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OgreMath.cpp @ 44

Last change on this file since 44 was 5, checked in by anonymous, 17 years ago
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1	/*
2	-----------------------------------------------------------------------------
3	This source file is part of OGRE
4	(Object-oriented Graphics Rendering Engine)
5	For the latest info, see http://www.ogre3d.org/
6
7	Copyright (c) 2000-2006 Torus Knot Software Ltd
8	Also see acknowledgements in Readme.html
9
10	This program is free software; you can redistribute it and/or modify it under
11	the terms of the GNU Lesser General Public License as published by the Free Software
12	Foundation; either version 2 of the License, or (at your option) any later
13	version.
14
15	This program is distributed in the hope that it will be useful, but WITHOUT
16	ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
17	FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
18
19	You should have received a copy of the GNU Lesser General Public License along with
20	this program; if not, write to the Free Software Foundation, Inc., 59 Temple
21	Place - Suite 330, Boston, MA 02111-1307, USA, or go to
22	http://www.gnu.org/copyleft/lesser.txt.
23
24	You may alternatively use this source under the terms of a specific version of
25	the OGRE Unrestricted License provided you have obtained such a license from
26	Torus Knot Software Ltd.
27	-----------------------------------------------------------------------------
28	*/
29	#include "OgreStableHeaders.h"
30
31	#include "OgreMath.h"
32	#include "asm_math.h"
33	#include "OgreVector2.h"
34	#include "OgreVector3.h"
35	#include "OgreVector4.h"
36	#include "OgreRay.h"
37	#include "OgreSphere.h"
38	#include "OgreAxisAlignedBox.h"
39	#include "OgrePlane.h"
40
41
42	namespace Ogre
43	{
44
45	const Real Math::POS_INFINITY = std::numeric_limits<Real>::infinity();
46	const Real Math::NEG_INFINITY = -std::numeric_limits<Real>::infinity();
47	const Real Math::PI = Real( 4.0 * atan( 1.0 ) );
48	const Real Math::TWO_PI = Real( 2.0 * PI );
49	const Real Math::HALF_PI = Real( 0.5 * PI );
50	const Real Math::fDeg2Rad = PI / Real(180.0);
51	const Real Math::fRad2Deg = Real(180.0) / PI;
52
53	int Math::mTrigTableSize;
54	Math::AngleUnit Math::msAngleUnit;
55
56	Real Math::mTrigTableFactor;
57	Real *Math::mSinTable = NULL;
58	Real *Math::mTanTable = NULL;
59
60	//-----------------------------------------------------------------------
61	Math::Math( unsigned int trigTableSize )
62	{
63	msAngleUnit = AU_DEGREE;
64
65	mTrigTableSize = trigTableSize;
66	mTrigTableFactor = mTrigTableSize / Math::TWO_PI;
67
68	mSinTable = new Real[mTrigTableSize];
69	mTanTable = new Real[mTrigTableSize];
70
71	buildTrigTables();
72	}
73
74	//-----------------------------------------------------------------------
75	Math::~Math()
76	{
77	delete [] mSinTable;
78	delete [] mTanTable;
79	}
80
81	//-----------------------------------------------------------------------
82	void Math::buildTrigTables(void)
83	{
84	// Build trig lookup tables
85	// Could get away with building only PI sized Sin table but simpler this
86	// way. Who cares, it'll ony use an extra 8k of memory anyway and I like
87	// simplicity.
