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Fixed missing xrtraps.c
This commit is contained in:
Carl Worth
parent
f7f194c47d
commit
9ee45ab816
2 changed files with 988 additions and 0 deletions
494
src/xrtraps.c
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494
src/xrtraps.c
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/*
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* $XFree86: $
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*
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* Copyright © 2002 Keith Packard, member of The XFree86 Project, Inc.
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*
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* Permission to use, copy, modify, distribute, and sell this software and its
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* documentation for any purpose is hereby granted without fee, provided that
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* the above copyright notice appear in all copies and that both that
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* copyright notice and this permission notice appear in supporting
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* documentation, and that the name of Keith Packard not be used in
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* advertising or publicity pertaining to distribution of the software without
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* specific, written prior permission. Keith Packard makes no
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* representations about the suitability of this software for any purpose. It
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* is provided "as is" without express or implied warranty.
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*
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* KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
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* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
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* EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
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* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
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* DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
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* TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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*
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* 2002-07-15: Converted from XRenderCompositeDoublePoly to XrTrap. Carl D. Worth
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*/
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#include "xrint.h"
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#define XR_TRAPS_GROWTH_INC 10
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typedef struct _Edge Edge;
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struct _Edge {
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XLineFixed edge;
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XFixed current_x;
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XFixed next_x;
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Bool clockWise;
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Edge *next, *prev;
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};
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/* private functions */
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static void
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_XrTrapsGrowBy(XrTraps *traps, int additional);
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static int
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_ComparePointFixedByY (const void *v1, const void *v2);
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static int
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_CompareEdgeByTop (const void *v1, const void *v2);
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static XFixed
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_ComputeX (XLineFixed *line, XFixed y);
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static double
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_ComputeInverseSlope (XLineFixed *l);
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static double
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_ComputeXIntercept (XLineFixed *l, double inverse_slope);
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static XFixed
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_ComputeIntersect (XLineFixed *l1, XLineFixed *l2);
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static void
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_XrTrapsTessellateEdges (XrTraps *traps,
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Edge *edges,
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int nedges,
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int winding);
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XrTraps *
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XrTrapsCreate(void)
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{
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XrTraps *traps;
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traps = Xmalloc(sizeof(XrTraps));
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XrTrapsInit(traps);
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return traps;
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}
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void
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XrTrapsInit(XrTraps *traps)
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{
