SndAudioFader.h

//
//  $Id: SndAudioFader.h 3449 2009-04-04 16:52:47Z leighsmith $
//
//  Original Author: Stephen Brandon <stephen@brandonitconsulting.co.uk>
//
//  Copyright (c) 2001, The MusicKit Project.  All rights reserved.
//
//  Permission is granted to use and modify this code for commercial and 
//  non-commercial purposes so long as the author attribution and copyright 
//  messages remain intact and accompany all relevant code.
//

#ifndef __SNDAUDIOFADER_H__
#define __SNDAUDIOFADER_H__

#import <Foundation/Foundation.h>

#import "SndEnvelope.h"
#import "SndAudioProcessor.h"

@class SndStreamManager;
@class SndStreamMixer;
@class SndAudioProcessor;
@class SndAudioBuffer;

#define SND_FADER_ATTACH_RAMP_RIGHT 1
#define SND_FADER_ATTACH_RAMP_LEFT  2

/* this value limits the number of envelope points that can be held
 * in the unified (amp + balance) envelope. Unless providing for almost
 * sample-level enveloping, the specified figure will be more than enough.
 */
#define MAX_ENV_POINTS_PER_BUFFER 256

typedef struct _UEE {
    double          xVal;
    int             ampFlags;
    int             balanceFlags;
    float           ampY;
    float           balanceY;
    float           balanceL;
    float           balanceR;
} SndUnifiedEnvelopeEntry;

enum SndFaderParam {
    faderAmp       = 0, 
    faderBalance   = 1,
    faderNumParams = 2
};

/* Squeeze the last drop of performance out of this class by caching IMPs.
 * See also +initialize and -init for the initialization of selectors, which
 * are static "class" variables.
 * To use, cache the following:
 *  bpBeforeOrEqual = [ENVCLASS instanceMethodForSelector:bpBeforeOrAfterSel];
 * then use like this:
 *  y = bpbeforeOrEqual(myEnv,bpBeforeOrAfterSel,myX);
 */
typedef int (*BpBeforeOrEqualIMP)(id, SEL, double);
typedef int (*BpAfterIMP)(id, SEL, double);
typedef int (*FlagsForBpIMP)(id, SEL, int);
typedef float (*YForBpIMP)(id, SEL, int);
typedef float (*YForXIMP)(id, SEL, double);
typedef float (*XForBpIMP)(id, SEL, int);

@interface SndAudioFader : SndAudioProcessor
{
  id     envClass; 
  id     <SndEnveloping, NSObject> ampEnv;
  float  staticAmp;
  id     <SndEnveloping,NSObject> balanceEnv;
  float  staticBalance;

  SndUnifiedEnvelopeEntry *uee;
  
  NSLock *envelopesLock;
  NSLock *balanceEnvLock;
  NSLock *ampEnvLock;

@public
  BpBeforeOrEqualIMP  bpBeforeOrEqual;
  BpAfterIMP          bpAfter;
  FlagsForBpIMP       flagsForBp;
  YForBpIMP           yForBp;
  YForXIMP            yForX;
  XForBpIMP           xForBp;
}

+ (void) setEnvelopeClass: (id) aClass;

+ (id) envelopeClass;

- (void) setEnvelopeClass: (id) aClass;

- (id) envelopeClass;

/*
 * "instantaneous" getting and setting; applies from start of buffer
 */

- setBalance: (float) newBalance clearingEnvelope: (BOOL) clear;

- (float) getBalance;

- setAmp: (float) amp clearingEnvelope:(BOOL)clear;

- (float) getAmp;

/*
 * "future" getting and setting; transparently reads and writes
 * from/to the envelope object(s)
 */
- setBalance:(float)balance atTime:(double)atTime;

- (float)getBalanceAtTime:(double)atTime;

- setAmp: (float) amp atTime: (double) atTime;

- (float) getAmpAtTime: (double) atTime;

- (BOOL) rampAmpFrom:(float)startRampLevel
                  to:(float)endRampLevel
           startTime:(double)startRampTime
             endTime:(double)endRampTime;

- (BOOL) rampBalanceFrom:(float)startRampLevel
                      to:(float)endRampLevel
               startTime:(double)startRampTime
                 endTime:(double)endRampTime;

- (float) paramValue: (const int) index;

- (NSString *) paramName: (const int) index;

- (void) setParam: (const int) index toValue: (const float) v;

- (BOOL) processReplacingInputBuffer: (SndAudioBuffer *) inB
                        outputBuffer: (SndAudioBuffer *) outB;

@end

#endif

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