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

/* shadebobs, Copyright (c) 1999 Shane Smit <blackend@inconnect.com>
 *
 * 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 - "shadebobs.c"
 *
 * Description:
 *  There are two little shading circles (bobs) that zip around the screen.
 *  one of them shades up towards white, and the other shades down toward
 *  black.
 *  This keeps the screen in color balance at a chosen color.
 *
 *  Its kinda like 'The Force'
 *   There is a light side, a dark side, and it keeps the world in balance.
 *
 * [05/23/99] - Shane Smit: Creation
 * [05/26/99] - Shane Smit: Port to C/screenhack for use with XScreenSaver
 * [06/11/99] - Shane Smit: Stopped trying to rape the palette.
 * [06/20/99] - jwz: cleaned up ximage handling, gave resoources short names,
 *                introduced delay, made it restart after N iterations.
 * [06/21/99] - Shane Smit: Modified default values slightly, color changes
 *                on cycle, and the extents of the sinus pattern change in
 *                real-time.
 * [06/22/99] - Shane Smit: Fixed delay to be fast and use little CPU :).
 * [09/17/99] - Shane Smit: Made all calculations based on the size of the
 *                window. Thus, it'll look the same at 100x100 as it does at
 *                1600x1200 ( Only smaller :).
 * [04/24/00] - Shane Smit: Revamped entire source code:
 *                Shade Bob movement is calculated very differently.
 *                Base color can be any color now.
 */

#include <math.h>
#include "screenhack.h"
#include <X11/Xutil.h>

/* #define VERBOSE */

char *progclass = "ShadeBobs";

char *defaults [] = {
  ".background: black",
  ".foreground: white",
  "*degrees:  0",       /* default: Automatic degree calculation */
  "*color:    random",
  "*count:    4",
  "*cycles:   10",
  "*ncolors:  64",    /* changing this doesn't work particularly well */
  "*delay:    5000",
  0
};

XrmOptionDescRec options [] = {
  { "-degrees", ".degrees", XrmoptionSepArg, 0 },
  { "-color",   ".color",   XrmoptionSepArg, 0 },
  { "-ncolors", ".ncolors", XrmoptionSepArg, 0 },
  { "-count",   ".count",   XrmoptionSepArg, 0 },
  { "-delay",   ".delay",   XrmoptionSepArg, 0 },
  { "-cycles",  ".cycles",  XrmoptionSepArg, 0 },
  { 0, 0, 0, 0 }
};

static unsigned short iDegreeCount;
static double *anSinTable, *anCosTable;
static unsigned short iWinWidth, iWinHeight;
static unsigned short iWinCenterX, iWinCenterY;
static char *sColor;
static unsigned char iBobRadius, iBobDiameter; 
static unsigned char iVelocity;

#define RANDOM() ((int) (random() & 0X7FFFFFFFL))


/* Ahem. Chocolate is a flavor; not a food. Thank you */


typedef struct
{
        signed char *anDeltaMap;
        double nAngle, nAngleDelta, nAngleInc;
        double nPosX, nPosY;
} SShadeBob;


static void ResetShadeBob( SShadeBob *pShadeBob )
{
        pShadeBob->nPosX = RANDOM() % iWinWidth;
        pShadeBob->nPosY = RANDOM() % iWinHeight;
        pShadeBob->nAngle = RANDOM() % iDegreeCount;
        pShadeBob->nAngleDelta = ( RANDOM() % iDegreeCount ) - ( iDegreeCount / 2.0F );
        pShadeBob->nAngleInc = pShadeBob->nAngleDelta / 50.0F; 
        if( pShadeBob->nAngleInc == 0.0F )      
                pShadeBob->nAngleInc = ( pShadeBob->nAngleDelta > 0.0F ) ? 0.0001F : -0.0001F;
}


static void InitShadeBob( SShadeBob *pShadeBob, Bool bDark )
{
        double nDelta;
        int iWidth, iHeight;

        if( ( pShadeBob->anDeltaMap = calloc( iBobDiameter * iBobDiameter, sizeof(char) ) ) == NULL )
        {
                fprintf( stderr, "%s: Could not allocate Delta Map!\n", progclass );
                return;
        }

        for( iHeight=-iBobRadius; iHeight<iBobRadius; iHeight++ )
                for( iWidth=-iBobRadius; iWidth<iBobRadius; iWidth++ )
                {
                        nDelta = 9 - ( ( sqrt( pow( iWidth+0.5, 2 ) + pow( iHeight+0.5, 2 ) ) / iBobRadius ) * 8 );
                        if( nDelta < 0 )  nDelta = 0;
                        if( bDark ) nDelta = -nDelta;
                        pShadeBob->anDeltaMap[ ( iWidth + iBobRadius ) * iBobDiameter + iHeight + iBobRadius ] = (char)nDelta;
                }
  
