Clemens Valens / SoundEngine

This is a part of the Kinetiszer project.

Dependencies:   inc

Dependents:   kinetisizer

flange.c@1:8ae4ab73ca6a, 2014-10-28 (annotated)

Committer:
Clemo
Date:
Tue Oct 28 20:09:12 2014 +0000
Revision:
1:8ae4ab73ca6a
Parent:
0:cb80470434eb 
First publication (untested)

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Clemo 0:cb80470434eb 1 /*
Clemo 0:cb80470434eb 2 Copyright 2013 Paul Soulsby www.soulsbysynths.com
Clemo 0:cb80470434eb 3 This file is part of Atmegatron.
Clemo 0:cb80470434eb 4
Clemo 0:cb80470434eb 5 Atmegatron is free software: you can redistribute it and/or modify
Clemo 0:cb80470434eb 6 it under the terms of the GNU General Public License as published by
Clemo 0:cb80470434eb 7 the Free Software Foundation, either version 3 of the License, or
Clemo 0:cb80470434eb 8 (at your option) any later version.
Clemo 0:cb80470434eb 9
Clemo 0:cb80470434eb 10 Atmegatron is distributed in the hope that it will be useful,
Clemo 0:cb80470434eb 11 but WITHOUT ANY WARRANTY; without even the implied warranty of
Clemo 0:cb80470434eb 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
Clemo 0:cb80470434eb 13 GNU General Public License for more details.
Clemo 0:cb80470434eb 14
Clemo 0:cb80470434eb 15 You should have received a copy of the GNU General Public License
Clemo 0:cb80470434eb 16 along with Atmegatron. If not, see <http://www.gnu.org/licenses/>.
Clemo 0:cb80470434eb 17 */
Clemo 0:cb80470434eb 18
Clemo 0:cb80470434eb 19 //*******PHASER - referred to as Flanger in code***************
Clemo 0:cb80470434eb 20 //Adds delayed copy of waveform to output + feedback
Clemo 0:cb80470434eb 21
Clemo 0:cb80470434eb 22 #include "atmegatron.h"
Clemo 0:cb80470434eb 23
Clemo 0:cb80470434eb 24
Clemo 0:cb80470434eb 25 byte flange_lfoamt = 0; //set maximum wave offset (0-31)
Clemo 0:cb80470434eb 26 //signed char flange_store[WAVE_LEN*2]; //buffer to store 2x waveform + feedback. need 2x waveform when delay = max (31)
Clemo 0:cb80470434eb 27 sample_t flange_store[WAVE_LEN*2]; //buffer to store 2x waveform + feedback. need 2x waveform when delay = max (31)
Clemo 0:cb80470434eb 28 sample_t flange_store_ch2[WAVE_LEN*2]; //buffer to store 2x waveform + feedback. need 2x waveform when delay = max (31)
Clemo 0:cb80470434eb 29
Clemo 0:cb80470434eb 30 //lets and gets
Clemo 0:cb80470434eb 31 void Flange_Let_LFOAmt(byte newamt)
Clemo 0:cb80470434eb 32 {
Clemo 0:cb80470434eb 33 if (newamt!=flange_lfoamt) //if new value different to current
Clemo 0:cb80470434eb 34 {
Clemo 0:cb80470434eb 35 if (flange_lfoamt==0) //if new value is off:
Clemo 0:cb80470434eb 36 {
Clemo 0:cb80470434eb 37 Flange_ClearBuffer(); //clear flange buffer.
Clemo 0:cb80470434eb 38 }
Clemo 0:cb80470434eb 39 flange_lfoamt = newamt;
Clemo 0:cb80470434eb 40 }
Clemo 0:cb80470434eb 41 }
Clemo 0:cb80470434eb 42
Clemo 0:cb80470434eb 43
Clemo 0:cb80470434eb 44 byte Flange_Get_LFOAmt(void)
Clemo 0:cb80470434eb 45 {
Clemo 0:cb80470434eb 46 return flange_lfoamt;
Clemo 0:cb80470434eb 47 }
Clemo 0:cb80470434eb 48
Clemo 0:cb80470434eb 49
Clemo 0:cb80470434eb 50 //Flanger meat
Clemo 0:cb80470434eb 51 void Flange_Process(void)
Clemo 0:cb80470434eb 52 {
Clemo 0:cb80470434eb 53 byte i;
Clemo 0:cb80470434eb 54 sample_t s, o;
Clemo 0:cb80470434eb 55 long curindex, maxindex;
Clemo 0:cb80470434eb 56 //if flanger (phaser) on:
Clemo 0:cb80470434eb 57 if (flange_lfoamt > 0)
Clemo 0:cb80470434eb 58 {
Clemo 0:cb80470434eb 59 maxindex = (WAVE_LEN - flange_lfoamt); //intermediate value (don't -1 from maxindex, so min flangestore offset is 1 (not 0) i.e. always offset by some amount)