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traps->num_xtraps = 0;
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traps->xtraps_size = 0;
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traps->xtraps = NULL;
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}
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void
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XrTrapsDeinit(XrTraps *traps)
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{
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if (traps->xtraps_size) {
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free(traps->xtraps);
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traps->xtraps_size = 0;
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traps->num_xtraps = 0;
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}
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}
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void
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XrTrapsDestroy(XrTraps *traps)
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{
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XrTrapsDeinit(traps);
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Xfree(traps);
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}
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void
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XrTrapsAddTrap(XrTraps *traps, XFixed top, XFixed bottom,
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XLineFixed left, XLineFixed right)
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{
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XTrapezoid *trap;
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if (traps->num_xtraps >= traps->xtraps_size) {
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_XrTrapsGrowBy(traps, XR_TRAPS_GROWTH_INC);
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}
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trap = &traps->xtraps[traps->num_xtraps];
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trap->top = top;
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trap->bottom = bottom;
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trap->left = left;
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trap->right = right;
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traps->num_xtraps++;
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}
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void
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XrTrapsAddTrapFromPoints(XrTraps *traps, XFixed top, XFixed bottom,
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XPointFixed left_p1, XPointFixed left_p2,
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XPointFixed right_p1, XPointFixed right_p2)
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{
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XLineFixed left;
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XLineFixed right;
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left.p1 = left_p1;
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left.p2 = left_p2;
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right.p1 = right_p1;
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right.p2 = right_p2;
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XrTrapsAddTrap(traps, top, bottom, left, right);
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}
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static void
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_XrTrapsGrowBy(XrTraps *traps, int additional)
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{
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XTrapezoid *new_xtraps;
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int old_size = traps->xtraps_size;
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int new_size = traps->num_xtraps + additional;
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if (new_size <= traps->xtraps_size) {
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return;
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}
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traps->xtraps_size = new_size;
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new_xtraps = realloc(traps->xtraps, traps->xtraps_size * sizeof(XTrapezoid));
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if (new_xtraps) {
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traps->xtraps = new_xtraps;
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} else {
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/* XXX: BUG: How do we really want to handle this out of memory error? */
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traps->xtraps_size = old_size;
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}
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}
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static int
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_ComparePointFixedByY (const void *v1, const void *v2)
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{
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const XPointFixed *p1 = v1, *p2 = v2;
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return p1->y - p2->y;
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}
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void
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XrTrapsTessellateTriangle (XrTraps *traps, XPointDouble *tri)
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{
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XPointFixed t[4];
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int i;
