3 // Written by Harald JOHNSEN, started April 2005.
5 // Copyright (C) 2005 Harald JOHNSEN - hjohnsen@evc.net
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program 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.
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, 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA
24 # include <simgear_config.h>
27 #include <simgear/compiler.h>
31 #include <simgear/math/sg_random.h>
32 #include <simgear/misc/sg_path.hxx>
34 #include STL_ALGORITHM
37 #include "cloudfield.hxx"
38 #include "newcloud.hxx"
44 static ssgTexture *cloudTextures[SGNewCloud::CLTexture_max];
47 bool SGNewCloud::useAnisotropic = true;
48 SGBbCache *SGNewCloud::cldCache = 0;
49 static bool texturesLoaded = false;
50 static float minx, maxx, miny, maxy, minz, maxz;
52 float SGNewCloud::nearRadius = 3500.0f;
53 bool SGNewCloud::lowQuality = false;
54 sgVec3 SGNewCloud::sunlight = {0.5f, 0.5f, 0.5f};
55 sgVec3 SGNewCloud::ambLight = {0.5f, 0.5f, 0.5f};
56 sgVec3 SGNewCloud::modelSunDir = {0,1,0};
59 void SGNewCloud::init(void) {
66 familly = CLFamilly_nn;
68 sgSetVec3(center, 0.0f, 0.0f, 0.0f);
69 sgSetVec3(cloudpos, 0.0f, 0.0f, 0.0f);
72 list_spriteContainer.reserve(8);
73 list_spriteDef.reserve(40);
76 cldCache = new SGBbCache;
82 SGNewCloud::SGNewCloud(CLFamilly_type classification)
85 familly = classification;
88 SGNewCloud::SGNewCloud(string classification)
91 if( classification == "cu" )
92 familly = CLFamilly_cu;
93 else if( classification == "cb" )
94 familly = CLFamilly_cb;
95 else if( classification == "st" )
96 familly = CLFamilly_st;
97 else if( classification == "ns" )
98 familly = CLFamilly_ns;
99 else if( classification == "sc" )
100 familly = CLFamilly_sc;
101 else if( classification == "as" )
102 familly = CLFamilly_as;
103 else if( classification == "ac" )
104 familly = CLFamilly_ac;
105 else if( classification == "ci" )
106 familly = CLFamilly_ci;
107 else if( classification == "cc" )
108 familly = CLFamilly_cc;
109 else if( classification == "cs" )
110 familly = CLFamilly_cs;
113 SGNewCloud::~SGNewCloud() {
114 list_spriteDef.clear();
115 list_spriteContainer.clear();
116 cldCache->free( bbId, cloudId );
120 // load all textures used to draw cloud sprites
121 void SGNewCloud::loadTextures(const string &tex_path) {
124 texturesLoaded = true;
128 cloud_path.set(tex_path);
129 cloud_path.append("cl_cumulus.rgb");
130 cloudTextures[ CLTexture_cumulus ] = new ssgTexture( cloud_path.str().c_str(), false, false, false );
131 cloudTextures[ CLTexture_cumulus ]->ref();
133 cloud_path.set(tex_path);
134 cloud_path.append("cl_stratus.rgb");
135 cloudTextures[ CLTexture_stratus ] = new ssgTexture( cloud_path.str().c_str(), false, false, false );
136 cloudTextures[ CLTexture_stratus ]->ref();
140 void SGNewCloud::startFade(bool direction, float duration, float pauseLength) {
141 if(duration <= 0.0) {
145 this->direction = direction;