        ResetShadeBob( pShadeBob );
}


/* A delta is calculated, and the shadebob turns at an increment.  When the delta
 * falls to 0, a new delta and increment are calculated. */
static void MoveShadeBob( SShadeBob *pShadeBob )
{
        pShadeBob->nAngle          += pShadeBob->nAngleInc;
        pShadeBob->nAngleDelta -= pShadeBob->nAngleInc;

        if( pShadeBob->nAngle >= iDegreeCount ) pShadeBob->nAngle -= iDegreeCount;
        else if( pShadeBob->nAngle < 0 )                pShadeBob->nAngle += iDegreeCount;
        
        if( ( pShadeBob->nAngleInc>0.0F  && pShadeBob->nAngleDelta<pShadeBob->nAngleInc ) ||
            ( pShadeBob->nAngleInc<=0.0F && pShadeBob->nAngleDelta>pShadeBob->nAngleInc ) )
        {
                pShadeBob->nAngleDelta = ( RANDOM() % iDegreeCount ) - ( iDegreeCount / 2.0F );
                pShadeBob->nAngleInc = pShadeBob->nAngleDelta / 50.0F;
                if( pShadeBob->nAngleInc == 0.0F )
                        pShadeBob->nAngleInc = ( pShadeBob->nAngleDelta > 0.0F ) ? 0.0001F : -0.0001F;
        }
        
        pShadeBob->nPosX = ( anSinTable[ (int)pShadeBob->nAngle ] * iVelocity ) + pShadeBob->nPosX;
        pShadeBob->nPosY = ( anCosTable[ (int)pShadeBob->nAngle ] * iVelocity ) + pShadeBob->nPosY;

        /* This wraps it around the screen. */
        if( pShadeBob->nPosX >= iWinWidth )     pShadeBob->nPosX -= iWinWidth;
        else if( pShadeBob->nPosX < 0 )         pShadeBob->nPosX += iWinWidth;
        
        if( pShadeBob->nPosY >= iWinHeight )    pShadeBob->nPosY -= iWinHeight;
        else if( pShadeBob->nPosY < 0 )                 pShadeBob->nPosY += iWinHeight;
}


static void Execute( SShadeBob *pShadeBob, Display *pDisplay,
                     Window MainWindow,
                     GC *pGC, XImage *pImage,
                     signed short iColorCount, unsigned long *aiColorVals )
{
        unsigned long iColor;
        short iColorVal;
        int iPixelX, iPixelY;
        unsigned int iWidth, iHeight;

        MoveShadeBob( pShadeBob );
        
        for( iHeight=0; iHeight<iBobDiameter; iHeight++ )
        {
                iPixelY = pShadeBob->nPosY + iHeight;
                if( iPixelY >= iWinHeight )     iPixelY -= iWinHeight;

                for( iWidth=0; iWidth<iBobDiameter; iWidth++ )
                {
                        iPixelX = pShadeBob->nPosX + iWidth;
                        if( iPixelX >= iWinWidth )      iPixelX -= iWinWidth;

                        iColor = XGetPixel( pImage, iPixelX, iPixelY );

                        /*  FIXME: Here is a loop I'd love to take out. */
                        for( iColorVal=0; iColorVal<iColorCount; iColorVal++ )
                                if( aiColorVals[ iColorVal ] == iColor )
                                        break;

                        iColorVal += pShadeBob->anDeltaMap[ iWidth * iBobDiameter + iHeight ];
                        if( iColorVal >= iColorCount ) iColorVal = iColorCount - 1;
                        if( iColorVal < 0 )                        iColorVal = 0;

                        XPutPixel( pImage, iPixelX, iPixelY, aiColorVals[ iColorVal ] );
                }
        }

        /* FIXME: if it's next to the top or left sides of screen this will break. However, it's not noticable. */
        XPutImage( pDisplay, MainWindow, *pGC, pImage,
             pShadeBob->nPosX, pShadeBob->nPosY, pShadeBob->nPosX, pShadeBob->nPosY, iBobDiameter, iBobDiameter );
        XSync( pDisplay, False );
}


static void CreateTables( unsigned int nDegrees )
{
        double nRadian;
        unsigned int iDegree;
        anSinTable = calloc( nDegrees, sizeof(double) );
        anCosTable = calloc( nDegrees, sizeof(double) );

        for( iDegree=0; iDegree<nDegrees; iDegree++ )
        {
                nRadian = ( (double)(2*iDegree) / (double)nDegrees ) * M_PI;
                anSinTable[ iDegree ] = sin( nRadian );
                anCosTable[ iDegree ] = cos( nRadian );
        }
}


static unsigned long * SetPalette(Display *pDisplay, Window Win, char *sColor, signed short *piColorCount )
{
        XWindowAttributes XWinAttribs;
        XColor Color, *aColors;
        unsigned long *aiColorVals;
        signed short iColor;
        float nHalfColors;
        