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for (i = 0; i < 3; i++) {
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t[i].x = XDoubleToFixed(tri[i].x);
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t[i].y = XDoubleToFixed(tri[i].y);
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}
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qsort(t, 3, sizeof(XPointFixed), _ComparePointFixedByY);
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if (t[1].x > t[2].x) {
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XrTrapsAddTrapFromPoints(traps, t[0].y, t[1].y, t[0], t[2], t[0], t[1]);
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XrTrapsAddTrapFromPoints(traps, t[1].y, t[2].y, t[0], t[2], t[1], t[2]);
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} else {
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XrTrapsAddTrapFromPoints(traps, t[0].y, t[1].y, t[0], t[1], t[0], t[2]);
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XrTrapsAddTrapFromPoints(traps, t[1].y, t[2].y, t[1], t[2], t[0], t[2]);
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}
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}
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void
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XrTrapsTessellateConvexQuad (XrTraps *traps, XPointDouble *quad)
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{
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XPointFixed q[4];
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int i;
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for (i = 0; i < 4; i++) {
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q[i].x = XDoubleToFixed(quad[i].x);
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q[i].y = XDoubleToFixed(quad[i].y);
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}
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qsort(q, 4, sizeof(XPointFixed), _ComparePointFixedByY);
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if (q[1].x > q[2].x) {
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XrTrapsAddTrapFromPoints(traps, q[0].y, q[1].y, q[0], q[2], q[0], q[1]);
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XrTrapsAddTrapFromPoints(traps, q[1].y, q[2].y, q[0], q[2], q[1], q[3]);
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XrTrapsAddTrapFromPoints(traps, q[2].y, q[3].y, q[2], q[3], q[1], q[3]);
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} else {
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XrTrapsAddTrapFromPoints(traps, q[0].y, q[1].y, q[0], q[1], q[0], q[2]);
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XrTrapsAddTrapFromPoints(traps, q[1].y, q[2].y, q[1], q[3], q[0], q[2]);
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XrTrapsAddTrapFromPoints(traps, q[2].y, q[3].y, q[1], q[3], q[2], q[3]);
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}
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}
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void
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XrTrapsTessellatePath (XrTraps *traps, XrPath *path, int winding)
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{
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XrSubPath *subpath;
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for (subpath = path->head; subpath; subpath = subpath->next) {
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XrTrapsTessellateSubPath(traps, subpath, winding);
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}
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}
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void
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XrTrapsTessellateSubPath (XrTraps *traps, XrSubPath *subpath, int winding)
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{
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Edge *edges;
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int i, nedges, npoints = subpath->num_pts;
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XFixed x, y, prevx = 0, prevy = 0, firstx = 0, firsty = 0;
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XFixed top = 0, bottom = 0; /* GCCism */
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edges = (Edge *) Xmalloc (npoints * sizeof (Edge));
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if (!edges)
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return;
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_XrTrapsGrowBy(traps, npoints * npoints);
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/* XXX: CLEANUP: This code is still in the same form it was in
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when I brought it over from Xrender. The right thing to do here
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is to probably move the edge information into XrPath/XrSubPath
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and construct all edges during path construction. */
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nedges = 0;
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for (i = 0; i <= npoints; i++) {
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if (i == npoints) {
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x = firstx;
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y = firsty;
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}
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else {
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x = XDoubleToFixed (subpath->pts[i].x);
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y = XDoubleToFixed (subpath->pts[i].y);
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}
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if (i) {
