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Fix glitches in soft saturation algorithm - dsp.h #214

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Fix glitches in soft saturation algorithm - dsp.h #214

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20 changes: 6 additions & 14 deletions Source/Utility/dsp.h
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Original file line number Diff line number Diff line change
Expand Up @@ -269,14 +269,14 @@ inline void TestFloat(float &x, float y = 0.f)

/** Based on soft saturate from:
[musicdsp.org](musicdsp.org/en/latest/Effects/42-soft-saturation.html)
with 0 <= thresh <= 1
Bram de Jong (2002-01-17)
This still needs to be tested/fixed. Definitely does some weird stuff
described as:
x < a:
x <= a:
f(x) = x
x > a:
f(x) = a + (x-a)/(1+((x-a)/(1-a))^2)
x > 1:
x >= 1:
f(x) = (a + 1)/2
*/
inline float soft_saturate(float in, float thresh)
Expand All @@ -287,11 +287,11 @@ inline float soft_saturate(float in, float thresh)
out = 0.f;
flip = in < 0.0f;
val = flip ? -in : in;
if(val < thresh)
if(val <= thresh)
{
out = in;
}
else if(val > 1.0f)
else if(val >= 1.0f)
{
out = (thresh + 1.0f) / 2.0f;
if(flip)
Expand All @@ -306,16 +306,8 @@ inline float soft_saturate(float in, float thresh)
out *= -1.0f;
}
return out;
// return val < thresh
// ? val
// : val > 1.0f
// ? (thresh + 1.0f) / 2.0f
// : thresh
// + (val - thresh)
// / (1.0f
// + (((val - thresh) / (1.0f - thresh))
// * ((val - thresh) / (1.0f - thresh))));
}

constexpr bool is_power2(uint32_t x)
{
return ((x - 1) & x) == 0;
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