firmware/main: For candle mode, make max brightness random

This makes it look a bit smoother and also reduces the average
current, saving a bit of power.

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>

firmware/main/led_anim.c

@@ -174,6 +174,7 @@ static const struct led_anim la_sparkle2 = {
 
 struct la_candle_state {
 	struct candle_state cdl[N_LEDS];
+	uint8_t brg[N_LEDS];
 };
 
 static void
@@ -181,8 +182,10 @@ la_candle_init(void *state)
 {
 	struct la_candle_state *s = state;
 
-	for (int i=0; i<N_LEDS; i++)
+	for (int i=0; i<N_LEDS; i++) {
 		candle_init(&s->cdl[i]);
+		s->brg[i] = 128 + (rand16() & 127);
+	}
 }
 
 static void
@@ -192,7 +195,7 @@ la_candle_render(void *state, uint16_t *leds,
 	struct la_candle_state *s = state;
 
 	for (int i=0; i<N_LEDS; i++)
-		leds[i] = (3750 * conf->dim * candle_exec(&s->cdl[i], conf->speed)) >> 8;
+		leds[i] = (3750UL * s->brg[i] * conf->dim * candle_exec(&s->cdl[i], conf->speed)) >> 16;
 }
 
 static const struct led_anim la_candle = {
@@ -277,9 +280,9 @@ la_breathe_render(void *state, uint16_t *leds,
 		s->leds[i].pha = pha;
 
 		/* Early OverBright release */
-			/* After pha >= 40000, we're not overbright anyway, so
-			 * allow another led to use it early */
-		if (s->leds[i].ob && (s->leds[i].pha > 40000)) {
+			/* After pha >= 28000, we know that it's safe to allow a new overbright led
+			 * because we'll be past the peak by the time they start needing overbright */
+		if (s->leds[i].ob && (s->leds[i].pha > 28000)) {
 			s->leds[i].ob = false;
 			s->n_ob--;
 		}