/* $XFree86: xc/programs/Xserver/hw/xfree86/accel/agx/agxLine.c,v 3.4 1995/01/28 15:49:04 dawes Exp $ */ /*********************************************************** Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts, and the Massachusetts Institute of Technology, Cambridge, Massachusetts. Copyright 1994 by Henry A. Worth, Sunnyvale, Ca. 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 names of Digital or MIT not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. DIGITAL, KEVIN E. MARTIN, TIAGO GONS, AND HENRY A. WORTH DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL DIGITAL, KEVIN E. MARTIN, TIAGO GONS, OR HENRY A. WORTH 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. Modified for the 8514/A by Kevin E. Martin (martin@cs.unc.edu) Further modifications by Tiago Gons (tiago@comosjn.hobby.nl) Modified for the AGX by Henry A. Worth (haw30@eng.amdahl.com) $XConsortium: agxLine.c,v 1.2 95/01/05 20:29:54 kaleb Exp $ ******************************************************************/ #include "X.h" #include "gcstruct.h" #include "windowstr.h" #include "pixmapstr.h" #include "regionstr.h" #include "scrnintstr.h" #include "mistruct.h" #include "miline.h" #include "cfb.h" #include "cfbmskbits.h" #include "regagx.h" #include "agx.h" /* single-pixel lines on a color frame buffer NON-SLOPED LINES horizontal lines are always drawn left to right; we have to move the endpoints right by one after they're swapped. horizontal lines will be confined to a single band of a region. the code finds that band (giving up if the lower bound of the band is above the line we're drawing); then it finds the first box in that band that contains part of the line. we clip the line to subsequent boxes in that band. vertical lines are always drawn top to bottom (y-increasing.) this requires adding one to the y-coordinate of each endpoint after swapping. SLOPED LINES when clipping a sloped line, we bring the second point inside the clipping box, rather than one beyond it, and then add 1 to the length of the line before drawing it. this lets us use the same box for finding the outcodes for both endpoints. since the equation for clipping the second endpoint to an edge gives us 1 beyond the edge, we then have to move the point towards the first point by one step on the major axis. eventually, there will be a diagram here to explain what's going on. the method uses Cohen-Sutherland outcodes to determine outsideness, and a method similar to Pike's layers for doing the actual clipping. */ /* #define OUTCODES(result, x, y, pbox) \ if (x < pbox->x1) \ result |= OUT_LEFT; \ else if (x >= pbox->x2) \ result |= OUT_RIGHT; \ if (y < pbox->y1) \ result |= OUT_ABOVE; \ else if (y >= pbox->y2) \ result |= OUT_BELOW; */ void agxLine(pDrawable, pGC, mode, npt, pptInit) DrawablePtr pDrawable; GCPtr pGC; int mode; /* Origin or Previous */ int npt; /* number of points */ DDXPointPtr pptInit; { int nboxInit; register int nbox; BoxPtr pboxInit; register BoxPtr pbox; register DDXPointPtr ppt; /* pointer to list of translated points */ unsigned int oc1; /* outcode of point 1 */ unsigned int oc2; /* outcode of point 2 */ int xorg, yorg; /* origin of window */ int adx; /* abs values of dx and dy */ int ady; int signdx; /* sign of dx and dy */ int signdy; int e, e1, e2; /* bresenham error and increments */ register int len; /* length of segment */ int axis; /* major axis */ short cmd2; short fix; Bool first = TRUE; /* a bunch of temporaries */ int tmp; register int y1, y2; register int x1, x2; RegionPtr cclip; cfbPrivGCPtr devPriv; /* 4-5-93 TCG : is VT visible */ if (!xf86VTSema) { cfbLineSS(pDrawable, pGC, mode, npt, pptInit); return; } devPriv = (cfbPrivGC *)(pGC->devPrivates[cfbGCPrivateIndex].ptr); cclip = devPriv->pCompositeClip; pboxInit = REGION_RECTS(cclip); nboxInit = REGION_NUM_RECTS(cclip); xorg = pDrawable->x; yorg = pDrawable->y; ppt = pptInit; x2 = ppt->x + xorg; y2 = ppt->y + yorg; while(--npt) { nbox = nboxInit; pbox = pboxInit; x1 = x2; y1 = y2; ++ppt; if (mode == CoordModePrevious) { xorg = x1; yorg = y1; } x2 = ppt->x + xorg; y2 = ppt->y + yorg; if (x1 == x2) { /* make the line go top to bottom of screen, keeping endpoint semantics */ if (y1 > y2) { register int tmp; tmp = y2; y2 = y1 + 1; y1 = tmp + 1; } /* get to first band that might contain part of line */ while ((nbox) && (pbox->y2 <= y1)) { pbox++; nbox--; } /* stop when lower edge of box is beyond end of line */ while((nbox) && (y2 >= pbox->y1)) { if ((x1 >= pbox->x1) && (x1 < pbox->x2)) { int y1t, y2t; /* this box has part of the line in it */ y1t = max(y1, pbox->y1); y2t = min(y2, pbox->y2); if (y1t != y2t) { register unsigned int opDim = (y2t-y1t-1) << 16; register unsigned int mapCoOrd = y1t << 16 | x1; GE_WAIT_IDLE(); if (first) { first = FALSE; MAP_SET_SRC_AND_DST( GE_MS_MAP_A ); GE_OUT_B(GE_FRGD_MIX, (char) pGC->alu); GE_OUT_D(GE_PIXEL_BIT_MASK, (int) pGC->planemask); GE_OUT_D(GE_FRGD_CLR, (int) pGC->fgPixel); } GE_OUT_D( GE_DEST_MAP_X, mapCoOrd ); GE_OUT_D( GE_OP_DIM_WIDTH, opDim ); GE_START_CMD( GE_OP_BITBLT | GE_OP_MASK_DISABLED | GE_OP_PAT_FRGD | GE_OP_FRGD_SRC_CLR | GE_OP_SRC_MAP_A | GE_OP_DEST_MAP_A | GE_OP_INC_X | GE_OP_INC_Y ); } } nbox--; pbox++; } y2 = ppt->y + yorg; } else if (y1 == y2) { /* force line from left to right, keeping endpoint semantics */ if (x1 > x2) { register int tmp; tmp = x2; x2 = x1 + 1; x1 = tmp + 1; } /* find the correct band */ while( (nbox) && (pbox->y2 <= y1)) { pbox++; nbox--; } while((nbox) && (pbox->y1 <= y1) && (pbox->x1 < x2)) { int x1t, x2t; if (pbox->x2 > x1) { x1t = max(x1, pbox->x1); x2t = min(x2, pbox->x2); if (x1t != x2t) { register unsigned int opDim = x2t-x1t-1; register unsigned int mapCoOrd = y1 << 16 | x1t; GE_WAIT_IDLE(); if (first) { first = FALSE; MAP_SET_SRC_AND_DST( GE_MS_MAP_A ); GE_OUT_B(GE_FRGD_MIX, (char) pGC->alu); GE_OUT_D(GE_PIXEL_BIT_MASK, (int) pGC->planemask); GE_OUT_D(GE_FRGD_CLR, (int) pGC->fgPixel); } GE_OUT_D( GE_DEST_MAP_X, mapCoOrd ); GE_OUT_D( GE_OP_DIM_WIDTH, opDim ); GE_START_CMD( GE_OP_BITBLT | GE_OP_MASK_DISABLED | GE_OP_PAT_FRGD | GE_OP_FRGD_SRC_CLR | GE_OP_SRC_MAP_A | GE_OP_DEST_MAP_A | GE_OP_INC_X | GE_OP_INC_Y ); } } nbox--; pbox++; } x2 = ppt->x + xorg; } else /* sloped line */ { cmd2 = 0; signdx = 1; fix = -1; if ((adx = x2 - x1) < 0) { adx = -adx; signdx = -1; fix = 0; cmd2 |= GE_OP_DEC_X; } signdy = 1; if ((ady = y2 - y1) < 0) { ady = -ady; signdy = -1; cmd2 |= GE_OP_DEC_Y; } if (adx > ady) { axis = X_AXIS; len = adx; e1 = ady << 1; } else { axis = Y_AXIS; len = ady; e1 = adx << 1; cmd2 |= GE_OP_Y_MAJ; } e = e1 - len; e2 = e - len; /* we have bresenham parameters and two points. all we have to do now is clip and draw. */ while(nbox--) { oc1 = 0; oc2 = 0; OUTCODES(oc1, x1, y1, pbox); OUTCODES(oc2, x2, y2, pbox); if ((oc1 | oc2) == 0) { register unsigned int mapCoOrd = y1 << 16 | x1; GE_WAIT_IDLE(); if (first) { first = FALSE; MAP_SET_SRC_AND_DST( GE_MS_MAP_A ); GE_OUT_B(GE_FRGD_MIX, (char) pGC->alu); GE_OUT_D(GE_PIXEL_BIT_MASK, (int) pGC->planemask); GE_OUT_D(GE_FRGD_CLR, (int) pGC->fgPixel); } GE_OUT_D( GE_DEST_MAP_X, mapCoOrd ); GE_OUT_W( GE_OP_DIM_LINE_MAJ, len ); GE_OUT_W( GE_BRES_ERROR_TERM, e+fix ); GE_OUT_W( GE_BRES_CONST_K1, e1 ); GE_OUT_W( GE_BRES_CONST_K2, e2 ); GE_START_CMD( GE_OP_LINE_DRAW_WR | GE_OP_FRGD_SRC_CLR | GE_OP_SRC_MAP_A | GE_OP_DEST_MAP_A | GE_OP_DRAW_LAST_NULL | GE_OP_PAT_FRGD | cmd2 ); break; } else if (oc1 & oc2) { pbox++; } else { /* * let the mi helper routine do our work; * better than duplicating code... */ int err; /* modified bresenham error term */ int clip1=0, clip2=0; /* clippedness of the endpoints */ int clipdx, clipdy; /* difference between clipped and unclipped start point */ int new_x1 = x1, new_y1 = y1, new_x2 = x2, new_y2 = y2; if (miZeroClipLine(pbox->x1, pbox->y1, pbox->x2-1, pbox->y2-1, &new_x1, &new_y1, &new_x2, &new_y2, adx, ady, &clip1, &clip2, axis, (signdx == signdy), oc1, oc2) == -1) { pbox++; continue; } if (axis == X_AXIS) len = abs(new_x2 - new_x1); else len = abs(new_y2 - new_y1); len -= (clip2 == 0); if (len > 0) { register unsigned int mapCoOrd = new_y1 << 16 | new_x1; /* unwind bresenham error term to first point */ if (clip1) { clipdx = abs(new_x1 - x1); clipdy = abs(new_y1 - y1); if (axis == X_AXIS) err = e+((clipdy*e2) + ((clipdx-clipdy)*e1)); else err = e+((clipdx*e2) + ((clipdy-clipdx)*e1)); } else err = e; if ( abs(err) > 8192 || abs(e1) > 8192 || abs(e2) > 8192 ) { int div; if (abs(err) > abs(e1)) div = (abs(err) > abs(e2)) ? (abs(err) + 8192)/ 8192 : (abs(e2) + 8191)/ 8192; else div = (abs(e1) > abs(e2)) ? (abs(e1) + 8191)/ 8192 : (abs(e2) + 8191)/ 8192; err /= div; e1 /= div; e2 /= div; } GE_WAIT_IDLE(); if (first) { first = FALSE; MAP_SET_SRC_AND_DST( GE_MS_MAP_A ); GE_OUT_B(GE_FRGD_MIX, (char) pGC->alu); GE_OUT_D(GE_PIXEL_BIT_MASK, (int) pGC->planemask); GE_OUT_D(GE_FRGD_CLR, (int) pGC->fgPixel); GE_OUT_W( GE_PIXEL_OP, GE_OP_PAT_FRGD | GE_OP_MASK_DISABLED | GE_OP_DRAW_LAST_NULL | cmd2 ); } GE_OUT_D( GE_DEST_MAP_X, mapCoOrd ); GE_OUT_W( GE_OP_DIM_LINE_MAJ, (short) len ); GE_OUT_W( GE_BRES_ERROR_TERM, (short) err+fix ); GE_OUT_W( GE_BRES_CONST_K1, (short) e1 ); GE_OUT_W( GE_BRES_CONST_K2, (short) e2 ); GE_START_CMD( GE_OP_LINE_DRAW_WR | GE_OP_FRGD_SRC_CLR | GE_OP_SRC_MAP_A | GE_OP_DEST_MAP_A | GE_OP_DRAW_ALL | GE_OP_PAT_FRGD | cmd2 ); } pbox++; } } /* while (nbox--) */ } /* sloped line */ } /* while (nline--) */ /* paint the last point if the end style isn't CapNotLast. (Assume that a projecting, butt, or round cap that is one pixel wide is the same as the single pixel of the endpoint.) */ if ((pGC->capStyle != CapNotLast) && ((ppt->x + xorg != pptInit->x + pDrawable->x) || (ppt->y + yorg != pptInit->y + pDrawable->y) || (ppt == pptInit + 1))) { nbox = nboxInit; pbox = pboxInit; while (nbox--) { if ((x2 >= pbox->x1) && (y2 >= pbox->y1) && (x2 < pbox->x2) && (y2 < pbox->y2)) { register unsigned int mapCoOrd = y2 << 16 | x2; GE_WAIT_IDLE(); if (first) { first = FALSE; MAP_SET_SRC_AND_DST( GE_MS_MAP_A ); GE_OUT_B(GE_FRGD_MIX, (char) pGC->alu); GE_OUT_D(GE_PIXEL_BIT_MASK, (int) pGC->planemask); GE_OUT_D(GE_FRGD_CLR, (int) pGC->fgPixel); } GE_OUT_D( GE_DEST_MAP_X, mapCoOrd ); GE_OUT_W( GE_OP_DIM_LINE_MAJ, (short) 0 ); GE_START_CMD( GE_OP_LINE_DRAW_WR | GE_OP_FRGD_SRC_CLR | GE_OP_SRC_MAP_A | GE_OP_DEST_MAP_A | GE_OP_PAT_FRGD | GE_OP_INC_X | GE_OP_INC_Y ); break; } else pbox++; } } GE_WAIT_IDLE_EXIT(); }