147 this->duration = duration;
148 this->pauseLength = pauseLength;
152 void SGNewCloud::setFade(float howMuch) {
160 static inline float rayleighCoeffAngular(float cosAngle) {
161 return 3.0f / 4.0f * (1.0f + cosAngle * cosAngle);
164 // cp is normalized (len==1)
165 static void CartToPolar3d(sgVec3 cp, sgVec3 polar) {
166 polar[0] = atan2(cp[1], cp[0]);
167 polar[1] = SG_PI / 2.0f - atan2(sqrt (cp[0] * cp[0] + cp[1] * cp[1]), cp[2]);
171 static void PolarToCart3d(sgVec3 p, sgVec3 cart) {
172 float tmp = cos(p[1]);
173 cart[0] = cos(p[0]) * tmp;
174 cart[1] = sin(p[0]) * tmp;
179 // compute the light for a cloud sprite corner
180 // from the normal and the sun, scaled by the Rayleigh factor
181 // and finaly added to the ambient light
182 static inline void lightFunction(sgVec3 normal, sgVec4 light, float pf) {
183 float cosAngle = sgScalarProductVec3( normal, SGNewCloud::modelSunDir);
184 float vl = (1.0f - 0.5f + cosAngle * 0.5f) * pf;
185 sgScaleVec3( light, SGNewCloud::sunlight, 0.25f + 0.75f * vl );
186 sgAddVec3( light, SGNewCloud::ambLight );
187 // we need to clamp or else the light will bug when adding transparency
188 if( light[0] > 1.0 ) light[0] = 1.0;
189 if( light[1] > 1.0 ) light[1] = 1.0;
190 if( light[2] > 1.0 ) light[2] = 1.0;
194 // compute the light for a cloud sprite
195 // we use ambient light and orientation versus sun position
196 void SGNewCloud::computeSimpleLight(sgVec3 FakeEyePos) {
197 // constant Rayleigh factor if we are not doing Anisotropic lighting
200 list_of_spriteDef::iterator iSprite;
201 for( iSprite = list_spriteDef.begin() ; iSprite != list_spriteDef.end() ; iSprite++ ) {
202 if( useAnisotropic ) {
204 sgSubVec3(eyeDir, iSprite->pos, FakeEyePos);
205 sgNormaliseVec3(eyeDir);
206 float cosAngle = sgScalarProductVec3(eyeDir, modelSunDir);
207 pf = rayleighCoeffAngular(cosAngle);
209 lightFunction(iSprite->n0, iSprite->l0, pf);
210 lightFunction(iSprite->n1, iSprite->l1, pf);
211 lightFunction(iSprite->n2, iSprite->l2, pf);
212 lightFunction(iSprite->n3, iSprite->l3, pf);
218 // add a new box to the cloud
219 void SGNewCloud::addContainer (float x, float y, float z, float r, CLbox_type type) {
220 spriteContainer cont;
221 sgSetVec3( cont.pos, x, y, z );
223 cont.cont_type = type;
224 sgSetVec3( cont.center, 0.0f, 0.0f, 0.0f);
225 list_spriteContainer.push_back( cont );
226 // don't place cloud below his base
227 if( y - r*0.50 < delta_base )
228 delta_base = y - r*0.50;
231 // add a sprite inside a box
232 void SGNewCloud::addSprite(float x, float y, float z, float r, CLbox_type type, int box) {
233 spriteDef newSpriteDef;
234 int rank = list_spriteDef.size();
235 sgSetVec3( newSpriteDef.pos, x, y - delta_base, z);
236 newSpriteDef.box = box;
237 newSpriteDef.sprite_type = type;
238 newSpriteDef.rank = rank;
240 list_spriteDef.push_back( newSpriteDef );
241 spriteContainer *thisBox = &list_spriteContainer[box];
