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/* Copyright (c) 1998 Silicon Graphics, Inc. */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ SGI"; |
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#endif |
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|
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/* |
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* sm_stree.c |
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* An stree (spherical quadtree) is defined by an octahedron in |
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* canonical form,and a world center point. Each face of the |
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* octahedron is adaptively subdivided as a planar triangular quadtree. |
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* World space geometry is projected onto the quadtree faces from the |
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* sphere center. |
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*/ |
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#include "standard.h" |
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#include "sm_flag.h" |
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#include "sm_geom.h" |
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#include "sm_qtree.h" |
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#include "sm_stree.h" |
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|
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#ifdef TEST_DRIVER |
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extern FVECT Pick_point[500],Pick_v0[500],Pick_v1[500],Pick_v2[500]; |
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extern int Pick_cnt; |
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#endif |
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/* octahedron coordinates */ |
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FVECT stDefault_base[6] = { {1.,0.,0.},{0.,1.,0.}, {0.,0.,1.}, |
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{-1.,0.,0.},{0.,-1.,0.},{0.,0.,-1.}}; |
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/* octahedron triangle vertices */ |
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int stBase_verts[8][3] = { {2,1,0},{1,5,0},{5,1,3},{1,2,3}, |
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{4,2,0},{4,0,5},{3,4,5},{4,3,2}}; |
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/* octahedron triangle nbrs ; nbr i is the face opposite vertex i*/ |
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int stBase_nbrs[8][3] = { {1,4,3},{5,0,2},{3,6,1},{7,2,0}, |
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{0,5,7},{1,6,4},{5,2,7},{3,4,6}}; |
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/* look up table for octahedron point location */ |
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int stlocatetbl[8] = {6,7,2,3,5,4,1,0}; |
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|
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|
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/* Initializes an stree structure with origin 'center': |
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Frees existing quadtrees hanging off of the roots |
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*/ |
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stInit(st) |
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STREE *st; |
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{ |
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ST_TOP_ROOT(st) = qtAlloc(); |
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ST_BOTTOM_ROOT(st) = qtAlloc(); |
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ST_INIT_ROOT(st); |
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} |
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|
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/* Frees the children of the 2 quadtrees rooted at st, |
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Does not free root nodes: just clears |
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*/ |
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stClear(st) |
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STREE *st; |
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{ |
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qtDone(); |
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stInit(st); |
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} |
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|
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/* Allocates a stree structure and creates octahedron base */ |
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STREE |
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*stAlloc(st) |
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STREE *st; |
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{ |
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int i,m; |
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FVECT v0,v1,v2; |
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FVECT n; |
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|
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if(!st) |
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if(!(st = (STREE *)malloc(sizeof(STREE)))) |
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error(SYSTEM,"stAlloc(): Unable to allocate memory\n"); |
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|
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/* Allocate the top and bottom quadtree root nodes */ |
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stInit(st); |
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|
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/* Set the octahedron base */ |
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ST_SET_BASE(st,stDefault_base); |
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|
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/* Calculate octahedron face and edge normals */ |
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for(i=0; i < ST_NUM_ROOT_NODES; i++) |
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{ |
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VCOPY(v0,ST_NTH_V(st,i,0)); |
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VCOPY(v1,ST_NTH_V(st,i,1)); |
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VCOPY(v2,ST_NTH_V(st,i,2)); |
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tri_plane_equation(v0,v1,v2, &ST_NTH_PLANE(st,i),FALSE); |
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m = max_index(FP_N(ST_NTH_PLANE(st,i)),NULL); |
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FP_X(ST_NTH_PLANE(st,i)) = (m+1)%3; |
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FP_Y(ST_NTH_PLANE(st,i)) = (m+2)%3; |
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FP_Z(ST_NTH_PLANE(st,i)) = m; |
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VCROSS(ST_EDGE_NORM(st,i,0),v0,v1); |
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VCROSS(ST_EDGE_NORM(st,i,1),v1,v2); |
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VCROSS(ST_EDGE_NORM(st,i,2),v2,v0); |
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} |
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return(st); |
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} |
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|
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|
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/* Return quadtree leaf node containing point 'p'*/ |
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QUADTREE |
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stPoint_locate(st,p) |
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STREE *st; |
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FVECT p; |
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{ |
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int i; |
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QUADTREE root,qt; |
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|
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/* Find root quadtree that contains p */ |
