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Diffstat (limited to 'mi/mipolyutil.c')
| -rw-r--r-- | mi/mipolyutil.c | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/mi/mipolyutil.c b/mi/mipolyutil.c new file mode 100644 index 000000000..879bd6e1d --- /dev/null +++ b/mi/mipolyutil.c @@ -0,0 +1,398 @@ +/*********************************************************** + +Copyright 1987, 1998 The Open Group + +Permission to use, copy, modify, distribute, and sell this software and its +documentation for any purpose is hereby granted without fee, provided that +the above copyright notice appear in all copies and that both that +copyright notice and this permission notice appear in supporting +documentation. + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN +AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN +CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + +Except as contained in this notice, the name of The Open Group shall not be +used in advertising or otherwise to promote the sale, use or other dealings +in this Software without prior written authorization from The Open Group. + + +Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts. + + All Rights Reserved + +Permission to use, copy, modify, and distribute this software and its +documentation for any purpose and without fee is hereby granted, +provided that the above copyright notice appear in all copies and that +both that copyright notice and this permission notice appear in +supporting documentation, and that the name of Digital not be +used in advertising or publicity pertaining to distribution of the +software without specific, written prior permission. + +DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING +ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL +DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR +ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, +WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, +ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS +SOFTWARE. + +******************************************************************/ +/* $Xorg: mipolyutil.c,v 1.4 2001/02/09 02:05:21 xorgcvs Exp $ */ +#include "miscstruct.h" +#include "gc.h" +#include "miscanfill.h" +#include "mipoly.h" + +#define MAXINT 0x7fffffff +#define MININT -MAXINT + +/* + * fillUtils.c + * + * Written by Brian Kelleher; Oct. 1985 + * + * This module contains all of the utility functions + * needed to scan convert a polygon. + * + */ + +/* + * InsertEdgeInET + * + * Insert the given edge into the edge table. + * First we must find the correct bucket in the + * Edge table, then find the right slot in the + * bucket. Finally, we can insert it. + * + */ +Bool +miInsertEdgeInET(ET, ETE, scanline, SLLBlock, iSLLBlock) + EdgeTable *ET; + EdgeTableEntry *ETE; + int scanline; + ScanLineListBlock **SLLBlock; + int *iSLLBlock; +{ + register EdgeTableEntry *start, *prev; + register ScanLineList *pSLL, *pPrevSLL; + ScanLineListBlock *tmpSLLBlock; + + /* + * find the right bucket to put the edge into + */ + pPrevSLL = &ET->scanlines; + pSLL = pPrevSLL->next; + while (pSLL && (pSLL->scanline < scanline)) + { + pPrevSLL = pSLL; + pSLL = pSLL->next; + } + + /* + * reassign pSLL (pointer to ScanLineList) if necessary + */ + if ((!pSLL) || (pSLL->scanline > scanline)) + { + if (*iSLLBlock > SLLSPERBLOCK-1) + { + tmpSLLBlock = + (ScanLineListBlock *)xalloc(sizeof(ScanLineListBlock)); + if (!tmpSLLBlock) + return FALSE; + (*SLLBlock)->next = tmpSLLBlock; + tmpSLLBlock->next = (ScanLineListBlock *)NULL; + *SLLBlock = tmpSLLBlock; + *iSLLBlock = 0; + } + pSLL = &((*SLLBlock)->SLLs[(*iSLLBlock)++]); + + pSLL->next = pPrevSLL->next; + pSLL->edgelist = (EdgeTableEntry *)NULL; + pPrevSLL->next = pSLL; + } + pSLL->scanline = scanline; + + /* + * now insert the edge in the right bucket + */ + prev = (EdgeTableEntry *)NULL; + start = pSLL->edgelist; + while (start && (start->bres.minor < ETE->bres.minor)) + { + prev = start; + start = start->next; + } + ETE->next = start; + + if (prev) + prev->next = ETE; + else + pSLL->edgelist = ETE; + return TRUE; +} + +/* + * CreateEdgeTable + * + * This routine creates the edge table for + * scan converting polygons. + * The Edge Table (ET) looks like: + * + * EdgeTable + * -------- + * | ymax | ScanLineLists + * |scanline|-->------------>-------------->... + * -------- |scanline| |scanline| + * |edgelist| |edgelist| + * --------- --------- + * | | + * | | + * V V + * list of ETEs list of ETEs + * + * where ETE is an EdgeTableEntry data structure, + * and there is one ScanLineList per