243 sgSubVec3( deltaPos, newSpriteDef.pos, thisBox->pos );
244 sgAddVec3( thisBox->center, deltaPos );
246 r = r * 0.65f; // 0.5 * 1.xxx
262 // return a random number between -n/2 and n/2
263 static float Rnd(float n) {
264 return n * (-0.5f + sg_random());
267 // generate all sprite with defined boxes
268 void SGNewCloud::genSprites( void ) {
271 minx = miny = minz = 99999.0;
272 maxx = maxy = maxz = -99999.0;
274 N = list_spriteContainer.size();
275 for(int i = 0 ; i < N ; i++ ) {
276 spriteContainer *thisBox = & list_spriteContainer[i];
277 // the type defines how the sprites can be positioned inside the box, their size, etc
278 switch(thisBox->cont_type) {
281 r = thisBox->r + Rnd(0.2f);
282 x = thisBox->pos[SG_X] + Rnd(thisBox->r * 0.75f);
283 y = thisBox->pos[SG_Y] + Rnd(thisBox->r * 0.75f);
284 z = thisBox->pos[SG_Z] + Rnd(thisBox->r * 0.75f);
285 addSprite(x, y, z, r, thisBox->cont_type, i);
290 x = thisBox->pos[SG_X];
291 y = thisBox->pos[SG_Y];
292 z = thisBox->pos[SG_Z];
293 addSprite(x, y, z, r, thisBox->cont_type, i);
296 for( sc = 0 ; sc <= 4 ; sc ++ ) {
297 r = thisBox->r + Rnd(0.2f);
298 x = thisBox->pos[SG_X] + Rnd(thisBox->r * 0.75f);
299 y = thisBox->pos[SG_Y] + Rnd(thisBox->r * 0.5f);
300 z = thisBox->pos[SG_Z] + Rnd(thisBox->r * 0.75f);
301 if ( y < thisBox->pos[SG_Y] - thisBox->r / 10.0f )
302 y = thisBox->pos[SG_Y] - thisBox->r / 10.0f;
303 addSprite(x, y, z, r, thisBox->cont_type, i);
307 for( sc = 0 ; sc <= 4 ; sc ++ ) {
308 r = thisBox->r + Rnd(0.2f);
309 x = thisBox->pos[SG_X] + Rnd(thisBox->r);
310 y = thisBox->pos[SG_Y] + Rnd(thisBox->r);
311 z = thisBox->pos[SG_Z] + Rnd(thisBox->r);
312 addSprite(x, y, z, r, thisBox->cont_type, i);
316 sgScaleVec3(thisBox->center, 1.0f / sc);
319 radius = maxx - minx;
320 if ( (maxy - miny) > radius )
321 radius = (maxy - miny);
322 if ( (maxz - minz) > radius )
323 radius = (maxz - minz);
325 sgSetVec3( center, (maxx + minx) / 2.0f, (maxy + miny) / 2.0f, (maxz + minz) / 2.0f );
327 const float ang = 45.0f * SG_PI / 180.0f;
330 list_of_spriteDef::iterator iSprite;
331 for( iSprite = list_spriteDef.begin() ; iSprite != list_spriteDef.end() ; iSprite++ ) {
333 spriteContainer *thisSpriteContainer = &list_spriteContainer[iSprite->box];
334 if( familly == CLFamilly_sc || familly == CLFamilly_cu || familly == CLFamilly_cb) {
335 sgSubVec3(normal, iSprite->pos, center);
337 sgSubVec3(normal, iSprite->pos, thisSpriteContainer->pos);
338 sgSubVec3(normal, thisSpriteContainer->center);
339 sgSubVec3(normal, cloudpos);
341 if( normal[0] == 0.0f && normal[1] == 0.0f && normal[2] == 0.0f )
342 sgSetVec3( normal, 0.0f, 1.0f, 0.0f );
343 sgNormaliseVec3(normal);
344 // use exotic lightning function, this will give more 'relief' to the clouds
345 // compute a normal for each vextex this will simulate a smooth shading for a round shape
347 // I suspect this code to be bugged...