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if (y < top) {
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top = y;
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} else if (y > bottom) {
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bottom = y;
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}
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if (prevy < y) {
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edges[nedges].edge.p1.x = prevx;
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edges[nedges].edge.p1.y = prevy;
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edges[nedges].edge.p2.x = x;
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edges[nedges].edge.p2.y = y;
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edges[nedges].clockWise = True;
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nedges++;
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}
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else if (prevy > y) {
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edges[nedges].edge.p1.x = x;
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edges[nedges].edge.p1.y = y;
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edges[nedges].edge.p2.x = prevx;
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edges[nedges].edge.p2.y = prevy;
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edges[nedges].clockWise = False;
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nedges++;
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}
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/* drop horizontal edges */
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} else {
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top = y;
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bottom = y;
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firstx = x;
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firsty = y;
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}
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prevx = x;
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prevy = y;
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}
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_XrTrapsTessellateEdges (traps, edges, nedges, winding);
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Xfree (edges);
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}
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static int
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_CompareEdgeByTop (const void *v1, const void *v2)
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{
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const Edge *e1 = v1, *e2 = v2;
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return e1->edge.p1.y - e2->edge.p1.y;
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}
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static XFixed
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_ComputeX (XLineFixed *line, XFixed y)
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{
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XFixed dx = line->p2.x - line->p1.x;
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double ex = (double) (y - line->p1.y) * (double) dx;
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XFixed dy = line->p2.y - line->p1.y;
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return (XFixed) line->p1.x + (XFixed) (ex / dy);
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}
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static double
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_ComputeInverseSlope (XLineFixed *l)
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{
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return (XFixedToDouble (l->p2.x - l->p1.x) /
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XFixedToDouble (l->p2.y - l->p1.y));
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}
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static double
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_ComputeXIntercept (XLineFixed *l, double inverse_slope)
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{
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return XFixedToDouble (l->p1.x) - inverse_slope * XFixedToDouble (l->p1.y);
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}
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static XFixed
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_ComputeIntersect (XLineFixed *l1, XLineFixed *l2)
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{
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/*
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* x = m1y + b1
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* x = m2y + b2
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* m1y + b1 = m2y + b2
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* y * (m1 - m2) = b2 - b1
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* y = (b2 - b1) / (m1 - m2)
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*/
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double m1 = _ComputeInverseSlope (l1);
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double b1 = _ComputeXIntercept (l1, m1);
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double m2 = _ComputeInverseSlope (l2);
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double b2 = _ComputeXIntercept (l2, m2);
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return XDoubleToFixed ((b2 - b1) / (m1 - m2));
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}
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static void
