diff options
| -rw-r--r-- | applause.lua | 82 |
1 files changed, 79 insertions, 3 deletions
diff --git a/applause.lua b/applause.lua index d72f4dc..634bb93 100644 --- a/applause.lua +++ b/applause.lua @@ -41,19 +41,28 @@ typedef enum { int clock_gettime(clockid_t clk_id, struct timespec *tp); ]] --- measure time required to execute fnc() +-- Measure time required to execute fnc() +-- See also Stream:benchmark() function benchmark(fnc) local t1 = ffi.new("struct timespec[1]") local t2 = ffi.new("struct timespec[1]") + -- See Stream:play(): Try to be more realtime-friendly + collectgarbage("collect") + local old_pause = collectgarbage("setpause", 100) + local old_stepmul = collectgarbage("setstepmul", 100) + C.clock_gettime("CLOCK_PROCESS_CPUTIME_ID", t1) fnc() C.clock_gettime("CLOCK_PROCESS_CPUTIME_ID", t2) + collectgarbage("setpause", old_pause) + collectgarbage("setstepmul", old_stepmul) + local t1_ms = t1[0].tv_sec*1000 + t1[0].tv_nsec/1000000 local t2_ms = t2[0].tv_sec*1000 + t2[0].tv_nsec/1000000 - print("Elapsed CPU time: "..(t2_ms - t1_ms).."ms") + print("Elapsed CPU time: "..tonumber(t2_ms - t1_ms).."ms") end -- @@ -485,6 +494,16 @@ function Stream:foreach(fnc) end end +function Stream:benchmark() + if self:len() == math.huge then + error("Cannot benchmark infinite stream") + end + + benchmark(function() + self:foreach(function() end) + end) +end + -- TODO: Use a buffer to improve perfomance (e.g. 1024 samples) function Stream:save(filename, format) if self:len() == math.huge then @@ -1410,7 +1429,6 @@ function ZipStream:len() return max end --- FIXME: Different kinds of Noise, e.g. pink or brown noise NoiseStream = DeriveClass(Stream) function NoiseStream:tick() @@ -1421,6 +1439,64 @@ function NoiseStream:tick() end end +-- NOTE: Adapted from the algorithm used here: +-- http://vellocet.com/dsp/noise/VRand.html +function BrownNoise() + return NoiseStream():scan(function(brown, white) + brown = (brown or 0) + white + return (brown < -8 or brown > 8) and brown - white or brown + end):mul(0.0625) +end + +PinkNoiseStream = DeriveClass(Stream) + +-- NOTE: Adapted from the algorithm used here: +-- http://vellocet.com/dsp/noise/VRand.html +function PinkNoiseStream:tick() + local random = math.random + local band, rshift = bit.band, bit.rshift + local max = math.max + + local store = table.new(16, 0) + for i = 1, 16 do store[i] = 0 end + + local pink = 0 + local count = 0 + + return function() + local k = 0 + + -- Find the first bit set. This is still way faster + -- than doing it using the libc's ffs() function. + -- Someday the bit library will hopefully support ffs + while band(rshift(count, k), 1) == 0 and k < 4 do + k = k + 1 + end + k = band(k, 0x0F) + 1 + + local last_r = store[k] + + while true do + local r = random()*2 - 1 + + store[k] = r + + local next_pink = pink + r - last_r + + if next_pink >= -4 and next_pink <= 4 then + pink = next_pink + break + end + end + + -- Make sure count wraps. This is for some reason much slower + -- than using a FFI integer. + count = band(count + 1, 0x0F) + + return (random()*2 - 1 + pink)*0.125 + end +end + -- -- MIDI Support -- |