pan.c

#include "fix.h"
#include "pan.h"
#include "table.h"

#define PAN_SINE_BUF_SIZE 1024
#define PAN_SINE_BUF_SIZE_MASK 1023
// shift down from unipolar fract32 to get 16.16 index
#define PAN_SINE_BUF_RSHIFT 5
#define PAN_SINE_BUF_SIZE_FIX (1024 << 16)
#define PAN_SINE_BUF_MAX16 (1024 * FIX16_ONE - 1)

/*
static fract32 sineTab[PAN_SINE_BUF_SIZE] = {
#include "halfsine_1024.inc"
};
*/


//------------------------------
//--- linear

// return balanced sum of two inputs 
// given pan coefficient in [0,1]

// just calculate balanced coefficients 
// given pan coefficient in [0,1]

//----------------------
//--- equal-power balanced pan

fract32 pan_bal_mix(fract32 inX, fract32 inY, fract32 pan) {
  /*
  //  fix16 yIdx = fix16_mul_fract(FRACT_FIX16(pan), PAN_SINE_BUF_MAX16);
  // shift to get 16.16 idx
  fix16 yIdx = pan >> PAN_SINE_BUF_RSHIFT;
  fix16 xIdx = fix16_sub(PAN_SINE_BUF_MAX16, yIdx);
  fract32 xmul = table_lookup_idx_mask(sineTab, PAN_SINE_BUF_MASK, xIdx);
  fract32 ymul = table_lookup_idx(sineTab, PAN_SINE_BUF_MASK, yIdx);
  return add_fr1x32( mult_fr1x32x32(inX, xmul), mult_fr1x32x32(inY, ymul) ); 
  */
  return 0;
}

void pan_bal_coeff(fract32* a, fract32* b, fract32 pan) {
  /*
  fix16 yIdx = pan >> PAN_SINE_BUF_RSHIFT;
  fix16 xIdx = fix16_sub(PAN_SINE_BUF_MAX16, yIdx);
  *a = table_lookup_idx_mask(sineTab, PAN_SINE_BUF_MASK, xIdx);
  *b = table_lookup_idx(sineTab, PAN_SINE_BUF_MASK, yIdx);
  */
  /* fix16 yIdx = fix16_mul_fract(FRACT_FIX16(pan), PAN_SINE_BUF_MAX16); */
  /* fix16 xIdx = fix16_sub(PAN_SINE_BUF_MAX16, yIdx); */
  /* *a = table_lookup_idx(sineTab, PAN_SINE_BUF_SIZE, xIdx); */
  /* *b = table_lookup_idx(sineTab, PAN_SINE_BUF_SIZE, yIdx); */
}