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livetrax/scripts/scope.lua

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Lua
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ardour {
["type"] = "dsp",
name = "Inline Scope",
license = "GPLv2",
author = "Robin Gareus",
email = "robin@gareus.org",
site = "http://gareus.org",
description = [[An Example DSP Plugin to display the waveform on the mixer strip]]
}
-- return possible i/o configurations
function dsp_ioconfig ()
-- -1, -1 = any number of channels as long as input and output count matches
return { [1] = { audio_in = -1, audio_out = -1}, }
end
function dsp_params ()
return
{
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{ ["type"] = "input", name = "Timescale", min = .1, max = 5, default = 2, unit="sec", logarithmic = true },
{ ["type"] = "input", name = "Logscale", min = 0, max = 1, default = 0, toggled = true },
{ ["type"] = "input", name = "Height", min = 0, max = 3, default = 1, unit="dB", enum = true, scalepoints =
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{
["Min"] = 0,
["16:10"] = 1,
["1:1"] = 2,
["Max"] = 3
}
},
}
end
function dsp_init (rate)
-- global variables (DSP part only)
samplerate = rate
bufsiz = 6 * rate
dpy_hz = rate / 25
dpy_wr = 0
end
function dsp_configure (ins, outs)
-- store configuration in global variable
audio_ins = ins:n_audio ()
local audio_outs = outs:n_audio ()
assert (audio_ins == audio_outs)
-- allocate shared memory area
-- this is used to speed up DSP computaton (using a C array)
-- and to share data with the GUI
self:shmem ():allocate (4 + bufsiz * audio_ins)
self:shmem ():clear ()
self:shmem ():atomic_set_int (0, 0)
local cfg = self:shmem ():to_int (1):array ()
cfg[1] = samplerate
cfg[2] = bufsiz
cfg[3] = audio_ins
end
function dsp_runmap (bufs, in_map, out_map, n_samples, offset)
local shmem = self:shmem ()
local write_ptr = shmem:atomic_get_int (0)
for c = 1,audio_ins do
-- Note: lua starts counting at 1, ardour's ChanMapping::get() at 0
local ib = in_map:get (ARDOUR.DataType ("audio"), c - 1); -- get id of mapped input buffer for given cannel
assert (ib ~= ARDOUR.ChanMapping.Invalid)
local chn_off = 4 + bufsiz * (c - 1)
if (write_ptr + n_samples < bufsiz) then
ARDOUR.DSP.copy_vector (shmem:to_float (write_ptr + chn_off), bufs:get_audio (ib):data (offset), n_samples)
else
local w0 = bufsiz - write_ptr;
ARDOUR.DSP.copy_vector (shmem:to_float (write_ptr + chn_off), bufs:get_audio (ib):data (offset), w0)
ARDOUR.DSP.copy_vector (shmem:to_float (chn_off) , bufs:get_audio (ib):data (offset), n_samples - w0)
end
end
write_ptr = (write_ptr + n_samples) % bufsiz
shmem:atomic_set_int (0, write_ptr)
-- emit QueueDraw every FPS
dpy_wr = dpy_wr + n_samples
if (dpy_wr > dpy_hz) then
dpy_wr = dpy_wr % dpy_hz;
self:queue_draw ()
end
end
-- helper function for drawing symmetric grid
function gridline (ctx, x, xr, h, val)
ctx:move_to (math.floor (.5 + x + val * xr) -.5, 1)
ctx:line_to (math.floor (.5 + x + val * xr) -.5, h - 1)
ctx:stroke ()
ctx:move_to (math.floor (.5 + x - val * xr) -.5, 1)
ctx:line_to (math.floor (.5 + x - val * xr) -.5, h - 1)