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i = stPoint_in_root(p); |
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root = ST_NTH_ROOT(st,i); |
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|
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/* Traverse quadtree to leaf level */ |
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qt = qtRoot_point_locate(root,ST_NTH_V(st,i,0),ST_NTH_V(st,i,1), |
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ST_NTH_V(st,i,2),ST_NTH_PLANE(st,i),p); |
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return(qt); |
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} |
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|
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/* Add triangle 'id' with coordinates 't0,t1,t2' to the stree: returns |
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FALSE on error, TRUE otherwise |
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*/ |
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|
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stAdd_tri(st,id,t0,t1,t2) |
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STREE *st; |
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int id; |
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FVECT t0,t1,t2; |
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{ |
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int i; |
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QUADTREE root; |
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|
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for(i=0; i < ST_NUM_ROOT_NODES; i++) |
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{ |
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root = ST_NTH_ROOT(st,i); |
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ST_NTH_ROOT(st,i) = qtRoot_add_tri(root,ST_NTH_V(st,i,0),ST_NTH_V(st,i,1), |
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ST_NTH_V(st,i,2),t0,t1,t2,id,0); |
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} |
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} |
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|
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/* Remove triangle 'id' with coordinates 't0,t1,t2' to the stree: returns |
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FALSE on error, TRUE otherwise |
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*/ |
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|
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stRemove_tri(st,id,t0,t1,t2) |
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STREE *st; |
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int id; |
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FVECT t0,t1,t2; |
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{ |
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int i; |
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QUADTREE root; |
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|
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for(i=0; i < ST_NUM_ROOT_NODES; i++) |
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{ |
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root = ST_NTH_ROOT(st,i); |
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ST_NTH_ROOT(st,i)=qtRoot_remove_tri(root,id,ST_NTH_V(st,i,0),ST_NTH_V(st,i,1), |
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ST_NTH_V(st,i,2),t0,t1,t2); |
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} |
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} |
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|
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/* Visit all nodes that are intersected by the edges of triangle 't0,t1,t2' |
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and apply 'func' |
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*/ |
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|
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stVisit_tri_edges(st,t0,t1,t2,func,fptr,argptr) |
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STREE *st; |
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FVECT t0,t1,t2; |
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int (*func)(),*fptr; |
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int *argptr; |
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{ |
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int id,i,w,next; |
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QUADTREE root; |
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FVECT v[3],i_pt; |
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|
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VCOPY(v[0],t0); VCOPY(v[1],t1); VCOPY(v[2],t2); |
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w = -1; |
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|
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/* Locate the root containing triangle vertex v0 */ |
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i = stPoint_in_root(v[0]); |
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/* Mark the root node as visited */ |
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QT_SET_FLAG(ST_ROOT(st,i)); |
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root = ST_NTH_ROOT(st,i); |
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|
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ST_NTH_ROOT(st,i) = qtRoot_visit_tri_edges(root,ST_NTH_V(st,i,0), |
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ST_NTH_V(st,i,1),ST_NTH_V(st,i,2),ST_NTH_PLANE(st,i),v,i_pt,&w, |
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&next,func,fptr,argptr); |
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if(QT_FLAG_IS_DONE(*fptr)) |
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return; |
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|
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/* Crossed over to next node: id = nbr */ |
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while(1) |
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{ |
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/* test if ray crosses plane between this quadtree triangle and |
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its neighbor- if it does then find intersection point with |
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ray and plane- this is the new start point |
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*/ |
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i = stBase_nbrs[i][next]; |
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root = ST_NTH_ROOT(st,i); |
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ST_NTH_ROOT(st,i) = |
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qtRoot_visit_tri_edges(root,ST_NTH_V(st,i,0),ST_NTH_V(st,i,1), |
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ST_NTH_V(st,i,2),ST_NTH_PLANE(st,i),v,i_pt,&w,&next,func,fptr,argptr); |
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if(QT_FLAG_IS_DONE(*fptr)) |
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return; |
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} |
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} |
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|
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/* Trace ray 'orig-dir' through stree and apply 'func(qtptr,f,argptr)' at each |
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node that it intersects |
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*/ |
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int |
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stTrace_ray(st,orig,dir,func,argptr) |
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STREE *st; |
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FVECT orig,dir; |
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int (*func)(); |
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int *argptr; |
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{ |
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int next,last,i,f=0; |
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QUADTREE root; |
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FVECT o,n,v; |
