/* xscreensaver, Copyright (c) 2000 Paul "Joey" Clark * * 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. * * 19971004: Johannes Keukelaar : Use helix screen * eraser. */ /* WhirlwindWarp: moving stars. Ported from QBasic by Joey. Version 1.2. FF parameters now driven by a dampened-walked velocity, making them smoother. This code adapted from original program by jwz/jk above. Freely distrubtable. Please keep this tag with this code, and add your own if you contribute. I would be delighted to hear if have made use of this code. If you find this code useful or have any queries, please contact me: pclark@cs.bris.ac.uk / joeyclark@usa.net Paul "Joey" Clark, hacking for humanity, Feb 99 www.cs.bris.ac.uk/~pclark | www.changetheworld.org.uk */ #include #include "screenhack.h" #include "erase.h" #include "hsv.h" static GC draw_gc, erase_gc; static unsigned int default_fg_pixel; /* Maximum number of points, tails, and fields (hard-coded) */ #define maxps 1000 #define maxts 30 #define fs 10 /* Screen width and height */ static int scrwid,scrhei; /* Current x,y of stars in realspace */ static float cx[maxps]; static float cy[maxps]; /* Previous x,y plots in pixelspace for removal later */ static int tx[maxps*maxts]; static int ty[maxps*maxts]; /* The force fields and their parameters */ static char *name[fs]; static int fon[fs]; /* Is field on or off? */ static float var[fs]; /* Current parameter */ static float op[fs]; /* Optimum (central/mean) value */ static float damp[fs]; /* Dampening (how much drawn between current and optimal) */ static float force[fs]; /* Amount of change per moment */ static float acc[fs]; /* Number of points and tails */ static int ps=500; static int ts=5; /* Show meters or not? */ static Bool meters; static Bool init_whirlwindwarp(Display *dpy, Window window) { XGCValues gcv; Colormap cmap; XWindowAttributes xgwa; XGetWindowAttributes (dpy, window, &xgwa); cmap = xgwa.colormap; gcv.foreground = default_fg_pixel = get_pixel_resource ("foreground", "Foreground", dpy, cmap); draw_gc = XCreateGC (dpy, window, GCForeground, &gcv); gcv.foreground = get_pixel_resource ("background", "Background", dpy, cmap); erase_gc = XCreateGC (dpy, window, GCForeground, &gcv); ps = get_integer_resource ("points", "Integer"); ts = get_integer_resource ("tails", "Integer"); meters = get_boolean_resource ("meters", "Show meters"); if (ps>maxps || ts>maxts) return 0; return 1; } static float myrnd(void) { /* between -1.0 and +1.0 */ return 2.0*((float)((random()%10000000)/10000000.0)-0.5); } float mysgn(float x) { return ( x < 0 ? -1 : x > 0 ? +1 : 0 ); } void stars_newp(int p) { cx[p]=myrnd(); cy[p]=myrnd(); } /* Adjust a variable var about optimum op, with damp = dampening about op force = force of random perturbation */ float stars_perturb(float var,float op,float damp,float force) { var=op+damp*(var-op)+force*myrnd()/4.0; /* if (fabs(var-op)>0.1) // (to keep within bounds) var=op+0.1*mysgn(var-op);*/ return var; } /* Get pixel coordinates of a star */ int stars_scrpos_x(int p) { return scrwid*(cx[p]+1.0)/2.0; } int stars_scrpos_y(int p) { return scrhei*(cy[p]+1.0)/2.0; } /* Draw a meter of a forcefield's parameter */ void stars_draw_meter(Display *dpy,Window window,GC draw_gc,int f) { int x,y,w,h; x=scrwid/2; y=f*10; w=(var[f]-op[f])*scrwid*4; h=7; if (w<0) { w=-w; x=x-w; } if (fon[f]) XFillRectangle(dpy,window,draw_gc,x,y,w,h); else