scanline at + * which an edge is initially entered. + * + */ + +Bool +miCreateETandAET(count, pts, ET, AET, pETEs, pSLLBlock) + register int count; + register DDXPointPtr pts; + EdgeTable *ET; + EdgeTableEntry *AET; + register EdgeTableEntry *pETEs; + ScanLineListBlock *pSLLBlock; +{ + register DDXPointPtr top, bottom; + register DDXPointPtr PrevPt, CurrPt; + int iSLLBlock = 0; + + int dy; + + if (count < 2) return TRUE; + + /* + * initialize the Active Edge Table + */ + AET->next = (EdgeTableEntry *)NULL; + AET->back = (EdgeTableEntry *)NULL; + AET->nextWETE = (EdgeTableEntry *)NULL; + AET->bres.minor = MININT; + + /* + * initialize the Edge Table. + */ + ET->scanlines.next = (ScanLineList *)NULL; + ET->ymax = MININT; + ET->ymin = MAXINT; + pSLLBlock->next = (ScanLineListBlock *)NULL; + + PrevPt = &pts[count-1]; + + /* + * for each vertex in the array of points. + * In this loop we are dealing with two vertices at + * a time -- these make up one edge of the polygon. + */ + while (count--) + { + CurrPt = pts++; + + /* + * find out which point is above and which is below. + */ + if (PrevPt->y > CurrPt->y) + { + bottom = PrevPt, top = CurrPt; + pETEs->ClockWise = 0; + } + else + { + bottom = CurrPt, top = PrevPt; + pETEs->ClockWise = 1; + } + + /* + * don't add horizontal edges to the Edge table. + */ + if (bottom->y != top->y) + { + pETEs->ymax = bottom->y-1; /* -1 so we don't get last scanline */ + + /* + * initialize integer edge algorithm + */ + dy = bottom->y - top->y; + BRESINITPGONSTRUCT(dy, top->x, bottom->x, pETEs->bres); + + if (!miInsertEdgeInET(ET, pETEs, top->y, &pSLLBlock, &iSLLBlock)) + { + miFreeStorage(pSLLBlock->next); + return FALSE; + } + + ET->ymax = max(ET->ymax, PrevPt->y); + ET->ymin = min(ET->ymin, PrevPt->y); + pETEs++; + } + + PrevPt = CurrPt; + } + return TRUE; +} + +/* + * loadAET + * + * This routine moves EdgeTableEntries from the + * EdgeTable into the Active Edge Table, + * leaving them sorted by smaller x coordinate. + * + */ + +void +miloadAET(AET, ETEs) + register EdgeTableEntry *AET, *ETEs; +{ + register EdgeTableEntry *pPrevAET; + register EdgeTableEntry *tmp; + + pPrevAET = AET; + AET = AET->next; + while (ETEs) + { + while (AET && (AET->bres.minor < ETEs->bres.minor)) + { + pPrevAET = AET; + AET = AET->next; + } + tmp = ETEs->next; + ETEs->next = AET; + if (AET) + AET->back = ETEs; + ETEs->back = pPrevAET; + pPrevAET->next = ETEs; + pPrevAET = ETEs; + + ETEs = tmp; + } +} + +/* + * computeWAET + * + * This routine links the AET by the + * nextWETE (winding EdgeTableEntry) link for + * use by the winding number rule. The final + * Active Edge Table (AET) might look something + * like: + * + * AET + * ---------- --------- --------- + * |ymax | |ymax | |ymax | + * | ... | |... | |... | + * |next |->|next |->|next |->... + * |nextWETE| |nextWETE| |nextWETE| + * --------- --------- ^-------- + * | | | + * V-------------------> V---> ... + * + */ +void +micomputeWAET(AET) + register EdgeTableEntry *AET; +{ + register EdgeTableEntry *pWETE; + register int inside = 1; + register int isInside = 0; + + AET->nextWETE = (EdgeTableEntry *)NULL; + pWETE = AET; + AET = AET->next; + while (AET) + { + if (AET->ClockWise) + isInside++; + else + isInside--; + + if ((!inside && !isInside) || + ( inside && isInside)) + { + pWETE->nextWETE = AET; + pWETE = AET; + inside = !inside; + } + AET = AET->next; + } + pWETE->nextWETE = (EdgeTableEntry *)NULL; +} + +/* + * InsertionSort + * + * Just a simple insertion sort using + * pointers and back pointers to sort the Active + * Edge Table. + * + */ + +int +miInsertionSort(AET) + register EdgeTableEntry *AET; +{ + register EdgeTableEntry *pETEchase; + register EdgeTableEntry *pETEinsert; + register EdgeTableEntry *pETEchaseBackTMP; + register int changed = 0; + + AET = AET->next; + while (AET) + { + pETEinsert = AET; + pETEchase = AET; + while (pETEchase->back->bres.minor > AET->bres.minor) + pETEchase = pETEchase->back; + + AET = AET->next; + if (pETEchase != pETEinsert) + { + pETEchaseBackTMP = pETEchase->back; + pETEinsert->back->next = AET; + if (AET) + AET->back = pETEinsert->back; + pETEinsert->next = pETEchase; + pETEchase->back->next = pETEinsert; + pETEchase->back = pETEinsert; + pETEinsert->back = pETEchaseBackTMP; + changed = 1; + } + } + return(changed); +} + +/* + * Clean up our act. + */ +void +miFreeStorage(pSLLBlock) + register ScanLineListBlock *pSLLBlock; +{ + register ScanLineListBlock *tmpSLLBlock; + + while (pSLLBlock) + { + tmpSLLBlock = pSLLBlock->next; + xfree(pSLLBlock); + pSLLBlock = tmpSLLBlock; + } +} |