/* Eruption, Copyright (c) 2002-2003 W.P. van Paassen <peter@paassen.tmfweb.nl>
*
* 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. No representations are made about the suitability of this
* software for any purpose. It is provided "as is" without express or
* implied warranty.
*
* Module - "eruption.c"
*
* [02-2003] - W.P. van Paassen: Improvements, added some code of jwz from the pyro hack for a spherical distribution of the particles
* [01-2003] - W.P. van Paassen: Port to X for use with XScreenSaver, the shadebob hack by Shane Smit was used as a template
* [04-2002] - W.P. van Paassen: Creation for the Demo Effects Collection (http://demo-effects.sourceforge.net)
*/
#include <math.h>
#include "screenhack.h"
/*#define VERBOSE*/
/* Slightly whacked, for better explosions
*/
#define PI_2000 6284
#define SPREAD 15
/*particle structure*/
typedef struct
{
short xpos, ypos, xdir, ydir;
unsigned char colorindex;
unsigned char dead;
} PARTICLE;
struct state {
Display *dpy;
Window window;
int sin_cache[PI_2000];
int cos_cache[PI_2000];
PARTICLE *particles;
unsigned short iWinWidth, iWinHeight;
unsigned char **fire;
unsigned short nParticleCount;
unsigned char xdelta, ydelta, decay;
signed char gravity;
signed short heat;
int cycles, delay;
GC gc;
signed short iColorCount;
unsigned long *aiColorVals;
XImage *pImage;
int draw_i;
};
static void
cache(struct state *st) /* jwz */
{ /*needs to be run once. Could easily be */
int i; /*reimplemented to run and cache at compile-time,*/
double dA;
for (i=0; i<PI_2000; i++)
{
dA=sin(((double) (random() % (PI_2000/2)))/1000.0);
/*Emulation of spherical distribution*/
dA+=asin(frand(1.0))/M_PI_2*0.1;
/*Approximating the integration of the binominal, for
well-distributed randomness*/
st->cos_cache[i]=-abs((int) (cos(((double)i)/1000.0)*dA*st->ydelta));
st->sin_cache[i]=(int) (sin(((double)i)/1000.0)*dA*st->xdelta);
}
}
static void init_particle(struct state *st, PARTICLE* particle, unsigned short xcenter, unsigned short ycenter)
{
int v = random() % PI_2000;
particle->xpos = xcenter - SPREAD + (random() % (SPREAD * 2));
particle->ypos = ycenter - SPREAD + (random() % (SPREAD * 2));;
particle->xdir = st->sin_cache[v];
particle->ydir = st->cos_cache[v];
particle->colorindex = st->iColorCount-1;
particle->dead = 0;
}
static void Execute( struct state *st )
{
int i, j;
unsigned int temp;
/* move and draw particles into st->fire array */
for (i = 0; i < st->nParticleCount; i++)
{
if (!st->particles[i].dead)
{
st->particles[i].xpos += st->particles[i].xdir;
st->particles[i].ypos += st->particles[i].ydir;
/* is particle dead? */
if (st->particles[i].colorindex == 0)
{
st->particles[i].dead = 1;
continue;
}
if (st->particles[i].xpos < 1)
{
st->particles[i].xpos = 1;
st->particles[i].xdir = -st->particles[i].xdir - 4;
st->particles[i].colorindex = st->iColorCount;
}
else if (st->particles[i].xpos >= st->iWinWidth - 2)
{
st->particles[i].xpos = st->iWinWidth - 2;
if (st->particles[i].xpos < 1) st->particles[i].xpos = 1;
st->particles[i].xdir = -st->particles[i].xdir + 4;
st->particles[i].colorindex = st->iColorCount;
}
if (st->particles[i].ypos < 1)
{
st->particles[i].ypos = 1;
st->particles[i].ydir = -st->particles[i].ydir;