88	Real angle;
89	for (int i = 0; i < mTrigTableSize; ++i)
90	{
91	angle = Math::TWO_PI * i / mTrigTableSize;
92	mSinTable[i] = sin(angle);
93	mTanTable[i] = tan(angle);
94	}
95	}
96	//-----------------------------------------------------------------------
97	Real Math::SinTable (Real fValue)
98	{
99	// Convert range to index values, wrap if required
100	int idx;
101	if (fValue >= 0)
102	{
103	idx = int(fValue * mTrigTableFactor) % mTrigTableSize;
104	}
105	else
106	{
107	idx = mTrigTableSize - (int(-fValue * mTrigTableFactor) % mTrigTableSize) - 1;
108	}
109
110	return mSinTable[idx];
111	}
112	//-----------------------------------------------------------------------
113	Real Math::TanTable (Real fValue)
114	{
115	// Convert range to index values, wrap if required
116	int idx = int(fValue *= mTrigTableFactor) % mTrigTableSize;
117	return mTanTable[idx];
118	}
119	//-----------------------------------------------------------------------
120	int Math::ISign (int iValue)
121	{
122	return ( iValue > 0 ? +1 : ( iValue < 0 ? -1 : 0 ) );
123	}
124	//-----------------------------------------------------------------------
125	Radian Math::ACos (Real fValue)
126	{
127	if ( -1.0 < fValue )
128	{
129	if ( fValue < 1.0 )
130	return Radian(acos(fValue));
131	else
132	return Radian(0.0);
133	}
134	else
135	{
136	return Radian(PI);
137	}
138	}
139	//-----------------------------------------------------------------------
140	Radian Math::ASin (Real fValue)
141	{
142	if ( -1.0 < fValue )
143	{
144	if ( fValue < 1.0 )
145	return Radian(asin(fValue));
146	else
147	return Radian(HALF_PI);
148	}
149	else
150	{
151	return Radian(-HALF_PI);
152	}
153	}
154	//-----------------------------------------------------------------------
155	Real Math::Sign (Real fValue)
156	{
157	if ( fValue > 0.0 )
158	return 1.0;
159
160	if ( fValue < 0.0 )
161	return -1.0;
162
163	return 0.0;
164	}
165	//-----------------------------------------------------------------------
166	Real Math::InvSqrt(Real fValue)
167	{
168	return Real(asm_rsq(fValue));
169	}
170	//-----------------------------------------------------------------------
171	Real Math::UnitRandom ()
172	{
173	return asm_rand() / asm_rand_max();
174	}
175
176	//-----------------------------------------------------------------------
177	Real Math::RangeRandom (Real fLow, Real fHigh)
178	{
179	return (fHigh-fLow)*UnitRandom() + fLow;
180	}
181
182	//-----------------------------------------------------------------------
183	Real Math::SymmetricRandom ()
184	{
185	return 2.0f * UnitRandom() - 1.0f;
186	}
187
188	//-----------------------------------------------------------------------
189	void Math::setAngleUnit(Math::AngleUnit unit)
190	{
191	msAngleUnit = unit;
192	}
193	//-----------------------------------------------------------------------
194	Math::AngleUnit Math::getAngleUnit(void)
195	{
196	return msAngleUnit;
197	}
198	//-----------------------------------------------------------------------
199	Real Math::AngleUnitsToRadians(Real angleunits)
200	{
201	if (msAngleUnit == AU_DEGREE)
202	return angleunits * fDeg2Rad;
203	else
204	return angleunits;
205	}
206
207	//-----------------------------------------------------------------------
208	Real Math::RadiansToAngleUnits(Real radians)
209	{
210	if (msAngleUnit == AU_DEGREE)
211	return radians * fRad2Deg;
212	else
213	return radians;
214	}
215
216	//-----------------------------------------------------------------------
217	Real Math::AngleUnitsToDegrees(Real angleunits)
218	{
219	if (msAngleUnit == AU_RADIAN)
220	return angleunits * fRad2Deg;
221	else
222	return angleunits;
223	}
224
225	//-----------------------------------------------------------------------
226	Real Math::DegreesToAngleUnits(Real degrees)
227	{
228	if (msAngleUnit == AU_RADIAN)
229	return degrees * fDeg2Rad;
230	else
231	return degrees;
232	}
233
234	//-----------------------------------------------------------------------
235	bool Math::pointInTri2D(const Vector2& p, const Vector2& a,
236	const Vector2& b, const Vector2& c)
237	{
238	// Winding must be consistent from all edges for point to be inside
