fluid_dsp_float.c
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- /* FluidSynth - A Software Synthesizer
- *
- * Copyright (C) 2003 Peter Hanappe and others.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public License
- * as published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this library; if not, write to the Free
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- * 02111-1307, USA
- */
- #include "fluidsynth_priv.h"
- #include "fluid_phase.h"
- /* Purpose:
- *
- * Interpolates audio data (obtains values between the samples of the original
- * waveform data).
- *
- * Variables loaded from the voice structure (assigned in fluid_voice_write()):
- * - dsp_data: Pointer to the original waveform data
- * - dsp_phase: The position in the original waveform data.
- * This has an integer and a fractional part (between samples).
- * - dsp_phase_incr: For each output sample, the position in the original
- * waveform advances by dsp_phase_incr. This also has an integer
- * part and a fractional part.
- * If a sample is played at root pitch (no pitch change),
- * dsp_phase_incr is integer=1 and fractional=0.
- * - dsp_amp: The current amplitude envelope value.
- * - dsp_amp_incr: The changing rate of the amplitude envelope.
- *
- * A couple of variables are used internally, their results are discarded:
- * - dsp_i: Index through the output buffer
- * - dsp_buf: Output buffer of floating point values (FLUID_BUFSIZE in length)
- */
- #include "fluidsynth_priv.h"
- #include "fluid_synth.h"
- #include "fluid_voice.h"
- /* Interpolation (find a value between two samples of the original waveform) */
- /* Linear interpolation table (2 coefficients centered on 1st) */
- static fluid_real_t interp_coeff_linear[FLUID_INTERP_MAX][2];
- /* 4th order (cubic) interpolation table (4 coefficients centered on 2nd) */
- static fluid_real_t interp_coeff[FLUID_INTERP_MAX][4];
- /* 7th order interpolation (7 coefficients centered on 3rd) */
- static fluid_real_t sinc_table7[FLUID_INTERP_MAX][7];
- #define SINC_INTERP_ORDER 7 /* 7th order constant */
- /* Initializes interpolation tables */
- void fluid_dsp_float_config (void)
- {
- int i, i2;
- double x, v;
- double i_shifted;
- /* Initialize the coefficients for the interpolation. The math comes
- * from a mail, posted by Olli Niemitalo to the music-dsp mailing
- * list (I found it in the music-dsp archives
- * http://www.smartelectronix.com/musicdsp/). */
- for (i = 0; i < FLUID_INTERP_MAX; i++)
- {
- x = (double) i / (double) FLUID_INTERP_MAX;
- interp_coeff[i][0] = (fluid_real_t)(x * (-0.5 + x * (1 - 0.5 * x)));
- interp_coeff[i][1] = (fluid_real_t)(1.0 + x * x * (1.5 * x - 2.5));
- interp_coeff[i][2] = (fluid_real_t)(x * (0.5 + x * (2.0 - 1.5 * x)));
- interp_coeff[i][3] = (fluid_real_t)(0.5 * x * x * (x - 1.0));
- interp_coeff_linear[i][0] = (fluid_real_t)(1.0 - x);
- interp_coeff_linear[i][1] = (fluid_real_t)x;
- }