st->particles[i].colorindex = st->iColorCount;
}
else if (st->particles[i].ypos >= st->iWinHeight - 3)
{
st->particles[i].ypos = st->iWinHeight- 3;
if (st->particles[i].ypos < 1) st->particles[i].ypos = 1;
st->particles[i].ydir = (-st->particles[i].ydir >> 2) - (random() % 2);
st->particles[i].colorindex = st->iColorCount;
}
/* st->gravity kicks in */
st->particles[i].ydir += st->gravity;
/* particle cools off */
st->particles[i].colorindex--;
/* draw particle */
if (st->iWinHeight <= 2 || st->iWinWidth <= 2) continue;
st->fire[st->particles[i].ypos][st->particles[i].xpos] = st->particles[i].colorindex;
st->fire[st->particles[i].ypos][st->particles[i].xpos - 1] = st->particles[i].colorindex;
st->fire[st->particles[i].ypos + 1][st->particles[i].xpos] = st->particles[i].colorindex;
st->fire[st->particles[i].ypos - 1][st->particles[i].xpos] = st->particles[i].colorindex;
st->fire[st->particles[i].ypos][st->particles[i].xpos + 1] = st->particles[i].colorindex;
}
}
/* create st->fire effect */
for (i = 0; i < st->iWinHeight; i++)
{
for (j = 0; j < st->iWinWidth; j++)
{
if (j + 1 >= st->iWinWidth)
temp = 0;
else
temp = st->fire[i][j + 1];
if (j - 1 >= 0)
temp += st->fire[i][j - 1];
if (i - 1 >= 0)
{
temp += st->fire[i - 1][j];
if (j - 1 >= 0)
temp += st->fire[i - 1][j - 1];
if (j + 1 < st->iWinWidth)
temp += st->fire[i - 1][j + 1];
}
if (i + 1 < st->iWinHeight)
{
temp += st->fire[i + 1][j];
if (j + 1 < st->iWinWidth)
temp += st->fire[i + 1][j + 1];
if (j - 1 >= 0)
temp += st->fire[i + 1][j - 1];
}
temp >>= 3;
if (temp > st->decay)
{
temp -= st->decay;
}
else
temp = 0;
st->fire[i][j] = temp;
}
}
memset( st->pImage->data, 0, st->pImage->bytes_per_line * st->pImage->height );
/* draw st->fire array to screen */
for (i = 0; i < st->iWinHeight; ++i)
{
for (j = 0; j < st->iWinWidth; ++j)
{
if (st->fire[i][j] > 0)
XPutPixel( st->pImage, j, i, st->aiColorVals[ st->fire[i][j] ] );
}
}
XPutImage( st->dpy, st->window, st->gc, st->pImage,
0,0,0,0, st->iWinWidth, st->iWinHeight );
}
static unsigned long * SetPalette(struct state *st)
{
XWindowAttributes XWinAttribs;
XColor Color, *aColors;
signed short iColor;
XGetWindowAttributes( st->dpy, st->window, &XWinAttribs );
st->iColorCount = get_integer_resource(st->dpy, "ncolors", "Integer" );
if( st->iColorCount < 16 ) st->iColorCount = 16;
if( st->iColorCount > 255 ) st->iColorCount = 256;
aColors = calloc( st->iColorCount, sizeof(XColor) );
st->aiColorVals = calloc( st->iColorCount, sizeof(unsigned long) );
Color.red = Color.green = Color.blue = 65535 / st->iColorCount;
/* create st->fire palette */
for( iColor=0; iColor < st->iColorCount; iColor++ )
{
if (iColor < st->iColorCount >> 3)
{
/* black to blue */
aColors[iColor].red = 0;
aColors[iColor].green = 0;
aColors[iColor].blue = Color.blue * (iColor << 1);
}
else if (iColor < st->iColorCount >> 2)
{
/* blue to red */
signed short temp = (iColor - (st->iColorCount >> 3));
aColors[iColor].red = Color.red * (temp << 3);
aColors[iColor].green = 0;
aColors[iColor].blue = 16383 - Color.blue * (temp << 1);
}
else if (iColor < (st->iColorCount >> 2) + (st->iColorCount >> 3))
{
/* red to yellow */
signed short temp = (iColor - (st->iColorCount >> 2)) << 3;
aColors[iColor].red = 65535;
