
 557             {
 558                 sgSetVec3( vertex, layer_span*(i-1)/2, layer_span*(j-2)/2,
 559                                 alt_diff * (sin((i+1)*mpi) + sin(j*mpi) - 2) );
 560
 561                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 562                             base[1] + layer_scale * j/4 );
 563
 564                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 565                                 ( (j == 0) || (i == 3)) ?
 566                                 ( (j == 0) && (i == 3)) ? 0.0f : 0.15f : 1.0f );
 567
 568                 cl[i]->add( color );
 569                 vl[i]->add( vertex );
 570                 tl[i]->add( tc );
 571
 572
 573                 sgSetVec3( vertex, layer_span*(i-2)/2, layer_span*(j-1)/2,
 574                                 alt_diff * (sin(i*mpi) + sin((j+1)*mpi) - 2) );
 575
 576                 sgSetVec2( tc, base[0] + layer_scale * i/4,
 577                             base[1] + layer_scale * (j+1)/4 );
 578
 579                 sgSetVec4( color, 1.0f, 1.0f, 1.0f,
 580                                 ((j == 3) || (i == 0)) ?
 581                                 ((j == 3) && (i == 0)) ? 0.0f : 0.15f : 1.0f );
 582                 cl[i]->add( color );
 583                 vl[i]->add( vertex );
 584                 tl[i]->add( tc );
 585             }
 586
 587             sgSetVec3( vertex, layer_span*(i-1)/2, layer_span,
 588                             alt_diff * (sin((i+1)*mpi) - 2) );
 589
 590             sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 591                         base[1] + layer_scale );
 592
 593             sgSetVec4( color, 1.0f, 1.0f, 1.0f, (i == 3) ? 0.0f : 0.15f );
 594
 595             cl[i]->add( color );
 596             vl[i]->add( vertex );
 597             tl[i]->add( tc );
 598
 599             layer[i] = new ssgVtxTable(GL_TRIANGLE_STRIP, vl[i], NULL, tl[i], cl[i]);
 600             layer_transform->addKid( layer[i] );
 601
 602             if ( layer_states[layer_coverage] != NULL ) {
 603                 layer[i]->setState( layer_states[layer_coverage] );
 604             }
 605             state_sel = layer_states[layer_coverage];
 606         }
 607
 608         // force a repaint of the sky colors with arbitrary defaults
 609         repaint( color );
 610     }
 611 }
 612
 613
 614 // repaint the cloud layer colors
 615 bool SGCloudLayer::repaint( sgVec3 fog_color ) {
 616
 617     if ( bump_mapping && enable_bump_mapping ) {
 618
 619         for ( int i = 0; i < 25; i++ ) {
 620             sgCopyVec3( vertices[ i ].color, fog_color );
 621         }
 622
 623     } else {
 624         float *color;
 625
 626         for ( int i = 0; i < 4; i++ ) {
 627             color = cl[i]->get( 0 );
 628             sgCopyVec3( color, fog_color );
 629             color[3] = (i == 0) ? 0.0f : cloud_alpha * 0.15f;
 630
 631             for ( int j = 0; j < 4; ++j ) {
 632                 color = cl[i]->get( (2*j) + 1 );
 633                 sgCopyVec3( color, fog_color );
 634                 color[3] =
 635                     ((j == 0) || (i == 3)) ?
 636                     ((j == 0) && (i == 3)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 637
 638                 color = cl[i]->get( (2*j) + 2 );
 639                 sgCopyVec3( color, fog_color );
 640                 color[3] =
 641                     ((j == 3) || (i == 0)) ?