- /* i: Offset in terms of whole samples */
- for (i = 0; i < SINC_INTERP_ORDER; i++)
- { /* i2: Offset in terms of fractional samples ('subsamples') */
- for (i2 = 0; i2 < FLUID_INTERP_MAX; i2++)
- {
- /* center on middle of table */
- i_shifted = (double)i - ((double)SINC_INTERP_ORDER / 2.0)
- + (double)i2 / (double)FLUID_INTERP_MAX;
- /* sinc(0) cannot be calculated straightforward (limit needed for 0/0) */
- if (fabs (i_shifted) > 0.000001)
- {
- v = (fluid_real_t)sin (i_shifted * M_PI) / (M_PI * i_shifted);
- /* Hamming window */
- v *= (fluid_real_t)0.5 * (1.0 + cos (2.0 * M_PI * i_shifted / (fluid_real_t)SINC_INTERP_ORDER));
- }
- else v = 1.0;
- sinc_table7[FLUID_INTERP_MAX - i2 - 1][i] = v;
- }
- }
- #if 0
- for (i = 0; i < FLUID_INTERP_MAX; i++)
- {
- printf ("%d %0.3f %0.3f %0.3f %0.3f %0.3f %0.3f %0.3fn",
- i, sinc_table7[0][i], sinc_table7[1][i], sinc_table7[2][i],
- sinc_table7[3][i], sinc_table7[4][i], sinc_table7[5][i], sinc_table7[6][i]);
- }
- #endif
- fluid_check_fpe("interpolation table calculation");
- }
- /* No interpolation. Just take the sample, which is closest to
- * the playback pointer. Questionable quality, but very
- * efficient. */
- int
- fluid_dsp_float_interpolate_none (fluid_voice_t *voice)
- {
- fluid_phase_t dsp_phase = voice->phase;
- fluid_phase_t dsp_phase_incr;
- short int *dsp_data = voice->sample->data;
- fluid_real_t *dsp_buf = voice->dsp_buf;
- fluid_real_t dsp_amp = voice->amp;
- fluid_real_t dsp_amp_incr = voice->amp_incr;
- unsigned int dsp_i = 0;
- unsigned int dsp_phase_index;
- unsigned int end_index;
- int looping;
- /* Convert playback "speed" floating point value to phase index/fract */
- fluid_phase_set_float (dsp_phase_incr, voice->phase_incr);
- /* voice is currently looping? */
- looping = _SAMPLEMODE (voice) == FLUID_LOOP_DURING_RELEASE
- || (_SAMPLEMODE (voice) == FLUID_LOOP_UNTIL_RELEASE
- && voice->volenv_section < FLUID_VOICE_ENVRELEASE);
- end_index = looping ? voice->loopend - 1 : voice->end;
- while (1)
- {
- dsp_phase_index = fluid_phase_index_round (dsp_phase); /* round to nearest point */
- /* interpolate sequence of sample points */
- for ( ; dsp_i < FLUID_BUFSIZE && dsp_phase_index <= end_index; dsp_i++)
- {
- dsp_buf[dsp_i] = dsp_amp * dsp_data[dsp_phase_index];
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index_round (dsp_phase); /* round to nearest point */
- dsp_amp += dsp_amp_incr;
- }
- /* break out if not looping (buffer may not be full) */
- if (!looping) break;
- /* go back to loop start */
- if (dsp_phase_index > end_index)
- {
- fluid_phase_sub_int (dsp_phase, voice->loopend - voice->loopstart);
- voice->has_looped = 1;
- }
- /* break out if filled buffer */
- if (dsp_i >= FLUID_BUFSIZE) break;
- }
- voice->phase = dsp_phase;
- voice->amp = dsp_amp;
- return (dsp_i);
- }
- /* Straight line interpolation.
- * Returns number of samples processed (usually FLUID_BUFSIZE but could be
- * smaller if end of sample occurs).