        XGetWindowAttributes( pDisplay, Win, &XWinAttribs );
        
        Color.red =   RANDOM() % 0xFFFF;
        Color.green = RANDOM() % 0xFFFF;
        Color.blue =  RANDOM() % 0xFFFF;

        if( strcasecmp( sColor, "random" ) && !XParseColor( pDisplay, XWinAttribs.colormap, sColor, &Color ) )
                fprintf( stderr, "%s: color %s not found in database. Choosing to random...\n", progname, sColor );

#ifdef VERBOSE
        printf( "%s: Base color (RGB): <%d, %d, %d>\n", progclass, Color.red, Color.green, Color.blue );
#endif  /*  VERBOSE */

        *piColorCount = get_integer_resource( "ncolors", "Integer" );
        if( *piColorCount <   2 )       *piColorCount = 2;
        if( *piColorCount > 255 )       *piColorCount = 255;

        aColors    = calloc( *piColorCount, sizeof(XColor) );
        aiColorVals = calloc( *piColorCount, sizeof(unsigned long) );
        
        for( iColor=0; iColor<*piColorCount; iColor++ )
        {
                nHalfColors = *piColorCount / 2.0F;
                /* Black -> Base Color */
                if( iColor < (*piColorCount/2) )
                {
                        aColors[ iColor ].red   = ( Color.red   / nHalfColors ) * iColor;
                        aColors[ iColor ].green = ( Color.green / nHalfColors ) * iColor;
                        aColors[ iColor ].blue  = ( Color.blue  / nHalfColors ) * iColor;
                }
                /* Base Color -> White */
                else
                {
                        aColors[ iColor ].red   = ( ( ( 0xFFFF - Color.red )   / nHalfColors ) * ( iColor - nHalfColors ) ) + Color.red;
                        aColors[ iColor ].green = ( ( ( 0xFFFF - Color.green ) / nHalfColors ) * ( iColor - nHalfColors ) ) + Color.green;
                        aColors[ iColor ].blue  = ( ( ( 0xFFFF - Color.blue )  / nHalfColors ) * ( iColor - nHalfColors ) ) + Color.blue;
                }

                if( !XAllocColor( pDisplay, XWinAttribs.colormap, &aColors[ iColor ] ) )
                {
                        /* start all over with less colors */   
                        XFreeColors( pDisplay, XWinAttribs.colormap, aiColorVals, iColor, 0 );
                        free( aColors );
                        free( aiColorVals );
                        piColorCount--;
                        aColors     = calloc( *piColorCount, sizeof(XColor) );
                        aiColorVals = calloc( *piColorCount, sizeof(unsigned long) );
                        iColor = -1;
                }
                else
                        aiColorVals[ iColor ] = aColors[ iColor ].pixel;
        }

        free( aColors );

        XSetWindowBackground( pDisplay, Win, aiColorVals[ 0 ] );

        return aiColorVals;
}


static void Initialize( Display *pDisplay, Window Win, GC *pGC, XImage **ppImage )
{
        XGCValues gcValues;
        XWindowAttributes XWinAttribs;
        int iBitsPerPixel;

        /* Create the Image for drawing */
        XGetWindowAttributes( pDisplay, Win, &XWinAttribs );

        /* Find the preferred bits-per-pixel. (jwz) */
        {
                int i, pfvc = 0;
                XPixmapFormatValues *pfv = XListPixmapFormats( pDisplay, &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. */
        *pGC = XCreateGC( pDisplay, Win, 0, &gcValues );

        *ppImage = XCreateImage( pDisplay, XWinAttribs.visual, XWinAttribs.depth, ZPixmap, 0, NULL,
                                                          XWinAttribs.width, XWinAttribs.height, BitmapPad( pDisplay ), 0 );
        (*ppImage)->data = calloc((*ppImage)->bytes_per_line, (*ppImage)->height);

        iWinWidth = XWinAttribs.width;
        iWinHeight = XWinAttribs.height;

