Post-filter to decolorate oscillator waveshapers when antialiasing is on.
This linear time-invariant filter can be added in series of oscillator waveshapers that use PolyBLEP antialiasing (i.e., bw_osc_saw, bw_osc_pulse, bw_osc_tri) to compensate for high-frequency attenuation.
Version: 1.2.0
License:
Requires:
Included in Brickworks, which is:
Module type: DSP
typedef struct bw_osc_filt_state bw_osc_filt_state;
Internal state and related.
static inline float bw_osc_filt_reset_state(
bw_osc_filt_state * BW_RESTRICT state,
float x_0);
Resets the given state
to its initial values using the given initial input value x_0
.
Returns the corresponding initial output value.
static inline void bw_osc_filt_reset_state_multi(
bw_osc_filt_state * BW_RESTRICT const * BW_RESTRICT state,
const float * x_0,
float * y_0,
size_t n_channels);
Resets each of the n_channels
state
s to its initial values using the corresponding initial input value in the x_0
array.
The corresponding initial output values are written into the y_0
array, if not BW_NULL
.
static inline float bw_osc_filt_process1(
bw_osc_filt_state * BW_RESTRICT state,
float x);
Processes one input sample x
using and updating state
. Returns the corresponding output sample.
static inline void bw_osc_filt_process(
bw_osc_filt_state * BW_RESTRICT state,
const float * x,
float * y,
size_t n_samples);
Processes the first n_samples
of the input buffer x
and fills the first n_samples
of the output buffer y
, while using and updating state
.
static inline void bw_osc_filt_process_multi(
bw_osc_filt_state * BW_RESTRICT const * BW_RESTRICT state,
const float * const * x,
float * const * y,
size_t n_channels,
size_t n_samples);
Processes the first n_samples
of the n_channels
input buffers x
and fills the first n_samples
of the n_channels
output buffers y
, while using and updating each of the n_channels
state
s.
static inline char bw_osc_filt_state_is_valid(
const bw_osc_filt_state * BW_RESTRICT state);
Tries to determine whether state
is valid and returns non-0
if it seems to be the case and 0
if it is certainly not. False positives are possible, false negatives are not.
state
must at least point to a readable memory block of size greater than or equal to that of bw_osc_filt_state
.
template<size_t N_CHANNELS>
class OscFilt {
public:
OscFilt();
void reset(
float x0 = 0.f,
float * BW_RESTRICT y0 = nullptr);
# ifndef BW_CXX_NO_ARRAY
void reset(
float x0,
std::array<float, N_CHANNELS> * BW_RESTRICT y0);
# endif
void reset(
const float * x0,
float * y0 = nullptr);
# ifndef BW_CXX_NO_ARRAY
void reset(
std::array<float, N_CHANNELS> x0,
std::array<float, N_CHANNELS> * BW_RESTRICT y0 = nullptr);
# endif
void process(
const float * const * x,
float * const * y,
size_t nSamples);
# ifndef BW_CXX_NO_ARRAY
void process(
std::array<const float *, N_CHANNELS> x,
std::array<float *, N_CHANNELS> y,
size_t nSamples);
# endif
...
}
BW_INCLUDE_WITH_QUOTES
, BW_NO_CXX
, and BW_CXX_NO_EXTERN_C
.bw_osc_filt_process_multi()
to ensure that buffers used for both input and output appear at the same channel indices.BW_NULL
and BW_CXX_NO_ARRAY
.bw_osc_filt_reset_state()
.bw_osc_filt_reset_state_multi()
and updated C++ API in this regard.bw_osc_filt_reset_state()
returns the initial output value.reset()
functions taking arrays as arguments.bw_osc_filt_process()
and bw_osc_filt_process_multi()
now use size_t
to count samples and channels.const
and BW_RESTRICT
specifiers to input arguments and implementation.process()
function taking C-style arrays as arguments.bw_osc_filt_process_multi()
.