source: trunk/third/xscreensaver/hacks/spiral.c @ 20148

/* -*- Mode: C; tab-width: 4 -*- */
/* spiral --- spiraling dots */

#if 0
static const char sccsid[] = "@(#)spiral.c      5.00 2000/11/01 xlockmore";
#endif

/*-
 * Copyright (c) 1994 by Darrick Brown.
 *
 * 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.
 *
 * This file is provided AS IS with no warranties of any kind.  The author
 * shall have no liability with respect to the infringement of copyrights,
 * trade secrets or any patents by this file or any part thereof.  In no
 * event will the author be liable for any lost revenue or profits or
 * other special, indirect and consequential damages.
 *
 * Revision History:
 * 01-Nov-2000: Allocation checks
 * 10-May-1997: jwz@jwz.org: turned into a standalone program.
 * 24-Jul-1995: Fix to allow cycles not to have an arbitrary value by
 *              Peter Schmitzberger (schmitz@coma.sbg.ac.at).
 * 06-Mar-1995: Finished cleaning up and final testing.
 * 03-Mar-1995: Cleaned up code.
 * 12-Jul-1994: Written.
 *
 * Low CPU usage mode.
 * Idea based on a graphics demo I saw a *LONG* time ago.
 */

#ifdef STANDALONE
#define MODE_spiral
#define PROGCLASS "Spiral"
#define HACK_INIT init_spiral
#define HACK_DRAW draw_spiral
#define spiral_opts xlockmore_opts
#define DEFAULTS "*delay: 50000 \n" \
 "*count: 40 \n" \
 "*cycles: 350 \n" \
 "*ncolors: 64 \n"
#define SMOOTH_COLORS
#include "xlockmore.h"          /* from the xscreensaver distribution */
#else /* !STANDALONE */
#include "xlock.h"              /* from the xlockmore distribution */
#endif /* !STANDALONE */

#ifdef MODE_spiral

ModeSpecOpt spiral_opts =
{0, (XrmOptionDescRec *) NULL, 0, (argtype *) NULL, (OptionStruct *) NULL};

#ifdef USE_MODULES
ModStruct   spiral_description =
{"spiral", "init_spiral", "draw_spiral", "release_spiral",
 "refresh_spiral", "init_spiral", (char *) NULL, &spiral_opts,
 5000, -40, 350, 1, 64, 1.0, "",
 "Shows a helical locus of points", 0, NULL};

#endif

#define MAXTRAIL 512            /* The length of the trail */
#define MAXDOTS 40
#define MINDOTS 1
#define TWOPI (2.0*M_PI)        /* for convienence */
#define JAGGINESS 4             /* This sets the "Craziness" of the spiral (I like 4) */
#define SPEED 2.0

/* How many segments to draw per cycle when redrawing */
#define REDRAWSTEP 3


typedef struct {
        float       hx, hy, ha, hr;
} Traildots;

typedef struct {
        Traildots  *traildots;
        float       cx, cy;
        float       angle;
        float       radius;
        float       dr, da;
        float       dx, dy;
        int         erase;
        int         inc;
        float       colors;
        int         width, height;
        float       top, bottom, left, right;
        int         dots, nlength;
        int         redrawing, redrawpos;
} spiralstruct;

static spiralstruct *spirals = (spiralstruct *) NULL;

static void draw_dots(ModeInfo * mi, int in);

#define TFX(sp,x) ((int)((x/sp->right)*(float)sp->width))
#define TFY(sp,y) ((int)((y/sp->top)*(float)sp->height))

static void
draw_dots(ModeInfo * mi, int in)
{

        float       i, inc;
        float       x, y;

        spiralstruct *sp = &spirals[MI_SCREEN(mi)];

        inc = TWOPI / (float) sp->dots;
        for (i = 0.0; i < TWOPI; i += inc) {
                x = sp->traildots[in].hx + COSF(i + sp->traildots[in].ha) *
                        sp->traildots[in].hr;
                y = sp->traildots[in].hy + SINF(i + sp->traildots[in].ha) *
                        sp->traildots[in].hr;
                XDrawPoint(MI_DISPLAY(mi), MI_WINDOW(mi), MI_GC(mi),
                           TFX(sp, x), TFY(sp, y));
        }
}

void
init_spiral(ModeInfo * mi)
{
        spiralstruct *sp;
        int         i;

        if (spirals == NULL) {
                if ((spirals = (spiralstruct *) calloc(MI_NUM_SCREENS(mi),
                                             sizeof (spiralstruct))) == NULL)
                        return;
        }
        sp = &spirals[MI_SCREEN(mi)];

        sp->width = MI_WIDTH(mi);
        sp->height = MI_HEIGHT(mi);

        MI_CLEARWINDOW(mi);

        /* Init */
        sp->nlength = MI_CYCLES(mi);

        if (!sp->traildots)
                if ((sp->traildots = (Traildots *) malloc(sp->nlength *
                                sizeof (Traildots))) == NULL) {
                        return;
                }

        /* initialize the allocated array */
        for (i = 0; i < sp->nlength; i++) {
                sp->traildots[i].hx = 0.0;
                sp->traildots[i].hy = 0.0;
                sp->traildots[i].ha = 0.0;
                sp->traildots[i].hr = 0.0;
        }
        sp->redrawing = 0;

        /* keep the window parameters proportional */
        sp->top = 10000.0;
        sp->bottom = 0;
        sp->right = (float) (sp->width) / (float) (sp->height) * (10000.0);
        sp->left = 0;