 642                     ((j == 3) && (i == 0)) ? 0.0f : cloud_alpha * 0.15f : cloud_alpha;
 643             }
 644
 645             color = cl[i]->get( 9 );
 646             sgCopyVec3( color, fog_color );
 647             color[3] = (i == 3) ? 0.0f : cloud_alpha * 0.15f;
 648         }
 649     }
 650
 651     return true;
 652 }
 653
 654 // reposition the cloud layer at the specified origin and orientation
 655 // lon specifies a rotation about the Z axis
 656 // lat specifies a rotation about the new Y axis
 657 // spin specifies a rotation about the new Z axis (and orients the
 658 // sunrise/set effects
 659 bool SGCloudLayer::reposition( sgVec3 p, sgVec3 up, double lon, double lat,
 660                                double alt, double dt )
 661 {
 662     sgMat4 T1, LON, LAT;
 663     sgVec3 axis;
 664
 665     // combine p and asl (meters) to get translation offset
 666     sgVec3 asl_offset;
 667     sgCopyVec3( asl_offset, up );
 668     sgNormalizeVec3( asl_offset );
 669     if ( alt <= layer_asl ) {
 670         sgScaleVec3( asl_offset, layer_asl );
 671     } else {
 672         sgScaleVec3( asl_offset, layer_asl + layer_thickness );
 673     }
 674     // cout << "asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 675     //      << "," << asl_offset[2] << endl;
 676     sgAddVec3( asl_offset, p );
 677     // cout << "  asl_offset = " << asl_offset[0] << "," << asl_offset[1]
 678     //      << "," << asl_offset[2] << endl;
 679
 680     // Translate to zero elevation
 681     // Point3D zero_elev = current_view.get_cur_zero_elev();
 682     sgMakeTransMat4( T1, asl_offset );
 683
 684     // printf("  Translated to %.2f %.2f %.2f\n",
 685     //        zero_elev.x, zero_elev.y, zero_elev.z );
 686
 687     // Rotate to proper orientation
 688     // printf("  lon = %.2f  lat = %.2f\n",
 689     //        lon * SGD_RADIANS_TO_DEGREES,
 690     //        lat * SGD_RADIANS_TO_DEGREES);
 691     sgSetVec3( axis, 0.0, 0.0, 1.0 );
 692     sgMakeRotMat4( LON, lon * SGD_RADIANS_TO_DEGREES, axis );
 693
 694     sgSetVec3( axis, 0.0, 1.0, 0.0 );
 695     sgMakeRotMat4( LAT, 90.0 - lat * SGD_RADIANS_TO_DEGREES, axis );
 696
 697     sgMat4 TRANSFORM;
 698
 699     sgCopyMat4( TRANSFORM, T1 );
 700     sgPreMultMat4( TRANSFORM, LON );
 701     sgPreMultMat4( TRANSFORM, LAT );
 702
 703     sgCoord layerpos;
 704     sgSetCoord( &layerpos, TRANSFORM );
 705
 706     layer_transform->setTransform( &layerpos );
 707
 708     // now calculate update texture coordinates
 709     if ( last_lon < -900 ) {
 710         last_lon = lon;
 711         last_lat = lat;
 712     }
 713
 714     double sp_dist = speed*dt;
 715
 716     if ( lon != last_lon || lat != last_lat || sp_dist != 0 ) {
 717         Point3D start( last_lon, last_lat, 0.0 );
 718         Point3D dest( lon, lat, 0.0 );
 719         double course = 0.0, dist = 0.0;
 720
 721         calc_gc_course_dist( dest, start, &course, &dist );
 722         // cout << "course = " << course << ", dist = " << dist << endl;
 723
 724         // if start and dest are too close together,
 725         // calc_gc_course_dist() can return a course of "nan".  If
 726         // this happens, lets just use the last known good course.
 727         // This is a hack, and it would probably be better to make
 728         // calc_gc_course_dist() more robust.
