--- /dev/null
+/* vfeedback, Copyright (c) 2018 Jamie Zawinski <jwz@jwz.org>
+ *
+ * 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.
+ *
+ * Simulates video feedback: pointing a video camera at an NTSC television.
+ *
+ * Created: 4-Aug-2018.
+ *
+ * TODO:
+ *
+ * - Figure out better UI gestures on mobile to pan, zoom and rotate.
+ *
+ * - When zoomed in really far, grab_rectangle should decompose pixels
+ * into RGB phosphor dots.
+ *
+ * - Maybe load an image and chroma-key it, letting transparency bleed,
+ * for that Amiga Genlock, Cabaret Voltaire look.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include "screenhack.h"
+#include "analogtv.h"
+
+#include <time.h>
+
+#undef DEBUG
+#undef DARKEN
+
+#ifdef DEBUG
+# include "ximage-loader.h"
+# include "images/gen/testcard_bbcf_png.h"
+#endif
+
+#undef countof
+#define countof(x) (sizeof((x))/sizeof((*x)))
+
+#define RANDSIGN() ((random() & 1) ? 1 : -1)
+
+struct state {
+ Display *dpy;
+ Window window;
+ XWindowAttributes xgwa;
+ int w, h;
+ Pixmap pix;
+ GC gc;
+ double start, last_time;
+ double noise;
+ double zoom, rot;
+ double value, svalue, speed, dx, dy, ds, dth;
+
+ struct { double x, y, w, h, th; } rect, orect;
+ struct { int x, y, s; } specular;
+
+ enum { POWERUP, IDLE, MOVE } state;
+ analogtv *tv;
+ analogtv_reception rec;
+ Bool button_down_p;
+ int mouse_x, mouse_y;
+ double mouse_th;
+ Bool dragmode;
+
+# ifdef DEBUG
+ XImage *tcimg;
+# endif
+
+};
+
+
+static void
+twiddle_knobs (struct state *st)
+{
+ st->rec.ofs = random() % ANALOGTV_SIGNAL_LEN; /* roll picture once */
+ st->rec.level = 0.8 + frand(1.0); /* signal strength (low = dark, static) */
+ st->tv->color_control = frand(1.0) * RANDSIGN();
+ st->tv->contrast_control = 0.4 + frand(1.0);
+ st->tv->tint_control = frand(360);
+}
+
+
+static void
+twiddle_camera (struct state *st)
+{
+# if 0
+ st->rect.x = 0;
+ st->rect.y = 0;
+ st->rect.w = 1;
+ st->rect.h = 1;
+ st->rect.th = 0;
+# else
+ st->rect.x = frand(0.1) * RANDSIGN();
+ st->rect.y = frand(0.1) * RANDSIGN();
+ st->rect.w = st->rect.h = 1 + frand(0.4) * RANDSIGN();
+ st->rect.th = 0.2 + frand(1.0) * RANDSIGN();
+# endif
+}
+
+
+static void *
+vfeedback_init (Display *dpy, Window window)
+{
+ struct state *st = (struct state *) calloc (1, sizeof(*st));
+ XGCValues gcv;
+
+ st->dpy = dpy;
+ st->window = window;
+ st->tv = analogtv_allocate (st->dpy, st->window);
+ analogtv_set_defaults (st->tv, "");
+ st->tv->need_clear = 1;
+ st->rec.input = analogtv_input_allocate();
+ analogtv_setup_sync (st->rec.input, 1, 0);
+ st->tv->use_color = 1;
+ st->tv->powerup = 0;
+ st->rec.multipath = 0;
+ twiddle_camera (st);
+ twiddle_knobs (st);
+ st->noise = get_float_resource (st->dpy, "noise", "Float");
+ st->speed = get_float_resource (st->dpy, "speed", "Float");
+
+ XGetWindowAttributes (dpy, window, &st->xgwa);
+
+ st->state = POWERUP;
+ st->value = 0;
+
+ st->w = 640;
+ st->h = 480;
