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more lua-script updates:

* comments and explain amp4.lua
* move amp1-3 to "Example" category
This commit is contained in:
Robin Gareus 2016-07-04 01:47:52 +02:00
parent e6621c4405
commit 11d2074ee6
4 changed files with 23 additions and 24 deletions

View File

@ -1,7 +1,7 @@
ardour {
["type"] = "dsp",
name = "Simple Amp",
category = "Amplifier",
category = "Example",
license = "MIT",
author = "Robin Gareus",
email = "robin@gareus.org",

View File

@ -1,7 +1,7 @@
ardour {
["type"] = "dsp",
name = "Simple Amp II",
category = "Amplifier",
category = "Example",
license = "MIT",
author = "Robin Gareus",
email = "robin@gareus.org",

View File

@ -1,7 +1,7 @@
ardour {
["type"] = "dsp",
name = "Simple Amp III",
category = "Amplifier",
category = "Example",
license = "MIT",
author = "Robin Gareus",
email = "robin@gareus.org",

View File

@ -6,12 +6,13 @@ ardour {
author = "Robin Gareus",
email = "robin@gareus.org",
site = "http://gareus.org",
description = [[ Versatile +/- 20dB multichannel amplifier]]
description = [[Versatile +/- 20dB multichannel amplifier]]
}
function dsp_ioconfig ()
return
{
-- -1, -1 = any number of channels as long as input and output count matches
{ audio_in = -1, audio_out = -1},
}
end
@ -25,7 +26,7 @@ function dsp_params ()
end
local lpf = 0.02 -- parameter low-pass filter time-constant
local cur_gain = 0 -- current gain (dB)
local cur_gain = 0 -- current smoothed gain (dB)
-- called once when plugin is instantiated
function dsp_init (rate)
@ -40,22 +41,15 @@ function low_pass_filter_param (old, new, limit)
end
end
-- use ardour's vectorized functions
--
-- This is as efficient as Ardour doing it itself in C++
-- Lua function overhead is negligible
--
-- this also exemplifies the /simpler/ way of delegating the
-- channel-mapping to ardour.
-- the DSP callback function
-- "ins" and "outs" are http://manual.ardour.org/lua-scripting/class_reference/#C:FloatArray
function dsp_run (ins, outs, n_samples)
assert (#ins == #outs) -- ensure that we can run in-place (channel count matches)
local ctrl = CtrlPorts:array() -- get control port array (read/write)
local siz = n_samples
local off = 0
local siz = n_samples -- samples remaining to process
local off = 0 -- already processed samples
local changed = false
-- if the gain parameter was changed, process at most 64 samples at a time
-- if the gain parameter was changed, process at most 32 samples at a time
-- and interpolate gain until the current settings match the target values
if cur_gain ~= ctrl[1] then
changed = true
@ -63,12 +57,14 @@ function dsp_run (ins, outs, n_samples)
end
while n_samples > 0 do
if siz > n_samples then siz = n_samples end
if siz > n_samples then siz = n_samples end -- process at most "remaining samples"
if changed then
cur_gain = low_pass_filter_param (cur_gain, ctrl[1], 0.05)
-- smooth gain changes above 0.02 dB difference
cur_gain = low_pass_filter_param (cur_gain, ctrl[1], 0.02)
end
local gain = ARDOUR.DSP.dB_to_coefficient (cur_gain) -- 10 ^ (0.05 * cur_gain)
for c = 1,#ins do -- process all channels
-- check if output and input buffers for this channel are identical
-- http://manual.ardour.org/lua-scripting/class_reference/#C:FloatArray
@ -76,7 +72,7 @@ function dsp_run (ins, outs, n_samples)
-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP
ARDOUR.DSP.copy_vector (outs[c]:offset (off), ins[c]:offset (off), siz)
end
ARDOUR.DSP.apply_gain_to_buffer (outs[c]:offset (off), siz, gain); -- process in-place
ARDOUR.DSP.apply_gain_to_buffer (outs[c]:offset (off), siz, gain); -- apply-gain, process in-place
end
n_samples = n_samples - siz
off = off + siz
@ -90,18 +86,21 @@ end
-------------------------------------------------------------------------------
--- inline display + text example
local txt = nil -- cache globally
local txt = nil -- cache pango context globally
function render_inline (ctx, w, max_h)
local ctrl = CtrlPorts:array ()
local ctrl = CtrlPorts:array () -- get control ports
if not txt then
-- allocate PangoLayout and set font
--http://manual.ardour.org/lua-scripting/class_reference/#Cairo:PangoLayout
txt = Cairo.PangoLayout (ctx, "Mono 8px")
end
txt:set_text (string.format ("%+.2f dB", ctrl[1]));
tw, th = txt:get_pixel_size ()
local h = math.ceil (th + 4) -- use text-height with 4px padding
local h = th + 4 -- use text-height with 4px padding
if (h > max_h) then h = max_h end -- but at most max-height
-- clear background
@ -111,7 +110,7 @@ function render_inline (ctx, w, max_h)
-- center text
ctx:set_source_rgba (.8, .8, .8, 1.0)
ctx:move_to ( .5 * (w - tw), .5 * (h - th))
ctx:move_to (.5 * (w - tw), .5 * (h - th))
txt:show_in_cairo_context (ctx)
return {w, h}