239	Vector2 v1, v2;
240	Real dot[3];
241	bool zeroDot[3];
242
243	v1 = b - a;
244	v2 = p - a;
245
246	// Note we don't care about normalisation here since sign is all we need
247	// It means we don't have to worry about magnitude of cross products either
248	dot[0] = v1.crossProduct(v2);
249	zeroDot[0] = Math::RealEqual(dot[0], 0.0f, 1e-3);
250
251
252	v1 = c - b;
253	v2 = p - b;
254
255	dot[1] = v1.crossProduct(v2);
256	zeroDot[1] = Math::RealEqual(dot[1], 0.0f, 1e-3);
257
258	// Compare signs (ignore colinear / coincident points)
259	if(!zeroDot[0] && !zeroDot[1]
260	&& Math::Sign(dot[0]) != Math::Sign(dot[1]))
261	{
262	return false;
263	}
264
265	v1 = a - c;
266	v2 = p - c;
267
268	dot[2] = v1.crossProduct(v2);
269	zeroDot[2] = Math::RealEqual(dot[2], 0.0f, 1e-3);
270	// Compare signs (ignore colinear / coincident points)
271	if((!zeroDot[0] && !zeroDot[2]
272	&& Math::Sign(dot[0]) != Math::Sign(dot[2])) \|\|
273	(!zeroDot[1] && !zeroDot[2]
274	&& Math::Sign(dot[1]) != Math::Sign(dot[2])))
275	{
276	return false;
277	}
278
279
280	return true;
281	}
282	//-----------------------------------------------------------------------
283	bool Math::pointInTri3D(const Vector3& p, const Vector3& a,
284	const Vector3& b, const Vector3& c, const Vector3& normal)
285	{
286	// Winding must be consistent from all edges for point to be inside
287	Vector3 v1, v2;
288	Real dot[3];
289	bool zeroDot[3];
290
291	v1 = b - a;
292	v2 = p - a;
293
294	// Note we don't care about normalisation here since sign is all we need
295	// It means we don't have to worry about magnitude of cross products either
296	dot[0] = v1.crossProduct(v2).dotProduct(normal);
297	zeroDot[0] = Math::RealEqual(dot[0], 0.0f, 1e-3);
298
299
300	v1 = c - b;
301	v2 = p - b;
302
303	dot[1] = v1.crossProduct(v2).dotProduct(normal);
304	zeroDot[1] = Math::RealEqual(dot[1], 0.0f, 1e-3);
305
306	// Compare signs (ignore colinear / coincident points)
307	if(!zeroDot[0] && !zeroDot[1]
308	&& Math::Sign(dot[0]) != Math::Sign(dot[1]))
309	{
310	return false;
311	}
312
313	v1 = a - c;
314	v2 = p - c;
315
316	dot[2] = v1.crossProduct(v2).dotProduct(normal);
317	zeroDot[2] = Math::RealEqual(dot[2], 0.0f, 1e-3);
318	// Compare signs (ignore colinear / coincident points)
319	if((!zeroDot[0] && !zeroDot[2]
320	&& Math::Sign(dot[0]) != Math::Sign(dot[2])) \|\|
321	(!zeroDot[1] && !zeroDot[2]
322	&& Math::Sign(dot[1]) != Math::Sign(dot[2])))
323	{
324	return false;
325	}
326
327
328	return true;
329	}
330	//-----------------------------------------------------------------------
331	bool Math::RealEqual( Real a, Real b, Real tolerance )
332	{
333	if (fabs(b-a) <= tolerance)
334	return true;
335	else
336	return false;
337	}
338
339	//-----------------------------------------------------------------------
340	std::pair<bool, Real> Math::intersects(const Ray& ray, const Plane& plane)
341	{
342
343	Real denom = plane.normal.dotProduct(ray.getDirection());
344	if (Math::Abs(denom) < std::numeric_limits<Real>::epsilon())
345	{
346	// Parallel
347	return std::pair<bool, Real>(false, 0);
348	}
349	else
350	{
351	Real nom = plane.normal.dotProduct(ray.getOrigin()) + plane.d;
352	Real t = -(nom/denom);
353	return std::pair<bool, Real>(t >= 0, t);
354	}
355
356	}
357	//-----------------------------------------------------------------------
358	std::pair<bool, Real> Math::intersects(const Ray& ray,
359	const std::vector<Plane>& planes, bool normalIsOutside)
360	{
361	std::vector<Plane>::const_iterator planeit, planeitend;
362	planeitend = planes.end();
363	bool allInside = true;
364	std::pair<bool, Real> ret;
365	ret.first = false;
366	ret.second = 0.0f;
367
368	// derive side
369	// NB we don't pass directly since that would require Plane::Side in
370	// interface, which results in recursive includes since Math is so fundamental
371	Plane::Side outside = normalIsOutside ? Plane::POSITIVE_SIDE : Plane::NEGATIVE_SIDE;
372
373	for (planeit = planes.begin(); planeit != planeitend; ++planeit)
374	{
375	const Plane& plane = *planeit;
376	// is origin outside?
