seg_hfm.c

/* mehPL:
 *    This is Open Source, but NOT GPL. I call it mehPL.
 *    I'm not too fond of long licenses at the top of the file.
 *    Please see the bottom.
 *    Enjoy!
 */












//seg_hfm.c (uses the rowSegBuffer):
//Uses "High-Frequency Modulation" to display an interesting pattern...
// HFM is kinda like PWM. The idea is to have an output ON for
//  a certain percentage of the time...
//  In PWM, that's done by turning it on for a fraction of a cycle 
//  (the "width" of the pulse), then off for the remainder.
//  In HFM, it's accomplished by knowing the fraction of time it should be
//  on... (the "power"). The fractions are automatically reduced 5/10->1/2.
//  e.g. if the on-time should be 1/100th of the time, it will be on
//  during one update-period, and off for 99, then repeat.
//  If the on-time should be 1/2 of the time, it will be on during one
//  update, off during the next, on again, and so-on.
//  If the on-time is some strange fraction, like 3/5, it will distribute
//  the pulses accordingly (e.g. on, off, on, off, on, repeat)
//  Thus, the output toggles as quickly as possible to achieve the desired
//  power... thus "High-Frequency"
//  (See _commonCode.../hfModulation/...)
//  I've been using HFM in ways never originally intended: e.g. it can be
//  used for smoothing lines between two distant points...
//  It's used this way in "SEG_RACER" in order to use a low-resolution
//  course in memory, and increase the resolution by knowing that there are
//  a certain number of rows in which it has to get from point1 to point2
//  so the "power" of the HFM is set to (p2-p1)/numRows.
//  The nice thing about it, is it doesn't use any actual division (which
//  is quite slow) because it knows that every point inbetween will be 
//  traversed.
// SEG_HFM visualizes that, and actually looks pretty cool. Like moire
//  patterns, or magnetic-field-lines.
// Each row increases in power, essentially: rowNum/NUM_SEGMENTS
// (Experimenting with NUM_SEGMENTS is fun, in this case, just don't exceed
//  the available memory, and keep in mind that there's a stack and stuff)




void segHFM_loadRow(uint16_t rowNum) {
   segClear();
   //Just some experimenting... 1024/3+16 seems to be the width...
   // == 357 segments (Where does this come from?)
//Pixel Segments...
#define BORDER_PSEGS   1
#define SEGS_AVAILABLE (NUM_SEGMENTS-2)
#define PSEGS_AVAILABLE   (NUM_PSEGS-BORDER_PSEGS*2)
#define HFM_PSEGS   (PSEGS_AVAILABLE/SEGS_AVAILABLE)
#define HFM_PSEGS_REMAINDER   (PSEGS_AVAILABLE%SEGS_AVAILABLE)
   addSegfb(BORDER_PSEGS,_W);

   hfm_t hfmThing;
   hfm_setup(&hfmThing, (uint8_t)((uint32_t)rowNum*(uint32_t)SEGS_AVAILABLE/V_COUNT), SEGS_AVAILABLE);

   hfm_t hfmColStretcher;
   hfm_setup(&hfmColStretcher, HFM_PSEGS_REMAINDER, SEGS_AVAILABLE);

   uint16_t pseg;
   for(pseg=0; pseg<SEGS_AVAILABLE; pseg++)
   {
      if(hfm_nextOutput(&hfmThing))
         addSegfb(HFM_PSEGS + hfm_nextOutput(&hfmColStretcher),_R);
      else
         addSegfb(HFM_PSEGS + hfm_nextOutput(&hfmColStretcher),_C);
   }

   //addSegfb(NUM_PSEGS-BORDER_PSEGS*2-SEGS_AVAILABLE*HFM_PSEGS, _M);
   addSegfb(BORDER_PSEGS,_W);
   segTerminate();
}
/* mehPL:
 *    I would love to believe in a world where licensing shouldn't be
 *    necessary; where people would respect others' work and wishes, 
 *    and give credit where it's due. 
 *    A world where those who find people's work useful would at least 
 *    send positive vibes--if not an email.
 *    A world where we wouldn't have to think about the potential
 *    legal-loopholes that others may take advantage of.
 *
 *    Until that world exists:
 *
 *    This software and associated hardware design is free to use,
 *    modify, and even redistribute, etc. with only a few exceptions
 *    I've thought-up as-yet (this list may be appended-to, hopefully it
 *    doesn't have to be):
 * 
 *    1) Please do not change/remove this licensing info.
 *    2) Please do not change/remove others' credit/licensing/copyright 
 *         info, where noted. 
 *    3) If you find yourself profiting from my work, please send me a
 *         beer, a trinket, or cash is always handy as well.
 *         (Please be considerate. E.G. if you've reposted my work on a
 *          revenue-making (ad-based) website, please think of the
 *          years and years of hard work that went into this!)
 *    4) If you *intend* to profit from my work, you must get my
 *         permission, first. 
 *    5) No permission is given for my work to be used in Military, NSA,
 *         or other creepy-ass purposes. No exceptions. And if there's 
 *         any question in your mind as to whether your project qualifies
 *         under this category, you must get my explicit permission.
 *
 *    The open-sourced project this originated from is ~98% the work of
 *    the original author, except where otherwise noted.
 *    That includes the "commonCode" and makefiles.
 *    Thanks, of course, should be given to those who worked on the tools
 *    I've used: avr-dude, avr-gcc, gnu-make, vim, usb-tiny, and 
 *    I'm certain many others. 
 *    And, as well, to the countless coders who've taken time to post
 *    solutions to issues I couldn't solve, all over the internets.
 *
 *
 *    I'd love to hear of how this is being used, suggestions for
 *    improvements, etc!
 *         
 *    The creator of the original code and original hardware can be
 *    contacted at:
 *
 *        EricWazHung At Gmail Dotcom
 *
 *    This code's origin (and latest versions) can be found at:
 *
 *        https://code.google.com/u/ericwazhung/
 *
 *    The site associated with the original open-sourced project is at:
 *
 *        https://sites.google.com/site/geekattempts/
 *
 *    If any of that ever changes, I will be sure to note it here, 
 *    and add a link at the pages above.
 *
 * This license added to the original file located at:
 * /Users/meh/_avrProjects/LCDdirectLVDS/93-checkingProcessAgain/seg_hfm.c
 *
 *    (Wow, that's a lot longer than I'd hoped).
 *
 *    Enjoy!
 */