XDrawRectangle(dpy,window,draw_gc,x,y,w,h); } /* Move a star according to acting forcefields */ void stars_move(int p) { float nx,ny; float x=cx[p]; float y=cy[p]; if (fon[1]) { x = x * var[1]; y = y * var[1]; } if (fon[2]) { nx=x*cos(var[2])+y*sin(var[2]); ny=-x*sin(var[2])+y*cos(var[2]); x=nx; y=ny; } if (fon[3]) { y=y*var[3]; } if (fon[4]) { x=(x-1.0)*var[3]+1.0; } if (fon[5]) { x=x+var[5]*x; } if (fon[6]) { x = mysgn(x) * pow(fabs(x),var[6]); y = mysgn(y) * pow(fabs(y),var[6]); } if (fon[7]) { if (fon[0]) { if (fon[9]) { x=x+var[7]*(-1.0+2.0*(float)(p%2)); } else { x=x+var[7]*(-1.0+2.0*(float)((p%50)/49.0)); } } } if (fon[8]) { if (fon[0]) { if (fon[9]) { y=y+var[8]*(-1.0+2.0*(float)(p%2)); } else { y=y+var[8]*(-1.0+2.0*(float)((p%50)/49.0)); } } } cx[p]=x; cy[p]=y; } static void do_whirlwindwarp(Display *dpy, Window window) { Colormap cmap; XWindowAttributes xgwa; int got_color = 0; XColor color[maxps]; XColor bgcolor; int p,f,nt, sx,sy, resets,lastresets,cnt; XClearWindow (dpy, window); XGetWindowAttributes (dpy, window, &xgwa); cmap = xgwa.colormap; scrwid = xgwa.width; scrhei = xgwa.height; /* Setup colours */ hsv_to_rgb (0.0, 0.0, 0.0, &bgcolor.red, &bgcolor.green, &bgcolor.blue); got_color = XAllocColor (dpy, cmap, &bgcolor); for (p=0;p0) color[p]=color[0]; else color[p].pixel=default_fg_pixel; } } /* Set up parameter movements for the different forcefields */ name[1] = "Velocity"; op[1] = 1; damp[1] = .999; force[1] = .002; name[2] = "Rotation"; op[2] = 0; damp[2] = .999; force[2] = .002; name[3] = "Drip"; op[3] = 1; damp[3] = .999; force[3] = .005; name[4] = "Dribble"; op[4] = 1; damp[4] = .999; force[4] = .005; name[5] = "Slide"; op[5] = 0; damp[5] = .999; force[5] = .002; name[6] = "Accelerate"; op[6] = 1.0; damp[6] = .999; force[6] = .005; name[7] = "xDisplace"; op[7] = 0; damp[7] = .999; force[7] = .005; name[8] = "yDisplace"; op[8] = 0; damp[8] = .999; force[8] = .005; /* 0 and 9 are options for splitting displacements [no var] */ name[0] = "Split"; op[0] = 0; damp[0] = 0; force[0] = 0; name[9] = "2d/3d split"; op[9] = 0; damp[9] = 0; force[9] = 0; /* Initialise parameters to optimum, all off */ for (f=0;f+1.0 || cy[p]<-1.0 || cy[p]>+1.0 || fabs(cx[p])<.0001 || fabs(cy[p])<.0001) { stars_newp(p); resets++; } else if (myrnd()>0.99) /* Reset at random */ stars_newp(p); /* Draw point */ sx=stars_scrpos_x(p); sy=stars_scrpos_y(p); XSetForeground (dpy, draw_gc, color[p].pixel); XDrawPoint(dpy,window,draw_gc,sx,sy); /* Remember it for removal later */ tx[nt]=sx; ty[nt]=sy; nt=(nt+1)%(ps*ts); } /* Adjust force fields */ cnt=0; for (f=0;f0.998) /* Turn it on/off ? */ fon[f]=(myrnd()<0.0); /* fon[f]=!fon[f]; */ if (meters) { /* Redraw the meter */ XSetForeground(dpy, draw_gc, color[f].pixel); stars_draw_meter(dpy,window,draw_gc,f); } if (fon[f]) cnt++; } if (cnt==0) { /* Ensure at least one is on! */ f=random() % fs; fon[f]=1; } if (meters) { XSetForeground(dpy, draw_gc, bgcolor.pixel); XDrawRectangle(dpy,window,draw_gc,0,0,lastresets*5,3); XSetForeground(dpy, draw_gc, default_fg_pixel); XDrawRectangle(dpy,window,draw_gc,0,0,resets*5,3); } /* if (resets*5>scrwid) { Turn one off a field if too many points are flying off screen */ /* This was a problem when one of the force-fields was acting wrong, but not really needed any more unless we need to debug new ones ...! */ /* for (f=0;f