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_XrTrapsTessellateEdges (XrTraps *traps,
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Edge *edges,
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int nedges,
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int winding)
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{
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int inactive;
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Edge *active;
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Edge *e, *en, *next;
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XFixed y, next_y, intersect;
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int in_out;
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qsort (edges, nedges, sizeof (Edge), _CompareEdgeByTop);
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y = edges[0].edge.p1.y;
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active = 0;
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inactive = 0;
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while (active || inactive < nedges)
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{
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/* insert new active edges into list */
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while (inactive < nedges)
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{
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e = &edges[inactive];
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if (e->edge.p1.y > y)
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break;
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/* move this edge into the active list */
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inactive++;
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e->next_x = _ComputeX (&e->edge, y);
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e->next = active;
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e->prev = 0;
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if (active)
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active->prev = e;
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active = e;
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}
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/* find next inflection point */
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next_y = active->edge.p2.y;
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for (e = active; e; e = en)
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{
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if (e->edge.p2.y < next_y)
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next_y = e->edge.p2.y;
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en = e->next;
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/* check intersect */
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if (en && e->edge.p2.x > en->edge.p2.x)
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{
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intersect = _ComputeIntersect (&e->edge, &e->next->edge);
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/* make sure this point is below the actual intersection */
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intersect = intersect + 1;
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if (intersect < next_y && intersect > y)
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next_y = intersect;
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}
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}
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/* check next inactive point */
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if (inactive < nedges && edges[inactive].edge.p1.y < next_y)
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next_y = edges[inactive].edge.p1.y;
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/* compute x coordinates along this group */
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for (e = active; e; e = e->next) {
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e->current_x = e->next_x;
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e->next_x = _ComputeX (&e->edge, next_y);
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}
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/* sort active list */
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for (e = active; e; e = next)
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{
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next = e->next;
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/*
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* Find one later in the list that belongs before the
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* current one
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*/
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for (en = next; en; en = en->next)
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{
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if (en->current_x < e->current_x ||
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(en->current_x == e->current_x &&
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en->next_x < e->next_x))
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{
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/*
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* insert en before e
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*
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* extract en
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*/
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en->prev->next = en->next;
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if (en->next)
