Fixed a bug in SilhouetteGeomEngine::ImageToWorldParameter() that caused

instability issues regarding the view map creation.  A new iterative
solver of the 2D-to-3D inverse projection transformation problem was
implemented.  Instead of directly solving the problem in the direction
from the 2D to 3D space, the new solver starts with an initial guess of
an approximated solution and asymptotically approaches to the true
solution by iteratively performing the forward 3D-to-2D projection
transformation and improving the approximation.  Preliminary tests with
one simple and another complex scenes showed that the solver converges
quickly (more and less 20 iterations in many cases, with a stopping
criterion of a residual distance between the true and approximated
solutions less than 1e-6 Blender Unit).
This commit is contained in:
2010-01-10 14:08:59 +00:00
parent 05603fa110
commit 622a65a297
5 changed files with 77 additions and 9 deletions

View File

@@ -24,6 +24,18 @@ NodeGroup* BlenderFileLoader::Load()
// creation of the scene root node
_Scene = new NodeGroup;
_viewplane_left= _re->viewplane.xmin;
_viewplane_right= _re->viewplane.xmax;
_viewplane_bottom= _re->viewplane.ymin;
_viewplane_top= _re->viewplane.ymax;
_z_near= _re->clipsta;
_z_far= _re->clipend;
#if 0
cout << "frustrum: l " << _viewplane_left << " r " << _viewplane_right
<< " b " << _viewplane_bottom << " t " << _viewplane_top
<< " n " << _z_near << " f " << _z_far << endl;
#endif
int id = 0;
for(obi= (ObjectInstanceRen *) _re->instancetable.first; obi; obi=obi->next) {
if (!(obi->lay & _re->scene->lay & _srl->lay))

View File

@@ -58,6 +58,11 @@ protected:
NodeGroup* _Scene;
unsigned _numFacesRead;
real _minEdgeSize;
float _viewplane_left;
float _viewplane_right;
float _viewplane_bottom;
float _viewplane_top;
float _z_near, _z_far;
};
#endif // BLENDER_FILE_LOADER_H

View File

@@ -19,6 +19,7 @@ extern "C" {
#include "BKE_main.h"
#include "BLI_blenlib.h"
#include "BLI_math.h"
#include "BPY_extern.h"
#include "renderpipeline.h"
@@ -106,6 +107,9 @@ extern "C" {
for( int i = 0; i < 4; i++ )
for( int j = 0; j < 4; j++ )
freestyle_proj[i][j] = re->winmat[i][j];
//print_m4("mv", freestyle_mv);
//print_m4("proj", freestyle_proj);
}

View File

@@ -155,6 +155,7 @@ real SilhouetteGeomEngine::ImageToWorldParameter(FEdge *fe, real t)
// we need to compute for each parameter t the corresponding
// parameter T which gives the intersection in 3D.
#if 0
//currentEdge = (*fe);
Vec3r A = (fe)->vertexA()->point3D();
Vec3r B = (fe)->vertexB()->point3D();
@@ -175,6 +176,46 @@ real SilhouetteGeomEngine::ImageToWorldParameter(FEdge *fe, real t)
real T;
T = (Ic[2]*Ac[1] - Ic[1]*Ac[2])/(Ic[1]*(Bc[2]-Ac[2])-Ic[2]*(Bc[1]-Ac[1]));
#else
// suffix w for world, i for image
Vec3r Aw = (fe)->vertexA()->point3D();
Vec3r Bw = (fe)->vertexB()->point3D();
Vec3r Ai = (fe)->vertexA()->point2D();
Vec3r Bi = (fe)->vertexB()->point2D();
Vec3r Ii = Ai + t * (Bi - Ai); // the intersection point in 2D
Vec3r Pw, Pi;
real T_sta = 0.0;
real T_end = 1.0;
real T;
real delta_x, delta_y, dist, dist_threshold = 1e-6;
int i, max_iters = 100;
for (i = 0; i < max_iters; i++) {
T = T_sta + 0.5 * (T_end - T_sta);
Pw = Aw + T * (Bw - Aw);
GeomUtils::fromWorldToImage(Pw, Pi, _transform, _viewport);
delta_x = Ii[0] - Pi[0];
delta_y = Ii[1] - Pi[1];
dist = sqrt(delta_x * delta_x + delta_y * delta_y);
if (dist < dist_threshold)
break;
if (Ai[0] < Bi[0]) {
if (Pi[0] < Ii[0])
T_sta = T;
else
T_end = T;
} else {
if (Pi[0] > Ii[0])
T_sta = T;
else
T_end = T;
}
}
#if 0
printf("SilhouetteGeomEngine::ImageToWorldParameter(): #iters = %d, dist = %e\n", i, dist);
#endif
if (i == max_iters)
printf("SilhouetteGeomEngine::ImageToWorldParameter(): reached to max_iters (dist = %e)\n", dist);
#endif
return T;
}

View File

@@ -946,14 +946,20 @@ void ViewMapBuilder::ComputeSweepLineIntersections(ViewMap *ioViewMap, real epsi
real tb = (*i)->tB;
if((ta < -epsilon) || (ta > 1+epsilon))
cerr << "Warning: intersection out of range for edge " << fA->vertexA()->getId() << " - " << fA->vertexB()->getId() << endl;
cerr << "Warning: 2D intersection out of range for edge " << fA->vertexA()->getId() << " - " << fA->vertexB()->getId() << endl;
if((tb < -epsilon) || (tb > 1+epsilon))
cerr << "Warning: intersection out of range for edge " << fB->vertexA()->getId() << " - " << fB->vertexB()->getId() << endl;
cerr << "Warning: 2D intersection out of range for edge " << fB->vertexA()->getId() << " - " << fB->vertexB()->getId() << endl;
real Ta = SilhouetteGeomEngine::ImageToWorldParameter(fA, ta);
real Tb = SilhouetteGeomEngine::ImageToWorldParameter(fB, tb);
if((Ta < -epsilon) || (Ta > 1+epsilon))
cerr << "Warning: 3D intersection out of range for edge " << fA->vertexA()->getId() << " - " << fA->vertexB()->getId() << endl;
if((Tb < -epsilon) || (Tb > 1+epsilon))
cerr << "Warning: 3D intersection out of range for edge " << fB->vertexA()->getId() << " - " << fB->vertexB()->getId() << endl;
TVertex * tvertex = ioViewMap->CreateTVertex(Vec3r(A1 + Ta*(A2-A1)), Vec3r(a1 + ta*(a2-a1)), fA,
Vec3r(B1 + Tb*(B2-B1)), Vec3r(b1 + tb*(b2-b1)), fB, id);