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source: downloads/OgreMain/src/OgreShadowCameraSetupPlaneOptimal.cpp @ 3

Last change on this file since 3 was 3, checked in by anonymous, 17 years ago
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File size: 11.7 KB

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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) 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	*/
25
26	#include "OgreStableHeaders.h"
27	#include "OgreCommon.h"
28	#include "OgreSceneManager.h"
29	#include "OgreLight.h"
30	#include "OgreShadowCameraSetupPlaneOptimal.h"
31	#include "OgreNumerics.h"
32	#include "OgreCamera.h"
33	#include "OgreViewport.h"
34
35
36	namespace Ogre
37	{
38	// --------------------------------------------------------------------
39	Matrix4 PlaneOptimalShadowCameraSetup::computeConstrainedProjection(
40	const Vector4& pinhole,
41	const std::vector<Vector4>& fpoint,
42	const std::vector<Vector2>& constraint) const
43	{
44	// NOTE: will assume the z coordinates should be decided such that
45	// the first 3 points (in fpoint) will have post projective
46	// z coordinates of about +1 and the 4th (in fpoint) will have a
47	// post projective z coordinate of about -1.
48
49	// TODO: could use SVD to avoid arbitrarily choosing one
50	// matrix element to be 1.0 (and thereby fix the scale).
51
52	Matrix4 ret;
53	int i;
54	bool incrPrecision = false; // use to control numerical solving
55
56	if(fpoint.size() < 4 \|\| constraint.size() < 4) {
57	return Matrix4::IDENTITY;
58	}
59
60	// allocate memory
61	PreciseReal **mat = NULL;
62	PreciseReal **backmat = NULL;
63	{
64	mat = new PreciseReal*[11];
65	if(incrPrecision)
66	backmat = new PreciseReal*[11];
67	for(i=0; i<11; i++)
68	{
69	mat[i] = new PreciseReal[11];
70	if(incrPrecision)
71	backmat[i] = new PreciseReal[11];
72	}
73	}
74
75	// set up linear system to solve for all rows of projective matrix
76	// except for the 3rd which corresponds to mapping of z values
77
78	// we choose a nonzero element of the last row to set to the arbitrary
79	// constant 1.0.
80	int nzind = 3;
81	PreciseReal col[11];
82	PreciseReal backcol[11];
83
84	// fill in light position constraints
85	mat[0][0] = pinhole.x;
86	mat[0][1] = pinhole.y;
87	mat[0][2] = pinhole.z;
88	mat[0][3] = pinhole.w;
89	for(i=4; i<11; i++)
90	mat[0][i] = 0.0;
91	col[0] = 0.0;
92
93	for(i=0; i<11; i++)
94	mat[1][i] = 0.0;
95	mat[1][4] = pinhole.x;
96	mat[1][5] = pinhole.y;
97	mat[1][6] = pinhole.z;
98	mat[1][7] = pinhole.w;
99	col[1] = 0.0;
100
101	PreciseReal larr[4];
102	larr[0] = pinhole.x;
103	larr[1] = pinhole.y;
104	larr[2] = pinhole.z;
105	larr[3] = pinhole.w;
106	for(i=0; i<8; i++)
107	mat[2][i] = 0.0;
108	int ind = 8;
109	for(i=0; i<4; i++)
110	{
111	if(nzind == i)
112	continue;
113	mat[2][ind++] = larr[i];
114	}
115	col[2] = -larr[nzind];
116
117	// fill in all the other constraints
118	int row=3;
119	for(i=0; i<4; i++)
120	{
121	int j;
122	larr[0] = fpoint[i].x;
123	larr[1] = fpoint[i].y;
124	larr[2] = fpoint[i].z;
125	larr[3] = fpoint[i].w;
126
127	// lexel s coordinate constraint
128	for(j=0; j<4; j++)
129	mat[row][j] = larr[j];
130	for(j=4; j<8; j++)
131	mat[row][j] = 0.0;
132	ind=8;
133	for(j=0; j<4; j++)
134	{
135	if(nzind==j)
136	continue;
137	mat[row][ind++] = larr[j] * (-constraint[i].x);
138	}
139	col[row] = larr[nzind] * constraint[i].x;
140	++row;
141
142	// lexel t coordinate constraint
143	for(j=0; j<4; j++)
144	mat[row][j] = 0.0;
145	for(j=4; j<8; j++)
146	mat[row][j] = larr[j-4];
147
148	ind=8;
149	for(j=0; j<4; j++)
150	{
151	if(nzind==j)
152	continue;
153	mat[row][ind++] = larr[j] * (-constraint[i].y);
154	}
155	col[row] = larr[nzind] * constraint[i].y;
156	++row;
157	}
158
159	// copy the matrix and vector for later computation
160	if(incrPrecision)
161	{
162	for (i=0; i<11; i++)
163	{
164	for(int j=0; j<11; j++)
165	backmat[i][j] = mat[i][j];
166	backcol[i] = col[i];
167	}
168	}
169
170	// solve for the matrix elements
