clean up a-HP/LP

diff --git a/scripts/HiAndLowPass.lua b/scripts/HiAndLowPass.lua
index 58908edd2381767520a526cb20793c2007872ff4..abaa51b8b86efffd9c1235f7945f9648cb97ae3c 100644 (file)
--- a/scripts/HiAndLowPass.lua
+++ b/scripts/HiAndLowPass.lua
@@ -2,7 +2,7 @@ ardour {
        ["type"]    = "dsp",
        name        = "a-High and Low Pass Filter",
        category    = "Filter",
        ["type"]    = "dsp",
        name        = "a-High and Low Pass Filter",
        category    = "Filter",

-       license     = "MIT",
+       license     = "GPLv2",

        author      = "Ardour Team",
        description = [[Example Ardour Lua DSP Plugin]]
 }
        author      = "Ardour Team",
        description = [[Example Ardour Lua DSP Plugin]]
 }


@@ -61,20 +61,24 @@ function dsp_init (rate)
 
        -- create a table of objects to share with the GUI
        local tbl = {}
 
        -- create a table of objects to share with the GUI
        local tbl = {}

-       tbl['rb'] = rb

        tbl['samplerate'] = rate
        self:table ():set (tbl)
 
        tbl['samplerate'] = rate
        self:table ():set (tbl)
 

-       -- interpolation time constant
-       lpf = 13000 / rate
+       -- interpolation time constant, 64fpp
+       lpf = 15000 / rate

 end
 
 function dsp_configure (ins, outs)
        assert (ins:n_audio () == outs:n_audio ())
        local tbl = self:table ():get () -- get shared memory table
 end
 
 function dsp_configure (ins, outs)
        assert (ins:n_audio () == outs:n_audio ())
        local tbl = self:table ():get () -- get shared memory table

-       local rate = tbl['samplerate']

 
        chn = ins:n_audio ()
 
        chn = ins:n_audio ()

+       cur = {0, 0, 0, 0, 0, 0}
+
+       hp = {}
+       lp = {}
+
+       collectgarbage ()

 
        for c = 1, chn do
                hp[c] = {}
 
        for c = 1, chn do
                hp[c] = {}


@@ -82,11 +86,10 @@ function dsp_configure (ins, outs)
                -- initialize filters
                -- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP:Biquad
                for k = 1,4 do
                -- initialize filters
                -- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP:Biquad
                for k = 1,4 do

-                       hp[c][k] = ARDOUR.DSP.Biquad (rate)
-                       lp[c][k] = ARDOUR.DSP.Biquad (rate)
+                       hp[c][k] = ARDOUR.DSP.Biquad (tbl['samplerate'])
+                       lp[c][k] = ARDOUR.DSP.Biquad (tbl['samplerate'])

                end
        end
                end
        end

-       cur = {0, 0, 0, 0, 0, 0}

 end
 
 -- helper functions for parameter interpolation
 end
 
 -- helper functions for parameter interpolation


@@ -133,6 +136,8 @@ end
 -- the actual DSP callback
 function dsp_run (ins, outs, n_samples)
        assert (n_samples < 8192)
 -- the actual DSP callback
 function dsp_run (ins, outs, n_samples)
        assert (n_samples < 8192)

+       assert (#ins == chn)
+

        local changed = false
        local siz = n_samples
        local off = 0
        local changed = false
        local siz = n_samples
        local off = 0


@@ -164,11 +169,15 @@ function dsp_run (ins, outs, n_samples)
 
                        -- initialize output
                        if hox == 0 then
 
                        -- initialize output
                        if hox == 0 then

+                               -- high pass is disabled, just copy data.

                                ARDOUR.DSP.copy_vector (outs[c]:offset (off), mem:to_float (off), siz)
                        else
                                ARDOUR.DSP.copy_vector (outs[c]:offset (off), mem:to_float (off), siz)
                        else

+                               -- clear output, The filter mixes into the output buffer

                                ARDOUR.DSP.memset (outs[c]:offset (off), 0, siz)
                        end
 
                                ARDOUR.DSP.memset (outs[c]:offset (off), 0, siz)
                        end
 

+                       -- high pass
+                       -- allways run all filters so that we can interplate as needed.

                        for k = 1,4 do
                                if xfade > 0 and k > ho and k <= ho + 1 then
                                        ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, 1 - xfade)
                        for k = 1,4 do
                                if xfade > 0 and k > ho and k <= ho + 1 then
                                        ARDOUR.DSP.mix_buffers_with_gain (outs[c]:offset (off), mem:to_float (off), siz, 1 - xfade)


@@ -187,9 +196,12 @@ function dsp_run (ins, outs, n_samples)
                        xfade = lox - lo
                        assert (xfade >= 0 and xfade < 1)
 
                        xfade = lox - lo
                        assert (xfade >= 0 and xfade < 1)
 

+                       -- copy output of high-pass into "processing memory"

                        ARDOUR.DSP.copy_vector (mem:to_float (off), outs[c]:offset (off), siz)
 
                        if lox > 0 then
                        ARDOUR.DSP.copy_vector (mem:to_float (off), outs[c]:offset (off), siz)
 