348 CartToPolar3d(normal, polar);
349 sgCopyVec3(iSprite->normal, normal);
351 // offset the normal vector by some angle for each vertex
352 sgSetVec3(pt, polar[0] - ang, polar[1] - ang, polar[2]);
353 PolarToCart3d(pt, iSprite->n0);
354 sgSetVec3(pt, polar[0] + ang, polar[1] - ang, polar[2]);
355 PolarToCart3d(pt, iSprite->n1);
356 sgSetVec3(pt, polar[0] + ang, polar[1] + ang, polar[2]);
357 PolarToCart3d(pt, iSprite->n2);
358 sgSetVec3(pt, polar[0] - ang, polar[1] + ang, polar[2]);
359 PolarToCart3d(pt, iSprite->n3);
362 // experimental : clouds are dissipating with time
363 if( familly == CLFamilly_cu ) {
364 startFade(true, 300.0f, 30.0f);
365 fadetimer = sg_random() * 300.0f;
370 // definition of a cu cloud, only for testing
371 void SGNewCloud::new_cu(void) {
373 float r = Rnd(1.0) + 0.5;
375 addContainer(0.0f, 0.0f, 0.0f, s, CLbox_cumulus);
376 addContainer(s, 0, 0, s, CLbox_cumulus);
377 addContainer(0, 0, 2 * s, s, CLbox_cumulus);
378 addContainer(s, 0, 2 * s, s, CLbox_cumulus);
380 addContainer(-1.2f * s, 0.2f * s, s, s * 1.4f, CLbox_cumulus);
381 addContainer(0.2f * s, 0.2f * s, s, s * 1.4f, CLbox_cumulus);
382 addContainer(1.6f * s, 0.2f * s, s, s * 1.4f, CLbox_cumulus);
383 } else if ( r < 0.90f ) {
384 addContainer(0, 0, 0, s * 1.2, CLbox_cumulus);
385 addContainer(s, 0, 0, s, CLbox_cumulus);
386 addContainer(0, 0, s, s, CLbox_cumulus);
387 addContainer(s * 1.1, 0, s, s * 1.2, CLbox_cumulus);
389 addContainer(-1.2 * s, 1 + 0.2 * s, s * 0.5, s * 1.4, CLbox_standard);
390 addContainer(0.2 * s, 1 + 0.25 * s, s * 0.5, s * 1.5, CLbox_standard);
391 addContainer(1.6 * s, 1 + 0.2 * s, s * 0.5, s * 1.4, CLbox_standard);
396 addContainer(0, 0, 0, s, CLbox_cumulus);
397 addContainer(0, 0, s, s, CLbox_cumulus);
398 addContainer(s, 0, s, s, CLbox_cumulus);
399 addContainer(s, 0, 0, s, CLbox_cumulus);
401 addContainer(s / 2, s, s / 2, s * 1.5, CLbox_standard);
403 addContainer(0, 2 * s, 0, s, CLbox_standard);
404 addContainer(0, 2 * s, s, s, CLbox_standard);
405 addContainer(s, 2 * s, s, s, CLbox_standard);
406 addContainer(s, 2 * s, 0, s, CLbox_standard);
413 // define the new position of the cloud (inside the cloud field, not on sphere)
414 void SGNewCloud::SetPos(sgVec3 newPos) {
415 int N = list_spriteDef.size();
417 sgSubVec3( deltaPos, newPos, cloudpos );
420 for(int i = 0 ; i < N ; i ++) {
421 sgAddVec3( list_spriteDef[i].pos, deltaPos );
423 sgAddVec3( center, deltaPos );
424 sgSetVec3( cloudpos, newPos[SG_X], newPos[SG_Y], newPos[SG_Z]);
430 void SGNewCloud::drawContainers() {
437 // sort on distance to eye because of transparency
438 void SGNewCloud::sortSprite( sgVec3 eye ) {
439 list_of_spriteDef::iterator iSprite;
441 // compute distance from sprite to eye
442 for( iSprite = list_spriteDef.begin() ; iSprite != list_spriteDef.end() ; iSprite++ ) {
444 sgSubVec3( dist, iSprite->pos, eye );
445 iSprite->dist = -(dist[0]*dist[0] + dist[1]*dist[1] + dist[2]*dist[2]);
447 std::sort( list_spriteDef.begin(), list_spriteDef.end() );
450 // render the cloud on screen or on the RTT texture to build the impostor
