keyboards/skog/breathing_custom.h

   1 /**
   2  * Breathing effect code for PS2AVRGB boards (ATMEGA32A)
   3  * Works in conjunction with `backlight.c`.
   4  *
   5  * Code adapted from `quantum.c` to register with the existing TIMER1 overflow
   6  * handler in `backlight.c` instead of setting up its own timer.
   7  * Kenneth A. (github.com/krusli | krusli.me)
   8  */
   9
  10 #ifdef BACKLIGHT_ENABLE
  11 #ifdef BACKLIGHT_BREATHING
  12
  13 #include "backlight_custom.h"
  14
  15 #ifndef BREATHING_PERIOD
  16 #define BREATHING_PERIOD 6
  17 #endif
  18
  19 #define breathing_min() do {breathing_counter = 0;} while (0)
  20 #define breathing_max() do {breathing_counter = breathing_period * 244 / 2;} while (0)
  21
  22 // TODO make this share code with quantum.c
  23
  24 #define BREATHING_NO_HALT  0
  25 #define BREATHING_HALT_OFF 1
  26 #define BREATHING_HALT_ON  2
  27 #define BREATHING_STEPS 128
  28
  29 static uint8_t breathing_period = BREATHING_PERIOD;
  30 static uint8_t breathing_halt = BREATHING_NO_HALT;
  31 static uint16_t breathing_counter = 0;
  32
  33 static bool breathing = false;
  34
  35 bool is_breathing(void) {
  36   return breathing;
  37 }
  38
  39 // See http://jared.geek.nz/2013/feb/linear-led-pwm
  40 static uint16_t cie_lightness(uint16_t v) {
  41   if (v <= 5243) // if below 8% of max
  42     return v / 9; // same as dividing by 900%
  43   else {
  44     uint32_t y = (((uint32_t) v + 10486) << 8) / (10486 + 0xFFFFUL); // add 16% of max and compare
  45     // to get a useful result with integer division, we shift left in the expression above
  46     // and revert what we've done again after squaring.
  47     y = y * y * y >> 8;
  48     if (y > 0xFFFFUL) // prevent overflow
  49       return 0xFFFFU;
  50     else
  51       return (uint16_t) y;
  52   }
  53 }
  54
  55 void breathing_enable(void) {
  56   breathing = true;
  57   breathing_counter = 0;
  58   breathing_halt = BREATHING_NO_HALT;
  59   // interrupt already registered
  60 }
  61
  62 void breathing_pulse(void) {
  63   if (get_backlight_level() == 0)
  64     breathing_min();
  65   else
  66     breathing_max();
  67   breathing_halt = BREATHING_HALT_ON;
  68   // breathing_interrupt_enable();
  69   breathing = true;
  70 }
  71
  72 void breathing_disable(void) {
  73   breathing = false;
  74   // backlight_set(get_backlight_level());
  75   b_led_set(get_backlight_level()); // custom implementation of backlight_set()
  76 }
  77
  78 void breathing_self_disable(void)
  79 {
  80   if (get_backlight_level() == 0)
  81     breathing_halt = BREATHING_HALT_OFF;
  82   else
  83     breathing_halt = BREATHING_HALT_ON;
  84 }
  85
  86 void breathing_toggle(void) {
  87   if (is_breathing())
  88     breathing_disable();
  89   else
  90     breathing_enable();
  91 }
  92
  93 void breathing_period_set(uint8_t value)
  94 {
  95   if (!value)
  96     value = 1;
  97   breathing_period = value;
  98 }
  99
 100 void breathing_period_default(void) {
 101   breathing_period_set(BREATHING_PERIOD);
 102 }
 103
 104 void breathing_period_inc(void)
 105 {
 106   breathing_period_set(breathing_period+1);
 107 }
 108
 109 void breathing_period_dec(void)
 110 {
 111   breathing_period_set(breathing_period-1);
 112 }
 113
 114 /* To generate breathing curve in python:
 115  * from math import sin, pi; [int(sin(x/128.0*pi)**4*255) for x in range(128)]
 116  */
 117 static const uint8_t breathing_table[BREATHING_STEPS] PROGMEM = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 17, 20, 24, 28, 32, 36, 41, 46, 51, 57, 63, 70, 76, 83, 91, 98, 106, 113, 121, 129, 138, 146, 154, 162, 170, 178, 185, 193, 200, 207, 213, 220, 225, 231, 235, 240, 244, 247, 250, 252, 253, 254, 255, 254, 253, 252, 250, 247, 244, 240, 235, 231, 225, 220, 213, 207, 200, 193, 185, 178, 170, 162, 154, 146, 138, 129, 121, 113, 106, 98, 91, 83, 76, 70, 63, 57, 51, 46, 41, 36, 32, 28, 24, 20, 17, 15, 12, 10, 8, 6, 5, 4, 3, 2, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
 118
 119 // Use this before the cie_lightness function.
 120 static inline uint16_t scale_backlight(uint16_t v) {
 121   return v / BACKLIGHT_LEVELS * get_backlight_level();
 122 }
 123
 124 void custom_breathing_handler(void) {
 125   uint16_t interval = (uint16_t) breathing_period * 244 / BREATHING_STEPS;
 126   // resetting after one period to prevent ugly reset at overflow.
 127   breathing_counter = (breathing_counter + 1) % (breathing_period * 244);
 128   uint8_t index = breathing_counter / interval % BREATHING_STEPS;
 129
 130   if (((breathing_halt == BREATHING_HALT_ON) && (index == BREATHING_STEPS / 2)) ||
 131       ((breathing_halt == BREATHING_HALT_OFF) && (index == BREATHING_STEPS - 1)))
 132   {
 133       // breathing_interrupt_disable();
 134   }
 135
 136   setPWM(cie_lightness(scale_backlight((uint16_t) pgm_read_byte(&breathing_table[index]) * 0x0101U)));
 137 }
 138
 139 #endif // BACKLIGHT_BREATHING
 140 #endif  // BACKLIGHT_ENABLE