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1 | // Created on: 2013-12-25 |
2 | // Created by: Varvara POSKONINA |
3 | // Copyright (c) 1999-2014 OPEN CASCADE SAS |
4 | // |
5 | // This file is part of Open CASCADE Technology software library. |
6 | // |
7 | // This library is free software; you can redistribute it and/or modify it under |
8 | // the terms of the GNU Lesser General Public License version 2.1 as published |
9 | // by the Free Software Foundation, with special exception defined in the file |
10 | // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT |
11 | // distribution for complete text of the license and disclaimer of any warranty. |
12 | // |
13 | // Alternatively, this file may be used under the terms of Open CASCADE |
14 | // commercial license or contractual agreement. |
15 | |
16 | #include <OpenGl_BVHTreeSelector.hxx> |
17 | #include <OpenGl_BVHClipPrimitiveSet.hxx> |
18 | |
19 | #include <vector> |
20 | #include <algorithm> |
21 | |
22 | // ======================================================================= |
23 | // function : DotProduct |
24 | // purpose : Calculates a dot product of 4-dimensional vectors in homogeneous coordinates |
25 | // ======================================================================= |
26 | static Standard_ShortReal DotProduct (const OpenGl_Vec4& theA, |
27 | const OpenGl_Vec4& theB) |
28 | { |
29 | return theA.x() * theB.x() + theA.y() * theB.y() + theA.z() * theB.z(); |
30 | } |
31 | |
32 | // ======================================================================= |
33 | // function : BinarySign |
34 | // purpose : |
35 | // ======================================================================= |
36 | static OpenGl_Vec4 BinarySign (const OpenGl_Vec4& theVec) |
37 | { |
38 | return OpenGl_Vec4 (theVec.x() > 0.0f ? 1.0f : 0.0f, |
39 | theVec.y() > 0.0f ? 1.0f : 0.0f, |
40 | theVec.z() > 0.0f ? 1.0f : 0.0f, |
41 | theVec.w() > 0.0f ? 1.0f : 0.0f); |
42 | } |
43 | |
44 | // ======================================================================= |
45 | // function : InversedBinarySign |
46 | // purpose : |
47 | // ======================================================================= |
48 | static OpenGl_Vec4 InversedBinarySign (const OpenGl_Vec4& theVec) |
49 | { |
50 | return OpenGl_Vec4 (theVec.x() > 0.0f ? 0.0f : 1.0f, |
51 | theVec.y() > 0.0f ? 0.0f : 1.0f, |
52 | theVec.z() > 0.0f ? 0.0f : 1.0f, |
53 | theVec.w() > 0.0f ? 0.0f : 1.0f); |
54 | } |
55 | |
56 | // ======================================================================= |
57 | // function : OpenGl_BVHTreeSelector |
58 | // purpose : |
59 | // ======================================================================= |
60 | OpenGl_BVHTreeSelector::OpenGl_BVHTreeSelector() |
61 | : myIsProjectionParallel (Standard_True), |
62 | myProjectionState (0), |
63 | myModelViewState (0) |
64 | { |
65 | // |
66 | } |
67 | |
68 | // ======================================================================= |
69 | // function : SetClipVolume |
70 | // purpose : Retrieves view volume's planes equations and its vertices from projection and modelview matrices. |
71 | // ======================================================================= |
72 | void OpenGl_BVHTreeSelector::SetViewVolume (const Handle(Graphic3d_Camera)& theCamera) |
73 | { |
74 | myIsProjectionParallel = theCamera->IsOrthographic(); |
75 | const OpenGl_Mat4& aProjMat = theCamera->ProjectionMatrixF(); |