- */
- int
- fluid_dsp_float_interpolate_linear (fluid_voice_t *voice)
- {
- fluid_phase_t dsp_phase = voice->phase;
- fluid_phase_t dsp_phase_incr;
- short int *dsp_data = voice->sample->data;
- fluid_real_t *dsp_buf = voice->dsp_buf;
- fluid_real_t dsp_amp = voice->amp;
- fluid_real_t dsp_amp_incr = voice->amp_incr;
- unsigned int dsp_i = 0;
- unsigned int dsp_phase_index;
- unsigned int end_index;
- short int point;
- fluid_real_t *coeffs;
- int looping;
- /* Convert playback "speed" floating point value to phase index/fract */
- fluid_phase_set_float (dsp_phase_incr, voice->phase_incr);
- /* voice is currently looping? */
- looping = _SAMPLEMODE (voice) == FLUID_LOOP_DURING_RELEASE
- || (_SAMPLEMODE (voice) == FLUID_LOOP_UNTIL_RELEASE
- && voice->volenv_section < FLUID_VOICE_ENVRELEASE);
- /* last index before 2nd interpolation point must be specially handled */
- end_index = (looping ? voice->loopend - 1 : voice->end) - 1;
- /* 2nd interpolation point to use at end of loop or sample */
- if (looping) point = dsp_data[voice->loopstart]; /* loop start */
- else point = dsp_data[voice->end]; /* duplicate end for samples no longer looping */
- while (1)
- {
- dsp_phase_index = fluid_phase_index (dsp_phase);
- /* interpolate the sequence of sample points */
- for ( ; dsp_i < FLUID_BUFSIZE && dsp_phase_index <= end_index; dsp_i++)
- {
- coeffs = interp_coeff_linear[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp * (coeffs[0] * dsp_data[dsp_phase_index]
- + coeffs[1] * dsp_data[dsp_phase_index+1]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- /* break out if buffer filled */
- if (dsp_i >= FLUID_BUFSIZE) break;
- end_index++; /* we're now interpolating the last point */
- /* interpolate within last point */
- for (; dsp_phase_index <= end_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = interp_coeff_linear[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp * (coeffs[0] * dsp_data[dsp_phase_index]
- + coeffs[1] * point);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr; /* increment amplitude */
- }
- if (!looping) break; /* break out if not looping (end of sample) */
- /* go back to loop start (if past */
- if (dsp_phase_index > end_index)
- {
- fluid_phase_sub_int (dsp_phase, voice->loopend - voice->loopstart);
- voice->has_looped = 1;
- }
- /* break out if filled buffer */
- if (dsp_i >= FLUID_BUFSIZE) break;
- end_index--; /* set end back to second to last sample point */
- }
- voice->phase = dsp_phase;
- voice->amp = dsp_amp;
- return (dsp_i);
- }
- /* 4th order (cubic) interpolation.
- * Returns number of samples processed (usually FLUID_BUFSIZE but could be
- * smaller if end of sample occurs).
- */
- int
- fluid_dsp_float_interpolate_4th_order (fluid_voice_t *voice)
- {
- fluid_phase_t dsp_phase = voice->phase;
- fluid_phase_t dsp_phase_incr;
- short int *dsp_data = voice->sample->data;
- fluid_real_t *dsp_buf = voice->dsp_buf;
- fluid_real_t dsp_amp = voice->amp;
- fluid_real_t dsp_amp_incr = voice->amp_incr;
- unsigned int dsp_i = 0;
- unsigned int dsp_phase_index;
- unsigned int start_index, end_index;
- short int start_point, end_point1, end_point2;
- fluid_real_t *coeffs;
- int looping;
- /* Convert playback "speed" floating point value to phase index/fract */
- fluid_phase_set_float (dsp_phase_incr, voice->phase_incr);
- /* voice is currently looping? */
- looping = _SAMPLEMODE (voice) == FLUID_LOOP_DURING_RELEASE
- || (_SAMPLEMODE (voice) == FLUID_LOOP_UNTIL_RELEASE
- && voice->volenv_section < FLUID_VOICE_ENVRELEASE);
- /* last index before 4th interpolation point must be specially handled */
- end_index = (looping ? voice->loopend - 1 : voice->end) - 2;
- if (voice->has_looped) /* set start_index and start point if looped or not */