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en->next->prev = en->prev;
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/*
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* insert en
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*/
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if (e->prev)
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e->prev->next = en;
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else
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active = en;
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en->prev = e->prev;
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e->prev = en;
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en->next = e;
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/*
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* start over at en
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*/
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next = en;
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break;
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}
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}
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}
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#if 0
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printf ("y: %6.3g:", y / 65536.0);
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for (e = active; e; e = e->next)
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{
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printf (" %6.3g", e->current_x / 65536.0);
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}
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printf ("\n");
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#endif
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/* walk the list generating trapezoids */
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in_out = 0;
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for (e = active; e && (en = e->next); e = e->next)
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{
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if (winding) {
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if (e->clockWise) {
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in_out++;
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} else {
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in_out--;
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}
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if (in_out == 0) {
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continue;
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}
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} else {
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in_out++;
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if (in_out % 2 == 0) {
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continue;
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}
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}
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XrTrapsAddTrap(traps, y, next_y, e->edge, en->edge);
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}
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y = next_y;
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/* delete inactive edges from list */
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for (e = active; e; e = next)
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{
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next = e->next;
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if (e->edge.p2.y <= y)
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||||
{
|
||||
if (e->prev)
|
||||
e->prev->next = e->next;
|
||||
else
|
||||
active = e->next;
|
||||
if (e->next)
|
||||
e->next->prev = e->prev;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
494
xrtraps.c
Normal file
494
xrtraps.c
Normal file
|
|
@ -0,0 +1,494 @@
|
|||
/*
|
||||
* $XFree86: $
|
||||
*
|
||||
* Copyright © 2002 Keith Packard, member of The XFree86 Project, Inc.
|
||||
*
|
||||
* 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, and that the name of Keith Packard not be used in
|
||||
* advertising or publicity pertaining to distribution of the software without
|
||||
* specific, written prior permission. Keith Packard makes no
|
||||
* representations about the suitability of this software for any purpose. It
|
||||
* is provided "as is" without express or implied warranty.
|
||||
*
|
||||
* KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
|
||||
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
|
||||
* EVENT SHALL KEITH PACKARD 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.
|
||||
*
|
||||
* 2002-07-15: Converted from XRenderCompositeDoublePoly to XrTrap. Carl D. Worth
|
||||
*/
|
||||
|
||||
#include "xrint.h"
|
||||
|
||||
#define XR_TRAPS_GROWTH_INC 10
|
||||
|
||||
typedef struct _Edge Edge;
|
||||
|
||||
struct _Edge {
|
||||
XLineFixed edge;
|
||||
XFixed current_x;
|
||||
XFixed next_x;
|
||||
Bool clockWise;
|
||||
Edge *next, *prev;
|
||||
};
|
||||
|
||||
/* private functions */
|
||||
|
||||
static void
|
||||
_XrTrapsGrowBy(XrTraps *traps, int additional);
|
||||
|
||||
static int
|
||||
_ComparePointFixedByY (const void *v1, const void *v2);
|
||||
|
||||
static int
|
||||
_CompareEdgeByTop (const void *v1, const void *v2);
|
||||
|
||||
static XFixed
|
||||
_ComputeX (XLineFixed *line, XFixed y);
|
||||
|
||||
static double
|
||||
_ComputeInverseSlope (XLineFixed *l);
|
||||
|
||||
static double
|
||||
_ComputeXIntercept (XLineFixed *l, double inverse_slope);
|
||||
|
||||
static XFixed
|
||||
_ComputeIntersect (XLineFixed *l1, XLineFixed *l2);
|
||||
|
||||
static void
|
||||