76 | const OpenGl_Mat4& aModelMat = theCamera->OrientationMatrixF(); |
77 | |
78 | Standard_ShortReal nLeft = 0.0f, nRight = 0.0f, nTop = 0.0f, nBottom = 0.0f; |
79 | Standard_ShortReal fLeft = 0.0f, fRight = 0.0f, fTop = 0.0f, fBottom = 0.0f; |
80 | Standard_ShortReal aNear = 0.0f, aFar = 0.0f; |
81 | if (!myIsProjectionParallel) |
82 | { |
83 | // handle perspective projection |
84 | aNear = aProjMat.GetValue (2, 3) / (- 1.0f + aProjMat.GetValue (2, 2)); |
85 | aFar = aProjMat.GetValue (2, 3) / ( 1.0f + aProjMat.GetValue (2, 2)); |
86 | // Near plane |
87 | nLeft = aNear * (aProjMat.GetValue (0, 2) - 1.0f) / aProjMat.GetValue (0, 0); |
88 | nRight = aNear * (aProjMat.GetValue (0, 2) + 1.0f) / aProjMat.GetValue (0, 0); |
89 | nTop = aNear * (aProjMat.GetValue (1, 2) + 1.0f) / aProjMat.GetValue (1, 1); |
90 | nBottom = aNear * (aProjMat.GetValue (1, 2) - 1.0f) / aProjMat.GetValue (1, 1); |
91 | // Far plane |
92 | fLeft = aFar * (aProjMat.GetValue (0, 2) - 1.0f) / aProjMat.GetValue (0, 0); |
93 | fRight = aFar * (aProjMat.GetValue (0, 2) + 1.0f) / aProjMat.GetValue (0, 0); |
94 | fTop = aFar * (aProjMat.GetValue (1, 2) + 1.0f) / aProjMat.GetValue (1, 1); |
95 | fBottom = aFar * (aProjMat.GetValue (1, 2) - 1.0f) / aProjMat.GetValue (1, 1); |
96 | } |
97 | else |
98 | { |
99 | // handle orthographic projection |
100 | aNear = (1.0f / aProjMat.GetValue (2, 2)) * (aProjMat.GetValue (2, 3) + 1.0f); |
101 | aFar = (1.0f / aProjMat.GetValue (2, 2)) * (aProjMat.GetValue (2, 3) - 1.0f); |
102 | // Near plane |
103 | nLeft = ( 1.0f + aProjMat.GetValue (0, 3)) / (-aProjMat.GetValue (0, 0)); |
104 | fLeft = nLeft; |
105 | nRight = ( 1.0f - aProjMat.GetValue (0, 3)) / aProjMat.GetValue (0, 0); |
106 | fRight = nRight; |
107 | nTop = ( 1.0f - aProjMat.GetValue (1, 3)) / aProjMat.GetValue (1, 1); |
108 | fTop = nTop; |
109 | nBottom = (-1.0f - aProjMat.GetValue (1, 3)) / aProjMat.GetValue (1, 1); |
110 | fBottom = nBottom; |
111 | } |
112 | |
113 | OpenGl_Vec4 aLeftTopNear (nLeft, nTop, -aNear, 1.0f), aRightBottomFar (fRight, fBottom, -aFar, 1.0f); |
114 | OpenGl_Vec4 aLeftBottomNear (nLeft, nBottom, -aNear, 1.0f), aRightTopFar (fRight, fTop, -aFar, 1.0f); |
115 | OpenGl_Vec4 aRightBottomNear (nRight, nBottom, -aNear, 1.0f), aLeftTopFar (fLeft, fTop, -aFar, 1.0f); |
116 | OpenGl_Vec4 aRightTopNear (nRight, nTop, -aNear, 1.0f), aLeftBottomFar (fLeft, fBottom, -aFar, 1.0f); |
117 | |
118 | const OpenGl_Mat4 aViewProj = aModelMat * aProjMat; |
119 | OpenGl_Mat4 anInvModelView; |
120 | aModelMat.Inverted(anInvModelView); |
121 | |
122 | myClipVerts[ClipVert_LeftTopNear] = anInvModelView * aLeftTopNear; |
123 | myClipVerts[ClipVert_RightBottomFar] = anInvModelView * aRightBottomFar; |
124 | myClipVerts[ClipVert_LeftBottomNear] = anInvModelView * aLeftBottomNear; |
125 | myClipVerts[ClipVert_RightTopFar] = anInvModelView * aRightTopFar; |
126 | myClipVerts[ClipVert_RightBottomNear] = anInvModelView * aRightBottomNear; |
127 | myClipVerts[ClipVert_LeftTopFar] = anInvModelView * aLeftTopFar; |
128 | myClipVerts[ClipVert_RightTopNear] = anInvModelView * aRightTopNear; |
129 | myClipVerts[ClipVert_LeftBottomFar] = anInvModelView * aLeftBottomFar; |
130 | |
131 | // UNNORMALIZED! |
132 | myClipPlanes[Plane_Left] = aViewProj.GetRow (3) + aViewProj.GetRow (0); |
133 | myClipPlanes[Plane_Right] = aViewProj.GetRow (3) - aViewProj.GetRow (0); |
