fix crash when copy'ing latent plugins

[ardour.git] / scripts / spectrogram.lua

diff --git a/scripts/spectrogram.lua b/scripts/spectrogram.lua
index b0a92df97b57f3cdaf398966e77cfb997b134563..4f55a654a72bdbfb416b57b36d5aec41118d3016 100644 (file)
--- a/scripts/spectrogram.lua
+++ b/scripts/spectrogram.lua
@@ -1,12 +1,10 @@
 ardour {
        ["type"]    = "dsp",
-       name        = "Inline Spectrogram",
+       name        = "a-Inline Spectrogram",
        category    = "Visualization",
-       license     = "GPLv2",
-       author      = "Robin Gareus",
-       email       = "robin@gareus.org",
-       site        = "http://gareus.org",
-       description = [[An Example DSP Plugin to display a spectrom on the mixer strip]]
+       license     = "MIT",
+       author      = "Ardour Team",
+       description = [[Mixer strip inline spectrum display]]
 }
 
 -- return possible i/o configurations
@@ -44,8 +42,10 @@ end
 
 -- a C memory area.
 -- It needs to be in global scope.
--- When the variable is set to nil, the allocated memory
--- is free()ed
+-- When the variable is set to nil, the allocated memory is free()ed.
+-- the memory can be interpeted as float* for use in DSP, or read/write
+-- to a C++ Ringbuffer instance.
+-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP:DspShm
 local cmem = nil
 
 function dsp_init (rate)
@@ -54,6 +54,7 @@ function dsp_init (rate)
        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)
 
        -- allocate memory, local mix buffer
@@ -72,6 +73,9 @@ function dsp_init (rate)
        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
@@ -80,10 +84,16 @@ function dsp_runmap (bufs, in_map, out_map, n_samples, offset)
        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
        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
-               local ib = in_map:get (ARDOUR.DataType ("audio"), c - 1) -- get id of mapped input buffer for given cannel
-               local ob = out_map:get (ARDOUR.DataType ("audio"), c - 1) -- get id of mapped output buffer for given cannel
+               local ib = in_map:get (ARDOUR.DataType ("audio"), c - 1) -- get index of mapped input buffer
+               local ob = out_map:get (ARDOUR.DataType ("audio"), c - 1) -- get index of mapped output buffer
+
+               -- check if the input is connected to a buffer
                if (ib ~= ARDOUR.ChanMapping.Invalid) then
+
+                       -- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:AudioBuffer
+                       -- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP
                        if c == 1 then
                                -- first channel, copy as-is
                                ARDOUR.DSP.copy_vector (mem, bufs:get_audio (ib):data (offset), n_samples)
@@ -104,8 +114,8 @@ function dsp_runmap (bufs, in_map, out_map, n_samples, offset)
        -- In case we're processing in-place some buffers may be identical,
        -- so this must be done  *after processing*.
        for c = 1,audio_ins do
-               local ib = in_map:get (ARDOUR.DataType ("audio"), c - 1) -- get id of mapped input buffer for given cannel
-               local ob = out_map:get (ARDOUR.DataType ("audio"), c - 1) -- get id of mapped output buffer for given cannel
+               local ib = in_map:get (ARDOUR.DataType ("audio"), c - 1)
+               local ob = out_map:get (ARDOUR.DataType ("audio"), c - 1)
                if (ib == ARDOUR.ChanMapping.Invalid and ob ~= ARDOUR.ChanMapping.Invalid) then
                        bufs:get_audio (ob):silence (n_samples, offset)
                end
@@ -122,6 +132,7 @@ function dsp_runmap (bufs, in_map, out_map, n_samples, offset)
        end
 
        -- write data to the ringbuffer
+       -- http://manual.ardour.org/lua-scripting/class_reference/#PBD:RingBufferF
        rb:write (mem, n_samples)
 
        -- emit QueueDraw every FPS