                        if lox > 0 then

+                               -- clear output, Low-pass mixes interpolated data into output,
+                               -- in which case we just keep the output

                                ARDOUR.DSP.memset (outs[c]:offset (off), 0, siz)
                        end
 
                                ARDOUR.DSP.memset (outs[c]:offset (off), 0, siz)
                        end
 


@@ -228,12 +240,12 @@ function round (n)
 end
 
 function freq_at_x (x, w)
 end
 
 function freq_at_x (x, w)

-       -- x-axis pixel for given freq, power-scale
+       -- frequency in Hz at given x-axis pixel

        return 20 * 1000 ^ (x / w)
 end
 
 function x_at_freq (f, w)
        return 20 * 1000 ^ (x / w)
 end
 
 function x_at_freq (f, w)

-       -- frequency at given x-axis pixel
+       -- x-axis pixel for given frequency, power-scale

        return w * math.log (f / 20.0) / math.log (1000.0)
 end
 
        return w * math.log (f / 20.0) / math.log (1000.0)
 end
 


@@ -246,6 +258,7 @@ end
 
 function grid_db (ctx, w, h, db)
        -- draw horizontal grid line
 
 function grid_db (ctx, w, h, db)
        -- draw horizontal grid line

+       -- note that a cairo pixel at Y spans [Y - 0.5 to Y + 0.5]

        local y = -.5 + round (db_to_y (db, h))
        ctx:move_to (0, y)
        ctx:line_to (w, y)
        local y = -.5 + round (db_to_y (db, h))
        ctx:move_to (0, y)
        ctx:line_to (w, y)


@@ -261,8 +274,10 @@ function grid_freq (ctx, w, h, f)
 end
 
 function response (ho, lo, f)
 end
 
 function response (ho, lo, f)

-               local db = ho * filt['hp']:dB_at_freq (f)
-               return db + lo * filt['lp']:dB_at_freq (f)
+       -- calculate transfer function response for given
+       -- hi/po pass order at given frequency [Hz]
+       local db = ho * filt['hp']:dB_at_freq (f)
+       return db + lo * filt['lp']:dB_at_freq (f)

 end
 
 function render_inline (ctx, w, max_h)
 end
 
 function render_inline (ctx, w, max_h)


@@ -297,8 +312,6 @@ function render_inline (ctx, w, max_h)
        ctx:clip ()
 
        -- set line width: 1px
        ctx:clip ()
 
        -- set line width: 1px

-       -- Note: a cairo pixel at [1,1]  spans [0.5->1.5 , 0.5->1.5]
-       -- hence the offset -0.5 in various move_to(), line_to() calls

        ctx:set_line_width (1.0)
 
        -- draw grid
        ctx:set_line_width (1.0)
 
        -- draw grid


@@ -306,10 +319,10 @@ function render_inline (ctx, w, max_h)
        local dash2 = C.DoubleVector ()
        dash2:add ({1, 2})
        dash3:add ({1, 3})
        local dash2 = C.DoubleVector ()
        dash2:add ({1, 2})
        dash3:add ({1, 3})

-       ctx:set_dash (dash2, 2) -- dotted line
+       ctx:set_dash (dash2, 2) -- dotted line: 1 pixel 2 space

        ctx:set_source_rgba (.5, .5, .5, .8)
        grid_db (ctx, w, h, 0)
        ctx:set_source_rgba (.5, .5, .5, .8)
        grid_db (ctx, w, h, 0)

-       ctx:set_dash (dash3, 2) -- dotted line
+       ctx:set_dash (dash3, 2) -- dashed line: 1 pixel 3 space

        ctx:set_source_rgba (.5, .5, .5, .5)
        grid_db (ctx, w, h, -12)
        grid_db (ctx, w, h, -24)
        ctx:set_source_rgba (.5, .5, .5, .5)
        grid_db (ctx, w, h, -12)
        grid_db (ctx, w, h, -24)


@@ -319,16 +332,17 @@ function render_inline (ctx, w, max_h)
        grid_freq (ctx, w, h, 10000)
        ctx:unset_dash ()
 
        grid_freq (ctx, w, h, 10000)
        ctx:unset_dash ()
 

+       -- draw transfer function line

        local ho = math.floor(cur[1])
        local lo = math.floor(cur[4])
 
        local ho = math.floor(cur[1])
        local lo = math.floor(cur[4])
 

-       -- draw transfer function line

        ctx:set_source_rgba (.8, .8, .8, 1.0)
        ctx:move_to (-.5, db_to_y (response(ho, lo, freq_at_x (0, w)), h))
        for x = 1,w do
                local db = response(ho, lo, freq_at_x (x, w))
                ctx:line_to (-.5 + x, db_to_y (db, h))
        end
        ctx:set_source_rgba (.8, .8, .8, 1.0)
        ctx:move_to (-.5, db_to_y (response(ho, lo, freq_at_x (0, w)), h))
        for x = 1,w do
                local db = response(ho, lo, freq_at_x (x, w))
                ctx:line_to (-.5 + x, db_to_y (db, h))
        end

+       -- stoke a line, keep the path

        ctx:stroke_preserve ()
 
        -- fill area to zero under the curve
        ctx:stroke_preserve ()
 
        -- fill area to zero under the curve