diff options
author | Robin Gareus <robin@gareus.org> | 2016-07-04 01:47:52 +0200 |
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committer | Robin Gareus <robin@gareus.org> | 2016-07-04 01:48:23 +0200 |
commit | 11d2074ee6c238cfdf06666988ad5bb4a5dd8608 (patch) | |
tree | 28f37244a6ada1bff064669a89ae0e8c85cbfb4f /scripts/amp4.lua | |
parent | e6621c4405b1acc854fca1cadfc91c58ecd8cf0a (diff) |
more lua-script updates:
* comments and explain amp4.lua
* move amp1-3 to "Example" category
Diffstat (limited to 'scripts/amp4.lua')
-rw-r--r-- | scripts/amp4.lua | 41 |
1 files changed, 20 insertions, 21 deletions
diff --git a/scripts/amp4.lua b/scripts/amp4.lua index a348d166f4..1fc8773592 100644 --- a/scripts/amp4.lua +++ b/scripts/amp4.lua @@ -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} |