 729         if ( isnan(course) ) {
 730             course = last_course;
 731         } else {
 732             last_course = course;
 733         }
 734
 735         // calculate cloud movement due to external forces
 736         double ax = 0.0, ay = 0.0, bx = 0.0, by = 0.0;
 737
 738         if (dist > 0.0) {
 739             ax = cos(course) * dist;
 740             ay = sin(course) * dist;
 741         }
 742
 743         if (sp_dist > 0) {
 744             bx = cos((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 745             by = sin((180.0-direction) * SGD_DEGREES_TO_RADIANS) * sp_dist;
 746         }
 747
 748
 749         double xoff = (ax + bx) / (2 * scale);
 750         double yoff = (ay + by) / (2 * scale);
 751
 752         const float layer_scale = layer_span / scale;
 753
 754         // cout << "xoff = " << xoff << ", yoff = " << yoff << endl;
 755
 756         float *base;
 757         if ( bump_mapping && enable_bump_mapping ) {
 758             base = vertices[12].texCoord;
 759         } else {
 760             base = tl[0]->get( 0 );
 761         }
 762         base[0] += xoff;
 763
 764         // the while loops can lead to *long* pauses if base[0] comes
 765         // with a bogus value.
 766         // while ( base[0] > 1.0 ) { base[0] -= 1.0; }
 767         // while ( base[0] < 0.0 ) { base[0] += 1.0; }
 768         if ( base[0] > -10.0 && base[0] < 10.0 ) {
 769             base[0] -= (int)base[0];
 770         } else {
 771             SG_LOG(SG_ASTRO, SG_DEBUG,
 772                 "Error: base = " << base[0] << "," << base[1] <<
 773                 " course = " << course << " dist = " << dist );
 774             base[0] = 0.0;
 775         }
 776
 777         base[1] += yoff;
 778         // the while loops can lead to *long* pauses if base[0] comes
 779         // with a bogus value.
 780         // while ( base[1] > 1.0 ) { base[1] -= 1.0; }
 781         // while ( base[1] < 0.0 ) { base[1] += 1.0; }
 782         if ( base[1] > -10.0 && base[1] < 10.0 ) {
 783             base[1] -= (int)base[1];
 784         } else {
 785             SG_LOG(SG_ASTRO, SG_DEBUG,
 786                     "Error: base = " << base[0] << "," << base[1] <<
 787                     " course = " << course << " dist = " << dist );
 788             base[1] = 0.0;
 789         }
 790
 791         if ( bump_mapping && enable_bump_mapping ) {
 792
 793             for ( int i = -2; i <= 2; i++ ) {
 794                 for ( int j = -2; j <= 2; j++ ) {
 795                     if ( i == 0 && j == 0 )
 796                         continue; // Already done on base
 797                     CloudVertex &v1 = vertices[ (i+2)*5 + (j+2) ];
 798                     sgSetVec2( v1.texCoord,
 799                             base[0] + layer_scale * i * 0.25,
 800                             base[1] + layer_scale * j * 0.25 );
 801                 }
 802             }
 803
 804         } else {
 805                 // cout << "base = " << base[0] << "," << base[1] << endl;
 806
 807             float *tc;
 808             for (int i = 0; i < 4; i++) {
 809                 tc = tl[i]->get( 0 );
 810                 sgSetVec2( tc, base[0] + layer_scale * i/4, base[1] );
 811
 812                 for (int j = 0; j < 4; j++)
 813                 {
 814                     tc = tl[i]->get( j*2+1 );
 815                     sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 816                                 base[1] + layer_scale * j/4 );
 817
 818                     tc = tl[i]->get( (j+1)*2 );
 819                     sgSetVec2( tc, base[0] + layer_scale * i/4,
 820                                 base[1] + layer_scale * (j+1)/4 );
 821                 }
 822
 823                 tc = tl[i]->get( 9 );
 824                 sgSetVec2( tc, base[0] + layer_scale * (i+1)/4,
 825                             base[1] + layer_scale );
 826             }
 827         }
 828
 829         last_lon = lon;
 830         last_lat = lat;
 831     }
 832
 833         layer3D->reposition( p, up, lon, lat, alt, dt, direction, speed);
 834     return true;
 835 }
 836
 837
 838 void SGCloudLayer::draw( bool top ) {
 839     if ( layer_coverage != SG_CLOUD_CLEAR ) {
 840
 841                 if ( SGCloudField::enable3D && layer3D->is3D())
 842                         layer3D->Render();
