diff options
Diffstat (limited to 'src/math.c')
| -rw-r--r-- | src/math.c | 93 |
1 files changed, 93 insertions, 0 deletions
@@ -9,8 +9,18 @@ extern struct hvr_global global; //might change this to use hashtables for faster lookups. c3_group_rot_t *get_group_relative(char *id) {//crashes in here somehwere... int i; + c3_group_rot_t *gr; + struct entry *tmp; + if((tmp=ht_getnode(&global.ht_group,id))) { + gr=tmp->target; + return gr; + }//if this didn't work, do fallback... for(i=0;global.group_rot[i];i++) { if(!strcmp(global.group_rot[i]->id,id)) {//should I use glob here and return an array? + if(gr != global.group_rot[i]) { + fprintf(stderr,"# %s ? %s ? %s\n",tmp->original,gr->id,global.group_rot[i]->id); + fprintf(stderr,"# %16x != %16x. wtf?\n",gr,global.group_rot[i]); + } return global.group_rot[i]; } } @@ -135,6 +145,7 @@ c3_s_t apply_group_relative(c3_s_t s,c3_group_rot_t *group_rot) { int i; s2.len=s.len; s2.id=s.id; + s2.attrib=s.attrib; if(group_rot) { gr=group_rot; } else { @@ -183,3 +194,85 @@ c3_t c3_add(c3_t p1,c3_t p2) { real distance3(c3_t p1,c3_t p2) { return sqrt(( (p1.x-p2.x)*(p1.x-p2.x) )+( (p1.y-p2.y)*(p1.y-p2.y) )+( (p1.z-p2.z)*(p1.z-p2.z) )); } + +/* epoch copied this from: http://geomalgorithms.com/a03-_inclusion.html */ +/* then edited it to work with hackvr ofc */ + +// Copyright 2000 softSurfer, 2012 Dan Sunday +// This code may be freely used and modified for any purpose +// providing that this copyright notice is included with it. +// SoftSurfer makes no warranty for this code, and cannot be held +// liable for any real or imagined damage resulting from its use. +// Users of this code must verify correctness for their application. + + +// a Point is defined by its coordinates {int x, y;} +//=================================================================== + + +// isLeft(): tests if a point is Left|On|Right of an infinite line. +// Input: three points P0, P1, and P2 +// Return: >0 for P2 left of the line through P0 and P1 +// =0 for P2 on the line +// <0 for P2 right of the line +// See: Algorithm 1 "Area of Triangles and Polygons" +inline int +isLeft( cs_t P0, cs_t P1, cs_t P2 ) +{ + return ( (P1.x - P0.x) * (P2.y - P0.y) + - (P2.x - P0.x) * (P1.y - P0.y) ); +} +//=================================================================== + + +// cn_PnPoly(): crossing number test for a point in a polygon +// Input: P = a point, +// V[] = vertex points of a polygon V[n+1] with V[n]=V[0] +// Return: 0 = outside, 1 = inside +// This code is patterned after [Franklin, 2000] +int +cn_PnPoly( cs_t P, cs_t *V, int n ) +{ + int cn = 0; // the crossing number counter + + // loop through all edges of the polygon + for (int i=0; i<n; i++) { // edge from V[i] to V[i+1] + if (((V[i].y <= P.y) && (V[i+1].y > P.y)) // an upward crossing + || ((V[i].y > P.y) && (V[i+1].y <= P.y))) { // a downward crossing + // compute the actual edge-ray intersect x-coordinate + float vt = (float)(P.y - V[i].y) / (V[i+1].y - V[i].y); + if (P.x < V[i].x + vt * (V[i+1].x - V[i].x)) // P.x < intersect + ++cn; // a valid crossing of y=P.y right of P.x + } + } + return (cn&1); // 0 if even (out), and 1 if odd (in) + +} +//=================================================================== + + +// wn_PnPoly(): winding number test for a point in a polygon +// Input: P = a point, +// V[] = vertex points of a polygon V[n+1] with V[n]=V[0] +// Return: wn = the winding number (=0 only when P is outside) +int +wn_PnPoly( cs_t P, cs_t *V, int n ) +{ + int wn = 0; // the winding number counter + + // loop through all edges of the polygon + for (int i=0; i<(n-1); i++) { // edge from V[i] to V[i+1] + if (V[i].y <= P.y) { // start y <= P.y + if (V[i+1].y > P.y) // an upward crossing + if (isLeft( V[i], V[i+1], P) > 0) // P left of edge + ++wn; // have a valid up intersect + } + else { // start y > P.y (no test needed) + if (V[i+1].y <= P.y) // a downward crossing + if (isLeft( V[i], V[i+1], P) < 0) // P right of edge + --wn; // have a valid down intersect + } + } + return wn; +} +//=================================================================== |