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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 03:01:46 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 03:01:46 +0000 |
commit | f8fe689a81f906d1b91bb3220acde2a4ecb14c5b (patch) | |
tree | 26484e9d7e2c67806c2d1760196ff01aaa858e8c /src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c | |
parent | Initial commit. (diff) | |
download | virtualbox-upstream.tar.xz virtualbox-upstream.zip |
Adding upstream version 6.0.4-dfsg.upstream/6.0.4-dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c')
-rw-r--r-- | src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c | 588 |
1 files changed, 588 insertions, 0 deletions
diff --git a/src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c b/src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c new file mode 100644 index 00000000..03143b0d --- /dev/null +++ b/src/VBox/HostServices/SharedOpenGL/crserverlib/server_clip.c @@ -0,0 +1,588 @@ +/* Copyright (c) 2001, Stanford University + * All rights reserved + * + * See the file LICENSE.txt for information on redistributing this software. + */ + +/* + * This code contributed by Karl Rasche <rkarl@vr.clemson.edu> + */ + + +#include <math.h> + +#include "cr_server.h" +#include "cr_mem.h" +#include "server.h" + + +static void +__find_intersection(double *s, double *e, double *clp, double *clp_next, + double *intr) +{ + double v1[2], v2[2]; + double A, B, T; + + v1[0] = e[0] - s[0]; + v1[1] = e[1] - s[1]; + v2[0] = clp_next[0] - clp[0]; + v2[1] = clp_next[1] - clp[1]; + + if ((v1[1]) && (v2[0])) + { + A = (clp[1]-s[1])/v1[1] + (v2[1]/v1[1])*(s[0]-clp[0])/v2[0]; + B = 1.-(v2[1]/v1[1])*(v1[0]/v2[0]); + if (B) + T = A/B; + else + { + T = 0; + } + + intr[0] = s[0]+T*v1[0]; + intr[1] = s[1]+T*v1[1]; + } + else + if (v1[1]) + { + /* clp -> clp_next is vertical */ + T = (clp[0]-s[0])/v1[0]; + + intr[0] = s[0]+T*v1[0]; + intr[1] = s[1]+T*v1[1]; + } + else + { + /* s -> e is horizontal */ + T = (s[1]-clp[1])/v2[1]; + + intr[0] = clp[0]+T*v2[0]; + intr[1] = clp[1]+T*v2[1]; + } + +} + +static void + __clip_one_side(double *poly, int npnts, double *clp, double *clp_next, + double *norm, + double **new_poly_in, int *new_npnts_in, + double **new_poly_out, int *new_npnts_out) +{ + int a, sin, ein; + double *s, *e, intr[2]; + + *new_poly_in = (double *)crAlloc(2*npnts*2*sizeof(double)); + *new_npnts_in = 0; + + *new_poly_out = (double *)crAlloc(2*npnts*2*sizeof(double)); + *new_npnts_out = 0; + + s = poly; + + for (a=0; a<npnts; a++) + { + e = poly+2*((a+1)%npnts); + + if (((e[0]-clp[0])*norm[0]) + ((e[1]-clp[1])*norm[1]) >= 0) + ein = 0; + else + ein = 1; + + if (((s[0]-clp[0])*norm[0]) + ((s[1]-clp[1])*norm[1]) >= 0) + sin = 0; + else + sin = 1; + + if (sin && ein) + { + /* case 1: */ + crMemcpy(*new_poly_in+2*(*new_npnts_in), e, 2*sizeof(double)); + (*new_npnts_in)++; + } + else + if (sin && (!ein)) + { + /* case 2: */ + + __find_intersection(s, e, clp, clp_next, intr); + + crMemcpy(*new_poly_in+2*(*new_npnts_in), intr, 2*sizeof(double)); + (*new_npnts_in)++; + + crMemcpy(*new_poly_out+2*(*new_npnts_out), intr, 2*sizeof(double)); + (*new_npnts_out)++; + crMemcpy(*new_poly_out+2*(*new_npnts_out), e, 