451 void SGNewCloud::Render3Dcloud( bool drawBB, sgVec3 FakeEyePos, sgVec3 deltaPos, float dist_center ) {
453 float step = ( list_spriteDef.size() * (direction ? fadetimer : duration-fadetimer)) / duration;
454 int clrank = (int) step;
455 float clfadeinrank = (step - clrank);
458 float CloudVisFade = 1.0 / (0.7f * SGCloudField::get_CloudVis());
459 // blend clouds with sky based on distance to limit the contrast of distant cloud
460 float t = 1.0f - dist_center * CloudVisFade;
464 computeSimpleLight( FakeEyePos );
466 // view point sort, we sort because of transparency
467 sortSprite( FakeEyePos );
469 float dark = (familly == CLFamilly_cb ? 0.9f : 1.0f);
471 GLint previousTexture = -1, thisTexture;
472 list_of_spriteDef::iterator iSprite;
473 for( iSprite = list_spriteDef.begin() ; iSprite != list_spriteDef.end() ; iSprite++ ) {
474 // skip this sprite if faded
475 if(iSprite->rank > clrank)
477 // choose texture to use depending on sprite type
478 switch(iSprite->sprite_type) {
480 thisTexture = CLTexture_stratus;
483 thisTexture = CLTexture_cumulus;
486 // in practice there is no texture switch (atm)
487 if( previousTexture != thisTexture ) {
488 previousTexture = thisTexture;
489 glBindTexture(GL_TEXTURE_2D, cloudTextures[thisTexture]->getHandle());
493 sgSubVec3( translate, iSprite->pos, deltaPos);
496 // flipx and flipy are random texture flip flags, this gives more random clouds
497 float flipx = (float) ( iSprite->rank & 1 );
498 float flipy = (float) ( (iSprite->rank >> 1) & 1 );
499 // cu texture have a flat bottom so we can't do a vertical flip
500 if( iSprite->sprite_type == CLbox_cumulus )
502 // if( iSprite->sprite_type == CLbox_stratus )
504 // adjust colors depending on cloud type
505 // TODO : rewrite that later, still experimental
506 switch(iSprite->sprite_type) {
509 sgScaleVec3(iSprite->l0, 0.8f * dark);
510 sgScaleVec3(iSprite->l1, 0.8f * dark);
511 sgScaleVec3(iSprite->l2, dark);
512 sgScaleVec3(iSprite->l3, dark);
516 if( familly == CLFamilly_st ) {
517 sgScaleVec3(iSprite->l0, 0.8f);
518 sgScaleVec3(iSprite->l1, 0.8f);
519 sgScaleVec3(iSprite->l2, 0.8f);
520 sgScaleVec3(iSprite->l3, 0.8f);
522 sgScaleVec3(iSprite->l0, 0.7f);
523 sgScaleVec3(iSprite->l1, 0.7f);
524 sgScaleVec3(iSprite->l2, 0.7f);
525 sgScaleVec3(iSprite->l3, 0.7f);
529 // darker bottom than top
530 sgScaleVec3(iSprite->l0, 0.8f);
531 sgScaleVec3(iSprite->l1, 0.8f);
534 float r = iSprite->r * 0.5f;
536 sgVec4 l0, l1, l2, l3;
537 sgCopyVec4 ( l0, iSprite->l0 );
538 sgCopyVec4 ( l1, iSprite->l1 );
539 sgCopyVec4 ( l2, iSprite->l2 );
540 sgCopyVec4 ( l3, iSprite->l3 );
542 // now clouds at the far plane are half blended
543 sgScaleVec4( l0, t );
544 sgScaleVec4( l1, t );
545 sgScaleVec4( l2, t );
546 sgScaleVec4( l3, t );
548 if( iSprite->rank == clrank ) {
549 sgScaleVec4( l0, clfadeinrank );
550 sgScaleVec4( l1, clfadeinrank );
551 sgScaleVec4( l2, clfadeinrank );
552 sgScaleVec4( l3, clfadeinrank );
554 // compute the rotations so that the quad is facing the camera
