Change handling of adjust layer to make it more LT(...) friendly. (#1625)

* Change handling of adjust layer to make it more LT(...) friendly.

* Update based on feedback from drashna.

* Change handling of adjust layer to make it more LT(...) friendly.  This reworks handling to make it a little more friendly to include in keymaps.

keyboards/planck/keymaps/default/keymap.c

@@ -34,12 +34,13 @@ enum planck_keycodes {
   COLEMAK,
   DVORAK,
   PLOVER,
-  LOWER,
-  RAISE,
   BACKLIT,
   EXT_PLV
 };
 
+#define LOWER MO(_LOWER)
+#define RAISE MO(_RAISE)
+
 const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
 
 /* Qwerty
@@ -177,6 +178,10 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
   float plover_gb_song[][2]  = SONG(PLOVER_GOODBYE_SOUND);
 #endif
 
+uint32_t layer_state_set_user(uint32_t state) {
+  return update_tri_layer_state(state, _LOWER, _RAISE, _ADJUST);
+}
+
 bool process_record_user(uint16_t keycode, keyrecord_t *record) {
   switch (keycode) {
     case QWERTY:
@@ -198,26 +203,6 @@ bool process_record_user(uint16_t keycode, keyrecord_t *record) {
       }
       return false;
       break;
-    case LOWER:
-      if (record->event.pressed) {
-        layer_on(_LOWER);
-        update_tri_layer(_LOWER, _RAISE, _ADJUST);
-      } else {
-        layer_off(_LOWER);
-        update_tri_layer(_LOWER, _RAISE, _ADJUST);
-      }
-      return false;
-      break;
-    case RAISE:
-      if (record->event.pressed) {
-        layer_on(_RAISE);
-        update_tri_layer(_LOWER, _RAISE, _ADJUST);
-      } else {
-        layer_off(_RAISE);
-        update_tri_layer(_LOWER, _RAISE, _ADJUST);
-      }
-      return false;
-      break;
     case BACKLIT:
       if (record->event.pressed) {
         register_code(KC_RSFT);

quantum/quantum.c

@@ -780,12 +780,14 @@ void set_single_persistent_default_layer(uint8_t default_layer) {
   default_layer_set(1U<<default_layer);
 }
 
+uint32_t update_tri_layer_state(uint32_t state, uint8_t layer1, uint8_t layer2, uint8_t layer3) {
+  uint32_t mask12 = (1UL << layer1) | (1UL << layer2);
+  uint32_t mask3 = 1UL << layer3;
+  return (state & mask12) == mask12 ? (state | mask3) : (state & ~mask3);
+}
+
 void update_tri_layer(uint8_t layer1, uint8_t layer2, uint8_t layer3) {
-  if (IS_LAYER_ON(layer1) && IS_LAYER_ON(layer2)) {
+  layer_state_set(update_tri_layer_state(layer_state, layer1, layer2, layer3));
-    layer_on(layer3);
-  } else {
-    layer_off(layer3);
-  }
 }
 
 void tap_random_base64(void) {

quantum/quantum.h

@@ -142,6 +142,7 @@ void send_char(char ascii_code);
 
 // For tri-layer
 void update_tri_layer(uint8_t layer1, uint8_t layer2, uint8_t layer3);
+uint32_t update_tri_layer_state(uint32_t state, uint8_t layer1, uint8_t layer2, uint8_t layer3);
 
 void set_single_persistent_default_layer(uint8_t default_layer);