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do_triangles.c
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1991-05-02
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/*****************************************************************************
Copyright 1988, 1989 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.
******************************************************************************/
#undef POLYTRIANGLE_HACK /* don't use this code */
#ifdef POLYTRIANGLE_HACK
#include <X11/Xlibint.h>
#endif
#include "x11perf.h"
#include "bitmaps.h"
#include <stdio.h>
#include <math.h>
#define NUM_POINTS 3 /* 3 points to a triangle */
static XPoint *points;
static GC pgc;
extern double sin();
extern double cos();
extern double sqrt();
#define PI 3.14159265357989
double Area(p1, p2, p3)
XPoint p1, p2, p3;
{
return
(p1.x*p2.y - p1.x*p3.y + p2.x*p3.y - p2.x*p1.y + p3.x*p1.y - p3.x*p2.y)/2;
}
double Distance(p1, p2)
XPoint p1, p2;
{
return sqrt((float) ((p1.x-p2.x)*(p1.x-p2.x) + (p1.y-p2.y)*(p1.y-p2.y)));
}
int InitTriangles(xp, p, reps)
XParms xp;
Parms p;
int reps;
{
int i, j, numPoints;
int rows;
int x, y;
int size, iradius;
double phi, phiinc, radius, delta, phi2, area, aarea;
XPoint *curPoint;
pgc = xp->fggc;
size = p->special;
phi = 0.0;
delta = 2.0 * PI / ((double) NUM_POINTS);
if (xp->version == VERSION1_2) {
radius = ((double) size) * sqrt(3.0)/2.0;
phiinc = delta/10.0;
} else {
/* Version 1.2's radius computation was completely bogus, and resulted
in triangles with sides about 50% longer than advertised. However,
this inadvertently resulted in triangles with areas just a little bit
smaller than the triangle that covers size^2 pixels, which would
make the area directly comparable to 10x10 rectangles and 10x10
trapezoids. So here's the new computation so -triangleN has the same
area as -rectN.
*/
radius = ((double) size) * sqrt(sqrt(16.0/27.0));
phiinc = 1.75*PI / ((double) p->objects);
}
iradius = (int) (radius + 0.5);
numPoints = (p->objects) * NUM_POINTS;
points = (XPoint *)malloc(numPoints * sizeof(XPoint));
curPoint = points;
x = iradius;
y = iradius;
rows = 0;
aarea = 0.0;
for (i = 0; i != p->objects; i++) {
for (j = 0; j != NUM_POINTS; j++) {
phi2 = phi + ((double) j) * delta;
curPoint->x = (int) ((double)x + (radius * cos(phi2)) + 0.5);
curPoint->y = (int) ((double)y + (radius * sin(phi2)) + 0.5);
curPoint++;
}
area = Area(curPoint[-1], curPoint[-2], curPoint[-3]);
aarea += area;
/* printf("%6.1lf %6.1lf %6.1lf %6.1lf\n",
Distance(curPoint[-1], curPoint[-2]),
Distance(curPoint[-1], curPoint[-3]),
Distance(curPoint[-2], curPoint[-3]),
area);
*/
phi += phiinc;
y += 2 * iradius;
rows++;
if (y + iradius > HEIGHT || rows == MAXROWS) {
rows = 0;
y = iradius;
x += 2 * iradius;
if (x + iradius > WIDTH) {
x = iradius;
}
}
}
/* printf("Average area = %6.2lf\n", aarea/p->objects); */
SetFillStyle(xp, p);
return reps;
}
#ifndef POLYTRIANGLE_HACK
void DoTriangles(xp, p, reps)
XParms xp;
Parms p;
int reps;
{
int i, j;
XPoint *curPoint;
for (i = 0; i != reps; i++) {
curPoint = points;
for (j = 0; j != p->objects; j++) {
XFillPolygon(xp->d, xp->w, pgc, curPoint, NUM_POINTS, Convex,
CoordModeOrigin);
curPoint += NUM_POINTS;
}
if (pgc == xp->bggc)
pgc = xp->fggc;
else
pgc = xp->bggc;
}
}
#else
void DoTriangles(xp, p, reps)
XParms xp;
Parms p;
int reps;
{
int i, j;
XPoint *curPoint;
for (i = 0; i != reps; i++) {
XPolyTriangle (xp->d, xp->w, pgc, points, p->objects, Convex,
CoordModeOrigin);
if (pgc == xp->bggc)
pgc = xp->fggc;
else
pgc = xp->bggc;
}
}
static xReq _dummy_request = {
0, 0, 0
};
XPolyTriangle(dpy, d, gc, points, n_triangles, shape, mode)
register Display *dpy;
Drawable d;
GC gc;
XPoint *points;
int n_triangles;
int shape;
int mode;
{
register xFillPolyReq *req;
register long nbytes;
int max_triangles;
int n_this_time;
int *buf, *pts;
int gcid;
int last;
max_triangles = (dpy->bufmax - dpy->buffer) / 28;
LockDisplay(dpy);
FlushGC(dpy, gc);
dpy->request += n_triangles;
pts = (int *) points;
gcid = gc->gid;
last = shape | (mode << 8);
while (n_triangles)
{
if ((n_this_time = max_triangles) > n_triangles)
n_this_time = n_triangles;
n_triangles -= n_this_time;
GetReqExtra(FillPoly,
(SIZEOF(xFillPolyReq) + 12) * n_this_time - SIZEOF(xFillPolyReq), req);
--dpy->request;
buf = req;
while (n_this_time--)
{
buf[0] = X_FillPoly | (7 << 16);
buf[1] = d;
buf[2] = gcid;
buf[3] = last;
buf[4] = pts[0];
buf[5] = pts[1];
buf[6] = pts[2];
buf += 7;
pts += 3;
}
}
dpy->last_req = &_dummy_request;
UnlockDisplay(dpy);
SyncHandle();
}
#endif
void EndTriangles(xp, p)
XParms xp;
Parms p;
{
free(points);
}