}
end
+-- symbolic names for shmem offsets
+local SHMEM_RATE = 0
+local SHMEM_WRITEPTR = 1
+local SHMEM_AUDIO = 2
+
-- a C memory area.
-- It needs to be in global scope.
-- When the variable is set to nil, the allocated memory is free()ed.
dpy_hz = rate / 25
dpy_wr = 0
- -- create a ringbuffer to hold (float) audio-data
- -- http://manual.ardour.org/lua-scripting/class_reference/#PBD:RingBufferF
- rb = PBD.RingBufferF (2 * rate)
+ -- create a shared memory area to hold the sample rate, the write_pointer,
+ -- and (float) audio-data. Make it big enough to store 2s of audio which
+ -- should be enough. If not, the DSP will overwrite the oldest data anyway.
+ self:shmem ():allocate(2 + 2 * rate)
+ self:shmem ():clear()
+ self:shmem ():atomic_set_int (SHMEM_RATE, rate)
+ self:shmem ():atomic_set_int (SHMEM_WRITEPTR, 0)
-- allocate memory, local mix buffer
cmem = ARDOUR.DSP.DspShm (8192)
-
- -- create a table of objects to share with the GUI
- local tbl = {}
- tbl['rb'] = rb;
- tbl['samplerate'] = rate
-
- -- "self" is a special DSP variable referring
- -- to the plugin instance itself.
- --
- -- "table()" is-a http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR.LuaTableRef
- -- which allows to store/retrieve lua-tables to share them other interpreters
- self:table ():set (tbl);
end
-- "dsp_runmap" uses Ardour's internal processor API, eqivalent to
-- 'connect_and_run()". There is no overhead (mapping, translating buffers).
-- The lua implementation is responsible to map all the buffers directly.
function dsp_runmap (bufs, in_map, out_map, n_samples, offset)
- -- here we sum all audio input channels channels and then copy the data to a ringbuffer
- -- for the GUI to process later
+ -- here we sum all audio input channels and then copy the data to a
+ -- custom-made circular table for the GUIs to process later
local audio_ins = in_map:count (): n_audio () -- number of audio input buffers
local ccnt = 0 -- processed channel count
local mem = cmem:to_float(0) -- a "FloatArray", float* for direct C API usage from the previously allocated buffer
+ local rate = self:shmem ():atomic_get_int (SHMEM_RATE)
+ local write_ptr = self:shmem ():atomic_get_int (SHMEM_WRITEPTR)
+
+ local ringsize = 2 * rate
+ local ptr_wrap = math.floor(2^50 / ringsize) * ringsize
+
for c = 1,audio_ins do
-- see http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:ChanMapping
-- Note: lua starts counting at 1, ardour's ChanMapping::get() at 0
ARDOUR.DSP.memset (mem, 0, n_samples)
end
- -- write data to the ringbuffer
- -- http://manual.ardour.org/lua-scripting/class_reference/#PBD:RingBufferF
- rb:write (mem, n_samples)
+ -- write data to the circular table
+ if (write_ptr % ringsize + n_samples < ringsize) then
+ ARDOUR.DSP.copy_vector (self:shmem ():to_float (SHMEM_AUDIO + write_ptr % ringsize), mem, n_samples)
+ else
+ local chunk = ringsize - write_ptr % ringsize
+ ARDOUR.DSP.copy_vector (self:shmem ():to_float (SHMEM_AUDIO + write_ptr % ringsize), mem, chunk)
+ ARDOUR.DSP.copy_vector (self:shmem ():to_float (SHMEM_AUDIO), cmem:to_float (chunk), n_samples - chunk)
+ end
+ self:shmem ():atomic_set_int (SHMEM_WRITEPTR, (write_ptr + n_samples) % ptr_wrap)
-- emit QueueDraw every FPS
-- TODO: call every FFT window-size worth of samples, at most every FPS
local fft_size = 0
local last_log = false
+
function render_inline (ctx, w, max_h)
local ctrl = CtrlPorts:array () -- get control port array (read/write)
- local tbl = self:table ():get () -- get shared memory table
- local rate = tbl['samplerate']
+ local rate = self:shmem ():atomic_get_int (SHMEM_RATE)
if not cmem then
cmem = ARDOUR.DSP.DspShm (0)
end
local f_b = w / math.log (fft_size / 2) -- inverse log-scale base
local f_l = math.log (fft_size / rate) * f_b -- inverse logscale lower-bound
- local rb = tbl['rb'];
local mem = cmem:to_float (0)
- while (rb:read_space() >= fft_size) do
- -- process one line / buffer
- rb:read (mem, fft_size)
+ local ringsize = 2 * rate
+ local ptr_wrap = math.floor(2^50 / ringsize) * ringsize
+
+ local write_ptr
+ function read_space()
+ write_ptr = self:shmem ():atomic_get_int (SHMEM_WRITEPTR)
+ local space = (write_ptr - read_ptr + ptr_wrap) % ptr_wrap
+ if space > ringsize then
+ -- the GUI lagged too much and unread data was overwritten
+ -- jump to the oldest audio still present in the ringtable
+ read_ptr = write_ptr - ringsize
+ space = ringsize
+ end
+ return space
+ end
+
+ while (read_space() >= fft_size) do
+ -- read one window from the circular table
+ if (read_ptr % ringsize + fft_size < ringsize) then
+ ARDOUR.DSP.copy_vector (mem, self:shmem ():to_float (SHMEM_AUDIO + read_ptr % ringsize), fft_size)
+ else
+ local chunk = ringsize - read_ptr % ringsize
+ ARDOUR.DSP.copy_vector (mem, self:shmem ():to_float (SHMEM_AUDIO + read_ptr % ringsize), chunk)
+ ARDOUR.DSP.copy_vector (cmem:to_float(chunk), self:shmem ():to_float (SHMEM_AUDIO), fft_size - chunk)
+ end
+ read_ptr = (read_ptr + fft_size) % ptr_wrap
+
+ -- process one line
fft:set_data_hann (mem, fft_size, 0)
fft:execute ()
projects / ardour.git / blobdiff