2*sizeof(double)); + (*new_npnts_out)++; + } + else + if ((!sin) && ein) + { + /* case 4: */ + __find_intersection(s, e, clp, clp_next, intr); + + crMemcpy((*new_poly_in)+2*(*new_npnts_in), intr, 2*sizeof(double)); + (*new_npnts_in)++; + crMemcpy((*new_poly_in)+2*(*new_npnts_in), e, 2*sizeof(double)); + (*new_npnts_in)++; + + crMemcpy(*new_poly_out+2*(*new_npnts_out), intr, 2*sizeof(double)); + (*new_npnts_out)++; + } + else + { + crMemcpy(*new_poly_out+2*(*new_npnts_out), e, 2*sizeof(double)); + (*new_npnts_out)++; + } + + s = e; + } +} + +/* + * Sutherland/Hodgman clipping for interior & exterior regions. + * length_of((*new_vert_out)[a]) == nclip_to_vert + */ +static void +__clip(double *poly, int nvert, double *clip_to_poly, int nclip_to_vert, + double **new_vert_in, int *nnew_vert_in, + double ***new_vert_out, int **nnew_vert_out) +{ + int a, side, *nout; + double *clip_normals, *s, *e, *n, *new_vert_src; + double *norm, *clp, *clp_next; + double **out; + + *new_vert_out = (double **)crAlloc(nclip_to_vert*sizeof(double *)); + *nnew_vert_out = (int *)crAlloc(nclip_to_vert*sizeof(int)); + + /* + * First, compute normals for the clip poly. This + * breaks for multiple (3+) adjacent colinear vertices + */ + clip_normals = (double *)crAlloc(nclip_to_vert*2*sizeof(double)); + for (a=0; a<nclip_to_vert; a++) + { + s = clip_to_poly+2*a; + e = clip_to_poly+2*((a+1)%nclip_to_vert); + n = clip_to_poly+2*((a+2)%nclip_to_vert); + + norm = clip_normals+2*a; + norm[0] = e[1]-s[1]; + norm[1] = -1*(e[0]-s[0]); + + /* + * if dot(norm, n-e) > 0), the normals are backwards, + * assuming the clip region is convex + */ + if (norm[0]*(n[0]-e[0]) + norm[1]*(n[1]-e[1]) > 0) + { + norm[0] *= -1; + norm[1] *= -1; + } + } + + new_vert_src = (double *)crAlloc(nvert*nclip_to_vert*2*sizeof(double)); + crMemcpy(new_vert_src, poly, 2*nvert*sizeof(double)); + + for (side=0; side<nclip_to_vert; side++) + { + clp = clip_to_poly+2*side; + clp_next = clip_to_poly+2*((side+1)%nclip_to_vert); + norm = clip_normals+2*side; + *nnew_vert_in = 0; + + nout = (*nnew_vert_out)+side; + out = (*new_vert_out)+side; + + __clip_one_side(new_vert_src, nvert, clp, clp_next, norm, + new_vert_in, nnew_vert_in, + out, nout); + + crMemcpy(new_vert_src, (*new_vert_in), 2*(*nnew_vert_in)*sizeof(double)); + if (side != nclip_to_vert-1) + crFree(*new_vert_in); + nvert = *nnew_vert_in; + } +} + +/* + * Given a bitmap and a group of 'base' polygons [the quads we are testing], + * perform the unions and differences specified by the map and return + * the resulting geometry + */ +static void +__execute_combination(CRPoly **base, int n, int *mask, CRPoly **head) +{ + int a, b, got_intr; + int nin, *nout, last; + double *in, **out; + CRPoly *intr, *diff, *p; + + *head = NULL; + + intr = (CRPoly *)crAlloc(sizeof(CRPoly)); + intr->next = NULL; + + got_intr = 0; + + /* first, intersect the first 2 polys marked */ + for (a=0; a<n; a++) + if (mask[a]) break; + for (b=a+1; b<n; b++) + if (mask[b]) break; + + __clip(base[a]->points, base[a]->npoints, + base[b]->points, base[b]->npoints, + &in, &nin, &out, &nout); + last = b; + + crFree (nout); + for (a=0; a<base[last]->npoints; a++) + if (out[a]) + crFree(out[a]); + crFree(out); + + + if (nin) + { + intr->npoints = nin; + intr->points = in; + got_intr = 1; + } + + while (1) + { + for (a=last+1; a<n; a++) + if (mask[a]) break; + + if (a == n) break; + + if (got_intr) + { + __clip(base[a]->points, base[a]->npoints, + intr->points, intr->npoints, + &in, &nin, &out, &nout); + + crFree (nout); + for (b=0; b<intr->npoints; b++) + if (out[b]) + crFree(out[b]); + crFree(out); + + if (nin) + { + intr->npoints = nin; + intr->points = in; + } + else + { + got_intr = 0; + break; + } + } + else + { + __clip(base[a]->points, base[a]->npoints, + base[last]->points, base[last]->npoints, + &in, &nin, &out, &nout); + + crFree (nout); + for (b=0; b<base[last]->npoints; b++) + { + if (out[b]) + crFree(out[b]); + } + crFree(out); + + + if (nin) + { + intr->npoints = nin; + intr->points = in; + got_intr = 1; + } + } + + last = a; + if (a == n) break; + } + + /* can't subtract something from nothing! */ + if (got_intr) + *head = intr; + else + return; + + /* find the first item to subtract */ + for (a=0; a<n; a++) + if (!mask[a]) break; + + if (a == n) return; + last = a; + + /* and subtract it */ + diff = NULL; + __clip(intr->points, intr->npoints, + base[last]->points, base[last]->npoints, + &in, &nin, &out, &nout); + + crFree(in); + + for (a=0; a<base[last]->npoints; a++) + { + if (!nout[a]) continue; + + p = (CRPoly *)crAlloc(sizeof(CRPoly)); + p->npoints = nout[a]; + p->points = out[a]; + p->next = diff; + diff = p; + } + *head = diff; + + while (1) + { + intr = diff; + diff = NULL; + + for (a=last+1; a<n; a++) + if (!mask[a]) break; + if (a == n) return; + + last = a; + + /* subtract mask[a] from everything in intr and + * plop it into diff */ + while (intr) + { + __clip(intr->points, intr->npoints, + base[last]->points, base[last]->npoints, + &in, &nin, &out, &nout); + + crFree(in); + + for (a=0; a<base[last]->npoints; a++) + { + if (!nout[a]) continue; + + p = (CRPoly *)crAlloc(sizeof(CRPoly)); + p->npoints = nout[a]; + p->points = out[a]; + p->next = diff; + diff = p; + } + + intr = intr->next; + } + + *head = diff; + } + +} + +/* + * Here we generate all valid bitmaps to represent union/difference + * combinations. Each bitmap is N elements long, where N is the + * number of polys [quads] that we are testing for overlap + */ +static void +__generate_masks(int n, int ***mask, int *nmasks) +{ + int a, b, c, d, e; + int i, idx, isec_size, add; + + *mask = (int **)crAlloc((unsigned int)pow(2, n)*sizeof(int)); + for (a=0; a<pow(2, n); a++) + (*mask)[a] = (int *)crAlloc(n*sizeof(int)); + + /* compute combinations */ + idx = 0; + for (isec_size=1; isec_size<n; isec_size++) + { + for (a=0; a<n; a++) + { + for (b=a+1; b<n; b++) + { + crMemset((*mask)[idx], 0, n*sizeof(int)); + (*mask)[idx][a] = 1; + + add = 1; + for (c=0; c<isec_size; c++) + { + i = (b+c) % n; + if (i == a) add = 0; + + (*mask)[idx][i] = 1; + } + + /* dup check */ + if ((add) && (idx)) + { + for (d=0; d<idx; d++) + { + add = 0; + for (e=0; e<n; e++) + { + if ((*mask)[idx][e] != (*mask)[d][e]) + add = 1; + } + + if (!add) + break; + } + } + + if (add) + idx++; + } + } + } + + *nmasks = idx; +} + +/* + * To compute the overlap between a series