ref: c8b187f9db503465460d8bafa2d7a758bbcf59ca
dir: /libmemdraw/fillpoly.c/
#include "lib9.h" #include "draw.h" #include "memdraw.h" #include "memlayer.h" typedef struct Seg Seg; struct Seg { Point p0; Point p1; long num; long den; long dz; long dzrem; long z; long zerr; long d; }; static void zsort(Seg **seg, Seg **ep); static int ycompare(void*, void*); static int xcompare(void*, void*); static int zcompare(void*, void*); static void xscan(Memimage *dst, Seg **seg, Seg *segtab, int nseg, int wind, Memimage *src, Point sp, int, int, int, int); static void yscan(Memimage *dst, Seg **seg, Seg *segtab, int nseg, int wind, Memimage *src, Point sp, int, int); static void fillcolor(Memimage *dst, int left, int right, int y, Memimage *src, Point p) { int srcval; USED(src); srcval = p.x; p.x = left; p.y = y; memset(byteaddr(dst, p), srcval, right-left); } static void fillline(Memimage *dst, int left, int right, int y, Memimage *src, Point p, int op) { Rectangle r; r.min.x = left; r.min.y = y; r.max.x = right; r.max.y = y+1; p.x += left; p.y += y; memdraw(dst, r, src, p, memopaque, p, op); } static void fillpoint(Memimage *dst, int x, int y, Memimage *src, Point p, int op) { Rectangle r; r.min.x = x; r.min.y = y; r.max.x = x+1; r.max.y = y+1; p.x += x; p.y += y; memdraw(dst, r, src, p, memopaque, p, op); } void memfillpoly(Memimage *dst, Point *vert, int nvert, int w, Memimage *src, Point sp, int op) { _memfillpolysc(dst, vert, nvert, w, src, sp, 0, 0, 0, op); } void _memfillpolysc(Memimage *dst, Point *vert, int nvert, int w, Memimage *src, Point sp, int detail, int fixshift, int clipped, int op) { Seg **seg, *segtab; Point p0; int i; if(nvert == 0) return; seg = malloc((nvert+2)*sizeof(Seg*)); if(seg == nil) return; segtab = malloc((nvert+1)*sizeof(Seg)); if(segtab == nil) { free(seg); return; } sp.x = (sp.x - vert[0].x) >> fixshift; sp.y = (sp.y - vert[0].y) >> fixshift; p0 = vert[nvert-1]; if(!fixshift) { p0.x <<= 1; p0.y <<= 1; } for(i = 0; i < nvert; i++) { segtab[i].p0 = p0; p0 = vert[i]; if(!fixshift) { p0.x <<= 1; p0.y <<= 1; } segtab[i].p1 = p0; segtab[i].d = 1; } if(!fixshift) fixshift = 1; xscan(dst, seg, segtab, nvert, w, src, sp, detail, fixshift, clipped, op); if(detail) yscan(dst, seg, segtab, nvert, w, src, sp, fixshift, op); free(seg); free(segtab); } static long mod(long x, long y) { long z; z = x%y; if((long)(((ulong)z)^((ulong)y)) > 0 || z == 0) return z; return z + y; } static long sdiv(long x, long y) { if((long)(((ulong)x)^((ulong)y)) >= 0 || x == 0) return x/y; return (x+((y>>30)|1))/y-1; } static long smuldivmod(long x, long y, long z, long *mod) { vlong vx; if(x == 0 || y == 0){ *mod = 0; return 0; } vx = x; vx *= y; *mod = vx % z; if(*mod < 0) *mod += z; /* z is always >0 */ if((vx < 0) == (z < 0)) return vx/z; return -((-vx)/z); } static void xscan(Memimage *dst, Seg **seg, Seg *segtab, int nseg, int wind, Memimage *src, Point sp, int detail, int fixshift, int clipped, int op) { long y, maxy, x, x2, xerr, xden, onehalf; Seg **ep, **next, **p, **q, *s; long n, i, iy, cnt, ix, ix2, minx, maxx; Point pt; void (*fill)(Memimage*, int, int, int, Memimage*, Point, int); fill = fillline; /* * This can only work on 8-bit destinations, since fillcolor is * just using memset on sp.x. * * I'd rather not even enable it then, since then if the general * code is too slow, someone will come up with a better improvement * than this sleazy hack. -rsc * if(clipped && (src->flags&Frepl) && src->depth==8 && Dx(src->r)==1 && Dy(src->r)==1) { fill = fillcolor; sp.x = membyteval(src); } * */ USED(clipped); for(i=0, s=segtab, p=seg; i<nseg; i++, s++) { *p = s; if(s->p0.y == s->p1.y) continue; if(s->p0.y > s->p1.y) { pt = s->p0; s->p0 = s->p1; s->p1 = pt; s->d = -s->d; } s->num = s->p1.x - s->p0.x; s->den = s->p1.y - s->p0.y; s->dz = sdiv(s->num, s->den) << fixshift; s->dzrem = mod(s->num, s->den) << fixshift; s->dz += sdiv(s->dzrem, s->den); s->dzrem = mod(s->dzrem, s->den); p++; } n = p-seg; if(n == 0) return; *p = 0; qsort(seg, p-seg , sizeof(Seg*), ycompare); onehalf = 0; if(fixshift) onehalf = 1 << (fixshift-1); minx = dst->clipr.min.x; maxx = dst->clipr.max.x; y = seg[0]->p0.y; if(y < (dst->clipr.min.y << fixshift)) y = dst->clipr.min.y << fixshift; iy = (y + onehalf) >> fixshift; y = (iy << fixshift) + onehalf; maxy = dst->clipr.max.y << fixshift; ep = next = seg; while(y<maxy) { for(q = p = seg; p < ep; p++) { s = *p; if(s->p1.y < y) continue; s->z += s->dz; s->zerr += s->dzrem; if(s->zerr >= s->den) { s->z++; s->zerr -= s->den; if(s->zerr < 0 || s->zerr >= s->den) print("bad ratzerr1: %ld den %ld dzrem %ld\n", s->zerr, s->den, s->dzrem); } *q++ = s; } for(p = next; *p; p++) { s = *p; if(s->p0.y >= y) break; if(s->p1.y < y) continue; s->z = s->p0.x; s->z += smuldivmod(y - s->p0.y, s->num, s->den, &s->zerr); if(s->zerr < 0 || s->zerr >= s->den) print("bad ratzerr2: %ld den %ld ratdzrem %ld\n", s->zerr, s->den, s->dzrem); *q++ = s; } ep = q; next = p; if(ep == seg) { if(*next == 0) break; iy = (next[0]->p0.y + onehalf) >> fixshift; y = (iy << fixshift) + onehalf; continue; } zsort(seg, ep); for(p = seg; p < ep; p++) { cnt = 0; x = p[0]->z; xerr = p[0]->zerr; xden = p[0]->den; ix = (x + onehalf) >> fixshift; if(ix >= maxx) break; if(ix < minx) ix = minx; cnt += p[0]->d; p++; for(;;) { if(p == ep) { print("xscan: fill to infinity"); return; } cnt += p[0]->d; if((cnt&wind) == 0) break; p++; } x2 = p[0]->z; ix2 = (x2 + onehalf) >> fixshift; if(ix2 <= minx) continue; if(ix2 > maxx) ix2 = maxx; if(ix == ix2 && detail) { if(xerr*p[0]->den + p[0]->zerr*xden > p[0]->den*xden) x++; ix = (x + x2) >> (fixshift+1); ix2 = ix+1; } (*fill)(dst, ix, ix2, iy, src, sp, op); } y += (1<<fixshift); iy++; } } static void yscan(Memimage *dst, Seg **seg, Seg *segtab, int nseg, int wind, Memimage *src, Point sp, int fixshift, int op) { long x, maxx, y, y2, yerr, yden, onehalf; Seg **ep, **next, **p, **q, *s; int n, i, ix, cnt, iy, iy2, miny, maxy; Point pt; for(i=0, s=segtab, p=seg; i<nseg; i++, s++) { *p = s; if(s->p0.x == s->p1.x) continue; if(s->p0.x > s->p1.x) { pt = s->p0; s->p0 = s->p1; s->p1 = pt; s->d = -s->d; } s->num = s->p1.y - s->p0.y; s->den = s->p1.x - s->p0.x; s->dz = sdiv(s->num, s->den) << fixshift; s->dzrem = mod(s->num, s->den) << fixshift; s->dz += sdiv(s->dzrem, s->den); s->dzrem = mod(s->dzrem, s->den); p++; } n = p-seg; if(n == 0) return; *p = 0; qsort(seg, n , sizeof(Seg*), xcompare); onehalf = 0; if(fixshift) onehalf = 1 << (fixshift-1); miny = dst->clipr.min.y; maxy = dst->clipr.max.y; x = seg[0]->p0.x; if(x < (dst->clipr.min.x << fixshift)) x = dst->clipr.min.x << fixshift; ix = (x + onehalf) >> fixshift; x = (ix << fixshift) + onehalf; maxx = dst->clipr.max.x << fixshift; ep = next = seg; while(x<maxx) { for(q = p = seg; p < ep; p++) { s = *p; if(s->p1.x < x) continue; s->z += s->dz; s->zerr += s->dzrem; if(s->zerr >= s->den) { s->z++; s->zerr -= s->den; if(s->zerr < 0 || s->zerr >= s->den) print("bad ratzerr1: %ld den %ld ratdzrem %ld\n", s->zerr, s->den, s->dzrem); } *q++ = s; } for(p = next; *p; p++) { s = *p; if(s->p0.x >= x) break; if(s->p1.x < x) continue; s->z = s->p0.y; s->z += smuldivmod(x - s->p0.x, s->num, s->den, &s->zerr); if(s->zerr < 0 || s->zerr >= s->den) print("bad ratzerr2: %ld den %ld ratdzrem %ld\n", s->zerr, s->den, s->dzrem); *q++ = s; } ep = q; next = p; if(ep == seg) { if(*next == 0) break; ix = (next[0]->p0.x + onehalf) >> fixshift; x = (ix << fixshift) + onehalf; continue; } zsort(seg, ep); for(p = seg; p < ep; p++) { cnt = 0; y = p[0]->z; yerr = p[0]->zerr; yden = p[0]->den; iy = (y + onehalf) >> fixshift; if(iy >= maxy) break; if(iy < miny) iy = miny; cnt += p[0]->d; p++; for(;;) { if(p == ep) { print("yscan: fill to infinity"); return; } cnt += p[0]->d; if((cnt&wind) == 0) break; p++; } y2 = p[0]->z; iy2 = (y2 + onehalf) >> fixshift; if(iy2 <= miny) continue; if(iy2 > maxy) iy2 = maxy; if(iy == iy2) { if(yerr*p[0]->den + p[0]->zerr*yden > p[0]->den*yden) y++; iy = (y + y2) >> (fixshift+1); fillpoint(dst, ix, iy, src, sp, op); } } x += (1<<fixshift); ix++; } } static void zsort(Seg **seg, Seg **ep) { int done; Seg **q, **p, *s; if(ep-seg < 20) { /* bubble sort by z - they should be almost sorted already */ q = ep; do { done = 1; q--; for(p = seg; p < q; p++) { if(p[0]->z > p[1]->z) { s = p[0]; p[0] = p[1]; p[1] = s; done = 0; } } } while(!done); } else { q = ep-1; for(p = seg; p < q; p++) { if(p[0]->z > p[1]->z) { qsort(seg, ep-seg, sizeof(Seg*), zcompare); break; } } } } static int ycompare(void *a, void *b) { Seg **s0, **s1; long y0, y1; s0 = a; s1 = b; y0 = (*s0)->p0.y; y1 = (*s1)->p0.y; if(y0 < y1) return -1; if(y0 == y1) return 0; return 1; } static int xcompare(void *a, void *b) { Seg **s0, **s1; long x0, x1; s0 = a; s1 = b; x0 = (*s0)->p0.x; x1 = (*s1)->p0.x; if(x0 < x1) return -1; if(x0 == x1) return 0; return 1; } static int zcompare(void *a, void *b) { Seg **s0, **s1; long z0, z1; s0 = a; s1 = b; z0 = (*s0)->z; z1 = (*s1)->z; if(z0 < z1) return -1; if(z0 == z1) return 0; return 1; }