Add fast clear animation

The old clear mechanism would write an empty cell in every layer,
which would take (0.3 seconds) * (11 layers) == about 3 seconds.

The new mechanism drives an animation which overwrites every character
slot simultaneously, taking only 0.1 seconds. A nice ~30x speedup.

* Fix the transcription exponential backoff logic. Saying new things
  will reset the delay to the minimum again.
* Clearing the board will also reset the transcription delay back to
  the minimum.
* Tune the noise detection minimum to 0.2 instead of 0.1. Speaking
  softly into the mic seems to fail to exceed the 0.1 threshold pretty
  often.

1 files changed, 11 insertions, 1 deletions

diff --git a/generate_utils.py b/generate_utils.py
index 68a455b..bf7e6c7 100644
--- a/generate_utils.py
+++ b/generate_utils.py
@@ -54,6 +54,10 @@ def getSpeechNoiseToggleParam():
 def getSpeechNoiseEnableParam():
     return "TaSTT_Speech_Noise_Enable"
 
+# When this is set to true, the board clears.
+def getClearBoardParam():
+    return "TaSTT_Clear_Board"
+
 def getLockWorldParam():
     return "TaSTT_Lock_World"
 
@@ -112,9 +116,15 @@ def getShaderParam(which_layer, s0, s1, s2, s3):
 
     return getShaderParamByRowCol(row, col)
 
-def getAnimationName(row, col, letter):
+# The name of the animation which writes `letter` at a specific position in the
+# display.
+def getLetterAnimationName(row, col, letter):
     return "R%02dC%02dL%02d" % (row, col, letter)
 
+# The name of the animation which clears the entire board.
+def getClearAnimationName():
+    return "TaSTT_Clear_Board"
+
 def getAnimationNameByLayerAndIndex(which_layer, s0, s1, s2, s3, letter):
     index = getBoardIndex(which_layer, s0, s1, s2, s3)