_XrTrapsTessellateEdges (XrTraps *traps,
|
||||
Edge *edges,
|
||||
int nedges,
|
||||
int winding);
|
||||
|
||||
XrTraps *
|
||||
XrTrapsCreate(void)
|
||||
{
|
||||
XrTraps *traps;
|
||||
|
||||
traps = Xmalloc(sizeof(XrTraps));
|
||||
|
||||
XrTrapsInit(traps);
|
||||
|
||||
return traps;
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsInit(XrTraps *traps)
|
||||
{
|
||||
traps->num_xtraps = 0;
|
||||
|
||||
traps->xtraps_size = 0;
|
||||
traps->xtraps = NULL;
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsDeinit(XrTraps *traps)
|
||||
{
|
||||
if (traps->xtraps_size) {
|
||||
free(traps->xtraps);
|
||||
traps->xtraps_size = 0;
|
||||
traps->num_xtraps = 0;
|
||||
}
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsDestroy(XrTraps *traps)
|
||||
{
|
||||
XrTrapsDeinit(traps);
|
||||
Xfree(traps);
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsAddTrap(XrTraps *traps, XFixed top, XFixed bottom,
|
||||
XLineFixed left, XLineFixed right)
|
||||
{
|
||||
XTrapezoid *trap;
|
||||
|
||||
if (traps->num_xtraps >= traps->xtraps_size) {
|
||||
_XrTrapsGrowBy(traps, XR_TRAPS_GROWTH_INC);
|
||||
}
|
||||
|
||||
trap = &traps->xtraps[traps->num_xtraps];
|
||||
trap->top = top;
|
||||
trap->bottom = bottom;
|
||||
trap->left = left;
|
||||
trap->right = right;
|
||||
|
||||
traps->num_xtraps++;
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsAddTrapFromPoints(XrTraps *traps, XFixed top, XFixed bottom,
|
||||
XPointFixed left_p1, XPointFixed left_p2,
|
||||
XPointFixed right_p1, XPointFixed right_p2)
|
||||
{
|
||||
XLineFixed left;
|
||||
XLineFixed right;
|
||||
|
||||
left.p1 = left_p1;
|
||||
left.p2 = left_p2;
|
||||
|
||||
right.p1 = right_p1;
|
||||
right.p2 = right_p2;
|
||||
|
||||
XrTrapsAddTrap(traps, top, bottom, left, right);
|
||||
}
|
||||
|
||||
static void
|
||||
_XrTrapsGrowBy(XrTraps *traps, int additional)
|
||||
{
|
||||
XTrapezoid *new_xtraps;
|
||||
int old_size = traps->xtraps_size;
|
||||
int new_size = traps->num_xtraps + additional;
|
||||
|
||||
if (new_size <= traps->xtraps_size) {
|
||||
return;
|
||||
}
|
||||
|
||||
traps->xtraps_size = new_size;
|
||||
new_xtraps = realloc(traps->xtraps, traps->xtraps_size * sizeof(XTrapezoid));
|
||||
|
||||
if (new_xtraps) {
|
||||
traps->xtraps = new_xtraps;
|
||||
} else {
|
||||
/* XXX: BUG: How do we really want to handle this out of memory error? */
|
||||
traps->xtraps_size = old_size;
|
||||
}
|
||||
}
|
||||
|
||||
static int
|
||||
_ComparePointFixedByY (const void *v1, const void *v2)
|
||||
{
|
||||
const XPointFixed *p1 = v1, *p2 = v2;
|
||||
|
||||
return p1->y - p2->y;
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsTessellateTriangle (XrTraps *traps, XPointDouble *tri)
|
||||
{
|
||||
XPointFixed t[4];
|
||||
int i;
|
||||
|
||||
for (i = 0; i < 3; i++) {
|
||||
t[i].x = XDoubleToFixed(tri[i].x);
|
||||
t[i].y = XDoubleToFixed(tri[i].y);
|
||||
}
|
||||
|
||||
qsort(t, 3, sizeof(XPointFixed), _ComparePointFixedByY);
|
||||
|
||||
if (t[1].x > t[2].x) {
|
||||
XrTrapsAddTrapFromPoints(traps, t[0].y, t[1].y, t[0], t[2], t[0], t[1]);
|
||||
XrTrapsAddTrapFromPoints(traps, t[1].y, t[2].y, t[0], t[2], t[1], t[2]);
|
||||
} else {
|
||||
XrTrapsAddTrapFromPoints(traps, t[0].y, t[1].y, t[0], t[1], t[0], t[2]);
|
||||
XrTrapsAddTrapFromPoints(traps, t[1].y, t[2].y, t[1], t[2], t[0], t[2]);
|
||||
}
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsTessellateConvexQuad (XrTraps *traps, XPointDouble *quad)
|
||||
{
|
||||
XPointFixed q[4];
|
||||
int i;
|
||||
|
||||
for (i = 0; i < 4; i++) {
|
||||
q[i].x = XDoubleToFixed(quad[i].x);
|
||||
q[i].y = XDoubleToFixed(quad[i].y);
|
||||
}
|
||||
|
||||
qsort(q, 4, sizeof(XPointFixed), _ComparePointFixedByY);
|
||||
|
||||
if (q[1].x > q[2].x) {
|
||||
XrTrapsAddTrapFromPoints(traps, q[0].y, q[1].y, q[0], q[2], q[0], q[1]);
|
||||
XrTrapsAddTrapFromPoints(traps, q[1].y, q[2].y, q[0], q[2], q[1], q[3]);
|
||||
XrTrapsAddTrapFromPoints(traps, q[2].y, q[3].y, q[2], q[3], q[1], q[3]);
|
||||
} else {
|
||||
XrTrapsAddTrapFromPoints(traps, q[0].y, q[1].y, q[0], q[1], q[0], q[2]);
|
||||
XrTrapsAddTrapFromPoints(traps, q[1].y, q[2].y, q[1], q[3], q[0], q[2]);
|
||||
XrTrapsAddTrapFromPoints(traps, q[2].y, q[3].y, q[1], q[3], q[2], q[3]);
|
||||
}
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsTessellatePath (XrTraps *traps, XrPath *path, int winding)
|
||||
{
|
||||
XrSubPath *subpath;
|
||||
|
||||
for (subpath = path->head; subpath; subpath = subpath->next) {
|
||||
XrTrapsTessellateSubPath(traps, subpath, winding);
|
||||
}
|
||||
}
|
||||
|
||||
void
|
||||
XrTrapsTessellateSubPath (XrTraps *traps, XrSubPath *subpath, int winding)
|
||||
{
|
||||
Edge *edges;
|
||||
int i, nedges, npoints = subpath->num_pts;
|
||||
XFixed x, y, prevx = 0, prevy = 0, firstx = 0, firsty = 0;
|
||||
XFixed top = 0, bottom = 0; /* GCCism */
|
||||
|
||||
edges = (Edge *) Xmalloc (npoints * sizeof (Edge));
|
||||
if (!edges)
|
||||
return;
|
||||
|
||||
_XrTrapsGrowBy(traps, npoints * npoints);
|
||||
|
||||
/* XXX: CLEANUP: This code is still in the same form it was in
|
||||
when I brought it over from Xrender. The right thing to do here
|
||||
is to probably move the edge information into XrPath/XrSubPath
|
||||
and construct all edges during path construction. */
|
||||
nedges = 0;
|
||||
for (i = 0; i <= npoints; i++) {
|
||||
if (i == npoints) {
|
||||
x = firstx;
|
||||
y = firsty;
|
||||
}
|
||||
else {
|
||||
x = XDoubleToFixed (subpath->pts[i].x);
|
||||
y = XDoubleToFixed (subpath->pts[i].y);
|
||||
}
|
||||
if (i) {
|
||||
if (y < top) {
|
||||
top = y;
|
||||
} else if (y > bottom) {
|
||||
bottom = y;
|
||||
}
|
||||
if (prevy < y) {
|
||||
edges[nedges].edge.p1.x = prevx;
|
||||
edges[nedges].edge.p1.y = prevy;
