Initial import of the CDE 2.1.30 sources from the Open Group.

cde/programs/dtscreen/flame.c

@@ -0,0 +1,176 @@
+/* $XConsortium: flame.c /main/3 1995/11/02 16:07:01 rswiston $ */
+/*
+ */
+/*                                                                      *
+ * (c) Copyright 1993, 1994 Hewlett-Packard Company                     *
+ * (c) Copyright 1993, 1994 International Business Machines Corp.       *
+ * (c) Copyright 1993, 1994 Sun Microsystems, Inc.                      *
+ * (c) Copyright 1993, 1994 Novell, Inc.                                *
+ */
+/*-
+ * flame.c - recursive fractal cosmic flames.
+ *
+ * Copyright (c) 1991 by Patrick J. Naughton.
+ *
+ * See dtscreen.c for copying information.
+ *
+ * Revision History:
+ * 27-Jun-91: vary number of functions used.
+ * 24-Jun-91: fixed portability problem with integer mod (%).
+ * 06-Jun-91: Written. (received from Scott Graves, spot@cs.cmu.edu).
+ */
+
+#include "dtscreen.h"
+#include <math.h>
+
+#define MAXTOTAL	10000
+#define MAXBATCH	10
+#define MAXLEV		4
+
+typedef struct {
+    double      f[2][3][MAXLEV];/* three non-homogeneous transforms */
+    int         max_levels;
+    int         cur_level;
+    int         snum;
+    int         anum;
+    int         width, height;
+    int         num_points;
+    int         total_points;
+    int         pixcol;
+    perwindow  *pwin;
+    XPoint      pts[MAXBATCH];
+}           flamestruct;
+
+static short
+halfrandom(mv)
+    int         mv;
+{
+    static short lasthalf = 0;
+    unsigned long r;
+
+    if (lasthalf) {
+	r = lasthalf;
+	lasthalf = 0;
+    } else {
+	r = random();
+	lasthalf = r >> 16;
+    }
+    return r % mv;
+}
+
+void
+initflame(pwin)
+    perwindow      *pwin;
+{
+    XWindowAttributes xwa;
+    flamestruct *fs;
+
+    if (pwin->data) free(pwin->data);
+    pwin->data = (void *)malloc(sizeof(flamestruct));
+    memset(pwin->data, '\0', sizeof(flamestruct));
+    fs = (flamestruct *)pwin->data;
+
+    srandom(time((time_t *) 0));
+
+    XGetWindowAttributes(dsp, pwin->w, &xwa);
+    fs->width = xwa.width;
+    fs->height = xwa.height;
+
+    fs->max_levels = batchcount;
+    fs->pwin = pwin;
+
+    XSetForeground(dsp, pwin->gc, BlackPixelOfScreen(pwin->perscreen->screen));
+    XFillRectangle(dsp, pwin->w, pwin->gc, 0, 0, fs->width, fs->height);
+
+    if (pwin->perscreen->npixels > 2) {
+      fs->pixcol = halfrandom(pwin->perscreen->npixels);
+      XSetForeground(dsp, pwin->gc, pwin->perscreen->pixels[fs->pixcol]);
+    } else {
+      XSetForeground(dsp, pwin->gc, WhitePixelOfScreen(pwin->perscreen->screen));
+    }
+}
+
+static      Bool
+recurse(fs, x, y, l)
+    flamestruct *fs;
+    register double x, y;
+    register int l;
+{
+    int         xp, yp, i;
+    double      nx, ny;
+
+    if (l == fs->max_levels) {
+	fs->total_points++;
+	if (fs->total_points > MAXTOTAL)	/* how long each fractal runs */
+	    return False;
+
+	if (x > -1.0 && x < 1.0 && y > -1.0 && y < 1.0) {
+	    xp = fs->pts[fs->num_points].x = (int) ((fs->width / 2)
+						    * (x + 1.0));
+	    yp = fs->pts[fs->num_points].y = (int) ((fs->height / 2)
+						    * (y + 1.0));
+	    fs->num_points++;
+	    if (fs->num_points > MAXBATCH) {	/* point buffer size */
+		XDrawPoints(dsp, fs->pwin->w, fs->pwin->gc, fs->pts,
+			    fs->num_points, CoordModeOrigin);
+		fs->num_points = 0;
+	    }
+	}
+    } else {
+	for (i = 0; i < fs->snum; i++) {
+	    nx = fs->f[0][0][i] * x + fs->f[0][1][i] * y + fs->f[0][2][i];
+	    ny = fs->f[1][0][i] * x + fs->f[1][1][i] * y + fs->f[1][2][i];
+	    if (i < fs->anum) {
+		nx = sin(nx);
+		ny = sin(ny);
+	    }
+	    if (!recurse(fs, nx, ny, l + 1))
+		return False;
+	}
+    }
+    return True;
+}
+
+
+void
+drawflame(pwin)
+    perwindow *pwin;
+{
+    flamestruct *fs = (flamestruct *)pwin->data;
+
+    int         i, j, k;
+    static      alt = 0;
+
+    if (!(fs->cur_level++ % fs->max_levels)) {
+	XClearWindow(dsp, fs->pwin->w);
+	alt = !alt;
+    } else {
+	if (pwin->perscreen->npixels > 2) {
+	    XSetForeground(dsp, pwin->gc,
+			   pwin->perscreen->pixels[fs->pixcol]);
+	    if (--fs->pixcol < 0)
+		fs->pixcol = pwin->perscreen->npixels - 1;
+	}
+    }
+
+    /* number of functions */
+    fs->snum = 2 + (fs->cur_level % (MAXLEV - 1));
+
+    /* how many of them are of alternate form */
+    if (alt)
+	fs->anum = 0;
+    else
+	fs->anum = halfrandom(fs->snum) + 2;
+
+    /* 6 dtfs per function */
+    for (k = 0; k < fs->snum; k++) {
+	for (i = 0; i < 2; i++)
+	    for (j = 0; j < 3; j++)
+		fs->f[i][j][k] = ((double) (random() & 1023) / 512.0 - 1.0);
+    }
+    fs->num_points = 0;
+    fs->total_points = 0;
+    (void) recurse(fs, 0.0, 0.0, 0);
+    XDrawPoints(dsp, pwin->w, pwin->gc,
+		fs->pts, fs->num_points, CoordModeOrigin);
+}