Clemo 0:cb80470434eb 60 curindex = ((127 - LFO_Get_Level()) * (long)flange_lfoamt * 8225 >> 21) + maxindex; //calculate delay length of delayed waveform (8225 >> 21 is way of doing / 255, without using slow divide)
Clemo 0:cb80470434eb 61 //****METHOD WITH FEEDBACK
Clemo 0:cb80470434eb 62 //cycle through wave form
Clemo 0:cb80470434eb 63 for (i=0; i<WAVE_LEN; i++)
Clemo 0:cb80470434eb 64 {
Clemo 0:cb80470434eb 65 s = Wave_Get_Process(i); //get sample
Clemo 0:cb80470434eb 66 o = (s >> 1) + (flange_store[i+curindex] >> 1); //divide amp of sample / 2. Then add offset sample from flange_store / 2. (both samples divided / 2 to prevent output clipping when zero offset)
Clemo 0:cb80470434eb 67 Wave_Let_Process(i, o); //write back to wave table
Clemo 0:cb80470434eb 68 }
Clemo 0:cb80470434eb 69 //now waveform processed, cycle through waveform again writing to flange_store
Clemo 0:cb80470434eb 70 for (i=0; i<WAVE_LEN; i++)
Clemo 0:cb80470434eb 71 {
Clemo 0:cb80470434eb 72 flange_store[i] = Wave_Get_Process(i);
Clemo 0:cb80470434eb 73 flange_store[i+WAVE_LEN] = flange_store[i];
Clemo 0:cb80470434eb 74 }
Clemo 0:cb80470434eb 75 //******METHOD WITHOUT FEEDBACK
Clemo 0:cb80470434eb 76 // for(i=0;i<WAVE_LEN;i++){
Clemo 0:cb80470434eb 77 // flange_store[i] = Wave_Get_Process(i);
Clemo 0:cb80470434eb 78 // flange_store[i+WAVE_LEN] = flange_store[i];
Clemo 0:cb80470434eb 79 // }
Clemo 0:cb80470434eb 80 // for(i=0;i<WAVE_LEN;i++){
Clemo 0:cb80470434eb 81 // o = (flange_store[i] >> 1) + (flange_store[i+curindex] >> 1);
Clemo 0:cb80470434eb 82 // Wave_Let_Process(i, o);
Clemo 0:cb80470434eb 83 // }
Clemo 0:cb80470434eb 84 }
Clemo 0:cb80470434eb 85 }
Clemo 0:cb80470434eb 86
Clemo 0:cb80470434eb 87
Clemo 0:cb80470434eb 88 void Flange_ClearBuffer(void)
Clemo 0:cb80470434eb 89 {
Clemo 0:cb80470434eb 90 // Clear buffer. Used to stop feedback making sound when key released
Clemo 0:cb80470434eb 91 // (this was a problem when flange was combined with distortion).
Clemo 0:cb80470434eb 92 memset(flange_store,0,sizeof(flange_store)); //quicker than loop
Clemo 0:cb80470434eb 93 // CPV addition.
Clemo 0:cb80470434eb 94 memset(flange_store_ch2,0,sizeof(flange_store_ch2)); //quicker than loop
Clemo 0:cb80470434eb 95 }
Clemo 0:cb80470434eb 96
Clemo 0:cb80470434eb 97
Clemo 0:cb80470434eb 98 // CPV addition.
Clemo 0:cb80470434eb 99 void Flange_Process_Channel2(void)
Clemo 0:cb80470434eb 100 {
Clemo 0:cb80470434eb 101 long curindex;
Clemo 0:cb80470434eb 102 //long maxindex;
Clemo 0:cb80470434eb 103 //if flanger (phaser) on:
Clemo 0:cb80470434eb 104 //if (flange_lfoamt>0)
Clemo 0:cb80470434eb 105 {
Clemo 0:cb80470434eb 106 //intermediate value (don't -1 from maxindex, so min flangestore offset is 1 (not 0) i.e. always offset by some amount)
Clemo 0:cb80470434eb 107 // maxindex = (WAVE_LEN - flange_lfoamt);
Clemo 0:cb80470434eb 108 //calculate delay length of delayed waveform (8225 >> 21 is way of doing / 255, without using slow divide)
Clemo 0:cb80470434eb 109 // curindex = ((127 - LFO_Get_Level()) * (long)flange_lfoamt * 8225 >> 21) + maxindex;
Clemo 0:cb80470434eb 110 curindex = 15; //((uint8_t)(127-LFO_Get_Level())) >> 4;
Clemo 0:cb80470434eb 111 memcpy(wave_process_ch2,flange_store_ch2+curindex,WAVE_LEN*sizeof(sample_t));
Clemo 0:cb80470434eb 112 memcpy(flange_store_ch2,wave_process,WAVE_LEN*sizeof(sample_t));
Clemo 0:cb80470434eb 113 memcpy(flange_store_ch2+WAVE_LEN,wave_process,WAVE_LEN*sizeof(sample_t));
Clemo 0:cb80470434eb 114 }
Clemo 0:cb80470434eb 115 }