|
||||
edges[nedges].edge.p2.x = x;
|
||||
edges[nedges].edge.p2.y = y;
|
||||
edges[nedges].clockWise = True;
|
||||
nedges++;
|
||||
}
|
||||
else if (prevy > y) {
|
||||
edges[nedges].edge.p1.x = x;
|
||||
edges[nedges].edge.p1.y = y;
|
||||
edges[nedges].edge.p2.x = prevx;
|
||||
edges[nedges].edge.p2.y = prevy;
|
||||
edges[nedges].clockWise = False;
|
||||
nedges++;
|
||||
}
|
||||
/* drop horizontal edges */
|
||||
} else {
|
||||
top = y;
|
||||
bottom = y;
|
||||
firstx = x;
|
||||
firsty = y;
|
||||
}
|
||||
prevx = x;
|
||||
prevy = y;
|
||||
}
|
||||
|
||||
_XrTrapsTessellateEdges (traps, edges, nedges, winding);
|
||||
Xfree (edges);
|
||||
}
|
||||
|
||||
static int
|
||||
_CompareEdgeByTop (const void *v1, const void *v2)
|
||||
{
|
||||
const Edge *e1 = v1, *e2 = v2;
|
||||
|
||||
return e1->edge.p1.y - e2->edge.p1.y;
|
||||
}
|
||||
|
||||
static XFixed
|
||||
_ComputeX (XLineFixed *line, XFixed y)
|
||||
{
|
||||
XFixed dx = line->p2.x - line->p1.x;
|
||||
double ex = (double) (y - line->p1.y) * (double) dx;
|
||||
XFixed dy = line->p2.y - line->p1.y;
|
||||
|
||||
return (XFixed) line->p1.x + (XFixed) (ex / dy);
|
||||
}
|
||||
|
||||
static double
|
||||
_ComputeInverseSlope (XLineFixed *l)
|
||||
{
|
||||
return (XFixedToDouble (l->p2.x - l->p1.x) /
|
||||
XFixedToDouble (l->p2.y - l->p1.y));
|
||||
}
|
||||
|
||||
static double
|
||||
_ComputeXIntercept (XLineFixed *l, double inverse_slope)
|
||||
{
|
||||
return XFixedToDouble (l->p1.x) - inverse_slope * XFixedToDouble (l->p1.y);
|
||||
}
|
||||
|
||||
static XFixed
|
||||
_ComputeIntersect (XLineFixed *l1, XLineFixed *l2)
|
||||
{
|
||||
/*
|
||||
* x = m1y + b1
|
||||
* x = m2y + b2
|
||||
* m1y + b1 = m2y + b2
|
||||
* y * (m1 - m2) = b2 - b1
|
||||
* y = (b2 - b1) / (m1 - m2)
|
||||
*/
|
||||
double m1 = _ComputeInverseSlope (l1);
|
||||
double b1 = _ComputeXIntercept (l1, m1);
|
||||
double m2 = _ComputeInverseSlope (l2);
|
||||
double b2 = _ComputeXIntercept (l2, m2);
|
||||
|
||||
return XDoubleToFixed ((b2 - b1) / (m1 - m2));
|
||||
}
|
||||
|
||||
static void
|
||||
_XrTrapsTessellateEdges (XrTraps *traps,
|
||||
Edge *edges,
|
||||
int nedges,
|
||||
int winding)
|
||||
{
|
||||
int inactive;
|
||||
Edge *active;
|
||||
Edge *e, *en, *next;
|
||||
XFixed y, next_y, intersect;
|
||||
int in_out;
|
||||
|
||||
qsort (edges, nedges, sizeof (Edge), _CompareEdgeByTop);
|
||||
|
||||
y = edges[0].edge.p1.y;
|
||||
active = 0;
|
||||
inactive = 0;
|
||||
while (active || inactive < nedges)
|
||||
{
|
||||
/* insert new active edges into list */
|
||||
while (inactive < nedges)
|
||||
{
|
||||
e = &edges[inactive];
|
||||
if (e->edge.p1.y > y)
|
||||
break;
|
||||
/* move this edge into the active list */
|
||||
inactive++;
|
||||
e->next_x = _ComputeX (&e->edge, y);
|
||||
e->next = active;
|
||||
e->prev = 0;
|
||||
if (active)
|
||||
active->prev = e;
|
||||
active = e;
|
||||
}
|
||||
|
||||
/* find next inflection point */
|
||||
next_y = active->edge.p2.y;
|
||||
for (e = active; e; e = en)
|
||||
{
|
||||
if (e->edge.p2.y < next_y)
|
||||
next_y = e->edge.p2.y;
|
||||
en = e->next;
|
||||
/* check intersect */
|
||||
if (en && e->edge.p2.x > en->edge.p2.x)
|
||||
{
|
||||
intersect = _ComputeIntersect (&e->edge, &e->next->edge);
|
||||
/* make sure this point is below the actual intersection */
|
||||
intersect = intersect + 1;
|
||||
if (intersect < next_y && intersect > y)
|
||||
next_y = intersect;
|
||||
}
|
||||
}
|
||||
/* check next inactive point */
|
||||
if (inactive < nedges && edges[inactive].edge.p1.y < next_y)
|
||||
next_y = edges[inactive].edge.p1.y;
|
||||
|
||||
/* compute x coordinates along this group */
|
||||
for (e = active; e; e = e->next) {
|
||||
e->current_x = e->next_x;
|
||||
e->next_x = _ComputeX (&e->edge, next_y);
|
||||
}
|
||||
|
||||
/* sort active list */
|
||||
for (e = active; e; e = next)
|
||||
{
|
||||
next = e->next;
|
||||
/*
|
||||
* Find one later in the list that belongs before the
|
||||
* current one
|
||||
*/
|
||||
for (en = next; en; en = en->next)
|
||||
{
|
||||
if (en->current_x < e->current_x ||
|
||||
(en->current_x == e->current_x &&
|
||||
en->next_x < e->next_x))
|
||||
{
|
||||
/*
|
||||
* insert en before e
|
||||
*
|
||||
* extract en
|
||||
*/
|
||||
en->prev->next = en->next;
|
||||
if (en->next)
|
||||
en->next->prev = en->prev;
|
||||
/*
|
||||
* insert en
|
||||
*/
|
||||
if (e->prev)
|
||||
e->prev->next = en;
|
||||
else
|
||||
active = en;
|
||||
en->prev = e->prev;
|
||||
e->prev = en;
|
||||
en->next = e;
|
||||
/*
|
||||
* start over at en
|
||||
*/
|
||||
next = en;
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
#if 0
|
||||
printf ("y: %6.3g:", y / 65536.0);
|
||||
for (e = active; e; e = e->next)
|
||||
{
|
||||
printf (" %6.3g", e->current_x / 65536.0);
|
||||
}
|
||||
printf ("\n");
|
||||
#endif
|
||||
|
||||
/* walk the list generating trapezoids */
|
||||
in_out = 0;
|
||||
for (e = active; e && (en = e->next); e = e->next)
|
||||
{
|
||||
if (winding) {
|
||||
if (e->clockWise) {
|
||||
in_out++;
|
||||
} else {
|
||||
in_out--;
|
||||
}
|
||||
if (in_out == 0) {
|
||||
continue;
|
||||
}
|
||||
} else {
|
||||
in_out++;
|
||||
if (in_out % 2 == 0) {
|
||||
continue;
|
||||
}
|
||||
}
|
||||
XrTrapsAddTrap(traps, y, next_y, e->edge, en->edge);
|
||||
}
|
||||
|
||||
y = next_y;
|
||||
|
||||
/* delete inactive edges from list */
|
||||
for (e = active; e; e = next)
|
||||
{
|
||||
next = e->next;
|
||||
if (e->edge.p2.y <= y)
|
||||
{
|
||||
if (e->prev)
|
||||
e->prev->next = e->next;
|
||||
else
|
||||
active = e->next;
|
||||
if (e->next)
|
||||
e->next->prev = e->prev;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
Loading…
Add table
Reference in a new issue