From da9b240ce1392f7b1d9d51d4938898868d8d1d83 Mon Sep 17 00:00:00 2001 From: David Robillard Date: Mon, 28 Jan 2013 01:33:10 +0000 Subject: Update metronome example to produce sensible book output. --- plugins/eg-metro.lv2/metro.c | 33 ++++++++++++++++++++++++++------- 1 file changed, 26 insertions(+), 7 deletions(-) (limited to 'plugins/eg-metro.lv2/metro.c') diff --git a/plugins/eg-metro.lv2/metro.c b/plugins/eg-metro.lv2/metro.c index d36ac15..97821a1 100644 --- a/plugins/eg-metro.lv2/metro.c +++ b/plugins/eg-metro.lv2/metro.c @@ -76,16 +76,35 @@ typedef struct { float* output; } ports; + /** The rate, bpm, and speed are the basic information sent by the host. */ double rate; float bpm; float speed; - uint32_t elapsed_len; /**< Frames since last click start */ - uint32_t wave_offset; /**< Current play offset in wave */ - float* wave; /**< One cycle of a sine wave */ - uint32_t wave_len; /**< Length of wave in frames */ - uint32_t attack_len; /**< Attack duration in frames */ - uint32_t decay_len; /**< Decay duration in frames */ - State state; /**< Play state */ + + /** To keep track of when to play the next click, we need to keep track of + a few pieces of information: */ + + /** - The frames since the start of the last click is stored */ + uint32_t elapsed_len; + + /** - The current play offset in the wave */ + uint32_t wave_offset; + + /** - The current play state (attack, decay, or off) */ + State state; + + /** The wave to play is a simple sine wave generated at instantiation time + based on the sample rate. The length in frames is stored in order to + continuously play the wave in a cycle to avoid discontinuity clicks. */ + float* wave; + uint32_t wave_len; + + /** The continuously playing sine wave is enveloped to provide an actual + metronome tick. This plugin uses a simple AD envelope with fixed + parameters. A more sophisticated implementation might use a more + advanced envelope and allow the user to modify these parameters. */ + uint32_t attack_len; + uint32_t decay_len; } Metro; static void -- cgit v1.2.1