556 sgSetVec3( pos, translate[SG_X], translate[SG_Z], translate[SG_Y] );
557 sgCopyVec3( translate, pos );
558 sgNormaliseVec3( translate );
560 // change view angle when near a sprite
561 sgVec3 trans={translate[0], translate[2], translate[1]};
562 float angle = sgScalarProductVec3( SGCloudField::view_vec, trans );
563 if( fabs(angle) < 0.85f ) {
564 // view not ok from under
565 sgSetVec3( translate, -SGCloudField::view_vec[0],-SGCloudField::view_vec[2],-SGCloudField::view_vec[1] );
566 // sgSetVec3( l0,1,0,0 );
567 // sgSetVec3( l1,1,0,0 );
568 // sgSetVec3( l2,1,0,0 );
569 // sgSetVec3( l3,1,0,0 );
572 sgVec3 x, y, up = {0.0f, 0.0f, 1.0f};
573 sgVectorProductVec3(x, translate, up);
574 sgVectorProductVec3(y, x, translate);
580 sgSetVec3( left, iSprite->pos[SG_X], iSprite->pos[SG_Z], iSprite->pos[SG_Y]);
582 sgCopyVec3( left, pos );
584 sgAddVec3 (right, left, x);
589 glTexCoord2f(flipx, 1.0f - flipy);
592 glTexCoord2f(1.0f - flipx, 1.0f - flipy);
594 sgScaleVec3( y, 2.0 );
596 sgAddVec3( right, y);
598 glTexCoord2f(1.0f - flipx, flipy);
601 glTexCoord2f(flipx, flipy);
610 // compute rotations so that a quad is facing the camera
611 // TODO:change obsolete code because we dont use glrotate anymore
612 void SGNewCloud::CalcAngles(sgVec3 refpos, sgVec3 FakeEyePos, float *angleY, float *angleX) {
613 sgVec3 upAux, lookAt, objToCamProj, objToCam;
616 sgSetVec3(objToCamProj, -FakeEyePos[SG_X] + refpos[SG_X], -FakeEyePos[SG_Z] + refpos[SG_Z], 0.0f);
617 sgNormaliseVec3(objToCamProj);
619 sgSetVec3(lookAt, 0.0f, 1.0f, 0.0f);
620 sgVectorProductVec3(upAux, lookAt, objToCamProj);
621 angle = sgScalarProductVec3(lookAt, objToCamProj);
622 if( (angle < 0.9999f) && (angle > -0.9999f) ) {
623 angle = acos(angle) * 180.0f / SG_PI;
624 if( upAux[2] < 0.0f )
629 sgSetVec3(objToCam, -FakeEyePos[SG_X] + refpos[SG_X], -FakeEyePos[SG_Z] + refpos[SG_Z], -FakeEyePos[SG_Y] + refpos[SG_Y]);
630 sgNormaliseVec3(objToCam);
632 angle2 = sgScalarProductVec3(objToCamProj, objToCam);
633 if( (angle2 < 0.9999f) && (angle2 > -0.9999f) ) {
634 angle2 = -acos(angle2) * 180.0f / SG_PI;
635 if( objToCam[2] > 0.0f )
646 // draw a cloud but this time we use the impostor texture
647 void SGNewCloud::RenderBB(sgVec3 deltaPos, bool first_time, float dist_center) {
650 sgSubVec3( translate, center, deltaPos);
652 // blend clouds with sky based on distance to limit the contrast of distant cloud
653 float CloudVisFade = (1.0f * SGCloudField::get_CloudVis());
655 float t = 1.0f - (dist_center - 1.0*radius) / CloudVisFade;
662 glColor4f(t, t, t, t);
664 // compute the rotations so that the quad is facing the camera
666 sgSetVec3( pos, translate[SG_X], translate[SG_Z], translate[SG_Y] );
667 sgCopyVec3( translate, pos );
668 sgNormaliseVec3( translate );
669 sgVec3 x, y, up = {0.0f, 0.0f, 1.0f};
670 sgVectorProductVec3(x, translate, up);
671 sgVectorProductVec3(y, x, translate);
673 sgCopyVec3( rotX, x );
674 sgCopyVec3( rotY, y );
675 } else if(fabs(sgScalarProductVec3(rotX, x)) < 0.93f || fabs(sgScalarProductVec3(rotY, y)) < 0.93f ) {