171	if(!NumericSolver::solveNxNLinearSysDestr(11, mat, col))
172	{
173	// error solving for projective matrix (rows 1,2,4)
174	}
175
176	// get a little more precision
177	if(incrPrecision)
178	{
179	for (int k=0; k<3; k++)
180	{
181	PreciseReal nvec[11];
182	for(i=0; i<11; i++)
183	{
184	int j;
185	nvec[i] = backmat[i][0] * col[0];
186	mat[i][0] = backmat[i][0];
187	for(j=1; j<11; j++)
188	{
189	nvec[i] += backmat[i][j] * col[j];
190	mat[i][j] = backmat[i][j];
191	}
192	nvec[i] -= backcol[i];
193	}
194	if(!NumericSolver::solveNxNLinearSysDestr(11, mat, nvec))
195	{
196	// error solving for increased precision rows 1,2,4
197	}
198	for(i=0; i<11; i++)
199	col[i] -= nvec[i];
200	}
201	}
202
203	PreciseReal row4[4];
204	ind = 8;
205	for(i=0; i<4; i++)
206	{
207	if (i == nzind)
208	row4[i] = 1.0;
209	else
210	row4[i] = col[ind++];
211	}
212
213
214	// now solve for the 3rd row which affects depth precision
215	PreciseReal zrow[4];
216
217	// we want the affine skew such that isoplanes of constant depth are parallel to
218	// the world plane of interest
219	// NOTE: recall we perturbed the last fpoint off the plane, so we'll again modify
220	// this one since we want 3 points on the plane = far plane, and 1 on the near plane
221	int nearind = 3;
222	for(i=0; i<3; i++)
223	{
224	mat[i][0] = fpoint[i].x;
225	mat[i][1] = fpoint[i].y;
226	mat[i][2] = fpoint[i].z;
227	mat[i][3] = 1.0;
228	zrow[i] = (row4[0] * fpoint[i].x +
229	row4[1] * fpoint[i].y +
230	row4[2] * fpoint[i].z +
231	row4[3]) * 0.99 ;
232	}
233	mat[3][0] = fpoint[nearind].x;
234	mat[3][1] = fpoint[nearind].y;
235	mat[3][2] = fpoint[nearind].z;
236	mat[3][3] = 1.0;
237	zrow[3] = -row4[0] * fpoint[nearind].x -
238	row4[1] * fpoint[nearind].y -
239	row4[2] * fpoint[nearind].z -
240	row4[3] ;
241
242	// solve for the z row of the matrix
243	if(!NumericSolver::solveNxNLinearSysDestr(4, mat, zrow))
244	{
245	// error solving for projective matrix (row 3)
246	}
247
248	// set projective texture matrix
249	ret = Matrix4( col[0], col[1], col[2], col[3],
250	col[4], col[5], col[6], col[7],
251	zrow[0], zrow[1], zrow[2], zrow[3],
252	row4[0], row4[1], row4[2], row4[3] );
253
254
255	// check for clip
256	Vector4 testCoord = ret * fpoint[0];
257	if(testCoord.w < 0.0)
258	ret = ret * (-1.0);
259
260	// free memory
261	for (i=0; i<11; i++)
262	{
263	if (mat[i])
264	delete [] mat[i];
265	if (incrPrecision)
266	delete [] backmat[i];
267	}
268	delete [] mat;
269	if(incrPrecision)
270	delete [] backmat;
271
272	return ret;
273
274	}
275
276	// --------------------------------------------------------------------
277
278	/// Construct object to consider a specified plane of interest
279	PlaneOptimalShadowCameraSetup::PlaneOptimalShadowCameraSetup(MovablePlane* plane)
280	{
281	m_plane = plane;
282	}
283
284	/// Destructor
285	PlaneOptimalShadowCameraSetup::~PlaneOptimalShadowCameraSetup() {}
286
287	/// Implements the plane optimal shadow camera setup algorithm
288	void PlaneOptimalShadowCameraSetup::getShadowCamera (const SceneManager sm, const Camera cam,
289	const Viewport vp, const Light light, Camera *texCam) const
290	{
291	// get the plane transformed by the parent node(s)
292	// Also, make sure the plane is normalized
293	Plane worldPlane = m_plane->_getDerivedPlane();
294	worldPlane.normalise();
295
296	// get camera's projection matrix
297	Matrix4 camProjection = cam->getProjectionMatrix() * cam->getViewMatrix();
298
299	// get the world points to constrain
300	std::vector<Vector4> vhull;
301	cam->forwardIntersect(worldPlane, &vhull);
302	if (vhull.size() < 4)
303	return;
304
305	// make sure the last point is a finite point (not point at infinity)
306	if (vhull[3].w == 0.0)
307	{
308	int finiteIndex = -1;
309	for (uint loopIndex = 0; loopIndex < vhull.size(); loopIndex++)
310	{
311	if (vhull[loopIndex].w != 0.0)
312	{
313	finiteIndex = loopIndex;
314	break;
315	}
316	}
317	if (finiteIndex == -1)
318	{
319	// there are no finite points, which means camera doesn't see plane of interest.