377	if (plane.getSide(ray.getOrigin()) == outside)
378	{
379	allInside = false;
380	// Test single plane
381	std::pair<bool, Real> planeRes =
382	ray.intersects(plane);
383	if (planeRes.first)
384	{
385	// Ok, we intersected
386	ret.first = true;
387	// Use the most distant result since convex volume
388	ret.second = std::max(ret.second, planeRes.second);
389	}
390	}
391	}
392
393	if (allInside)
394	{
395	// Intersecting at 0 distance since inside the volume!
396	ret.first = true;
397	ret.second = 0.0f;
398	}
399
400	return ret;
401	}
402	//-----------------------------------------------------------------------
403	std::pair<bool, Real> Math::intersects(const Ray& ray,
404	const std::list<Plane>& planes, bool normalIsOutside)
405	{
406	std::list<Plane>::const_iterator planeit, planeitend;
407	planeitend = planes.end();
408	bool allInside = true;
409	std::pair<bool, Real> ret;
410	ret.first = false;
411	ret.second = 0.0f;
412
413	// derive side
414	// NB we don't pass directly since that would require Plane::Side in
415	// interface, which results in recursive includes since Math is so fundamental
416	Plane::Side outside = normalIsOutside ? Plane::POSITIVE_SIDE : Plane::NEGATIVE_SIDE;
417
418	for (planeit = planes.begin(); planeit != planeitend; ++planeit)
419	{
420	const Plane& plane = *planeit;
421	// is origin outside?
422	if (plane.getSide(ray.getOrigin()) == outside)
423	{
424	allInside = false;
425	// Test single plane
426	std::pair<bool, Real> planeRes =
427	ray.intersects(plane);
428	if (planeRes.first)
429	{
430	// Ok, we intersected
431	ret.first = true;
432	// Use the most distant result since convex volume
433	ret.second = std::max(ret.second, planeRes.second);
434	}
435	}
436	}
437
438	if (allInside)
439	{
440	// Intersecting at 0 distance since inside the volume!
441	ret.first = true;
442	ret.second = 0.0f;
443	}
444
445	return ret;
446	}
447	//-----------------------------------------------------------------------
448	std::pair<bool, Real> Math::intersects(const Ray& ray, const Sphere& sphere,
449	bool discardInside)
450	{
451	const Vector3& raydir = ray.getDirection();
452	// Adjust ray origin relative to sphere center
453	const Vector3& rayorig = ray.getOrigin() - sphere.getCenter();
454	Real radius = sphere.getRadius();
455
456	// Check origin inside first
457	if (rayorig.squaredLength() <= radius*radius && discardInside)
458	{
459	return std::pair<bool, Real>(true, 0);
460	}
461
462	// Mmm, quadratics
463	// Build coeffs which can be used with std quadratic solver
464	// ie t = (-b +/- sqrt(b*b + 4ac)) / 2a
465	Real a = raydir.dotProduct(raydir);
466	Real b = 2 * rayorig.dotProduct(raydir);
467	Real c = rayorig.dotProduct(rayorig) - radius*radius;
468
469	// Calc determinant
470	Real d = (bb) - (4 a * c);
471	if (d < 0)
472	{
473	// No intersection
474	return std::pair<bool, Real>(false, 0);
475	}
476	else
477	{
478	// BTW, if d=0 there is one intersection, if d > 0 there are 2
479	// But we only want the closest one, so that's ok, just use the
480	// '-' version of the solver
481	Real t = ( -b - Math::Sqrt(d) ) / (2 * a);
482	if (t < 0)
483	t = ( -b + Math::Sqrt(d) ) / (2 * a);