- {
- start_index = voice->loopstart;
- start_point = dsp_data[voice->loopend - 1]; /* last point in loop (wrap around) */
- }
- else
- {
- start_index = voice->start;
- start_point = dsp_data[voice->start]; /* just duplicate the point */
- }
- /* get points off the end (loop start if looping, duplicate point if end) */
- if (looping)
- {
- end_point1 = dsp_data[voice->loopstart];
- end_point2 = dsp_data[voice->loopstart + 1];
- }
- else
- {
- end_point1 = dsp_data[voice->end];
- end_point2 = end_point1;
- }
- while (1)
- {
- dsp_phase_index = fluid_phase_index (dsp_phase);
- /* interpolate first sample point (start or loop start) if needed */
- for ( ; dsp_phase_index == start_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = interp_coeff[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp * (coeffs[0] * start_point
- + coeffs[1] * dsp_data[dsp_phase_index]
- + coeffs[2] * dsp_data[dsp_phase_index+1]
- + coeffs[3] * dsp_data[dsp_phase_index+2]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- /* interpolate the sequence of sample points */
- for ( ; dsp_i < FLUID_BUFSIZE && dsp_phase_index <= end_index; dsp_i++)
- {
- coeffs = interp_coeff[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp * (coeffs[0] * dsp_data[dsp_phase_index-1]
- + coeffs[1] * dsp_data[dsp_phase_index]
- + coeffs[2] * dsp_data[dsp_phase_index+1]
- + coeffs[3] * dsp_data[dsp_phase_index+2]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- /* break out if buffer filled */
- if (dsp_i >= FLUID_BUFSIZE) break;
- end_index++; /* we're now interpolating the 2nd to last point */
- /* interpolate within 2nd to last point */
- for (; dsp_phase_index <= end_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = interp_coeff[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp * (coeffs[0] * dsp_data[dsp_phase_index-1]
- + coeffs[1] * dsp_data[dsp_phase_index]
- + coeffs[2] * dsp_data[dsp_phase_index+1]
- + coeffs[3] * end_point1);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- end_index++; /* we're now interpolating the last point */
- /* interpolate within the last point */
- for (; dsp_phase_index <= end_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = interp_coeff[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp * (coeffs[0] * dsp_data[dsp_phase_index-1]
- + coeffs[1] * dsp_data[dsp_phase_index]
- + coeffs[2] * end_point1
- + coeffs[3] * end_point2);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- if (!looping) break; /* break out if not looping (end of sample) */
- /* go back to loop start */
- if (dsp_phase_index > end_index)
- {
- fluid_phase_sub_int (dsp_phase, voice->loopend - voice->loopstart);
- if (!voice->has_looped)
- {
- voice->has_looped = 1;
- start_index = voice->loopstart;
- start_point = dsp_data[voice->loopend - 1];
- }
- }
- /* break out if filled buffer */
- if (dsp_i >= FLUID_BUFSIZE) break;
- end_index -= 2; /* set end back to third to last sample point */
- }
- voice->phase = dsp_phase;
- voice->amp = dsp_amp;
- return (dsp_i);
- }
- /* 7th order interpolation.
- * Returns number of samples processed (usually FLUID_BUFSIZE but could be
- * smaller if end of sample occurs).
- */
- int
- fluid_dsp_float_interpolate_7th_order (fluid_voice_t *voice)
- {
- fluid_phase_t dsp_phase = voice->phase;
- fluid_phase_t dsp_phase_incr;
- short int *dsp_data = voice->sample->data;
- fluid_real_t *dsp_buf = voice->dsp_buf;
- fluid_real_t dsp_amp = voice->amp;
- fluid_real_t dsp_amp_incr = voice->amp_incr;
- unsigned int dsp_i = 0;
- unsigned int dsp_phase_index;
- unsigned int start_index, end_index;
- short int start_points[3];
- short int end_points[3];
- fluid_real_t *coeffs;
- int looping;