+ gcv.foreground = get_pixel_resource (st->dpy, st->xgwa.colormap,
+ "foreground", "Foreground");
+ st->gc = XCreateGC (dpy, st->window, GCForeground, &gcv);
+
+ st->orect = st->rect;
+
+# ifdef DEBUG
+ {
+ int w, h;
+ Pixmap p;
+ p = image_data_to_pixmap (dpy, window,
+ testcard_bbcf_png, sizeof(testcard_bbcf_png),
+ &w, &h, 0);
+ st->tcimg = XGetImage (dpy, p, 0, 0, w, h, ~0L, ZPixmap);
+ XFreePixmap (dpy, p);
+ }
+# endif
+
+# ifndef HAVE_JWXYZ
+ XSelectInput (dpy, window,
+ PointerMotionMask | st->xgwa.your_event_mask);
+# endif
+
+ return st;
+}
+
+
+static double
+ease_fn (double r)
+{
+ return cos ((r/2 + 1) * M_PI) + 1; /* Smooth curve up, end at slope 1. */
+}
+
+
+static double
+ease_ratio (double r)
+{
+ double ease = 0.5;
+ if (r <= 0) return 0;
+ else if (r >= 1) return 1;
+ else if (r <= ease) return ease * ease_fn (r / ease);
+ else if (r > 1-ease) return 1 - ease * ease_fn ((1 - r) / ease);
+ else return r;
+}
+
+
+static XImage *
+grab_rectangle (struct state *st)
+{
+ XImage *in, *out;
+
+ /* Under XQuartz we can't just do XGetImage on the Window, we have to
+ go through an intermediate Pixmap first. I don't understand why.
+ */
+ if (! st->pix)
+ st->pix = XCreatePixmap (st->dpy, st->window,
+ st->xgwa.width, st->xgwa.height, st->xgwa.depth);
+
+ XCopyArea (st->dpy, st->window, st->pix, st->gc, 0, 0,
+ st->xgwa.width, st->xgwa.height, 0, 0);
+
+ if (st->specular.s)
+ {
+ double p = 0.2;
+ double r = (st->svalue < p ? st->svalue/p :
+ st->svalue >= 1-p ? (1-st->svalue)/p :
+ 1);
+ double s = st->specular.s * ease_ratio (r * 2);
+ XFillArc (st->dpy, st->pix, st->gc,
+ st->specular.x - s/2,
+ st->specular.y - s/2,
+ s, s, 0, 360*64);
+ }
+
+# ifdef DEBUG
+ in = st->tcimg;
+# else
+ in = XGetImage (st->dpy, st->pix,
+ 0, 0, st->xgwa.width, st->xgwa.height,
+ ~0L, ZPixmap);
+ /* Could actually use st->tv->image here, except we don't have the
+ subrectangle being used (overall_top, usewidth, etc.) */
+# endif
+
+ out = XCreateImage (st->dpy, st->xgwa.visual, st->xgwa.depth,
+ ZPixmap, 0, NULL,
+ st->w, st->h, 8, 0);
+
+ if (! in) abort();
+ if (! out) abort();
+ out->data = (char *) calloc (out->height, out->bytes_per_line);
+ if (! out->data) abort();
+
+ {
+ double C = cos (st->rect.th);
+ double S = sin (st->rect.th);
+ unsigned long black = BlackPixelOfScreen (st->xgwa.screen);
+ int ox, oy;
+ for (oy = 0; oy < out->height; oy++)
+ {
+ double doy = (double) oy / out->height;
+ double diy = st->rect.h * doy + st->rect.y - 0.5;
+
+ float dix_mul = (float) st->rect.w / out->width;
+ float dix_add = (-0.5 + st->rect.x) * st->rect.w;
+ float ix_add = (-diy * S + 0.5) * in->width;
+ float iy_add = ( diy * C + 0.5) * in->height;
+ float ix_mul = C * in->width;
+ float iy_mul = S * in->height;
+
+ ix_add += dix_add * ix_mul;
+ iy_add += dix_add * iy_mul;
+ ix_mul *= dix_mul;
+ iy_mul *= dix_mul;
+
+ if (in->bits_per_pixel == 32 &&
+ out->bits_per_pixel == 32)
+ {
