analogtv.h

/* analogtv, Copyright (c) 2003, 2004 Trevor Blackwell <tlb@tlb.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.
 */

#ifndef _XSCREENSAVER_ANALOGTV_H
#define _XSCREENSAVER_ANALOGTV_H

#include <stdint.h>
#include <unistd.h>
#include <sys/time.h>

/*
  You'll need these to generate standard NTSC TV signals
 */
enum {
  /* We don't handle interlace here */
  ANALOGTV_V=262,
  ANALOGTV_TOP=30,
  ANALOGTV_VISLINES=200,
  ANALOGTV_BOT=ANALOGTV_TOP + ANALOGTV_VISLINES,

  /* This really defines our sampling rate, 4x the colorburst
     frequency. Handily equal to the Apple II's dot clock.
     You could also make a case for using 3x the colorburst freq,
     but 4x isn't hard to deal with. */
  ANALOGTV_H=912,

  /* Each line is 63500 nS long. The sync pulse is 4700 nS long, etc.
     Define sync, back porch, colorburst, picture, and front porch
     positions */
  ANALOGTV_SYNC_START=0,
  ANALOGTV_BP_START=4700*ANALOGTV_H/63500,
  ANALOGTV_CB_START=5800*ANALOGTV_H/63500,
  /* signal[row][ANALOGTV_PIC_START] is the first displayed pixel */
  ANALOGTV_PIC_START=9400*ANALOGTV_H/63500,
  ANALOGTV_PIC_LEN=52600*ANALOGTV_H/63500,
  ANALOGTV_FP_START=62000*ANALOGTV_H/63500,
  ANALOGTV_PIC_END=ANALOGTV_FP_START,

  /* TVs scan past the edges of the picture tube, so normally you only
     want to use about the middle 3/4 of the nominal scan line.
  */
  ANALOGTV_VIS_START=ANALOGTV_PIC_START + (ANALOGTV_PIC_LEN*1/8),
  ANALOGTV_VIS_END=ANALOGTV_PIC_START + (ANALOGTV_PIC_LEN*7/8),
  ANALOGTV_VIS_LEN=ANALOGTV_VIS_END-ANALOGTV_VIS_START,

  ANALOGTV_HASHNOISE_LEN=6,

  ANALOGTV_GHOSTFIR_LEN=4,

  /* analogtv.signal is in IRE units, as defined below: */
  ANALOGTV_WHITE_LEVEL=100,
  ANALOGTV_GRAY50_LEVEL=55,
  ANALOGTV_GRAY30_LEVEL=35,
  ANALOGTV_BLACK_LEVEL=10,
  ANALOGTV_BLANK_LEVEL=0,
  ANALOGTV_SYNC_LEVEL=-40,
  ANALOGTV_CB_LEVEL=20,

  ANALOGTV_SIGNAL_LEN=ANALOGTV_V*ANALOGTV_H,

  /* The number of intensity levels we deal with for gamma correction &c */
  ANALOGTV_CV_MAX=1024,

  /* MAX_LINEHEIGHT corresponds to 2400 vertical pixels, beyond which
     it interpolates extra black lines. */
  ANALOGTV_MAX_LINEHEIGHT=12

};

typedef struct analogtv_input_s {
  signed char signal[ANALOGTV_V+1][ANALOGTV_H];

} analogtv_input;

typedef struct analogtv_reception_s {

  analogtv_input *input;
  double ofs;
  double level;
  double multipath;

  double hfloss;

// private
  double ghostfir[ANALOGTV_GHOSTFIR_LEN];
  double ghostfir2[ANALOGTV_GHOSTFIR_LEN];

} analogtv_reception;

/*
  The rest of this should be considered mostly opaque to the analogtv module.
 */

typedef struct analogtv_s {
#if 0
  unsigned int onscreen_signature[ANALOGTV_V];
#endif

  float agclevel;

  float tint_control,color_control,brightness_control,contrast_control;
  float height_control, width_control, squish_control;
  float horiz_desync;
  float squeezebottom;
  float powerup;

  int width, height;
  uint8_t* image;
  int xrepl,subwidth;
  int bytes_per_line, bytes_per_pixel;

  int flutter_horiz_desync;

  struct timeval last_display_time;


  /* Add hash (in the radio sense, not the programming sense.) These
     are the small white streaks that appear in quasi-regular patterns
     all over the screen when someone is running the vacuum cleaner or
     the blender. We also set shrinkpulse for one period which
     squishes the image horizontally to simulate the temporary line
     voltate drop when someone turns on a big motor */
  #if 0
  double hashnoise_rpm;
  int hashnoise_counter;
  int hashnoise_times[ANALOGTV_V];
  int hashnoise_signal[ANALOGTV_V];
  int hashnoise_on;
  int hashnoise_enable;
  int shrinkpulse;
  #endif

  float crtload[ANALOGTV_V];

  unsigned int intensity[ANALOGTV_CV_MAX];

  int cur_hsync;
  int line_hsync[ANALOGTV_V];
  int cur_vsync;
  double cb_phase[4];
  double line_cb_phase[ANALOGTV_V][4];

  int channel_change_cycles;
  double rx_signal_level;
  float *rx_signal;

  struct {
    int index;
    double value;
  } leveltable[ANALOGTV_MAX_LINEHEIGHT+1][ANALOGTV_MAX_LINEHEIGHT+1];

  /* Only valid during draw. */
  unsigned random0, random1;
  double noiselevel;
  const analogtv_reception *const *recs;
  unsigned rec_count;

  float *signal_subtotals;

  float puheight;
} analogtv;


analogtv *analogtv_allocate(int width, int height);
analogtv_input *analogtv_input_allocate(void);


void analogtv_set_defaults(analogtv *it);
void analogtv_release(analogtv *it);
void analogtv_setup_frame(analogtv *it);
void analogtv_setup_synclevel(analogtv_input *input, int do_cb, int synclevel);
void analogtv_setup_sync(analogtv_input *input, int do_cb, int do_ssavi);
void analogtv_draw(analogtv *it, double noiselevel,
                   const analogtv_reception *const *recs, unsigned rec_count);

//int analogtv_load_ximage(analogtv *it, analogtv_input *input, XImage *pic_im);

void analogtv_reception_update(analogtv_reception *inp);


/* Functions for rendering content into an analogtv_input */

void analogtv_lcp_to_ntsc(double luma, double chroma, double phase,
                          int ntsc[4]);

void analogtv_rgb_to_ntsc(int r, int g, int b, int ntsc[4]);

void analogtv_draw_solid(analogtv_input *input,
                         int left, int right, int top, int bot,
                         int ntsc[4]);

void analogtv_draw_solid_rel_lcp(analogtv_input *input,
                                 double left, double right,
                                 double top, double bot,
                                 double luma, double chroma, double phase);

void analogtv_draw_xpm(analogtv *tv, analogtv_input *input,
                       const char * const *xpm, int left, int top);

int analogtv_handle_events (analogtv *it);

#ifndef USE_IPHONE
# define ANALOGTV_DEF_BRIGHTNESS 2
# define ANALOGTV_DEF_CONTRAST 150
#else
  /* Need to really crank this up for it to look good on the iPhone screen. */
# define ANALOGTV_DEF_BRIGHTNESS 3
# define ANALOGTV_DEF_CONTRAST 1000
#endif

#endif /* _XSCREENSAVER_ANALOGTV_H */