484	return std::pair<bool, Real>(true, t);
485	}
486
487
488	}
489	//-----------------------------------------------------------------------
490	std::pair<bool, Real> Math::intersects(const Ray& ray, const AxisAlignedBox& box)
491	{
492	if (box.isNull()) return std::pair<bool, Real>(false, 0);
493	if (box.isInfinite()) return std::pair<bool, Real>(true, 0);
494
495	Real lowt = 0.0f;
496	Real t;
497	bool hit = false;
498	Vector3 hitpoint;
499	const Vector3& min = box.getMinimum();
500	const Vector3& max = box.getMaximum();
501	const Vector3& rayorig = ray.getOrigin();
502	const Vector3& raydir = ray.getDirection();
503
504	// Check origin inside first
505	if ( rayorig > min && rayorig < max )
506	{
507	return std::pair<bool, Real>(true, 0);
508	}
509
510	// Check each face in turn, only check closest 3
511	// Min x
512	if (rayorig.x <= min.x && raydir.x > 0)
513	{
514	t = (min.x - rayorig.x) / raydir.x;
515	if (t >= 0)
516	{
517	// Substitute t back into ray and check bounds and dist
518	hitpoint = rayorig + raydir * t;
519	if (hitpoint.y >= min.y && hitpoint.y <= max.y &&
520	hitpoint.z >= min.z && hitpoint.z <= max.z &&
521	(!hit \|\| t < lowt))
522	{
523	hit = true;
524	lowt = t;
525	}
526	}
527	}
528	// Max x
529	if (rayorig.x >= max.x && raydir.x < 0)
530	{
531	t = (max.x - rayorig.x) / raydir.x;
532	if (t >= 0)
533	{
534	// Substitute t back into ray and check bounds and dist
535	hitpoint = rayorig + raydir * t;
536	if (hitpoint.y >= min.y && hitpoint.y <= max.y &&
537	hitpoint.z >= min.z && hitpoint.z <= max.z &&
538	(!hit \|\| t < lowt))
539	{
540	hit = true;
541	lowt = t;
542	}
543	}
544	}
545	// Min y
546	if (rayorig.y <= min.y && raydir.y > 0)
547	{
548	t = (min.y - rayorig.y) / raydir.y;
549	if (t >= 0)
550	{
551	// Substitute t back into ray and check bounds and dist
552	hitpoint = rayorig + raydir * t;
553	if (hitpoint.x >= min.x && hitpoint.x <= max.x &&
554	hitpoint.z >= min.z && hitpoint.z <= max.z &&
555	(!hit \|\| t < lowt))
556	{
557	hit = true;
558	lowt = t;
559	}
560	}
561	}
562	// Max y
563	if (rayorig.y >= max.y && raydir.y < 0)
564	{
565	t = (max.y - rayorig.y) / raydir.y;
566	if (t >= 0)
567	{
568	// Substitute t back into ray and check bounds and dist
569	hitpoint = rayorig + raydir * t;
570	if (hitpoint.x >= min.x && hitpoint.x <= max.x &&
571	hitpoint.z >= min.z && hitpoint.z <= max.z &&
572	(!hit \|\| t < lowt))
573	{
574	hit = true;
575	lowt = t;
576	}
577	}
578	}
579	// Min z
580	if (rayorig.z <= min.z && raydir.z > 0)
581	{
582	t = (min.z - rayorig.z) / raydir.z;
583	if (t >= 0)
584	{
585	// Substitute t back into ray and check bounds and dist
586	hitpoint = rayorig + raydir * t;
587	if (hitpoint.x >= min.x && hitpoint.x <= max.x &&
588	hitpoint.y >= min.y && hitpoint.y <= max.y &&
589	(!hit \|\| t < lowt))
590	{
591	hit = true;
592	lowt = t;
593	}
594	}
595	}
596	// Max z
597	if (rayorig.z >= max.z && raydir.z < 0)
598	{
599	t = (max.z - rayorig.z) / raydir.z;
600	if (t >= 0)
601	{
602	// Substitute t back into ray and check bounds and dist
603	hitpoint = rayorig + raydir * t;
604	if (hitpoint.x >= min.x && hitpoint.x <= max.x &&
605	hitpoint.y >= min.y && hitpoint.y <= max.y &&