+ /* Unwrapping XGetPixel and XPutPixel gains us several FPS here */
+ uint32_t *out_line =
+ (uint32_t *) (out->data + out->bytes_per_line * oy);
+ for (ox = 0; ox < out->width; ox++)
+ {
+ float dix = ox;
+ int ix = dix * ix_mul + ix_add;
+ int iy = dix * iy_mul + iy_add;
+ unsigned long p = (ix >= 0 && ix < in->width &&
+ iy >= 0 && iy < in->height
+ ? ((uint32_t *)
+ (in->data + in->bytes_per_line * iy))[ix]
+ : black);
+# ifdef HAVE_JWXYZ
+ p |= black; /* We get 0 instead of BlackPixel... */
+# endif
+ out_line[ox] = p;
+ }
+ }
+ else
+ for (ox = 0; ox < out->width; ox++)
+ {
+ float dix = ox;
+ int ix = dix * ix_mul + ix_add;
+ int iy = dix * iy_mul + iy_add;
+ unsigned long p = (ix >= 0 && ix < in->width &&
+ iy >= 0 && iy < in->height
+ ? XGetPixel (in, ix, iy)
+ : black);
+# ifdef HAVE_JWXYZ
+ p |= black; /* We get 0 instead of BlackPixel... */
+# endif
+ XPutPixel (out, ox, oy, p);
+ }
+ }
+ }
+
+# ifndef DEBUG
+ XDestroyImage (in);
+# endif
+
+ return out;
+}
+
+
+static double
+double_time (void)
+{
+ struct timeval now;
+# ifdef GETTIMEOFDAY_TWO_ARGS
+ struct timezone tzp;
+ gettimeofday(&now, &tzp);
+# else
+ gettimeofday(&now);
+# endif
+
+ return (now.tv_sec + ((double) now.tv_usec * 0.000001));
+}
+
+
+static unsigned long
+vfeedback_draw (Display *dpy, Window window, void *closure)
+{
+ struct state *st = (struct state *) closure;
+ const analogtv_reception *rec = &st->rec;
+ double then = double_time(), now, timedelta;
+ XImage *img = 0;
+
+ switch (st->state) {
+ case POWERUP: case IDLE: break;
+ case MOVE:
+ st->rect.x = st->orect.x + st->dx * ease_ratio (st->value);
+ st->rect.y = st->orect.y + st->dy * ease_ratio (st->value);
+ st->rect.th = st->orect.th + st->dth * ease_ratio (st->value);
+ st->rect.w = st->orect.w * (1 + (st->ds * ease_ratio (st->value)));
+ st->rect.h = st->orect.h * (1 + (st->ds * ease_ratio (st->value)));
+ break;
+ default:
+ abort();
+ break;
+ }
+
+ if (! st->button_down_p)
+ {
+ st->value += 0.03 * st->speed;
+ if (st->value > 1 || st->state == POWERUP)
+ {
+ st->orect = st->rect;
+ st->value = 0;
+ st->dx = st->dy = st->ds = st->dth = 0;
+
+ switch (st->state) {
+ case POWERUP:
+ /* Wait until the monitor has warmed up before turning on
+ the camcorder? */
+ /* if (st->tv->powerup > 4.0) */
+ st->state = IDLE;
+ break;
+ case IDLE:
+ st->state = MOVE;
+ if (! (random() % 5))
+ st->ds = frand(0.2) * RANDSIGN(); /* zoom */
+ if (! (random() % 3))
+ st->dth = frand(0.2) * RANDSIGN(); /* rotate */
+ if (! (random() % 8))
+ st->dx = frand(0.05) * RANDSIGN(), /* pan */
+ st->dy = frand(0.05) * RANDSIGN();
+ if (! (random() % 2000))
+ {
+ twiddle_knobs (st);
+ if (! (random() % 10))
+ twiddle_camera (st);
+ }
+ break;
+ case MOVE:
+ st->state = IDLE;
+ st->value = 0.3;
+ break;
+ default:
+ abort();
+ break;
+ }
+ }
+
+ /* Draw a specular reflection somewhere on the screen, to mix it up
+ with a little noise from environmental light.
