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Diffstat (limited to 'externals/grill/flext/tutorial/signal1/main.cpp')
| -rw-r--r-- | externals/grill/flext/tutorial/signal1/main.cpp | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/externals/grill/flext/tutorial/signal1/main.cpp b/externals/grill/flext/tutorial/signal1/main.cpp new file mode 100644 index 00000000..14818e6f --- /dev/null +++ b/externals/grill/flext/tutorial/signal1/main.cpp @@ -0,0 +1,129 @@ +// signal1~ - a flext tutorial external written by Frank Barknecht +// +// This is a commented port of the pan~ example from the PD-Externals-Howto to +// illustrate the usage of flext. You can get the original code at +// http://iem.kug.ac.at/pd/externals-HOWTO/ + +#include <flext.h> +#include <math.h> + +#if !defined(FLEXT_VERSION) || (FLEXT_VERSION < 300) +#error You need at least flext version 0.3.0 +#endif + + +// A flext dsp external ("tilde object") inherits from the class flext_dsp +class signal1: + public flext_dsp +{ + // Each external that is written in C++ needs to use #defines + // from flbase.h + // + // The define + // + // FLEXT_HEADER(NEW_CLASS, PARENT_CLASS) + // + // should be somewhere in your dsp file. + // A good place is here: + + FLEXT_HEADER(signal1, flext_dsp) + + public: + signal1(): + f_pan(0) // initialize f_pan + { + // The constructor of your class is responsible for + // setting up inlets and outlets and for registering + // inlet-methods: + + AddInSignal(2); // 2 audio ins + AddInFloat(); // 1 float in + AddOutSignal(); // 1 audio out [ == AddOutSignal(1) ] + + SetupInOut(); // set up inlets and outlets. + // Must be called once! + + // Now we need to bind the handler function to our + // panning inlet, which is inlet 2 (counting all inlets + // from 0). We want the function "setPan" to get + // called on incoming float messages: + + FLEXT_ADDMETHOD(2,setPan); + + // We're done constructing: + post("-- pan~ with flext ---"); + + } // end of constructor + + + protected: + // here we declare the virtual DSP function + virtual void m_signal(int n, float *const *in, float *const *out); + private: + float f_pan; // holds our panning factor + + // Before we can use "setPan" as a handler, we must register this + // function as a callback to PD or Max. This is done using the + // FLEXT_CALLBACK* macros. There are several of them. + // + // FLEXT_CALLBACK_F is a shortcut, that registers a function + // expecting one float arg (thus ending in "_F"). There are + // other shortcuts that register other types of functions. Look + // into flext.h. No semicolon at the end of line!!! + FLEXT_CALLBACK_F(setPan) + + // Now setPan can get declared and defined here. + void setPan(float f) + { + // set our private panning factor "f_pan" to the inlet + // value float "f" in the intervall [0,1] + f_pan = (f<0) ? 0.0f : (f>1) ? 1.0f : f ; + + // if you want to debug if this worked, comment out the + // following line: + //post("Set panning to %.2f, maybe clipped from %.2f", f_pan,f); + } // end setPan +}; // end of class declaration for signal1 + + +// Before we can run our signal1-class in PD, the object has to be registered as a +// PD object. Otherwise it would be a simple C++-class, and what good would +// that be for? Registering is made easy with the FLEXT_NEW_* macros defined +// in flext.h. For tilde objects without arguments call: + +FLEXT_NEW_DSP("signal1~ signal1~", signal1) +// T.Grill: there are two names for the object: signal1~ as main name and pan~ as its alias + +// Now we define our DSP function. It gets this arguments: +// +// int n: length of signal vector. Loop over this for your signal processing. +// float *const *in, float *const *out: +// These are arrays of the signals in the objects signal inlets rsp. +// oulets. We come to that later inside the function. + +void signal1::m_signal(int n, float *const *in, float *const *out) +{ + + const float *ins1 = in[0]; + const float *ins2 = in[1]; + // As said above "in" holds a list of the signal vectors in all inlets. + // After these two lines, ins1 holds the signal vector ofthe first + // inlet, index 0, and ins2 holds the signal vector of the second + // inlet, with index 1. + + float *outs = out[0]; + // Now outs holds the signal vector at the one signal outlet we have. + + // We are now ready for the main signal loop + while (n--) + { + + // The "++" after the pointers outs, ins1 and ins2 walks us + // through the signal vector with each n, of course. Before + // each step we change the signal value in the outlet *outs + // according to our panning factor "f_pan" and according to the + // signals at the two signal inlets, *ins1 and *ins2 + + *outs++ = (*ins1++) * (1-f_pan) + (*ins2++) * f_pan; + } +} // end m_signal |