332 bool Triangle::intersect_bbox(const BBox &bbox) const

   333 {

   334 	const Vector3 boxcenter = (bbox.L+bbox.H)*0.5;

   335 	const Vector3 boxhalfsize = (bbox.H-bbox.L)*0.5;

   336 	const Vector3 v0 = A->P - boxcenter;

   337 	const Vector3 v1 = B->P - boxcenter;

   338 	const Vector3 v2 = C->P - boxcenter;

   339 	const Vector3 e0 = v1-v0;

   340 	const Vector3 e1 = v2-v1;

   341 	const Vector3 e2 = v0-v2;

   342 

   343 	Float fex = fabsf(e0.x);

   344 	Float fey = fabsf(e0.y);

   345 	Float fez = fabsf(e0.z);

   346 

   347 	Float p0,p1,p2,min,max,rad;

   348 

   349 	p0 = e0.z*v0.y - e0.y*v0.z;

   350 	p2 = e0.z*v2.y - e0.y*v2.z;

   351 	if(p0<p2) {min=p0; max=p2;} else {min=p2; max=p0;}

   352 	rad = fez * boxhalfsize.y + fey * boxhalfsize.z;

   353 	if(min>rad || max<-rad) return false;

   354 

   355 	p0 = -e0.z*v0.x + e0.x*v0.z;

   356 	p2 = -e0.z*v2.x + e0.x*v2.z;

   357 	if(p0<p2) {min=p0; max=p2;} else {min=p2; max=p0;}

   358 	rad = fez * boxhalfsize.x + fex * boxhalfsize.z;

   359 	if(min>rad || max<-rad) return false;

   360 

   361 	p1 = e0.y*v1.x - e0.x*v1.y;

   362 	p2 = e0.y*v2.x - e0.x*v2.y;

   363 	if(p2<p1) {min=p2; max=p1;} else {min=p1; max=p2;}

   364 	rad = fey * boxhalfsize.x + fex * boxhalfsize.y;

   365 	if(min>rad || max<-rad) return false;

   366 

   367 	fex = fabsf(e1.x);

   368 	fey = fabsf(e1.y);

   369 	fez = fabsf(e1.z);

   370 

   371 	p0 = e1.z*v0.y - e1.y*v0.z;

   372 	p2 = e1.z*v2.y - e1.y*v2.z;

   373 	if(p0<p2) {min=p0; max=p2;} else {min=p2; max=p0;}

   374 	rad = fez * boxhalfsize.y + fey * boxhalfsize.z;

   375 	if(min>rad || max<-rad) return false;

   376 

   377 	p0 = -e1.z*v0.x + e1.x*v0.z;

   378 	p2 = -e1.z*v2.x + e1.x*v2.z;

   379 	if(p0<p2) {min=p0; max=p2;} else {min=p2; max=p0;}

   380 	rad = fez * boxhalfsize.x + fex * boxhalfsize.z;

   381 	if(min>rad || max<-rad) return false;

   382 

   383 	p0 = e1.y*v0.x - e1.x*v0.y;

   384 	p1 = e1.y*v1.x - e1.x*v1.y;

   385 	if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;}

   386 	rad = fey * boxhalfsize.x + fex * boxhalfsize.y;

   387 	if(min>rad || max<-rad) return false;

   388 

   389 	fex = fabsf(e2.x);

   390 	fey = fabsf(e2.y);

   391 	fez = fabsf(e2.z);

   392 

   393 	p0 = e2.z*v0.y - e2.y*v0.z;

   394 	p1 = e2.z*v1.y - e2.y*v1.z;

   395 	if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;}

   396 	rad = fez * boxhalfsize.y + fey * boxhalfsize.z;

   397 	if(min>rad || max<-rad) return false;

   398 

   399 	p0 = -e2.z*v0.x + e2.x*v0.z;

   400 	p1 = -e2.z*v1.x + e2.x*v1.z;

   401 	if(p0<p1) {min=p0; max=p1;} else {min=p1; max=p0;}

   402 	rad = fez * boxhalfsize.x + fex * boxhalfsize.z;

   403 	if(min>rad || max<-rad) return false;

   404 

   405 	p1 = e2.y*v1.x - e2.x*v1.y;

   406 	p2 = e2.y*v2.x - e2.x*v2.y;

   407 	if(p2<p1) {min=p2; max=p1;} else {min=p1; max=p2;}

   408 	rad = fey * boxhalfsize.x + fex * boxhalfsize.y;

   409 	if(min>rad || max<-rad) return false;

   410 

   411 	/* test overlap in the {x,y,z}-directions */

   412 	/* test in X-direction */

   413 	min = v0.x;

   414 	if (v1.x < min) min = v1.x;

   415 	if (v2.x < min) min = v2.x;

   416 	max = v0.x;

   417 	if (v1.x > max) max = v1.x;

   418 	if (v2.x > max) max = v2.x;

   419 	if(min>boxhalfsize.x || max<-boxhalfsize.x) return false;

   420 

   421 	/* test in Y-direction */

   422 	min = v0.y;

   423 	if (v1.y < min) min = v1.y;

   424 	if (v2.y < min) min = v2.y;

   425 	max = v0.y;

   426 	if (v1.y > max) max = v1.y;

   427 	if (v2.y > max) max = v2.y;

   428 	if(min>boxhalfsize.y || max<-boxhalfsize.y) return false;

   429 

   430 	/* test in Z-direction */

   431 	min = v0.z;

   432 	if (v1.z < min) min = v1.z;

   433 	if (v2.z < min) min = v2.z;

   434 	max = v0.z;

   435 	if (v1.z > max) max = v1.z;

   436 	if (v2.z > max) max = v2.z;

   437 	if(min>boxhalfsize.z || max<-boxhalfsize.z) return false;

   438 

   439 	/*  test if the box intersects the plane of the triangle */

   440 	Vector3 vmin,vmax;

   441 	Float v;

   442 	for(int q=0;q<3;q++)

   443 	{

   444 		v=v0[q];

   445 		if(N[q]>0.0f)

   446 		{

   447 			vmin.cell[q]=-boxhalfsize[q] - v;

   448 			vmax.cell[q]= boxhalfsize[q] - v;

   449 		}

   450 		else

   451 		{

   452 			vmin.cell[q]= boxhalfsize[q] - v;

   453 			vmax.cell[q]=-boxhalfsize[q] - v;

   454 		}

   455 	}

   456 	if(dot(N,vmin)>0.0f) return false;

   457 	if(dot(N,vmax)>=0.0f) return true;

   458 

   459 	return false;

   460 }

   461