 843                 else
 844         if ( bump_mapping && enable_bump_mapping ) {
 845
 846             sgMat4 modelview,
 847                    tmp,
 848                    transform;
 849             ssgGetModelviewMatrix( modelview );
 850             layer_transform->getTransform( transform );
 851
 852             sgTransposeNegateMat4( tmp, transform );
 853
 854             sgPostMultMat4( transform, modelview );
 855             ssgLoadModelviewMatrix( transform );
 856
 857             sgVec3 lightVec;
 858             ssgGetLight( 0 )->getPosition( lightVec );
 859             sgNegateVec3( lightVec );
 860             sgXformVec3( lightVec, tmp );
 861
 862             for ( int i = 0; i < 25; i++ ) {
 863                 CloudVertex &v = vertices[ i ];
 864                 sgSetVec3( v.tangentSpLight,
 865                            sgScalarProductVec3( v.sTangent, lightVec ),
 866                            sgScalarProductVec3( v.tTangent, lightVec ),
 867                            sgScalarProductVec3( v.normal, lightVec ) );
 868             }
 869
 870             ssgTexture *decal = color_map[ layer_coverage ][ top ? 1 : 0 ];
 871             if ( top && decal == 0 ) {
 872                 decal = color_map[ layer_coverage ][ 0 ];
 873             }
 874             ssgTexture *normal = normal_map[ layer_coverage ][ top ? 1 : 0 ];
 875             if ( top && normal == 0 ) {
 876                 normal = normal_map[ layer_coverage ][ 0 ];
 877             }
 878
 879             glDisable( GL_LIGHTING );
 880             glDisable( GL_CULL_FACE );
 881 //            glDisable( GL_ALPHA_TEST );
 882             if ( layer_coverage == SG_CLOUD_FEW ) {
 883                 glEnable( GL_ALPHA_TEST );
 884                 glAlphaFunc ( GL_GREATER, 0.01 );
 885             }
 886             glEnable( GL_BLEND );
 887             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
 888
 889             glShadeModel( GL_SMOOTH );
 890             glEnable( GL_COLOR_MATERIAL );
 891             sgVec4 color;
 892             float emis = 0.05;
 893             if ( 1 ) {
 894                 ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
 895                 emis = ( color[0]+color[1]+color[2] ) / 3.0;
 896                 if ( emis < 0.05 )
 897                     emis = 0.05;
 898             }
 899             sgSetVec4( color, emis, emis, emis, 0.0 );
 900             glMaterialfv( GL_FRONT_AND_BACK, GL_EMISSION, color );
 901             sgSetVec4( color, 1.0f, 1.0f, 1.0f, 0.0 );
 902             glMaterialfv( GL_FRONT_AND_BACK, GL_AMBIENT, color );
 903             sgSetVec4( color, 1.0, 1.0, 1.0, 0.0 );
 904             glMaterialfv( GL_FRONT_AND_BACK, GL_DIFFUSE, color );
 905             sgSetVec4( color, 0.0, 0.0, 0.0, 0.0 );
 906             glMaterialfv( GL_FRONT_AND_BACK, GL_SPECULAR, color );
 907
 908             glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
 909
 910             glActiveTexturePtr( GL_TEXTURE0_ARB );
 911             glBindTexture( GL_TEXTURE_2D, normal->getHandle() );
 912             glEnable( GL_TEXTURE_2D );
 913
 914             //Bind normalisation cube map to texture unit 1
 915             glActiveTexturePtr( GL_TEXTURE1_ARB );
 916             glBindTexture( GL_TEXTURE_CUBE_MAP_ARB, normalization_cube_map );
 917             glEnable( GL_TEXTURE_CUBE_MAP_ARB );
 918             glActiveTexturePtr( GL_TEXTURE0_ARB );
 919
 920             //Set vertex arrays for cloud
 921             glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
 922             glEnableClientState( GL_VERTEX_ARRAY );
 923 /*
 924             if ( nb_texture_unit >= 3 ) {
 925                 glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
 926                 glEnableClientState( GL_COLOR_ARRAY );
 927             }
 928 */
 929             //Send texture coords for normal map to unit 0
 930             glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 931             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 932
 933             //Send tangent space light vectors for normalisation to unit 1
 934             glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 935             glTexCoordPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].tangentSpLight );
