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/*
flext examples - henon
Copyright (c) 2003 Thomas Grill (xovo@gmx.net)
For information on usage and redistribution, and for a DISCLAIMER OF ALL
WARRANTIES, see the file, "license.txt," in this distribution.
-------------------------------------------------------------------------
This is a simple external featuring the chaotic Henon attractor.
See also http://improv.sapp.org/doc/examples/synthImprov/henontune/henontune.html
Thanks to David Casal for the pointer!
*/
// IMPORTANT: enable attribute processing (specify before inclusion of flext headers!)
// For clarity, this is done here, but you'd better specify it as a compiler definition
// FLEXT_ATTRIBUTES must be 0 or 1,
#define FLEXT_ATTRIBUTES 1
// include flext header
#include <flext.h>
// check for appropriate flext version
#if !defined(FLEXT_VERSION) || (FLEXT_VERSION < 401)
#error You need at least flext version 0.4.1
#endif
class henon:
public flext_base
{
FLEXT_HEADER_S(henon,flext_base,Setup)
public:
// constructor
henon(int argc,const t_atom *argv);
protected:
void m_bang();
void m_reset() { x = y = 0; }
void m_alpha(float a) { alpha = a; }
void m_beta(float b) { beta = b; }
float alpha,beta;
float x,y;
private:
static void Setup(t_classid c);
// method callbacks
FLEXT_CALLBACK(m_reset)
FLEXT_CALLBACK(m_bang)
FLEXT_CALLBACK_F(m_alpha)
FLEXT_CALLBACK_F(m_beta)
// define attribute callbacks for variables alpha and beta (with GET and SET properties)
FLEXT_ATTRVAR_F(alpha)
FLEXT_ATTRVAR_F(beta)
};
// instantiate the class
FLEXT_NEW_V("henon",henon)
henon::henon(int argc,const t_atom *argv):
alpha(0),beta(0),x(0),y(0) // initializations
{
// define inlets
AddInAnything("reset,bang,...");
AddInFloat("alpha");
AddInFloat("beta");
// define outlets
AddOutFloat();
// processing command line
if(argc == 2 && CanbeFloat(argv[0]) && CanbeFloat(argv[1])) {
// two float args
alpha = GetAFloat(argv[0]);
beta = GetAFloat(argv[1]);
}
}
void henon::Setup(t_classid c)
{
// register methods
FLEXT_CADDBANG(c,0,m_bang);
FLEXT_CADDMETHOD_(c,0,"reset",m_reset);
FLEXT_CADDMETHOD(c,1,m_alpha);
FLEXT_CADDMETHOD(c,2,m_beta);
// register attributes
FLEXT_CADDATTR_VAR1(c,"alpha",alpha); // register attribute "alpha"
FLEXT_CADDATTR_VAR1(c,"beta",beta); // register attribute "beta"
}
// Trigger output
void henon::m_bang()
{
float _alpha_ = alpha*1.5f-2.5f;
float _beta_ = beta-0.5f;
float newx = 1 + _alpha_ * x * x + _beta_ * y;
float newy = x;
x = newx;
y = newy;
float output = (x + 1.0f)/2.0f;
if(output < 0)
output = 0;
else if(output > 1)
output = 1;
// output value to outlet
ToOutFloat(0,output); // (0 stands for the outlet index 0)
}
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