+ */
+ if (st->specular.s)
+ {
+ st->svalue += 0.01 * st->speed;
+ if (st->svalue > 1)
+ {
+ st->svalue = 0;
+ st->specular.s = 0;
+ }
+ }
+ else if (! (random() % 300))
+ {
+# if 1
+ /* Center on the monitor's screen, depth 1 */
+ int cx = st->xgwa.width / 2;
+ int cy = st->xgwa.height / 2;
+# else
+ /* Center on the monitor's screen, depth 0 -- but this clips. */
+ int cx = (st->rect.x + st->rect.w / 2) * st->xgwa.width;
+ int cy = (st->rect.y + st->rect.h / 2) * st->xgwa.height;
+# endif
+ int ww = 4 + (st->rect.h * st->xgwa.height) / 12;
+ st->specular.x = cx + (random() % ww) * RANDSIGN();
+ st->specular.y = cy + (random() % ww) * RANDSIGN();
+ st->specular.s = ww * (0.8 + frand(0.4));
+ st->svalue = 0;
+ }
+ }
+
+ if (st->last_time == 0)
+ st->start = then;
+
+ if (st->state != POWERUP)
+ {
+ img = grab_rectangle (st);
+ analogtv_load_ximage (st->tv, st->rec.input, img, 0, 0, 0, 0, 0);
+ }
+
+ analogtv_reception_update (&st->rec);
+ analogtv_draw (st->tv, st->noise, &rec, 1);
+ if (img)
+ XDestroyImage (img);
+
+ now = double_time();
+ timedelta = (1 / 29.97) - (now - then);
+
+ st->tv->powerup = then - st->start;
+ st->last_time = then;
+
+ return timedelta > 0 ? timedelta * 1000000 : 0;
+}
+
+
+static void
+vfeedback_reshape (Display *dpy, Window window, void *closure,
+ unsigned int w, unsigned int h)
+{
+ struct state *st = (struct state *) closure;
+ analogtv_reconfigure (st->tv);
+ XGetWindowAttributes (dpy, window, &st->xgwa);
+
+ if (st->pix)
+ {
+ XFreePixmap (dpy, st->pix);
+ st->pix = 0;
+ }
+}
+
+
+static Bool
+vfeedback_event (Display *dpy, Window window, void *closure, XEvent *event)
+{
+ struct state *st = (struct state *) closure;
+ double i = 0.02;
+
+ /* Pan with left button and no modifier keys.
+ Rotate with other buttons, or left-with-modifiers.
+ */
+ if (event->xany.type == ButtonPress &&
+ (event->xbutton.button == Button1 ||
+ event->xbutton.button == Button2 ||
+ event->xbutton.button == Button3))
+ {
+ st->button_down_p = True;
+ st->mouse_x = event->xbutton.x;
+ st->mouse_y = event->xbutton.y;
+ st->mouse_th = st->rect.th;
+ st->dragmode = (event->xbutton.button == Button1 &&
+ !event->xbutton.state);
+ return True;
+ }
+ else if (event->xany.type == ButtonRelease &&
+ (event->xbutton.button == Button1 ||
+ event->xbutton.button == Button2 ||
+ event->xbutton.button == Button3))
+ {
+ st->button_down_p = False;
+ return True;
+ }
+ else if (event->xany.type == MotionNotify && st->button_down_p)
+ {
+ if (st->dragmode)
+ {
+ double dx = st->mouse_x - event->xmotion.x;
+ double dy = st->mouse_y - event->xmotion.y;
+ st->rect.x += dx / st->xgwa.width * st->rect.w;
+ st->rect.y += dy / st->xgwa.height * st->rect.h;
+ st->mouse_x = event->xmotion.x;
+ st->mouse_y = event->xmotion.y;
+ }
+ else
+ {
+ /* Angle between center and initial click */
+ double a1 = -atan2 (st->mouse_y - st->xgwa.height / 2,
+ st->mouse_x - st->xgwa.width / 2);
+ /* Angle between center and drag position */
+ double a2 = -atan2 (event->xmotion.y - st->xgwa.height / 2,
+ event->xmotion.x - st->xgwa.width / 2);
+ /* Cumulatively rotate by difference between them */
+ st->rect.th = a2 - a1 + st->mouse_th;