of quads (This should work + * for n-gons, but we'll only need quads..), first generate a series of + * bitmaps that represent which elements to union together, and which + * to difference. This goes into 'mask'. We then evaluate each bitmap with + * Sutherland-Hodgman clipping to find the interior (union) and exterior + * (difference) regions. + * + * In the map, 1 == union, 0 == difference + * + * (*res)[a] is the head of a poly list for all the polys that convert + * regions of overlap between a+1 polys ((*res)[0] == NULL) + */ +void +crComputeOverlapGeom(double *quads, int nquad, CRPoly ***res) +{ + int a, b, idx, isec_size, **mask; + CRPoly *p, *next, **base; + + base = (CRPoly **)crAlloc(nquad*sizeof(CRPoly *)); + for (a=0; a<nquad; a++) + { + p = (CRPoly *)crAlloc(sizeof(CRPoly)); + p->npoints = 4; + p->points = (double *)crAlloc(8*sizeof(double)); + for (b=0; b<8; b++) + { + p->points[b] = quads[8*a+b]; + } + p->next = NULL; + base[a] = p; + } + + *res = (CRPoly **)crAlloc(nquad*sizeof(CRPoly *)); + for (a=0; a<nquad; a++) + (*res)[a] = NULL; + + __generate_masks(nquad, &mask, &idx); + + for (a=0; a<idx; a++) + { + isec_size = 0; + for (b=0; b<nquad; b++) + if (mask[a][b]) isec_size++; + isec_size--; + + __execute_combination(base, nquad, mask[a], &p); + + while (p) + { + next = p->next; + + p->next = (*res)[isec_size]; + (*res)[isec_size] = p; + + p = next; + } + } + + for (a=0; a<nquad; a++) + { + crFree(base[a]->points); + crFree(base[a]); + } + crFree(base); + +} + +/* + * This is similar to ComputeOverlapGeom above, but for "knockout" + * edge blending. + * + * my_quad_idx is an index of quads indicating which display tile + * we are computing geometry for. From this, we either generate + * geometry, or not, such that all geometry can be drawn in black + * and only one tile will show through the blend as non-black. + * + * To add a combination to our set of geom, we must test that: + * + mask[a][my_quad_idx] is set + * + mask[a][my_quad_idx] is not the first element set in + * mask[a]. + * If these conditions hold, execute mask[a] and draw the resulting + * geometry in black + * + * Unlike ComputeOverlapGeom, res is just a list of polys to draw in black + */ +void +crComputeKnockoutGeom(double *quads, int nquad, int my_quad_idx, CRPoly **res) +{ + int a, b, idx, first, **mask; + CRPoly *p, *next, **base; + + base = (CRPoly **) crAlloc(nquad*sizeof(CRPoly *)); + for (a=0; a<nquad; a++) + { + p = (CRPoly *) crAlloc(sizeof(CRPoly)); + p->npoints = 4; + p->points = (double *) crAlloc(8*sizeof(double)); + for (b=0; b<8; b++) + { + p->points[b] = quads[8*a+b]; + } + p->next = NULL; + base[a] = p; + } + + (*res) = NULL; + + __generate_masks(nquad, &mask, &idx); + + for (a=0; a<idx; a++) + { + /* test for above conditions */ + if (!mask[a][my_quad_idx]) continue; + + first = -1; + for (b=0; b<nquad; b++) + if (mask[a][b]) + { + first = b; + break; + } + if (first == my_quad_idx) continue; + + + __execute_combination(base, nquad, mask[a], &p); + + while (p) + { + next = p->next; + + p->next = *res; + *res = p; + + p = next; + } + } + + for (a=0; a<nquad; a++) + { + crFree(base[a]->points); + crFree(base[a]); + } + crFree(base); +} |