enforce range of HP/LP

We must not assume that the host sends values within the the range
nor that the enum is always an integer.

diff --git a/scripts/HiAndLowPass.lua b/scripts/HiAndLowPass.lua
index 1c1b0686e5246a09efd92a55da69c5878bfdb824..5dd3dfa5588e741be5798308185ac9168f3a4170 100644 (file)
--- a/scripts/HiAndLowPass.lua
+++ b/scripts/HiAndLowPass.lua
@@ -53,6 +53,7 @@ local cur = {0, 0, 0, 0, 0, 0} -- current parameters
 local lpf = 0.03 -- parameter low-pass filter time-constant
 local chn = 0 -- channel/filter count
 local lpf_chunk = 0 -- chunk size for audio processing when interpolating parameters
+local max_freq = 20000
 
 local mem = nil -- memory x-fade buffer
 
@@ -60,11 +61,16 @@ function dsp_init (rate)
        -- allocate some mix-buffer
        mem = ARDOUR.DSP.DspShm (8192)
 
+       -- max allowed cut-off frequency
+       max_freq = .499 * rate
+
        -- create a table of objects to share with the GUI
        local tbl = {}
        tbl['samplerate'] = rate
+       tbl['max_freq'] = max_freq
        self:table ():set (tbl)
 
+
        -- Parameter smoothing: we want to filter out parameter changes that are
        -- faster than 15Hz, and interpolate between parameter values.
        -- For performance reasons, we want to ensure that two consecutive values
@@ -113,6 +119,21 @@ function dsp_configure (ins, outs)
        end
 end
 
+function santize_params (ctrl)
+       -- don't allow manual cross-fades. enforce enums
+       ctrl[1] = math.floor(ctrl[1] + .5)
+       ctrl[4] = math.floor(ctrl[4] + .5)
+
+       -- high pass, clamp range
+       ctrl[2] = math.min (max_freq, math.max (5, ctrl[2]))
+       ctrl[3] = math.min (6, math.max (0.1, ctrl[3]))
+
+       -- low pass, clamp range
+       ctrl[5] = math.min (max_freq, math.max (20, ctrl[5]))
+       ctrl[6] = math.min (6, math.max (0.1, ctrl[6]))
+       return ctrl
+end
+
 -- helper functions for parameter interpolation
 function param_changed (ctrl)
        for p = 1,6 do
@@ -158,6 +179,7 @@ end
 function dsp_run (ins, outs, n_samples)
        assert (n_samples < 8192)
        assert (#ins == chn)
+       local ctrl = santize_params (CtrlPorts:array ())
 
        local changed = false
        local siz = n_samples
@@ -166,13 +188,13 @@ function dsp_run (ins, outs, n_samples)
        -- if a parameter was changed, process at most lpf_chunk samples
        -- at a time and interpolate parameters until the current settings
        -- match the target values
-       if param_changed (CtrlPorts:array ()) then
+       if param_changed (ctrl) then
                changed = true
                siz = lpf_chunk
        end
 
        while n_samples > 0 do
-               if changed then apply_params (CtrlPorts:array ()) end
+               if changed then apply_params (ctrl) end
                if siz > n_samples then siz = n_samples end
 
                local ho = math.floor(cur[1])
@@ -304,11 +326,12 @@ function render_inline (ctx, w, max_h)
                filt = {}
                filt['hp'] = ARDOUR.DSP.Biquad (tbl['samplerate'])
                filt['lp'] = ARDOUR.DSP.Biquad (tbl['samplerate'])
+               max_freq   = tbl['max_freq']
        end
 
+       local ctrl = santize_params (CtrlPorts:array ())
        -- set filter coefficients if they have changed
-       if param_changed (CtrlPorts:array ()) then
-               local ctrl = CtrlPorts:array ()
+       if param_changed (ctrl) then
                for k = 1,6 do cur[k] = ctrl[k] end
                filt['hp']:compute (ARDOUR.DSP.BiquadType.HighPass, cur[2], cur[3], 0)
                filt['lp']:compute (ARDOUR.DSP.BiquadType.LowPass,  cur[5], cur[6], 0)