606	(!hit \|\| t < lowt))
607	{
608	hit = true;
609	lowt = t;
610	}
611	}
612	}
613
614	return std::pair<bool, Real>(hit, lowt);
615
616	}
617	//-----------------------------------------------------------------------
618	bool Math::intersects(const Ray& ray, const AxisAlignedBox& box,
619	Real* d1, Real* d2)
620	{
621	if (box.isNull())
622	return false;
623
624	if (box.isInfinite())
625	{
626	if (d1) *d1 = 0;
627	if (d2) *d2 = Math::POS_INFINITY;
628	return true;
629	}
630
631	const Vector3& min = box.getMinimum();
632	const Vector3& max = box.getMaximum();
633	const Vector3& rayorig = ray.getOrigin();
634	const Vector3& raydir = ray.getDirection();
635
636	Vector3 absDir;
637	absDir[0] = Math::Abs(raydir[0]);
638	absDir[1] = Math::Abs(raydir[1]);
639	absDir[2] = Math::Abs(raydir[2]);
640
641	// Sort the axis, ensure check minimise floating error axis first
642	int imax = 0, imid = 1, imin = 2;
643	if (absDir[0] < absDir[2])
644	{
645	imax = 2;
646	imin = 0;
647	}
648	if (absDir[1] < absDir[imin])
649	{
650	imid = imin;
651	imin = 1;
652	}
653	else if (absDir[1] > absDir[imax])
654	{
655	imid = imax;
656	imax = 1;
657	}
658
659	Real start = 0, end = Math::POS_INFINITY;
660
661	#define _CALC_AXIS(i) \
662	do { \
663	Real denom = 1 / raydir[i]; \
664	Real newstart = (min[i] - rayorig[i]) * denom; \
665	Real newend = (max[i] - rayorig[i]) * denom; \
666	if (newstart > newend) std::swap(newstart, newend); \
667	if (newstart > end \|\| newend < start) return false; \
668	if (newstart > start) start = newstart; \
669	if (newend < end) end = newend; \
670	} while(0)
671
672	// Check each axis in turn
673
674	_CALC_AXIS(imax);
675
676	if (absDir[imid] < std::numeric_limits<Real>::epsilon())
677	{
678	// Parallel with middle and minimise axis, check bounds only
679	if (rayorig[imid] < min[imid] \|\| rayorig[imid] > max[imid] \|\|
680	rayorig[imin] < min[imin] \|\| rayorig[imin] > max[imin])
681	return false;
682	}
683	else
684	{
685	_CALC_AXIS(imid);
686
687	if (absDir[imin] < std::numeric_limits<Real>::epsilon())
688	{
689	// Parallel with minimise axis, check bounds only
690	if (rayorig[imin] < min[imin] \|\| rayorig[imin] > max[imin])
691	return false;
692	}
693	else
694	{
695	_CALC_AXIS(imin);
696	}
697	}
698	#undef _CALC_AXIS
699
700	if (d1) *d1 = start;
701	if (d2) *d2 = end;
702
703	return true;
704	}
705	//-----------------------------------------------------------------------
706	std::pair<bool, Real> Math::intersects(const Ray& ray, const Vector3& a,
707	const Vector3& b, const Vector3& c, const Vector3& normal,
708	bool positiveSide, bool negativeSide)
709	{
710	//
711	// Calculate intersection with plane.
712	//
713	Real t;
714	{
715	Real denom = normal.dotProduct(ray.getDirection());
716
717	// Check intersect side
718	if (denom > + std::numeric_limits<Real>::epsilon())
719	{
720	if (!negativeSide)
721	return std::pair<bool, Real>(false, 0);
722	}
723	else if (denom < - std::numeric_limits<Real>::epsilon())
724	{
725	if (!positiveSide)
726	return std::pair<bool, Real>(false, 0);
727	}
728	else
729	{
730	// Parallel or triangle area is close to zero when
731	// the plane normal not normalised.
