annotate examples/stepper/render.cpp @ 337:5e2780bfbfed prerelease

Clean up of basic_libpd

/*
 * render.cpp
 *
 *  Created on: Oct 24, 2014
 *      Author: parallels
 */


#include <Bela.h>
#include <Utilities.h>

const int kStepLengthSlow = 1000;
const int kStepLengthFast = 500;

int gStepLengthSamples = kStepLengthSlow;

const int gPinA1 = P8_27;
const int gPinA2 = P8_28;
const int gPinB1 = P8_29;
const int gPinB2 = P8_30;
const int gPinServo = P9_16;

int gStepCounter = 0;
int gPhase = 0;

int gServoCounter = 0;


enum {
	kStateMoveRight1 = 0,
	kStateMoveLeft1,
	kStateMoveRight2,
	kStateMoveLeft2,
	kStateMoveRight3,
	kStateMoveLeft3,
	kStateSpin,
	kStateMax
};

int gState = 0;
int gStateCounter = 0;

// setup() is called once before the audio rendering starts.
// Use it to perform any initialisation and allocation which is dependent
// on the period size or sample rate.
//
// userData holds an opaque pointer to a data structure that was passed
// in from the call to initAudio().
//
// Return true on success; returning false halts the program.

bool setup(BelaContext *context, void *userData)
{	
	// This project makes the assumption that the audio and digital
	// sample rates are the same. But check it to be sure!
	if(context->audioFrames != context->digitalFrames) {
		rt_printf("Error: this project needs the audio and digital sample rates to be the same.\n");
		return false;
	}
	
	pinMode(context, 0, gPinA1, OUTPUT);
	pinMode(context, 0, gPinA2, OUTPUT);
	pinMode(context, 0, gPinB1, OUTPUT);
	pinMode(context, 0, gPinB2, OUTPUT);
	pinMode(context, 0, gPinServo, OUTPUT);
		
	return true;
}

// render() is called regularly at the highest priority by the audio engine.
// Input and output are given from the audio hardware and the other
// ADCs and DACs (if available). If only audio is available, numMatrixFrames
// will be 0.

void render(BelaContext *context, void *userData)
{
	for(unsigned int n = 0; n < context->audioFrames; n++) {
		if(gPhase == 0 || gPhase == 1) {
			digitalWriteOnce(context, n, gPinB1, HIGH);
			digitalWriteOnce(context, n, gPinB2, LOW);
		}
		else {
			digitalWriteOnce(context, n, gPinB1, LOW);
			digitalWriteOnce(context, n, gPinB2, HIGH);			
		}
		
		if(gPhase == 1 || gPhase == 2) {
			digitalWriteOnce(context, n, gPinA1, HIGH);
			digitalWriteOnce(context, n, gPinA2, LOW);
		}
		else {
			digitalWriteOnce(context, n, gPinA1, LOW);
			digitalWriteOnce(context, n, gPinA2, HIGH);			
		}
		
		if(--gServoCounter > 0) 
			digitalWriteOnce(context, n, gPinServo, HIGH);
		else
			digitalWriteOnce(context, n, gPinServo, LOW);
		
		if(++gStepCounter >= gStepLengthSamples) {
			gStateCounter++;
			
			switch(gState) {
				case kStateMoveRight1:
				case kStateMoveRight2:
				case kStateMoveRight3:
					gPhase = (gPhase + 1) & 3;
					break;
				case kStateMoveLeft1:
				case kStateMoveLeft2:
				case kStateMoveLeft3:				
					gPhase = (gPhase + 3) & 3;	
					break;
				case kStateSpin:
					gPhase = (gPhase + 1) & 3;
					break;		
			}
			
			if(gState == kStateSpin) {
				if(gStateCounter >= 48) {
					gStateCounter = 0;
					gState = 0;
					gStepLengthSamples = kStepLengthSlow;
				}				
			}
			else {
				if(gStateCounter >= 16) {
					gStateCounter = 0;
					gState++;
					if(gState & 1)
						gServoCounter = 120;
					else
						gServoCounter = 80;
					if(gState == kStateSpin)
						gStepLengthSamples = kStepLengthFast;
				}
			}
			
			gStepCounter = 0;
		}
	}
}

// cleanup() is called once at the end, after the audio has stopped.
// Release any resources that were allocated in setup().

void cleanup(BelaContext *context, void *userData)
{
	
}