aColors[iColor].green = Color.green * temp;
aColors[iColor].blue = 0;
}
else if (iColor < st->iColorCount >> 1)
{
/* yellow to white */
signed int temp = (iColor - ((st->iColorCount >> 2) + (st->iColorCount >> 3))) << 3;
aColors[iColor].red = 65535;
aColors[iColor].green = 65535;
aColors[iColor].blue = Color.blue * temp;
}
else
{
/* white */
aColors[iColor].red = aColors[iColor].green = aColors[iColor].blue = 65535;
}
if( !XAllocColor( st->dpy, XWinAttribs.colormap, &aColors[ iColor ] ) )
{
/* start all over with less colors */
XFreeColors( st->dpy, XWinAttribs.colormap, st->aiColorVals, iColor, 0 );
free( aColors );
free( st->aiColorVals );
(st->iColorCount)--;
aColors = calloc( st->iColorCount, sizeof(XColor) );
st->aiColorVals = calloc( st->iColorCount, sizeof(unsigned long) );
iColor = -1;
}
else
st->aiColorVals[ iColor ] = aColors[ iColor ].pixel;
}
if (st->heat < st->iColorCount)
st->iColorCount = st->heat;
free( aColors );
XSetWindowBackground( st->dpy, st->window, st->aiColorVals[ 0 ] );
return st->aiColorVals;
}
static void Initialize( struct state *st )
{
XGCValues gcValues;
XWindowAttributes XWinAttribs;
int /*iBitsPerPixel,*/ i;
/* Create the Image for drawing */
XGetWindowAttributes( st->dpy, st->window, &XWinAttribs );
/* Find the preferred bits-per-pixel. (jwz) */
{
int pfvc = 0;
XPixmapFormatValues *pfv = XListPixmapFormats( st->dpy, &pfvc );
for( i=0; i<pfvc; i++ )
if( pfv[ i ].depth == XWinAttribs.depth )
{
/*iBitsPerPixel = pfv[ i ].bits_per_pixel;*/
break;
}
if( pfv )
XFree (pfv);
}
/* Create the GC. */
st->gc = XCreateGC( st->dpy, st->window, 0, &gcValues );
st->pImage = XCreateImage( st->dpy, XWinAttribs.visual, XWinAttribs.depth, ZPixmap, 0, NULL,
XWinAttribs.width, XWinAttribs.height, BitmapPad( st->dpy ), 0 );
(st->pImage)->data = calloc((st->pImage)->bytes_per_line, (st->pImage)->height);
st->iWinWidth = XWinAttribs.width;
st->iWinHeight = XWinAttribs.height;
/* create st->fire array */
st->fire = calloc( st->iWinHeight, sizeof(unsigned char*));
for (i = 0; i < st->iWinHeight; ++i)
st->fire[i] = calloc( st->iWinWidth, sizeof(unsigned char));
/*create st->particles */
st->particles = malloc (st->nParticleCount * sizeof(PARTICLE));
}
static void *
eruption_init (Display *dpy, Window window)
{
struct state *st = (struct state *) calloc (1, sizeof(*st));
XWindowAttributes XWinAttribs;
unsigned short sum = 0;
#ifdef VERBOSE
time_t nTime = time( NULL );
unsigned short iFrame = 0;
#endif /* VERBOSE */
st->dpy = dpy;
st->window = window;
st->nParticleCount = get_integer_resource(st->dpy, "particles", "Integer" );
if (st->nParticleCount < 100)
st->nParticleCount = 100;
if (st->nParticleCount > 2000)
st->nParticleCount = 2000;
st->decay = get_integer_resource(st->dpy, "cooloff", "Integer" );
if (st->decay <= 0)
st->decay = 0;
if (st->decay > 10)
st->decay = 10;
st->gravity = get_integer_resource(st->dpy, "gravity", "Integer" );
if (st->gravity < -5)
st->gravity = -5;
if (st->gravity > 5)
st->gravity = 5;
st->heat = get_integer_resource(st->dpy, "heat", "Integer" );
if (st->heat < 64)
st->heat = 64;
if (st->heat > 256)
st->heat = 256;
#ifdef VERBOSE
printf( "%s: Allocated %d st->particles\n", progclass, st->nParticleCount );
#endif /* VERBOSE */
Initialize( st );