ctx:stroke ()
end
function render_inline (ctx, w, max_h)
local ctrl = CtrlPorts:array () -- get control port array (read/write)
local shmem = self:shmem () -- get shared memory region
local cfg = shmem:to_int (1):array () -- "cast" into lua-table
local rate = cfg[1]
local buf_size = cfg[2]
local n_chn = cfg[3]
-- get settings
local timescale = ctrl[1] or 1.0 -- display size in seconds
local logscale = ctrl[2] or 0; logscale = logscale > 0 -- logscale
local hmode = ctrl[3] or 1 -- height mode
-- calc height
if hmode == 0 then
h = math.ceil (w * 10 / 16)
if (h > 44) then
h = 44
end
elseif (hmode == 2) then
h = w
elseif (hmode == 3) then
h = max_h
else
h = math.ceil (w * 10 / 16)
end
if (h > max_h) then
h = max_h
end
-- display settings
local spp = math.floor (timescale * rate / (h - 2)) -- samples per pixel
local spl = spp * (h - 1) -- total number of audio samples to read
local read_ptr = (shmem:atomic_get_int (0) + buf_size - spl - 1) % buf_size -- read pointer
local xr = math.ceil ((w - 2) * (0.47 / n_chn)) -- x-axis range (per channel)
-- clear background
ctx:rectangle (0, 0, w, h)
ctx:set_source_rgba (.2, .2, .2, 1.0)
ctx:fill ()
-- prepare drawing
ctx:set_line_width (1.0)
local dash3 = ARDOUR.DoubleVector ()
dash3:add ({1, 3})
local dash4 = ARDOUR.DoubleVector ()
dash4:add ({1, 4})
-- plot every channel
for c = 1,n_chn do
local x = math.floor ((w - 2) * (c - .5) / n_chn) + 1.5 -- x-axis center for given channel
-- draw grid --
ctx:set_source_rgba (.5, .5, .5, 1.0)
ctx:move_to (x, 1) ctx:line_to (x, h - 1) ctx:stroke ()
ctx:set_dash (dash4, 2)
ctx:set_source_rgba (.4, .4, .4, 1.0)
if (logscale) then
gridline (ctx, x, xr, h, ARDOUR.DSP.log_meter(-18))
gridline (ctx, x, xr, h, ARDOUR.DSP.log_meter(-6))
ctx:set_dash (dash3, 2)
ctx:set_source_rgba (.5, .1, .1, 1.0)
gridline (ctx, x, xr, h, ARDOUR.DSP.log_meter(-3))
else
gridline (ctx, x, xr, h, .1258)
gridline (ctx, x, xr, h, .5)
ctx:set_dash (dash3, 2)
ctx:set_source_rgba (.5, .1, .1, 1.0)
gridline (ctx, x, xr, h, .7079)
end
ctx:unset_dash ()
ctx:set_source_rgba (.5, .1, .1, 0.7)
gridline (ctx, x, xr, h, 1)
-- prepare waveform display drawing
ctx:set_source_rgba (.8, .8, .8, .7)
ctx:save ()
ctx:rectangle (math.floor (x - xr), 0, math.ceil (2 * xr), h)
ctx:clip ()
local chn_off = 4 + buf_size * (c - 1)
local buf_off = read_ptr;
-- iterate over every y-axis pixel
for y = 1, h - 1 do
local s_min = 0
local s_max = 0
-- calc min/max values for given range
if (buf_off + spp < buf_size) then
_, s_min, s_max = table.unpack (ARDOUR.DSP.peaks (shmem:to_float (chn_off + buf_off), s_min, s_max, spp))
else
local r0 = buf_size - buf_off;
_, s_min, s_max = table.unpack (ARDOUR.DSP.peaks (shmem:to_float (chn_off + buf_off), s_min, s_max, r0))
_, s_min, s_max = table.unpack (ARDOUR.DSP.peaks (shmem:to_float (chn_off) , s_min, s_max, spp - r0))
end
buf_off = (buf_off + spp) % buf_size;
if (logscale) then
s_max = ARDOUR.DSP.log_meter_coeff (s_max)
s_min = - ARDOUR.DSP.log_meter_coeff (-s_min)
end
ctx:move_to (x + s_min * xr, h - y + .5)
ctx:line_to (x + s_max * xr, h - y + .5)
end
ctx:stroke ()
ctx:restore ()
end
return {w, h}
end