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393 lines
10 KiB
C
393 lines
10 KiB
C
/* $XFree86: xc/programs/Xserver/mi/mipolyutil.c,v 1.7 1998/10/04 09:39:31 dawes Exp $ */
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/***********************************************************
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Copyright 1987, 1998 The Open Group
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All Rights Reserved.
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The above copyright notice and this permission notice shall be included in
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all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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Except as contained in this notice, the name of The Open Group shall not be
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used in advertising or otherwise to promote the sale, use or other dealings
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in this Software without prior written authorization from The Open Group.
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Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and its
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documentation for any purpose and without fee is hereby granted,
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provided that the above copyright notice appear in all copies and that
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both that copyright notice and this permission notice appear in
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supporting documentation, and that the name of Digital not be
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used in advertising or publicity pertaining to distribution of the
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software without specific, written prior permission.
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DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
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ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
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DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
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ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
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WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
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ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
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SOFTWARE.
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******************************************************************/
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/* $TOG: mipolyutil.c /main/6 1998/02/09 14:48:12 kaleb $ */
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#include <limits.h>
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#include "mi.h"
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#include "miscanfill.h"
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#include "mipoly.h"
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/*
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* fillUtils.c
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*
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* Written by Brian Kelleher; Oct. 1985
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*
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* This module contains all of the utility functions
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* needed to scan convert a polygon.
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*
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*/
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/*
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* InsertEdgeInET
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*
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* Insert the given edge into the edge table.
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* First we must find the correct bucket in the
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* Edge table, then find the right slot in the
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* bucket. Finally, we can insert it.
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*
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*/
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gboolean
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miInsertEdgeInET(ET, ETE, scanline, SLLBlock, iSLLBlock)
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EdgeTable *ET;
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EdgeTableEntry *ETE;
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int scanline;
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ScanLineListBlock **SLLBlock;
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int *iSLLBlock;
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{
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register EdgeTableEntry *start, *prev;
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register ScanLineList *pSLL, *pPrevSLL;
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ScanLineListBlock *tmpSLLBlock;
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/*
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* find the right bucket to put the edge into
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*/
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pPrevSLL = &ET->scanlines;
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pSLL = pPrevSLL->next;
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while (pSLL && (pSLL->scanline < scanline))
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{
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pPrevSLL = pSLL;
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pSLL = pSLL->next;
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}
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/*
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* reassign pSLL (pointer to ScanLineList) if necessary
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*/
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if ((!pSLL) || (pSLL->scanline > scanline))
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{
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if (*iSLLBlock > SLLSPERBLOCK-1)
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{
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tmpSLLBlock =
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(ScanLineListBlock *)g_malloc(sizeof(ScanLineListBlock));
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if (!tmpSLLBlock)
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return FALSE;
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(*SLLBlock)->next = tmpSLLBlock;
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tmpSLLBlock->next = (ScanLineListBlock *)NULL;
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*SLLBlock = tmpSLLBlock;
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*iSLLBlock = 0;
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}
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pSLL = &((*SLLBlock)->SLLs[(*iSLLBlock)++]);
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pSLL->next = pPrevSLL->next;
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pSLL->edgelist = (EdgeTableEntry *)NULL;
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pPrevSLL->next = pSLL;
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}
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pSLL->scanline = scanline;
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/*
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* now insert the edge in the right bucket
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*/
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prev = (EdgeTableEntry *)NULL;
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start = pSLL->edgelist;
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while (start && (start->bres.minor < ETE->bres.minor))
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{
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prev = start;
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start = start->next;
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}
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ETE->next = start;
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if (prev)
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prev->next = ETE;
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else
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pSLL->edgelist = ETE;
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return TRUE;
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}
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/*
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* CreateEdgeTable
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*
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* This routine creates the edge table for
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* scan converting polygons.
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* The Edge Table (ET) looks like:
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*
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* EdgeTable
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* --------
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* | ymax | ScanLineLists
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* |scanline|-->------------>-------------->...
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* -------- |scanline| |scanline|
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* |edgelist| |edgelist|
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* --------- ---------
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* | |
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* | |
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* V V
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* list of ETEs list of ETEs
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*
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* where ETE is an EdgeTableEntry data structure,
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* and there is one ScanLineList per scanline at
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* which an edge is initially entered.
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*
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*/
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gboolean
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miCreateETandAET(count, pts, ET, AET, pETEs, pSLLBlock)
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register int count;
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register GdkPoint* pts;
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EdgeTable *ET;
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EdgeTableEntry *AET;
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register EdgeTableEntry *pETEs;
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ScanLineListBlock *pSLLBlock;
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{
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register GdkPoint* top, *bottom;
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register GdkPoint* PrevPt, *CurrPt;
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int iSLLBlock = 0;
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int dy;
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if (count < 2) return TRUE;
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/*
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* initialize the Active Edge Table
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*/
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AET->next = (EdgeTableEntry *)NULL;
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AET->back = (EdgeTableEntry *)NULL;
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AET->nextWETE = (EdgeTableEntry *)NULL;
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AET->bres.minor = INT_MIN;
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/*
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* initialize the Edge Table.
