From e1090eed41a7dae8a159cb04030a3c126f53dfd8 Mon Sep 17 00:00:00 2001 From: Jiri Hnidek Date: Fri, 2 May 2008 12:43:46 +0000 Subject: [PATCH] Fix for bug #8825. find_first_point() finds first points of implicite surface in better way now. It goes from center of every metalement to 26 directions and try to find every place, where implicite function crosses zero value. Size of step is size of polygonization cube. It can be proofed, that smaller size of step is useless. --- source/blender/blenkernel/intern/mball.c | 64 +++++++++++++++++------- 1 file changed, 46 insertions(+), 18 deletions(-) diff --git a/source/blender/blenkernel/intern/mball.c b/source/blender/blenkernel/intern/mball.c index 14e70075e32..16916381c95 100644 --- a/source/blender/blenkernel/intern/mball.c +++ b/source/blender/blenkernel/intern/mball.c @@ -1214,8 +1214,8 @@ void converge (MB_POINT *p1, MB_POINT *p2, float v1, float v2, p->y = neg.y; p->z = neg.z; while (1) { - p->x = 0.5f*(pos.x + neg.x); if (i++ == RES) return; + p->x = 0.5f*(pos.x + neg.x); if ((function(p->x,p->y,p->z)) > 0.0) pos.x = p->x; else neg.x = p->x; } } @@ -1224,8 +1224,8 @@ void converge (MB_POINT *p1, MB_POINT *p2, float v1, float v2, p->x = neg.x; p->z = neg.z; while (1) { - p->y = 0.5f*(pos.y + neg.y); if (i++ == RES) return; + p->y = 0.5f*(pos.y + neg.y); if ((function(p->x,p->y,p->z)) > 0.0) pos.y = p->y; else neg.y = p->y; } } @@ -1234,8 +1234,8 @@ void converge (MB_POINT *p1, MB_POINT *p2, float v1, float v2, p->x = neg.x; p->y = neg.y; while (1) { - p->z = 0.5f*(pos.z + neg.z); if (i++ == RES) return; + p->z = 0.5f*(pos.z + neg.z); if ((function(p->x,p->y,p->z)) > 0.0) pos.z = p->z; else neg.z = p->z; } } @@ -1300,6 +1300,8 @@ void find_first_points(PROCESS *mbproc, MetaBall *mb, int a) int index[3]={1,0,-1}; float f =0.0f; float in_v, out_v; + MB_POINT workp; + float tmp_v, workp_v, max_len, len, dx, dy, dz, nx, ny, nz, MAXN; ml = mainb[a]; @@ -1360,23 +1362,49 @@ void find_first_points(PROCESS *mbproc, MetaBall *mb, int a) out_v = mbproc->function(out.x, out.y, out.z); - /* find "first point" on Implicit Surface of MetaElemnt ml */ - converge(&in, &out, in_v, out_v, mbproc->function, &mbproc->start, mb, 0); - - /* indexes of CUBE, which includes "first point" */ - c_i= (int)floor(mbproc->start.x/mbproc->size ); - c_j= (int)floor(mbproc->start.y/mbproc->size ); - c_k= (int)floor(mbproc->start.z/mbproc->size ); - - mbproc->start.x= mbproc->start.y= mbproc->start.z= 0.0; + /* find "first points" on Implicit Surface of MetaElemnt ml */ + //converge(&in, &out, in_v, out_v, mbproc->function, &mbproc->start, mb, 0); + workp = in; + workp_v = in_v; + max_len = sqrt((out.x-in.x)*(out.x-in.x) + (out.y-in.y)*(out.y-in.y) + (out.z-in.z)*(out.z-in.z)); - /* add CUBE (with indexes c_i, c_j, c_k) to the stack, - * this cube includes found point of Implicit Surface */ - if (ml->flag & MB_NEGATIVE) - add_cube(mbproc, c_i, c_j, c_k, 2); - else - add_cube(mbproc, c_i, c_j, c_k, 1); + nx = abs((out.x - in.x)/mbproc->size); + ny = abs((out.y - in.y)/mbproc->size); + nz = abs((out.z - in.z)/mbproc->size); + + MAXN = MAX3(nx,ny,nz); + + dx = (out.x - in.x)/MAXN; + dy = (out.y - in.y)/MAXN; + dz = (out.z - in.z)/MAXN; + + len = 0.0; + while(len<=max_len) { + workp.x += dx; + workp.y += dy; + workp.z += dz; + /* compute value of implicite function */ + tmp_v = mbproc->function(workp.x, workp.y, workp.z); + /* add cube to the stack, when value of implicite function crosses zero value */ + if((tmp_v<0.0 && workp_v>=0.0)||(tmp_v>0.0 && workp_v<=0.0)) { + + /* indexes of CUBE, which includes "first point" */ + c_i= (int)floor(workp.x/mbproc->size); + c_j= (int)floor(workp.y/mbproc->size); + c_k= (int)floor(workp.z/mbproc->size); + + /* add CUBE (with indexes c_i, c_j, c_k) to the stack, + * this cube includes found point of Implicit Surface */ + if (ml->flag & MB_NEGATIVE) + add_cube(mbproc, c_i, c_j, c_k, 2); + else + add_cube(mbproc, c_i, c_j, c_k, 1); + } + len = sqrt((workp.x-in.x)*(workp.x-in.x) + (workp.y-in.y)*(workp.y-in.y) + (workp.z-in.z)*(workp.z-in.z)); + workp_v = tmp_v; + } + mbproc->start.x= mbproc->start.y= mbproc->start.z= 0.0; } }