676 // ask for a redraw of this impostor if the view angle changed too much
677 sgCopyVec3( rotX, x );
678 sgCopyVec3( rotY, y );
679 cldCache->invalidate(cloudId, bbId);
685 sgCopyVec3( left, pos );
687 sgAddVec3 (right, left, x);
691 glTexCoord2f(0.0f, 0.0f);
693 glTexCoord2f(1.0f, 0.0f);
695 sgScaleVec3( y, 2.0 );
697 sgAddVec3( right, y);
698 glTexCoord2f(1.0f, 1.0f);
700 glTexCoord2f(0.0f, 1.0f);
705 int age = cldCache->queryImpostorAge(bbId);
706 // draw a red border for the newly generated BBs else draw a white border
712 glBindTexture(GL_TEXTURE_2D, 0);
713 glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
720 glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
726 // determine if it is a good idea to use an impostor to render the cloud
727 bool SGNewCloud::isBillboardable(float dist) {
729 if( dist <= ( 2.1f * radius ) ) {
733 if( (dist-radius) <= nearRadius ) {
734 // near clouds we don't want to use BB
742 // render the cloud, fakepos is a relative position inside the cloud field
743 void SGNewCloud::Render(sgVec3 FakeEyePos) {
747 sgCopyVec3( deltaPos, FakeEyePos);
748 sgSubVec3( dist, center, FakeEyePos);
749 float dist_center = sgLengthVec3(dist);
752 fadetimer += SGCloudField::timer_dt;
753 if( fadetimer > duration + pauseLength ) {
754 // fade out after fade in, and vice versa
755 direction = ! direction;
760 if( !isBillboardable(dist_center) ) {
761 // not a good candidate for impostors, draw a real cloud
762 Render3Dcloud(false, FakeEyePos, deltaPos, dist_center);
765 bool first_time = false;
766 // lets use our impostor
768 texID = cldCache->QueryTexID(cloudId, bbId);
770 // ok someone took our impostor, so allocate a new one
772 // allocate a new Impostor
773 bbId = cldCache->alloc(cloudId);
774 texID = cldCache->QueryTexID(cloudId, bbId);
778 // no more free texture in the pool
779 Render3Dcloud(false, FakeEyePos, deltaPos, dist_center);
781 float angleX=0.0f, angleY=0.0f;
783 // force a redraw of the impostor if the cloud shape has changed enought
784 float step = ( list_spriteDef.size() * (direction ? fadetimer : duration-fadetimer)) / duration;
785 if( fabs(step - last_step) > 0.5f )
786 cldCache->invalidate(cloudId, bbId);
788 if( ! cldCache->isBbValid( cloudId, bbId, angleY, angleX)) {
789 // we must build or rebuild this billboard
790 // start render to texture
791 cldCache->beginCapture();
792 // set transformation matrices
793 cldCache->setRadius(radius, dist_center);
794 gluLookAt(FakeEyePos[SG_X], FakeEyePos[SG_Z], FakeEyePos[SG_Y], center[SG_X], center[SG_Z], center[SG_Y], 0.0, 0.0, 1.0);
796 Render3Dcloud(true, FakeEyePos, deltaPos, dist_center);
797 // save rotation angles for later use
798 // TODO:this is not ok
799 cldCache->setReference(cloudId, bbId, angleY, angleX);
800 // save the rendered cloud into the cache
801 cldCache->setTextureData( bbId );
802 // finish render to texture and go back into standard context
803 cldCache->endCapture();
805 // draw the newly built BB or an old one
806 glBindTexture(GL_TEXTURE_2D, texID);
807 RenderBB(deltaPos, first_time, dist_center);