134 | myClipPlanes[Plane_Top] = aViewProj.GetRow (3) - aViewProj.GetRow (1); |
135 | myClipPlanes[Plane_Bottom] = aViewProj.GetRow (3) + aViewProj.GetRow (1); |
136 | myClipPlanes[Plane_Near] = aViewProj.GetRow (3) + aViewProj.GetRow (2); |
137 | myClipPlanes[Plane_Far] = aViewProj.GetRow (3) - aViewProj.GetRow (2); |
138 | |
139 | gp_Pnt aPtCenter = theCamera->Center(); |
140 | OpenGl_Vec4 aCenter (static_cast<Standard_ShortReal> (aPtCenter.X()), |
141 | static_cast<Standard_ShortReal> (aPtCenter.Y()), |
142 | static_cast<Standard_ShortReal> (aPtCenter.Z()), |
143 | 1.0f); |
144 | |
145 | for (Standard_Integer aPlaneIter = 0; aPlaneIter < PlanesNB; ++aPlaneIter) |
146 | { |
147 | OpenGl_Vec4 anEq = myClipPlanes[aPlaneIter]; |
148 | if (SignedPlanePointDistance (anEq, aCenter) > 0) |
149 | { |
150 | anEq *= -1.0f; |
151 | myClipPlanes[aPlaneIter] = anEq; |
152 | } |
153 | } |
154 | } |
155 | |
156 | // ======================================================================= |
157 | // function : SignedPlanePointDistance |
158 | // purpose : |
159 | // ======================================================================= |
160 | Standard_ShortReal OpenGl_BVHTreeSelector::SignedPlanePointDistance (const OpenGl_Vec4& theNormal, |
161 | const OpenGl_Vec4& thePnt) |
162 | { |
163 | const Standard_ShortReal aNormLength = std::sqrt (theNormal.x() * theNormal.x() |
164 | + theNormal.y() * theNormal.y() |
165 | + theNormal.z() * theNormal.z()); |
166 | const Standard_ShortReal anInvNormLength = 1.0f / aNormLength; |
167 | const Standard_ShortReal aD = theNormal.w() * anInvNormLength; |
168 | const Standard_ShortReal anA = theNormal.x() * anInvNormLength; |
169 | const Standard_ShortReal aB = theNormal.y() * anInvNormLength; |
170 | const Standard_ShortReal aC = theNormal.z() * anInvNormLength; |
171 | return aD + (anA * thePnt.x() + aB * thePnt.y() + aC * thePnt.z()); |
172 | } |
173 | |
174 | // ======================================================================= |
175 | // function : CacheClipPtsProjections |
176 | // purpose : Caches view volume's vertices projections along its normals and AABBs dimensions |
177 | // Must be called at the beginning of each BVH tree traverse loop |
178 | // ======================================================================= |
179 | void OpenGl_BVHTreeSelector::CacheClipPtsProjections() |
180 | { |
181 | Standard_ShortReal aProjectedVerts[ClipVerticesNB]; |
182 | for (Standard_Integer aPlaneIter = 0; aPlaneIter < PlanesNB; ++aPlaneIter) |
183 | { |
184 | const OpenGl_Vec4 aPlane = myClipPlanes[aPlaneIter]; |
185 | for (Standard_Integer aCornerIter = 0; aCornerIter < ClipVerticesNB; ++aCornerIter) |
186 | { |
187 | Standard_ShortReal aProjection = DotProduct (aPlane, myClipVerts[aCornerIter]); |
188 | aProjectedVerts[aCornerIter] = aProjection; |
189 | } |
190 | myMaxClipProjectionPts[aPlaneIter] = *std::max_element (aProjectedVerts, aProjectedVerts + ClipVerticesNB); |
191 | myMinClipProjectionPts[aPlaneIter] = *std::min_element (aProjectedVerts, aProjectedVerts + ClipVerticesNB); |
192 | } |
193 | |
194 | OpenGl_Vec4 aDimensions[3] = |
195 | { |
196 | OpenGl_Vec4 (1.0f, 0.0f, 0.0f, 1.0f), |
197 | OpenGl_Vec4 (0.0f, 1.0f, 0.0f, 1.0f), |
198 | OpenGl_Vec4 (0.0f, 0.0f, 1.0f, 1.0f) |
199 | }; |
200 | |
201 | for (Standard_Integer aDim = 0; aDim < 3; ++aDim) |
202 | { |
203 | for (Standard_Integer aCornerIter = 0; aCornerIter < ClipVerticesNB; ++aCornerIter) |
204 | { |