- /* Convert playback "speed" floating point value to phase index/fract */
- fluid_phase_set_float (dsp_phase_incr, voice->phase_incr);
- /* add 1/2 sample to dsp_phase since 7th order interpolation is centered on
- * the 4th sample point */
- fluid_phase_incr (dsp_phase, (fluid_phase_t)0x80000000);
- /* voice is currently looping? */
- looping = _SAMPLEMODE (voice) == FLUID_LOOP_DURING_RELEASE
- || (_SAMPLEMODE (voice) == FLUID_LOOP_UNTIL_RELEASE
- && voice->volenv_section < FLUID_VOICE_ENVRELEASE);
- /* last index before 7th interpolation point must be specially handled */
- end_index = (looping ? voice->loopend - 1 : voice->end) - 3;
- if (voice->has_looped) /* set start_index and start point if looped or not */
- {
- start_index = voice->loopstart;
- start_points[0] = dsp_data[voice->loopend - 1];
- start_points[1] = dsp_data[voice->loopend - 2];
- start_points[2] = dsp_data[voice->loopend - 3];
- }
- else
- {
- start_index = voice->start;
- start_points[0] = dsp_data[voice->start]; /* just duplicate the start point */
- start_points[1] = start_points[0];
- start_points[2] = start_points[0];
- }
- /* get the 3 points off the end (loop start if looping, duplicate point if end) */
- if (looping)
- {
- end_points[0] = dsp_data[voice->loopstart];
- end_points[1] = dsp_data[voice->loopstart + 1];
- end_points[2] = dsp_data[voice->loopstart + 2];
- }
- else
- {
- end_points[0] = dsp_data[voice->end];
- end_points[1] = end_points[0];
- end_points[2] = end_points[0];
- }
- while (1)
- {
- dsp_phase_index = fluid_phase_index (dsp_phase);
- /* interpolate first sample point (start or loop start) if needed */
- for ( ; dsp_phase_index == start_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = sinc_table7[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp
- * (coeffs[0] * (fluid_real_t)start_points[2]
- + coeffs[1] * (fluid_real_t)start_points[1]
- + coeffs[2] * (fluid_real_t)start_points[0]
- + coeffs[3] * (fluid_real_t)dsp_data[dsp_phase_index]
- + coeffs[4] * (fluid_real_t)dsp_data[dsp_phase_index+1]
- + coeffs[5] * (fluid_real_t)dsp_data[dsp_phase_index+2]
- + coeffs[6] * (fluid_real_t)dsp_data[dsp_phase_index+3]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- start_index++;
- /* interpolate 2nd to first sample point (start or loop start) if needed */
- for ( ; dsp_phase_index == start_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = sinc_table7[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp
- * (coeffs[0] * (fluid_real_t)start_points[1]
- + coeffs[1] * (fluid_real_t)start_points[0]
- + coeffs[2] * (fluid_real_t)dsp_data[dsp_phase_index-1]
- + coeffs[3] * (fluid_real_t)dsp_data[dsp_phase_index]
- + coeffs[4] * (fluid_real_t)dsp_data[dsp_phase_index+1]
- + coeffs[5] * (fluid_real_t)dsp_data[dsp_phase_index+2]
- + coeffs[6] * (fluid_real_t)dsp_data[dsp_phase_index+3]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- start_index++;
- /* interpolate 3rd to first sample point (start or loop start) if needed */
- for ( ; dsp_phase_index == start_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = sinc_table7[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp
- * (coeffs[0] * (fluid_real_t)start_points[0]
- + coeffs[1] * (fluid_real_t)dsp_data[dsp_phase_index-2]
- + coeffs[2] * (fluid_real_t)dsp_data[dsp_phase_index-1]
- + coeffs[3] * (fluid_real_t)dsp_data[dsp_phase_index]
- + coeffs[4] * (fluid_real_t)dsp_data[dsp_phase_index+1]
- + coeffs[5] * (fluid_real_t)dsp_data[dsp_phase_index+2]
- + coeffs[6] * (fluid_real_t)dsp_data[dsp_phase_index+3]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- start_index -= 2; /* set back to original start index */
- /* interpolate the sequence of sample points */
- for ( ; dsp_i < FLUID_BUFSIZE && dsp_phase_index <= end_index; dsp_i++)
