Robin Gareus
f18a7e3fc3
This significantly reduces the DSP load of the noise generator (avg. process time is reduced by a factor of 8 or more).
112 lines
2.6 KiB
Lua
112 lines
2.6 KiB
Lua
ardour {
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["type"] = "dsp",
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name = "NoiseGen",
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category = "Instrument",
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license = "MIT",
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author = "Ardour Team",
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description = [[Noise Generator (v-1.02)]]
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}
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function dsp_params ()
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return
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{
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{ ["type"] = "input", name = "White/Pink", min = 0, max = 1, default = 0, toggled = true },
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{ ["type"] = "input", name = "Gain", min = -60, max = 0, default = -18, unit="dB" },
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}
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end
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function dsp_ioconfig ()
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return { [1] = { audio_in = -1, audio_out = -1}, }
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end
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local sr = 0
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function dsp_init (rate)
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sr = rate
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end
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local ao = 0
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local draw = 0
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function dsp_run (ins, outs, n_samples)
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local a = {} -- init array
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local ctrl = CtrlPorts:array ()
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local noise = ctrl[1] or 0
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local amplitude = ARDOUR.DSP.dB_to_coefficient (ctrl[2]) or ARDOUR.DSP.dB_to_coefficient (-18)
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local b0 = 0.0
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local b1 = 0.0
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local b2 = 0.0
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local b3 = 0.0
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local b4 = 0.0
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local b5 = 0.0
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local b6 = 0.0
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--Pink noise generation courtesy of Paul Kellet's refined method
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--http://www.musicdsp.org/files/pink.txt
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--If 'white' consists of uniform random numbers,
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--the pink noise will have an almost gaussian distribution.
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for s = 1, n_samples do
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if noise == 0 then
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a[s] = amplitude * 2 * (math.random() - 0.5)
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end
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if noise == 1 then
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white = (amplitude * 0.25) * 2 * (math.random() - 0.5)
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b0 = 0.99886 * b0 + white * 0.0555179;
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b1 = 0.99332 * b1 + white * 0.0750759;
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b2 = 0.96900 * b2 + white * 0.1538520;
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b3 = 0.86650 * b3 + white * 0.3104856;
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b4 = 0.55000 * b4 + white * 0.5329522;
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b5 = -0.7616 * b5 - white * 0.0168980;
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b6 = white * 0.115926;
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a[s] = b0 + b1 + b2 + b3 + b4 + b5 + b6 + white * 0.5362;
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end
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end
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if (draw > (sr/15)) then
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self:queue_draw()
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draw = 0
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end
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-- passes array a {} into buffer
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for c = 1,#outs do
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outs[c]:set_table(a, n_samples)
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end
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draw = draw + n_samples
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end
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function render_inline (ctx, w, max_h) --inline display
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local ctrl = CtrlPorts:array()
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h = 30
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p = 0
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inc = 0
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ycy = 0.5
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pink = false
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local amplitude = ARDOUR.DSP.dB_to_coefficient(ctrl[2])
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if ctrl[1] == 1 then pink = true end
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if pink then inc = 0.7/w end
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--draw rectangle
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ctx:rectangle(0, 0, w, h)
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ctx:set_source_rgba(0, 0, 0, 1.0)
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ctx:fill()
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ctx:set_line_width(1.5)
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ctx:set_source_rgba(0.8, 0.8, 0.8, 1.0)
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l_x = 0
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l_y = 0
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for x = 0,w do
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if pink then ycy = 0.3 else ycy = 0.5 end --slant slightly like an actual pink noise spectrum
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y = math.log(20^amplitude) * (math.random() - 0.5) - p
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yc = ycy * h + ((-0.5 * h) * y)
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ctx:move_to (x, yc + 3)
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ctx:line_to (l_x, l_y + 3)
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l_x = x
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l_y = yc
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ctx:stroke()
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p = p + inc
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end
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return {w, h + 6}
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end
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