732	return std::pair<bool, Real>(false, 0);
733	}
734
735	t = normal.dotProduct(a - ray.getOrigin()) / denom;
736
737	if (t < 0)
738	{
739	// Intersection is behind origin
740	return std::pair<bool, Real>(false, 0);
741	}
742	}
743
744	//
745	// Calculate the largest area projection plane in X, Y or Z.
746	//
747	size_t i0, i1;
748	{
749	Real n0 = Math::Abs(normal[0]);
750	Real n1 = Math::Abs(normal[1]);
751	Real n2 = Math::Abs(normal[2]);
752
753	i0 = 1; i1 = 2;
754	if (n1 > n2)
755	{
756	if (n1 > n0) i0 = 0;
757	}
758	else
759	{
760	if (n2 > n0) i1 = 0;
761	}
762	}
763
764	//
765	// Check the intersection point is inside the triangle.
766	//
767	{
768	Real u1 = b[i0] - a[i0];
769	Real v1 = b[i1] - a[i1];
770	Real u2 = c[i0] - a[i0];
771	Real v2 = c[i1] - a[i1];
772	Real u0 = t * ray.getDirection()[i0] + ray.getOrigin()[i0] - a[i0];
773	Real v0 = t * ray.getDirection()[i1] + ray.getOrigin()[i1] - a[i1];
774
775	Real alpha = u0 * v2 - u2 * v0;
776	Real beta = u1 * v0 - u0 * v1;
777	Real area = u1 * v2 - u2 * v1;
778
779	// epsilon to avoid float precision error
780	const Real EPSILON = 1e-3f;
781
782	Real tolerance = - EPSILON * area;
783
784	if (area > 0)
785	{
786	if (alpha < tolerance \|\| beta < tolerance \|\| alpha+beta > area-tolerance)
787	return std::pair<bool, Real>(false, 0);
788	}
789	else
790	{
791	if (alpha > tolerance \|\| beta > tolerance \|\| alpha+beta < area-tolerance)
792	return std::pair<bool, Real>(false, 0);
793	}
794	}
795
796	return std::pair<bool, Real>(true, t);
797	}
798	//-----------------------------------------------------------------------
799	std::pair<bool, Real> Math::intersects(const Ray& ray, const Vector3& a,
800	const Vector3& b, const Vector3& c,
801	bool positiveSide, bool negativeSide)
802	{
803	Vector3 normal = calculateBasicFaceNormalWithoutNormalize(a, b, c);
804	return intersects(ray, a, b, c, normal, positiveSide, negativeSide);
805	}
806	//-----------------------------------------------------------------------
807	bool Math::intersects(const Sphere& sphere, const AxisAlignedBox& box)
808	{
809	if (box.isNull()) return false;
810	if (box.isInfinite()) return true;
811
812	// Use splitting planes
813	const Vector3& center = sphere.getCenter();
814	Real radius = sphere.getRadius();
815	const Vector3& min = box.getMinimum();
816	const Vector3& max = box.getMaximum();
817
818	// Arvo's algorithm
819	Real s, d = 0;
820	for (int i = 0; i < 3; ++i)
821	{
822	if (center.ptr()[i] < min.ptr()[i])
823	{
824	s = center.ptr()[i] - min.ptr()[i];
825	d += s * s;
826	}
827	else if(center.ptr()[i] > max.ptr()[i])
828	{
829	s = center.ptr()[i] - max.ptr()[i];
830	d += s * s;
831	}
832	}
833	return d <= radius * radius;
834
835	}
836	//-----------------------------------------------------------------------
837	bool Math::intersects(const Plane& plane, const AxisAlignedBox& box)
838	{
839	return (plane.getSide(box) == Plane::BOTH_SIDE);
840	}
841	//-----------------------------------------------------------------------
842	bool Math::intersects(const Sphere& sphere, const Plane& plane)
843	{
844	return (
845	Math::Abs(plane.getDistance(sphere.getCenter()))
846	<= sphere.getRadius() );
847	}
848	//-----------------------------------------------------------------------
849	Vector3 Math::calculateTangentSpaceVector(
850	const Vector3& position1, const Vector3& position2, const Vector3& position3,
851	Real u1, Real v1, Real u2, Real v2, Real u3, Real v3)
852	{
853	//side0 is the vector along one side of the triangle of vertices passed in,
854	//and side1 is the vector along another side. Taking the cross product of these returns the normal.