st->ydelta = 0;
while (sum < (st->iWinHeight >> 1) - SPREAD)
{
st->ydelta++;
sum += st->ydelta;
}
sum = 0;
while (sum < (st->iWinWidth >> 3))
{
st->xdelta++;
sum += st->xdelta;
}
st->delay = get_integer_resource(st->dpy, "delay", "Integer" );
st->cycles = get_integer_resource(st->dpy, "cycles", "Integer" );
cache(st);
XGetWindowAttributes( st->dpy, st->window, &XWinAttribs );
XFreeColors( st->dpy, XWinAttribs.colormap, st->aiColorVals, st->iColorCount, 0 );
free( st->aiColorVals );
st->aiColorVals = SetPalette( st );
XClearWindow( st->dpy, st->window );
memset( st->pImage->data, 0, st->pImage->bytes_per_line * st->pImage->height );
st->draw_i = -1;
return st;
}
static unsigned long
eruption_draw (Display *dpy, Window window, void *closure)
{
struct state *st = (struct state *) closure;
if( st->draw_i < 0 || st->draw_i++ >= st->cycles )
{
/* compute random center */
unsigned short xcenter, ycenter;
xcenter = random() % st->iWinWidth;
ycenter = random() % st->iWinHeight;
for (st->draw_i = 0; st->draw_i < st->nParticleCount; st->draw_i++)
init_particle(st, st->particles + st->draw_i, xcenter, ycenter);
st->draw_i = 0;
}
Execute( st );
#ifdef VERBOSE
iFrame++;
if( nTime - time( NULL ) )
{
printf( "%s: %d FPS\n", progclass, iFrame );
nTime = time( NULL );
iFrame = 0;
}
#endif /* VERBOSE */
return st->delay;
}
static void
eruption_reshape (Display *dpy, Window window, void *closure,
unsigned int w, unsigned int h)
{
struct state *st = (struct state *) closure;
XWindowAttributes XWinAttribs;
int i;
for (i = 0; i < st->iWinHeight; ++i)
free (st->fire[i]);
st->iWinWidth = w;
st->iWinHeight = h;
free (st->fire);
st->fire = calloc( st->iWinHeight, sizeof(unsigned char*));
for (i = 0; i < st->iWinHeight; ++i)
st->fire[i] = calloc( st->iWinWidth, sizeof(unsigned char));
XDestroyImage( st->pImage );
XGetWindowAttributes( st->dpy, st->window, &XWinAttribs );
st->pImage = XCreateImage( st->dpy, XWinAttribs.visual, XWinAttribs.depth, ZPixmap, 0, NULL,
XWinAttribs.width, XWinAttribs.height, BitmapPad( st->dpy ), 0 );
(st->pImage)->data = calloc((st->pImage)->bytes_per_line, (st->pImage)->height);
st->draw_i = -1;
}
static Bool
eruption_event (Display *dpy, Window window, void *closure, XEvent *event)
{
return False;
}
static void
eruption_free (Display *dpy, Window window, void *closure)
{
#if 0
struct state *st = (struct state *) closure;
XDestroyImage( st->pImage );
free( st->aiColorVals );
for (i = 0; i < st->iWinHeight; ++i)
free( st->fire[i] );
free( st->fire );
free( st->particles );
#endif
}
static const char *eruption_defaults [] = {
".background: black",
".foreground: white",
"*fpsTop: true",
"*cycles: 80",
"*ncolors: 256",
"*delay: 10000",
"*particles: 300",
"*cooloff: 2",
"*gravity: 1",
"*heat: 256",
0
};
static XrmOptionDescRec eruption_options [] = {
{ "-ncolors", ".ncolors", XrmoptionSepArg, 0 },
{ "-delay", ".delay", XrmoptionSepArg, 0 },
{ "-cycles", ".cycles", XrmoptionSepArg, 0 },
{ "-particles", ".particles", XrmoptionSepArg, 0 },
{ "-cooloff", ".cooloff", XrmoptionSepArg, 0 },
{ "-gravity", ".gravity", XrmoptionSepArg, 0 },
{ "-heat", ".heat", XrmoptionSepArg, 0 },
{ 0, 0, 0, 0 }
};
XSCREENSAVER_MODULE ("Eruption", eruption)
/* End of Module - "eruption.c" */