//
// Modified By:   Craig Stuart Sapp <craig@ccrma.stanford.edu>
// Creation Date: Tue Mar 11 07:14:38 PST 2003
// Last Modified: Tue Mar 11 18:04:27 PST 2003
// Filename:      whitenoise.c
// Web Address:  http://peabody.sapp.org/class/dmp2/lab/whitenoise/whitenoise.c
// Syntax:        C; Max4/MSP2 External Object; CodeWarrior 6.0
// OS:            Mac OS 9; PPC
//
// Description:   A whitenoise generating object using rand() which 
//                can be seeded.
//

#include "ext.h"
#include "z_dsp.h"
#include <cstdlib>      /* included for rand() function */
#include <ctime>        /* included for time() function */

typedef struct {
   t_pxobject msp_data; // must always be the first field; used by MSP
} MyObject;

void*  object_data;     // pointer to data for object (created in setup());

// function declarations:
void   main             (void);
void*  create_object    (void);
void   InputSeed        (MyObject* mo, long value);
void   MessageDSP       (MyObject* mo, t_signal** signal, short* count);
t_int* Perform          (t_int *parameters);
float  randfloat        (void);


//////////////////////////////////////////////////////////////////////////
//
// Initialization functions:
//


void main(void) {
   setup((t_messlist**)&object_data, (method)create_object, 
         (method)dsp_free, (short)sizeof(MyObject), NULL, A_NOTHING);
   addint((method)InputSeed);    // input 1
   addmess((method)MessageDSP, "dsp", A_CANT, A_NOTHING);
   dsp_initclass();
}


 
//////////////////////////////
//
// create_object -- object initializing function.  
//

void* create_object(void) {
   MyObject *mo = (MyObject*)newobject(object_data);
   dsp_setup((t_pxobject*)mo, 0);           // create no signal inputs
   outlet_new((t_pxobject*)mo, "signal");   // signal output 1
   InputSeed(mo, time(NULL));               // randomize with current time
   return mo;
}



//////////////////////////////////////////////////////////////////////////
//
// Behavior functions:
//


//////////////////////////////
//
// InputSeed -- seed the random number generator.
//

void InputSeed(MyObject *mo, long value) {
   #pragma unused(mo)
   srand(value);
}



//////////////////////////////
//
// MessageDSP -- What to do when a "dsp" message arrives into the object.
//

void MessageDSP(MyObject* mo, t_signal** signal, short* count) {
   #pragma unused(mo)
   #pragma unused(count)
   dsp_add(Perform, 3, 3, signal[0]->s_vec, signal[0]->s_n);
}



//////////////////////////////
//
// Perform -- do the calculations for one sample group.
//

t_int* Perform(t_int *parameters) {
   long      pcount = (long)     (parameters[1]);
   t_float  *output = (t_float*) (parameters[2]);
   long      count  = (int)      (parameters[3]);
   long      i;

   for (i=0; i<count; i++) {
      output[i] = randfloat() * 2.0 - 1.0;
   }

   return parameters+pcount+1;   
}


////////////////////////////////////////////////////////////////////////////
//
// Helper functions:
//


//////////////////////////////
//
// randfloat -- return a number between 0.0 and 1.0.
//

float randfloat(void) {
   return (float)rand()/RAND_MAX;
}