andrewm@0: /*
andrewm@0:  * render.cpp
andrewm@0:  *
andrewm@0:  *  Created on: Oct 24, 2014
andrewm@0:  *      Author: parallels
andrewm@0:  */
andrewm@0: 
andrewm@0: 
andrewm@0: #include "../../include/render.h"
andrewm@0: #include <cmath>
andrewm@0: 
andrewm@0: float gFrequency;
andrewm@0: float gPhase;
andrewm@0: float gInverseSampleRate;
andrewm@0: 
andrewm@0: // initialise_render() is called once before the audio rendering starts.
andrewm@0: // Use it to perform any initialisation and allocation which is dependent
andrewm@0: // on the period size or sample rate.
andrewm@0: //
andrewm@0: // userData holds an opaque pointer to a data structure that was passed
andrewm@0: // in from the call to initAudio().
andrewm@0: //
andrewm@0: // Return true on success; returning false halts the program.
andrewm@0: 
andrewm@12: bool initialise_render(int numMatrixChannels, int numAudioChannels,
andrewm@12: 					   int numMatrixFramesPerPeriod,
andrewm@12: 					   int numAudioFramesPerPeriod,
andrewm@12: 					   float matrixSampleRate, float audioSampleRate,
andrewm@12: 					   void *userData)
andrewm@0: {
andrewm@0: 	// Retrieve a parameter passed in from the initAudio() call
andrewm@0: 	gFrequency = *(float *)userData;
andrewm@0: 
andrewm@0: 	gInverseSampleRate = 1.0 / audioSampleRate;
andrewm@0: 	gPhase = 0.0;
andrewm@0: 
andrewm@0: 	return true;
andrewm@0: }
andrewm@0: 
andrewm@0: // render() is called regularly at the highest priority by the audio engine.
andrewm@0: // Input and output are given from the audio hardware and the other
andrewm@0: // ADCs and DACs (if available). If only audio is available, numMatrixFrames
andrewm@0: // will be 0.
andrewm@0: 
andrewm@0: void render(int numMatrixFrames, int numAudioFrames, float *audioIn, float *audioOut,
andrewm@0: 			uint16_t *matrixIn, uint16_t *matrixOut)
andrewm@0: {
andrewm@0: 	for(int n = 0; n < numAudioFrames; n++) {
andrewm@0: 		float out = 0.8f * sinf(gPhase);
andrewm@0: 		gPhase += 2.0 * M_PI * gFrequency * gInverseSampleRate;
andrewm@0: 		if(gPhase > 2.0 * M_PI)
andrewm@0: 			gPhase -= 2.0 * M_PI;
andrewm@0: 
andrewm@13: 		for(int channel = 0; channel < gNumAudioChannels; channel++)
andrewm@13: 			audioOut[n * gNumAudioChannels + channel] = out;
andrewm@0: 	}
andrewm@0: }
andrewm@0: 
andrewm@0: // cleanup_render() is called once at the end, after the audio has stopped.
andrewm@0: // Release any resources that were allocated in initialise_render().
andrewm@0: 
andrewm@0: void cleanup_render()
andrewm@0: {
andrewm@0: 
andrewm@0: }