        /* assign the initial values */
        sp->cx = (float) (5000.0 - NRAND(2000)) / 10000.0 * sp->right;
        sp->cy = (float) (5000.0 - NRAND(2000));
        sp->radius = (float) (NRAND(200) + 200);
        sp->angle = 0.0;
        sp->dx = (float) (10 - NRAND(20)) * SPEED;
        sp->dy = (float) (10 - NRAND(20)) * SPEED;
        sp->dr = (float) ((NRAND(10) + 4) * (1 - (LRAND() & 1) * 2));
        sp->da = (float) NRAND(360) / 7200.0 + 0.01;
        if (MI_NPIXELS(mi) > 2)
                sp->colors = (float) NRAND(MI_NPIXELS(mi));
        sp->erase = 0;
        sp->inc = 0;
        sp->traildots[sp->inc].hx = sp->cx;
        sp->traildots[sp->inc].hy = sp->cy;
        sp->traildots[sp->inc].ha = sp->angle;
        sp->traildots[sp->inc].hr = sp->radius;
        sp->inc++;

        sp->dots = MI_COUNT(mi);
        if (sp->dots < -MINDOTS)
                sp->dots = NRAND(sp->dots - MINDOTS + 1) + MINDOTS;
        /* Absolute minimum */
        if (sp->dots < MINDOTS)
                sp->dots = MINDOTS;
}

void
draw_spiral(ModeInfo * mi)
{
        Display    *display = MI_DISPLAY(mi);
        GC          gc = MI_GC(mi);
        int         i, j;
        spiralstruct *sp;

        if (spirals == NULL)
                return;
        sp = &spirals[MI_SCREEN(mi)];
        if (sp->traildots == NULL)
                return;

        MI_IS_DRAWN(mi) = True;
        if (sp->erase == 1) {
                XSetForeground(display, gc, MI_BLACK_PIXEL(mi));
                draw_dots(mi, sp->inc);
        }
        sp->cx += sp->dx;
        sp->traildots[sp->inc].hx = sp->cx;

        if ((sp->cx > 9000.0) || (sp->cx < 1000.0))
                sp->dx *= -1.0;

        sp->cy += sp->dy;
        sp->traildots[sp->inc].hy = sp->cy;

        if ((sp->cy > 9000.0) || (sp->cy < 1000.0))
                sp->dy *= -1.0;

        sp->radius += sp->dr;
        sp->traildots[sp->inc].hr = sp->radius;

        if ((sp->radius > 2500.0) && (sp->dr > 0.0))
                sp->dr *= -1.0;
        else if ((sp->radius < 50.0) && (sp->radius < 0.0))
                sp->dr *= -1.0;

        /* Randomly give some variations to:  */

        /* spiral direction (if it is within the boundaries) */
        if ((NRAND(3000) < 1 * JAGGINESS) &&
            (((sp->cx > 2000.0) && (sp->cx < 8000.0)) &&
             ((sp->cy > 2000.0) && (sp->cy < 8000.0)))) {
                sp->dx = (float) (10 - NRAND(20)) * SPEED;
                sp->dy = (float) (10 - NRAND(20)) * SPEED;
        }
        /* The speed of the change in size of the spiral */
        if (NRAND(3000) < 1 * JAGGINESS) {
                if (LRAND() & 1)
                        sp->dr += (float) (NRAND(3) + 1);
                else
                        sp->dr -= (float) (NRAND(3) + 1);

                /* don't let it get too wild */
                if (sp->dr > 18.0)
                        sp->dr = 18.0;
                else if (sp->dr < 4.0)
                        sp->dr = 4.0;
        }
        /* The speed of rotation */
        if (NRAND(3000) < 1 * JAGGINESS)
                sp->da = (float) NRAND(360) / 7200.0 + 0.01;

        /* Reverse rotation */
        if (NRAND(3000) < 1 * JAGGINESS)
                sp->da *= -1.0;

        sp->angle += sp->da;
        sp->traildots[sp->inc].ha = sp->angle;

        if (sp->angle > TWOPI)
                sp->angle -= TWOPI;
        else if (sp->angle < 0.0)
                sp->angle += TWOPI;

        sp->colors += (float) MI_NPIXELS(mi) / ((float) (2 * sp->nlength));
        if (sp->colors >= (float) MI_NPIXELS(mi))
                sp->colors = 0.0;

        if (MI_NPIXELS(mi) > 2)
                XSetForeground(display, gc, MI_PIXEL(mi, (int) sp->colors));
        else
                XSetForeground(display, gc, MI_WHITE_PIXEL(mi));
        draw_dots(mi, sp->inc);
        sp->inc++;

        if (sp->inc > sp->nlength - 1) {
                sp->inc -= sp->nlength;
                sp->erase = 1;
        }
        if (sp->redrawing) {
                for (i = 0; i < REDRAWSTEP; i++) {
                        j = (sp->inc - sp->redrawpos + sp->nlength) % sp->nlength;
                        draw_dots(mi, j);

                        if (++(sp->redrawpos) >= sp->nlength) {
                                sp->redrawing = 0;
                                break;
                        }
                }
        }
}

void
release_spiral(ModeInfo * mi)
{
        if (spirals != NULL) {
                int         screen;

                for (screen = 0; screen < MI_NUM_SCREENS(mi); screen++) {
                        spiralstruct *sp = &spirals[screen];

                        if (sp->traildots)
                                (void) free((void *) sp->traildots);
                }
                (void) free((void *) spirals);
                spirals = (spiralstruct *) NULL;
        }
}

void
refresh_spiral(ModeInfo * mi)
{
        spiralstruct *sp;

        if (spirals == NULL)
                return;
        sp = &spirals[MI_SCREEN(mi)];

        MI_CLEARWINDOW(mi);
        sp->redrawing = 1;
        sp->redrawpos = 0;
}

#endif /* MODE_spiral */