        /*  These are precalculations used in Execute(). */
        iBobDiameter = ( ( iWinWidth < iWinHeight ) ? iWinWidth : iWinHeight ) / 25;
        iBobRadius = iBobDiameter / 2;
#ifdef VERBOSE
        printf( "%s: Bob Diameter = %d\n", progclass, iBobDiameter );
#endif

        iWinCenterX = ( XWinAttribs.width / 2 ) - iBobRadius;
        iWinCenterY = ( XWinAttribs.height / 2 ) - iBobRadius;

        iVelocity = ( ( iWinWidth < iWinHeight ) ? iWinWidth : iWinHeight ) / 150;
        
        /*  Create the Sin and Cosine lookup tables. */
        iDegreeCount = get_integer_resource( "degrees", "Integer" );
        if(      iDegreeCount == 0   ) iDegreeCount = ( XWinAttribs.width / 6 ) + 400;
        else if( iDegreeCount < 90   ) iDegreeCount = 90;
        else if( iDegreeCount > 5400 ) iDegreeCount = 5400;
        CreateTables( iDegreeCount );
#ifdef VERBOSE
        printf( "%s: Using a %d degree circle.\n", progclass );
#endif /* VERBOSE */
  
        /*  Get the base color. */
        sColor = get_string_resource( "color", "Color" );
}


void screenhack(Display *pDisplay, Window Win )
{
        GC gc;
        signed short iColorCount = 0;
        unsigned long *aiColorVals = NULL;
        XImage *pImage = NULL;
        unsigned char nShadeBobCount, iShadeBob;
        SShadeBob *aShadeBobs;
#ifdef VERBOSE
        time_t nTime = time( NULL );
        unsigned short iFrame = 0;
#endif  /*  VERBOSE */
        int delay, cycles, i;

        nShadeBobCount = get_integer_resource( "count", "Integer" );
        if( nShadeBobCount > 64 ) nShadeBobCount = 64;
        if( nShadeBobCount <  1 ) nShadeBobCount = 1;

        if( ( aShadeBobs = calloc( nShadeBobCount, sizeof(SShadeBob) ) ) == NULL )
        {
                fprintf( stderr, "%s: Could not allocate %d ShadeBobs\n", progclass, nShadeBobCount );
                return;
        }
#ifdef VERBOSE 
        printf( "%s: Allocated %d ShadeBobs\n", progclass, nShadeBobCount );
#endif  /*  VERBOSE */

        Initialize( pDisplay, Win, &gc, &pImage );

        for( iShadeBob=0; iShadeBob<nShadeBobCount; iShadeBob++ )
                InitShadeBob( &aShadeBobs[ iShadeBob ], iShadeBob % 2 );

        delay = get_integer_resource( "delay", "Integer" );
        cycles = get_integer_resource( "cycles", "Integer" ) * iDegreeCount;
        i = cycles;

        while( 1 )
        {
                screenhack_handle_events( pDisplay );

                if( i++ >= cycles )
                {
                        XWindowAttributes XWinAttribs;
                        XGetWindowAttributes( pDisplay, Win, &XWinAttribs );

                        i = 0;
                        memset( pImage->data, 0, pImage->bytes_per_line * pImage->height );
                        for( iShadeBob=0; iShadeBob<nShadeBobCount; iShadeBob++ )
                                ResetShadeBob( &aShadeBobs[ iShadeBob ] );
                        XFreeColors( pDisplay, XWinAttribs.colormap, aiColorVals, iColorCount, 0 );
                        free( aiColorVals );
                        aiColorVals = SetPalette( pDisplay, Win, sColor, &iColorCount );
                        XClearWindow( pDisplay, Win );
                }

                for( iShadeBob=0; iShadeBob<nShadeBobCount; iShadeBob++ )
                        Execute( &aShadeBobs[ iShadeBob ], pDisplay, Win, &gc, pImage, iColorCount, aiColorVals );

                if( delay && !(i % 4) )
                        usleep(delay);

#ifdef VERBOSE
                iFrame++;
                if( nTime - time( NULL ) )
                {
                        printf( "%s: %d FPS\n", progclass, iFrame );
                        nTime = time( NULL );
                        iFrame = 0;
                }
#endif  /*  VERBOSE */
        }

        free( anSinTable );
        free( anCosTable );
        free( pImage->data );
        XDestroyImage( pImage );
        for( iShadeBob=0; iShadeBob<nShadeBobCount; iShadeBob++ )
                free( aShadeBobs[ iShadeBob ].anDeltaMap );
        free( aShadeBobs );
        free( aiColorVals );
}


/* End of Module - "shadebobs.c" */

/* vim: ts=4
 */