 936             glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 937
 938             //Set up texture environment to do (tex0 dot tex1)*color
 939             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 940             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 941             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_REPLACE );
 942             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_TEXTURE );
 943             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 944
 945             glActiveTexturePtr( GL_TEXTURE1_ARB );
 946
 947             glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 948             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 949             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_DOT3_RGB_ARB );
 950             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 951             glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_ALPHA_ARB, GL_PREVIOUS_ARB );
 952             glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_ALPHA_ARB, GL_REPLACE );
 953
 954             if ( nb_texture_unit >= 3 ) {
 955                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 956                 glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
 957
 958                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 959                 glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
 960                 glEnableClientState( GL_TEXTURE_COORD_ARRAY );
 961
 962                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE_ARB );
 963                 glTexEnvi( GL_TEXTURE_ENV, GL_COMBINE_RGB_ARB, GL_ADD );
 964                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE0_RGB_ARB, GL_TEXTURE );
 965                 glTexEnvi( GL_TEXTURE_ENV, GL_SOURCE1_RGB_ARB, GL_PREVIOUS_ARB );
 966
 967                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 968                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 969
 970                 //Draw cloud layer
 971                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
 972                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
 973                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
 974                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
 975
 976                 glDisable( GL_TEXTURE_2D );
 977                 glActiveTexturePtr( GL_TEXTURE1_ARB );
 978                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
 979                 glActiveTexturePtr( GL_TEXTURE2_ARB );
 980                 glDisable( GL_TEXTURE_2D );
 981                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 982
 983                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 984                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
 985                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 986                 glClientActiveTexturePtr( GL_TEXTURE2_ARB );
 987                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
 988                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 989
 990                 glDisableClientState( GL_COLOR_ARRAY );
 991                 glEnable( GL_LIGHTING );
 992
 993                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
 994
 995             } else {
 996                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
 997                 glActiveTexturePtr( GL_TEXTURE0_ARB );
 998
 999                 //Draw cloud layer
1000                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1001                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1002                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1003                 glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1004
1005                 //Disable textures
1006                 glDisable( GL_TEXTURE_2D );
1007
1008                 glActiveTexturePtr( GL_TEXTURE1_ARB );
1009                 glDisable( GL_TEXTURE_CUBE_MAP_ARB );
1010                 glActiveTexturePtr( GL_TEXTURE0_ARB );
1011
1012                 //disable vertex arrays
1013                 glDisableClientState( GL_VERTEX_ARRAY );
1014