+ }
+ goto OK;
+ }
+
+ /* Zoom with mouse wheel */
+
+ else if (event->xany.type == ButtonPress &&
+ (event->xbutton.button == Button4 ||
+ event->xbutton.button == Button6))
+ {
+ i = 1-i;
+ goto ZZ;
+ }
+ else if (event->xany.type == ButtonPress &&
+ (event->xbutton.button == Button5 ||
+ event->xbutton.button == Button7))
+ {
+ i = 1+i;
+ goto ZZ;
+ }
+ else if (event->type == KeyPress)
+ {
+ KeySym keysym;
+ char c = 0;
+ XLookupString (&event->xkey, &c, 1, &keysym, 0);
+ switch (keysym) {
+ /* pan with arrow keys */
+ case XK_Up: st->rect.y += i; goto OK; break;
+ case XK_Down: st->rect.y -= i; goto OK; break;
+ case XK_Left: st->rect.x += i; goto OK; break;
+ case XK_Right: st->rect.x -= i; goto OK; break;
+ default: break;
+ }
+ switch (c) {
+
+ /* rotate with <> */
+ case '<': case ',': st->rect.th += i; goto OK; break;
+ case '>': case '.': st->rect.th -= i; goto OK; break;
+
+ /* zoom with += */
+ case '-': case '_':
+ i = 1+i;
+ goto ZZ;
+ case '=': case '+':
+ i = 1-i;
+ ZZ:
+ st->orect = st->rect;
+ st->rect.w *= i;
+ st->rect.h *= i;
+ st->rect.x += (st->orect.w - st->rect.w) / 2;
+ st->rect.y += (st->orect.h - st->rect.h) / 2;
+ goto OK;
+ break;
+
+ /* tv controls with T, C, B, O */
+ case 't': st->tv->tint_control += 5; goto OK; break;
+ case 'T': st->tv->tint_control -= 5; goto OK; break;
+ case 'c': st->tv->color_control += 0.1; goto OK; break;
+ case 'C': st->tv->color_control -= 0.1; goto OK; break;
+ case 'b': st->tv->brightness_control += 0.01; goto OK; break;
+ case 'B': st->tv->brightness_control -= 0.01; goto OK; break;
+ case 'o': st->tv->contrast_control += 0.1; goto OK; break;
+ case 'O': st->tv->contrast_control -= 0.1; goto OK; break;
+ case 'r': st->rec.level += 0.01; goto OK; break;
+ case 'R': st->rec.level -= 0.01; goto OK; break;
+ default: break;
+ }
+ goto NOPE;
+ OK:
+# if 0
+ fprintf (stderr, " %.6f x %.6f @ %.6f, %.6f %.6f\t",
+ st->rect.w, st->rect.h,
+ st->rect.x, st->rect.y, st->rect.th);
+ fprintf (stderr," T=%.2f C=%.2f B=%.2f O=%.2f R=%.3f\n",
+ st->tv->tint_control,
+ st->tv->color_control/* * 100*/,
+ st->tv->brightness_control/* * 100*/,
+ st->tv->contrast_control/* * 100*/,
+ st->rec.level);
+# endif
+ st->value = 0;
+ st->state = IDLE;
+ st->orect = st->rect;
+ return True;
+ }
+
+ NOPE:
+ if (screenhack_event_helper (dpy, window, event))
+ {
+ /* SPC or RET re-randomize the TV controls. */
+ twiddle_knobs (st);
+ goto OK;
+ }
+
+ return False;
+}
+
+
+static void
+vfeedback_free (Display *dpy, Window window, void *closure)
+{
+ struct state *st = (struct state *) closure;
+ analogtv_release (st->tv);
+ if (st->pix)
+ XFreePixmap (dpy, st->pix);
+ XFreeGC (dpy, st->gc);
+ free (st);
+}
+
+
+static const char *vfeedback_defaults [] = {
+
+ ".foreground: #CCCC44",
+ ".background: #000000",
+ "*noise: 0.02",
+ "*speed: 1.0",
+ ANALOGTV_DEFAULTS
+ "*TVBrightness: 1.5",
+ "*TVContrast: 150",
+ 0
+};
+
+static XrmOptionDescRec vfeedback_options [] = {
+ { "-noise", ".noise", XrmoptionSepArg, 0 },
+ { "-speed", ".speed", XrmoptionSepArg, 0 },
+ ANALOGTV_OPTIONS
+ { 0, 0, 0, 0 }
+};
+
+XSCREENSAVER_MODULE ("VFeedback", vfeedback)
projects / xscreensaver / blobdiff