- {
- coeffs = sinc_table7[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp
- * (coeffs[0] * (fluid_real_t)dsp_data[dsp_phase_index-3]
- + coeffs[1] * (fluid_real_t)dsp_data[dsp_phase_index-2]
- + coeffs[2] * (fluid_real_t)dsp_data[dsp_phase_index-1]
- + coeffs[3] * (fluid_real_t)dsp_data[dsp_phase_index]
- + coeffs[4] * (fluid_real_t)dsp_data[dsp_phase_index+1]
- + coeffs[5] * (fluid_real_t)dsp_data[dsp_phase_index+2]
- + coeffs[6] * (fluid_real_t)dsp_data[dsp_phase_index+3]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- /* break out if buffer filled */
- if (dsp_i >= FLUID_BUFSIZE) break;
- end_index++; /* we're now interpolating the 3rd to last point */
- /* interpolate within 3rd to last point */
- for (; dsp_phase_index <= end_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = sinc_table7[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp
- * (coeffs[0] * (fluid_real_t)dsp_data[dsp_phase_index-3]
- + coeffs[1] * (fluid_real_t)dsp_data[dsp_phase_index-2]
- + coeffs[2] * (fluid_real_t)dsp_data[dsp_phase_index-1]
- + coeffs[3] * (fluid_real_t)dsp_data[dsp_phase_index]
- + coeffs[4] * (fluid_real_t)dsp_data[dsp_phase_index+1]
- + coeffs[5] * (fluid_real_t)dsp_data[dsp_phase_index+2]
- + coeffs[6] * (fluid_real_t)end_points[0]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- end_index++; /* we're now interpolating the 2nd to last point */
- /* interpolate within 2nd to last point */
- for (; dsp_phase_index <= end_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = sinc_table7[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp
- * (coeffs[0] * (fluid_real_t)dsp_data[dsp_phase_index-3]
- + coeffs[1] * (fluid_real_t)dsp_data[dsp_phase_index-2]
- + coeffs[2] * (fluid_real_t)dsp_data[dsp_phase_index-1]
- + coeffs[3] * (fluid_real_t)dsp_data[dsp_phase_index]
- + coeffs[4] * (fluid_real_t)dsp_data[dsp_phase_index+1]
- + coeffs[5] * (fluid_real_t)end_points[0]
- + coeffs[6] * (fluid_real_t)end_points[1]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- end_index++; /* we're now interpolating the last point */
- /* interpolate within last point */
- for (; dsp_phase_index <= end_index && dsp_i < FLUID_BUFSIZE; dsp_i++)
- {
- coeffs = sinc_table7[fluid_phase_fract_to_tablerow (dsp_phase)];
- dsp_buf[dsp_i] = dsp_amp
- * (coeffs[0] * (fluid_real_t)dsp_data[dsp_phase_index-3]
- + coeffs[1] * (fluid_real_t)dsp_data[dsp_phase_index-2]
- + coeffs[2] * (fluid_real_t)dsp_data[dsp_phase_index-1]
- + coeffs[3] * (fluid_real_t)dsp_data[dsp_phase_index]
- + coeffs[4] * (fluid_real_t)end_points[0]
- + coeffs[5] * (fluid_real_t)end_points[1]
- + coeffs[6] * (fluid_real_t)end_points[2]);
- /* increment phase and amplitude */
- fluid_phase_incr (dsp_phase, dsp_phase_incr);
- dsp_phase_index = fluid_phase_index (dsp_phase);
- dsp_amp += dsp_amp_incr;
- }
- if (!looping) break; /* break out if not looping (end of sample) */
- /* go back to loop start */
- if (dsp_phase_index > end_index)
- {
- fluid_phase_sub_int (dsp_phase, voice->loopend - voice->loopstart);
- if (!voice->has_looped)
- {
- voice->has_looped = 1;
- start_index = voice->loopstart;
- start_points[0] = dsp_data[voice->loopend - 1];
- start_points[1] = dsp_data[voice->loopend - 2];
- start_points[2] = dsp_data[voice->loopend - 3];
- }
- }
- /* break out if filled buffer */
- if (dsp_i >= FLUID_BUFSIZE) break;
- end_index -= 3; /* set end back to 4th to last sample point */
- }
- /* sub 1/2 sample from dsp_phase since 7th order interpolation is centered on
- * the 4th sample point (correct back to real value) */
- fluid_phase_decr (dsp_phase, (fluid_phase_t)0x80000000);
- voice->phase = dsp_phase;
- voice->amp = dsp_amp;
- return (dsp_i);
- }