1015                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1016                 glClientActiveTexturePtr( GL_TEXTURE1_ARB );
1017                 glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1018                 glClientActiveTexturePtr( GL_TEXTURE0_ARB );
1019
1020                 //Return to standard modulate texenv
1021                 glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
1022
1023                 if ( layer_coverage == SG_CLOUD_OVERCAST ) {
1024                     glDepthFunc(GL_LEQUAL);
1025
1026                     glEnable( GL_LIGHTING );
1027                     sgVec4 color;
1028                     ssgGetLight( 0 )->getColour( GL_DIFFUSE, color );
1029                     float average = ( color[0] + color[1] + color[2] ) / 3.0f;
1030                     average = 0.15 + average/10;
1031                     sgVec4 averageColor;
1032                     sgSetVec4( averageColor, average, average, average, 1.0f );
1033                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, averageColor );
1034
1035                     glBlendColorPtr( average, average, average, 1.0f );
1036                     glBlendFunc( GL_ONE_MINUS_CONSTANT_COLOR, GL_CONSTANT_COLOR );
1037
1038                     //Perform a second pass to color the torus
1039                     //Bind decal texture
1040                     glBindTexture( GL_TEXTURE_2D, decal->getHandle() );
1041                     glEnable(GL_TEXTURE_2D);
1042
1043                     //Set vertex arrays for torus
1044                     glVertexPointer( 3, GL_FLOAT, sizeof(CloudVertex), &vertices[0].position );
1045                     glEnableClientState( GL_VERTEX_ARRAY );
1046
1047                     //glColorPointer( 4, GL_FLOAT, sizeof(CloudVertex), &vertices[0].color );
1048                     //glEnableClientState( GL_COLOR_ARRAY );
1049
1050                     glNormalPointer( GL_FLOAT, sizeof(CloudVertex), &vertices[0].normal );
1051                     glEnableClientState( GL_NORMAL_ARRAY );
1052
1053                     glTexCoordPointer( 2, GL_FLOAT, sizeof(CloudVertex), &vertices[0].texCoord );
1054                     glEnableClientState( GL_TEXTURE_COORD_ARRAY );
1055
1056                     //Draw cloud layer
1057                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[0] );
1058                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[10] );
1059                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[20] );
1060                     glDrawElements( GL_TRIANGLE_STRIP, 10, GL_UNSIGNED_INT, &indices[30] );
1061
1062                     ssgGetLight( 0 )->setColour( GL_DIFFUSE, color );
1063
1064                     glDisableClientState( GL_TEXTURE_COORD_ARRAY );
1065                 }
1066             }
1067             //Disable texture
1068             glDisable( GL_TEXTURE_2D );
1069
1070             glDisableClientState( GL_VERTEX_ARRAY );
1071             glDisableClientState( GL_NORMAL_ARRAY );
1072
1073             glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
1074             glEnable( GL_CULL_FACE );
1075             glDepthFunc(GL_LESS);
1076
1077             ssgLoadModelviewMatrix( modelview );
1078
1079         } else {
1080             state_sel->selectStep( top ? 1 : 0 );
1081             ssgCullAndDraw( layer_root );
1082         }
1083     }
1084 }
1085
1086
1087 // make an ssgSimpleState for a cloud layer given the named texture
1088 ssgSimpleState *sgCloudMakeState( const string &path ) {
1089     ssgSimpleState *state = new ssgSimpleState();
1090
1091     SG_LOG(SG_ASTRO, SG_INFO, " texture = ");
1092
1093     state->setTexture( (char *)path.c_str() );
1094     state->setShadeModel( GL_SMOOTH );
1095     state->disable( GL_LIGHTING );
1096     state->disable( GL_CULL_FACE );
1097     state->enable( GL_TEXTURE_2D );
1098     state->enable( GL_COLOR_MATERIAL );
1099     state->setColourMaterial( GL_AMBIENT_AND_DIFFUSE );
1100     state->setMaterial( GL_EMISSION, 0.05, 0.05, 0.05, 0.0 );
1101     state->setMaterial( GL_AMBIENT, 0.2, 0.2, 0.2, 0.0 );
1102     state->setMaterial( GL_DIFFUSE, 0.5, 0.5, 0.5, 0.0 );
1103     state->setMaterial( GL_SPECULAR, 0.0, 0.0, 0.0, 0.0 );
1104     state->enable( GL_BLEND );
1105     state->enable( GL_ALPHA_TEST );
1106     state->setAlphaClamp( 0.01 );
1107
1108     return state;
1109 }