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double pd,t,d; |
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|
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VCOPY(o,orig); |
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#ifdef TEST_DRIVER |
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Pick_cnt=0; |
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#endif; |
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/* Find the root node that o falls in */ |
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i = stPoint_in_root(o); |
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root = ST_NTH_ROOT(st,i); |
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|
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ST_NTH_ROOT(st,i) = |
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qtRoot_trace_ray(root,ST_NTH_V(st,i,0),ST_NTH_V(st,i,1), |
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ST_NTH_V(st,i,2),ST_NTH_PLANE(st,i),o,dir,&next,func,&f,argptr); |
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|
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if(QT_FLAG_IS_DONE(f)) |
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return(TRUE); |
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|
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d = DOT(orig,dir)/sqrt(DOT(orig,orig)); |
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VSUM(v,orig,dir,-d); |
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/* Crossed over to next cell: id = nbr */ |
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while(1) |
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{ |
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/* test if ray crosses plane between this quadtree triangle and |
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its neighbor- if it does then find intersection point with |
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ray and plane- this is the new origin |
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*/ |
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if(next == INVALID) |
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return(FALSE); |
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#if 0 |
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if(!intersect_ray_oplane(o,dir,ST_EDGE_NORM(st,i,(next+1)%3),NULL,o)) |
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#endif |
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if(DOT(o,v) < 0.0) |
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/* Ray does not cross into next cell: done and tri not found*/ |
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return(FALSE); |
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|
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VSUM(o,o,dir,10*FTINY); |
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i = stBase_nbrs[i][next]; |
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root = ST_NTH_ROOT(st,i); |
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|
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ST_NTH_ROOT(st,i) = |
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qtRoot_trace_ray(root, ST_NTH_V(st,i,0),ST_NTH_V(st,i,1), |
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ST_NTH_V(st,i,2),ST_NTH_PLANE(st,i),o,dir,&next,func,&f,argptr); |
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if(QT_FLAG_IS_DONE(f)) |
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return(TRUE); |
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} |
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} |
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|
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|
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/* Visit nodes intersected by tri 't0,t1,t2' and apply 'func(arg1,arg2,arg3): |
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assumes that stVisit_tri_edges has already been called such that all nodes |
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intersected by tri edges are already marked as visited |
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*/ |
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stVisit_tri(st,t0,t1,t2,func,f,argptr) |
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STREE *st; |
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FVECT t0,t1,t2; |
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int (*func)(),*f; |
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int *argptr; |
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{ |
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int i; |
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QUADTREE root; |
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FVECT n0,n1,n2; |
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|
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/* Calcuate the edge normals for tri */ |
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VCROSS(n0,t0,t1); |
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VCROSS(n1,t1,t2); |
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VCROSS(n2,t2,t0); |
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|
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for(i=0; i < ST_NUM_ROOT_NODES; i++) |
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{ |
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root = ST_NTH_ROOT(st,i); |
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ST_NTH_ROOT(st,i) = qtVisit_tri_interior(root,ST_NTH_V(st,i,0), |
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ST_NTH_V(st,i,1),ST_NTH_V(st,i,2),t0,t1,t2,n0,n1,n2,0,func,f,argptr); |
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|
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} |
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} |
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|
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/* Visit nodes intersected by tri 't0,t1,t2'.Apply 'edge_func(arg1,arg2,arg3)', |
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to those nodes intersected by edges, and interior_func to ALL nodes: |
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ie some Nodes will be visited more than once |
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*/ |
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int |
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stApply_to_tri(st,t0,t1,t2,edge_func,tri_func,argptr) |
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STREE *st; |
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FVECT t0,t1,t2; |
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int (*edge_func)(),(*tri_func)(); |
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int *argptr; |
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{ |
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int f; |
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FVECT dir; |
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|
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#ifdef TEST_DRIVER |
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Pick_cnt=0; |
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#endif; |
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/* First add all of the leaf cells lying on the triangle perimeter: |
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mark all cells seen on the way |
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*/ |
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f = 0; |
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/* Visit cells along edges of the tri */ |
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stVisit_tri_edges(st,t0,t1,t2,edge_func,&f,argptr); |
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|
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/* Now visit All cells interior */ |
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if(QT_FLAG_FILL_TRI(f) || QT_FLAG_UPDATE(f)) |
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stVisit_tri(st,t0,t1,t2,tri_func,&f,argptr); |
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} |
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