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*/
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ET->scanlines.next = (ScanLineList *)NULL;
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ET->ymax = INT_MIN;
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ET->ymin = INT_MAX;
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pSLLBlock->next = (ScanLineListBlock *)NULL;
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PrevPt = &pts[count-1];
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/*
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* for each vertex in the array of points.
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* In this loop we are dealing with two vertices at
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* a time -- these make up one edge of the polygon.
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*/
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while (count--)
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{
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CurrPt = pts++;
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/*
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* find out which point is above and which is below.
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*/
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if (PrevPt->y > CurrPt->y)
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{
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bottom = PrevPt, top = CurrPt;
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pETEs->ClockWise = 0;
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}
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else
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{
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bottom = CurrPt, top = PrevPt;
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pETEs->ClockWise = 1;
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}
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/*
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* don't add horizontal edges to the Edge table.
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*/
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if (bottom->y != top->y)
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{
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pETEs->ymax = bottom->y-1; /* -1 so we don't get last scanline */
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/*
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* initialize integer edge algorithm
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*/
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dy = bottom->y - top->y;
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BRESINITPGONSTRUCT(dy, top->x, bottom->x, pETEs->bres);
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if (!miInsertEdgeInET(ET, pETEs, top->y, &pSLLBlock, &iSLLBlock))
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{
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miFreeStorage(pSLLBlock->next);
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return FALSE;
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}
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ET->ymax = MAX(ET->ymax, PrevPt->y);
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ET->ymin = MIN(ET->ymin, PrevPt->y);
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pETEs++;
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}
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PrevPt = CurrPt;
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}
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return TRUE;
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}
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/*
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* loadAET
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*
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* This routine moves EdgeTableEntries from the
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* EdgeTable into the Active Edge Table,
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* leaving them sorted by smaller x coordinate.
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*
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*/
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void
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miloadAET(AET, ETEs)
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register EdgeTableEntry *AET, *ETEs;
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{
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register EdgeTableEntry *pPrevAET;
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register EdgeTableEntry *tmp;
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pPrevAET = AET;
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AET = AET->next;
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while (ETEs)
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{
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while (AET && (AET->bres.minor < ETEs->bres.minor))
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{
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pPrevAET = AET;
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AET = AET->next;
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}
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tmp = ETEs->next;
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ETEs->next = AET;
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if (AET)
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AET->back = ETEs;
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ETEs->back = pPrevAET;
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pPrevAET->next = ETEs;
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pPrevAET = ETEs;
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ETEs = tmp;
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}
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}
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/*
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* computeWAET
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*
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* This routine links the AET by the
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* nextWETE (winding EdgeTableEntry) link for
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* use by the winding number rule. The final
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* Active Edge Table (AET) might look something
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* like:
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*
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* AET
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* ---------- --------- ---------
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* |ymax | |ymax | |ymax |
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* | ... | |... | |... |
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* |next |->|next |->|next |->...
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* |nextWETE| |nextWETE| |nextWETE|
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* --------- --------- ^--------
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* | | |
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* V-------------------> V---> ...
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*
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*/
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void
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micomputeWAET(AET)
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register EdgeTableEntry *AET;
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{
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register EdgeTableEntry *pWETE;
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register int inside = 1;
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register int isInside = 0;
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AET->nextWETE = (EdgeTableEntry *)NULL;
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pWETE = AET;
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AET = AET->next;
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while (AET)
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{
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if (AET->ClockWise)
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isInside++;
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else
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isInside--;
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if ((!inside && !isInside) ||
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( inside && isInside))
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{
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pWETE->nextWETE = AET;
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pWETE = AET;
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inside = !inside;
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}
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AET = AET->next;
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}
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pWETE->nextWETE = (EdgeTableEntry *)NULL;
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}
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/*
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* InsertionSort
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*
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* Just a simple insertion sort using
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* pointers and back pointers to sort the Active
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* Edge Table.
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*
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*/
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int
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miInsertionSort(AET)
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register EdgeTableEntry *AET;
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{
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register EdgeTableEntry *pETEchase;
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register EdgeTableEntry *pETEinsert;
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register EdgeTableEntry *pETEchaseBackTMP;
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register int changed = 0;
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AET = AET->next;
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while (AET)
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{
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pETEinsert = AET;
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pETEchase = AET;
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while (pETEchase->back->bres.minor > AET->bres.minor)
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pETEchase = pETEchase->back;
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AET = AET->next;
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if (pETEchase != pETEinsert)
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{
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pETEchaseBackTMP = pETEchase->back;
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pETEinsert->back->next = AET;
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if (AET)
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AET->back = pETEinsert->back;
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pETEinsert->next = pETEchase;
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pETEchase->back->next = pETEinsert;
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pETEchase->back = pETEinsert;
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pETEinsert->back = pETEchaseBackTMP;
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changed = 1;
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}
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}
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return(changed);
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}
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/*
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* Clean up our act.
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*/
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void
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miFreeStorage(pSLLBlock)
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register ScanLineListBlock *pSLLBlock;
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{
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register ScanLineListBlock *tmpSLLBlock;
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while (pSLLBlock)
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{
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tmpSLLBlock = pSLLBlock->next;
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g_free(pSLLBlock);
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pSLLBlock = tmpSLLBlock;
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}
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}
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