855	Vector3 side0 = position1 - position2;
856	Vector3 side1 = position3 - position1;
857	//Calculate face normal
858	Vector3 normal = side1.crossProduct(side0);
859	normal.normalise();
860	//Now we use a formula to calculate the tangent.
861	Real deltaV0 = v1 - v2;
862	Real deltaV1 = v3 - v1;
863	Vector3 tangent = deltaV1 * side0 - deltaV0 * side1;
864	tangent.normalise();
865	//Calculate binormal
866	Real deltaU0 = u1 - u2;
867	Real deltaU1 = u3 - u1;
868	Vector3 binormal = deltaU1 * side0 - deltaU0 * side1;
869	binormal.normalise();
870	//Now, we take the cross product of the tangents to get a vector which
871	//should point in the same direction as our normal calculated above.
872	//If it points in the opposite direction (the dot product between the normals is less than zero),
873	//then we need to reverse the s and t tangents.
874	//This is because the triangle has been mirrored when going from tangent space to object space.
875	//reverse tangents if necessary
876	Vector3 tangentCross = tangent.crossProduct(binormal);
877	if (tangentCross.dotProduct(normal) < 0.0f)
878	{
879	tangent = -tangent;
880	binormal = -binormal;
881	}
882
883	return tangent;
884
885	}
886	//-----------------------------------------------------------------------
887	Matrix4 Math::buildReflectionMatrix(const Plane& p)
888	{
889	return Matrix4(
890	-2 * p.normal.x * p.normal.x + 1, -2 * p.normal.x * p.normal.y, -2 * p.normal.x * p.normal.z, -2 * p.normal.x * p.d,
891	-2 * p.normal.y * p.normal.x, -2 * p.normal.y * p.normal.y + 1, -2 * p.normal.y * p.normal.z, -2 * p.normal.y * p.d,
892	-2 * p.normal.z * p.normal.x, -2 * p.normal.z * p.normal.y, -2 * p.normal.z * p.normal.z + 1, -2 * p.normal.z * p.d,
893	0, 0, 0, 1);
894	}
895	//-----------------------------------------------------------------------
896	Vector4 Math::calculateFaceNormal(const Vector3& v1, const Vector3& v2, const Vector3& v3)
897	{
898	Vector3 normal = calculateBasicFaceNormal(v1, v2, v3);
899	// Now set up the w (distance of tri from origin
900	return Vector4(normal.x, normal.y, normal.z, -(normal.dotProduct(v1)));
901	}
902	//-----------------------------------------------------------------------
903	Vector3 Math::calculateBasicFaceNormal(const Vector3& v1, const Vector3& v2, const Vector3& v3)
904	{
905	Vector3 normal = (v2 - v1).crossProduct(v3 - v1);
906	normal.normalise();
907	return normal;
908	}
909	//-----------------------------------------------------------------------
910	Vector4 Math::calculateFaceNormalWithoutNormalize(const Vector3& v1, const Vector3& v2, const Vector3& v3)
911	{
912	Vector3 normal = calculateBasicFaceNormalWithoutNormalize(v1, v2, v3);
913	// Now set up the w (distance of tri from origin)
914	return Vector4(normal.x, normal.y, normal.z, -(normal.dotProduct(v1)));
915	}
916	//-----------------------------------------------------------------------
917	Vector3 Math::calculateBasicFaceNormalWithoutNormalize(const Vector3& v1, const Vector3& v2, const Vector3& v3)
918	{
919	Vector3 normal = (v2 - v1).crossProduct(v3 - v1);
920	return normal;
921	}
922	//-----------------------------------------------------------------------
923	Real Math::gaussianDistribution(Real x, Real offset, Real scale)
924	{
925	Real nom = Math::Exp(
926	-Math::Sqr(x - offset) / (2 * Math::Sqr(scale)));
927	Real denom = scale * Math::Sqrt(2 * Math::PI);
928
929	return nom / denom;
930
931	}
932	}

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source: downloads/ogre/OgreMain/src/OgreMath.cpp @ 44

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