205 | Standard_ShortReal aProjection = DotProduct (aDimensions[aDim], myClipVerts[aCornerIter]); |
206 | aProjectedVerts[aCornerIter] = aProjection; |
207 | } |
208 | myMaxOrthoProjectionPts[aDim] = *std::max_element (aProjectedVerts, aProjectedVerts + ClipVerticesNB); |
209 | myMinOrthoProjectionPts[aDim] = *std::min_element (aProjectedVerts, aProjectedVerts + ClipVerticesNB); |
210 | } |
211 | } |
212 | |
213 | // ======================================================================= |
214 | // function : Intersect |
215 | // purpose : Detects if AABB overlaps view volume using separating axis theorem (SAT) |
216 | // ======================================================================= |
217 | Standard_Boolean OpenGl_BVHTreeSelector::Intersect (const OpenGl_Vec4& theMinPt, |
218 | const OpenGl_Vec4& theMaxPt) const |
219 | { |
220 | // E1 |
221 | // |_ E0 |
222 | // / |
223 | // E2 |
224 | const OpenGl_Vec4 aShiftedBoxMax = theMaxPt - theMinPt; |
225 | Standard_ShortReal aBoxProjMax = 0.0f, aBoxProjMin = 0.0f; |
226 | Standard_ShortReal aFrustumProjMax = 0.0f, aFrustumProjMin = 0.0f; |
227 | |
228 | // E0 test |
229 | aBoxProjMax = aShiftedBoxMax.x(); |
230 | aFrustumProjMax = myMaxOrthoProjectionPts[0] - DotProduct (OpenGl_Vec4 (1.0f, 0.0f, 0.0f, 1.0f), theMinPt); |
231 | aFrustumProjMin = myMinOrthoProjectionPts[0] - DotProduct (OpenGl_Vec4 (1.0f, 0.0f, 0.0f, 1.0f), theMinPt); |
232 | if (aBoxProjMin > aFrustumProjMax |
233 | || aBoxProjMax < aFrustumProjMin) |
234 | { |
235 | return Standard_False; |
236 | } |
237 | |
238 | // E1 test |
239 | aBoxProjMax = aShiftedBoxMax.y(); |
240 | aFrustumProjMax = myMaxOrthoProjectionPts[1] - DotProduct (OpenGl_Vec4 (0.0f, 1.0f, 0.0f, 1.0f), theMinPt); |
241 | aFrustumProjMin = myMinOrthoProjectionPts[1] - DotProduct (OpenGl_Vec4 (0.0f, 1.0f, 0.0f, 1.0f), theMinPt); |
242 | if (aBoxProjMin > aFrustumProjMax |
243 | || aBoxProjMax < aFrustumProjMin) |
244 | { |
245 | return Standard_False; |
246 | } |
247 | |
248 | // E2 test |
249 | aBoxProjMax = aShiftedBoxMax.z(); |
250 | aFrustumProjMax = myMaxOrthoProjectionPts[2] - DotProduct (OpenGl_Vec4 (0.0f, 0.0f, 1.0f, 1.0f), theMinPt); |
251 | aFrustumProjMin = myMinOrthoProjectionPts[2] - DotProduct (OpenGl_Vec4 (0.0f, 0.0f, 1.0f, 1.0f), theMinPt); |
252 | if (aBoxProjMin > aFrustumProjMax |
253 | || aBoxProjMax < aFrustumProjMin) |
254 | { |
255 | return Standard_False; |
256 | } |
257 | |
258 | const Standard_Integer anIncFactor = myIsProjectionParallel ? 2 : 1; |
259 | for (Standard_Integer aPlaneIter = 0; aPlaneIter < 5; aPlaneIter += anIncFactor) |
260 | { |
261 | OpenGl_Vec4 aPlane = myClipPlanes[aPlaneIter]; |
262 | OpenGl_Vec4 aPt1 (0.0f), aPt2 (0.0f); |
263 | aPt1 = BinarySign (aPlane) * aShiftedBoxMax; |
264 | aBoxProjMax = DotProduct (aPlane, aPt1); |
265 | aFrustumProjMax = myMaxClipProjectionPts[aPlaneIter] - DotProduct (aPlane, theMinPt); |
266 | aFrustumProjMin = myMinClipProjectionPts[aPlaneIter] - DotProduct (aPlane, theMinPt); |
267 | if (aFrustumProjMin < aBoxProjMax |
268 | && aBoxProjMax < aFrustumProjMax) |
269 | { |
270 | continue; |
271 | } |
272 | |
273 | aPt2 = InversedBinarySign (aPlane) * aShiftedBoxMax; |
274 | aBoxProjMin = DotProduct (aPlane, aPt2); |
275 | if (aBoxProjMin > aFrustumProjMax |
276 | || aBoxProjMax < aFrustumProjMin) |
277 | { |
278 | return Standard_False; |
279 | } |
280 | } |
281 | |
282 | return Standard_True; |
283 | } |