320	// so we don't care what the shadow map matrix is
321	// We'll map points off the shadow map so they aren't even stored
322	Matrix4 crazyMat(0.0, 0.0, 0.0, 5.0,
323	0.0, 0.0, 0.0, 5.0,
324	0.0, 0.0, 0.0, 5.0,
325	0.0, 0.0, 0.0, 1.0);
326	texCam->setCustomViewMatrix(true, Matrix4::IDENTITY);
327	texCam->setCustomProjectionMatrix(true, crazyMat);
328	return;
329	}
330	// swap finite point to last point
331	std::swap(vhull[3], vhull[finiteIndex]);
332	}
333	vhull.resize(4);
334
335	// get the post-projective coordinate constraints
336	std::vector<Vector2> constraint;
337	for (int i=0; i<4; i++)
338	{
339	Vector4 postProjPt = camProjection * vhull[i];
340	postProjPt *= 1.0 / postProjPt.w;
341	constraint.push_back(Vector2(postProjPt.x, postProjPt.y));
342	}
343
344	// perturb one point so we don't have coplanarity
345	const Vector4& pinhole = light->getAs4DVector();
346	const Vector4& oldPt = vhull.back();
347	Vector4 newPt;
348	if (pinhole.w == 0)
349	{
350	// It's directional light
351	static const Real NEAR_SCALE = 100.0;
352	newPt = oldPt + (pinhole * (cam->getNearClipDistance() * NEAR_SCALE));
353	}
354	else
355	{
356	// It's point or spotlight
357	Vector4 displacement = oldPt - pinhole;
358	Vector3 displace3 = Vector3(displacement.x, displacement.y, displacement.z);
359	Real dotProd = fabs(displace3.dotProduct(worldPlane.normal));
360	static const Real NEAR_FACTOR = 0.05;
361	newPt = pinhole + (displacement * (cam->getNearClipDistance() * NEAR_FACTOR / dotProd));
362	}
363	vhull.back() = newPt;
364
365	// solve for the matrix that stabilizes the plane
366	Matrix4 customMatrix = computeConstrainedProjection(pinhole, vhull, constraint);
367
368	if (pinhole.w == 0)
369	{
370	// TODO: factor into view and projection pieces.
371	// Note: In fact, it's unnecessary to factor into view and projection pieces,
372	// but if we do, we will more according with academic requirement :)
373	texCam->setCustomViewMatrix(true, Matrix4::IDENTITY);
374	texCam->setCustomProjectionMatrix(true, customMatrix);
375	return;
376	}
377
378	Vector3 tempPos = Vector3(pinhole.x, pinhole.y, pinhole.z);
379
380	// factor into view and projection pieces
381	Matrix4 translation(1.0, 0.0, 0.0, tempPos.x,
382	0.0, 1.0, 0.0, tempPos.y,
383	0.0, 0.0, 1.0, tempPos.z,
384	0.0, 0.0, 0.0, 1.0);
385	Matrix4 invTranslation(1.0, 0.0, 0.0, -tempPos.x,
386	0.0, 1.0, 0.0, -tempPos.y,
387	0.0, 0.0, 1.0, -tempPos.z,
388	0.0, 0.0, 0.0, 1.0);
389	Matrix4 tempMatrix = customMatrix * translation;
390	Vector3 zRow(-tempMatrix[3][0], -tempMatrix[3][1], -tempMatrix[3][2]);
391	zRow.normalise();
392	Vector3 up;
393	if (zRow.y == 1.0)
394	up = Vector3(1,0,0);
395	else
396	up = Vector3(0,1,0);
397	Vector3 xDir = up.crossProduct(zRow);
398	xDir.normalise();
399	up = zRow.crossProduct(xDir);
400	Matrix4 rotation(xDir.x, up.x, zRow.x, 0.0,
401	xDir.y, up.y, zRow.y, 0.0,
402	xDir.z, up.z, zRow.z, 0.0,
403	0.0, 0.0, 0.0, 1.0 );
404	Matrix4 customProj = tempMatrix * rotation;
405	Matrix4 customView = rotation.transpose() * invTranslation;
406	// note: now customProj * (0,0,0,1)^t = (0, 0, k, 0)^t for k some constant
407	// note: also customProj's 4th row is (0, 0, c, 0) for some negative c.
408
409
410	// set the shadow map camera
411	texCam->setCustomViewMatrix(true, customView);
412	texCam->setCustomProjectionMatrix(true, customProj);
413	}
414
415	}
416

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