andrewm@13: /*
robert@372:  ____  _____ _        _    
robert@372: | __ )| ____| |      / \   
robert@372: |  _ \|  _| | |     / _ \  
robert@372: | |_) | |___| |___ / ___ \ 
robert@372: |____/|_____|_____/_/   \_\.io
robert@372: 
robert@372:  */
robert@372: 
robert@372:  /*
andrewm@13:  * render.cpp
andrewm@13:  *
andrewm@13:  *  Created on: Oct 24, 2014
andrewm@13:  *      Author: parallels
andrewm@13:  */
andrewm@13: 
robert@372: /**
robert@372: \example 1_basic_audio_analog_passthrough
robert@372: 
robert@372: Audio and analog passthrough: input to output
robert@372: -----------------------------------------
robert@372: 
robert@372: This sketch demonstrates how to read from and write to the audio and analog input and output buffers.
robert@372: 
robert@372: In `render()` you'll see a nested for loop structure. You'll see this in all Bela projects. 
robert@372: The first for loop cycles through `audioFrames`, the second through 
robert@372: `audioChannels` (in this case left 0 and right 1).
robert@372: 
robert@372: You can access any information about current audio and sensor settings you can do the following: 
robert@372: `context->name_of_item`. For example `context->audioChannels` returns current number of channels,
robert@372: `context->audioFrames` returns the current number of audio frames, 
robert@372: `context->audioSampleRate` returns the audio sample rate.
robert@372: 
robert@372: You can look at all the information you can access in ::BeagleRTContext.
robert@372: 
robert@372: Reading and writing from the audio buffers
robert@372: ------------------------------------------
robert@372: 
robert@372: The simplest way to read samples from the audio input buffer is with
robert@372: `audioRead()` which we pass three arguments: context, current audio 
robert@372: frame and current channel. In this example we have 
robert@372: `audioRead(context, n, ch)` where both `n` and `ch` are provided by 
robert@372: the nested for loop structure.
robert@372: 
robert@372: We can write samples to the audio output buffer in a similar way using 
robert@372: `audioWrite()`. This has a fourth argument which is the value of the output.
robert@372: For example `audioWrite(context, n, ch, value_to_output)`.
robert@372: 
robert@372: Reading and writing from the analog buffers
robert@372: -------------------------------------------
robert@372: 
robert@372: The same is true for `analogRead()` and `analogWrite()`.
robert@372: 
robert@372: Note that for the analog channels we write to and read from the buffers in a separate set 
robert@372: of nested for loops. This is because the they are sampled at half audio rate by default. 
robert@372: The first of these for loops cycles through `analogFrames`, the second through
robert@372: `analogChannels`.
robert@372: 
robert@372: By setting `audioWriteFrame(context, n, ch, audioReadFrame(context, n, ch))` and
robert@372: `analogWrite(context, n, ch, analogReadFrame(context, n, ch))` we have a simple 
robert@372: passthrough of audio input to output and analog input to output.
robert@372: 
robert@372: 
robert@372: It is also possible to address the buffers directly, for example: 
robert@372: `context->audioOut[n * context->audioChannels + ch]`.
robert@372: */
andrewm@13: 
giuliomoro@301: #include <Bela.h>
andrewm@13: #include <rtdk.h>
andrewm@13: 
andrewm@56: // setup() is called once before the audio rendering starts.
andrewm@13: // Use it to perform any initialisation and allocation which is dependent
andrewm@13: // on the period size or sample rate.
andrewm@13: //
andrewm@13: // userData holds an opaque pointer to a data structure that was passed
andrewm@13: // in from the call to initAudio().
andrewm@13: //
andrewm@13: // Return true on success; returning false halts the program.
andrewm@13: 
giuliomoro@301: bool setup(BelaContext *context, void *userData)
andrewm@13: {
andrewm@13: 	// Nothing to do here...
andrewm@13: 	return true;
andrewm@13: }
andrewm@13: 
andrewm@13: // render() is called regularly at the highest priority by the audio engine.
andrewm@13: // Input and output are given from the audio hardware and the other
andrewm@13: // ADCs and DACs (if available). If only audio is available, numMatrixFrames
andrewm@13: // will be 0.
andrewm@13: 
giuliomoro@301: void render(BelaContext *context, void *userData)
andrewm@13: {
andrewm@13: 	// Simplest possible case: pass inputs through to outputs
andrewm@52: 	for(unsigned int n = 0; n < context->audioFrames; n++) {
giuliomoro@180: 		for(unsigned int ch = 0; ch < context->audioChannels; ch++){
giuliomoro@180: 			// Two equivalent ways to write this code
giuliomoro@180: 
giuliomoro@180: 			// The long way, using the buffers directly:
giuliomoro@180: 			// context->audioOut[n * context->audioChannels + ch] =
giuliomoro@180: 			// 		context->audioIn[n * context->audioChannels + ch];
giuliomoro@180: 
giuliomoro@180: 			// Or using the macros:
andrewm@308: 			audioWrite(context, n, ch, audioRead(context, n, ch));
giuliomoro@180: 		}
andrewm@13: 	}
andrewm@13: 
giuliomoro@180: 	// Same with analog channelss
giuliomoro@180: 	for(unsigned int n = 0; n < context->analogFrames; n++) {
giuliomoro@180: 		for(unsigned int ch = 0; ch < context->analogChannels; ch++) {
giuliomoro@180: 			// Two equivalent ways to write this code
giuliomoro@180: 
giuliomoro@180: 			// The long way, using the buffers directly:
giuliomoro@180: 			// context->analogOut[n * context->analogChannels + ch] = context->analogIn[n * context->analogChannels + ch];
giuliomoro@180: 
giuliomoro@180: 			// Or using the macros:
andrewm@308: 			analogWrite(context, n, ch, analogRead(context, n, ch));
giuliomoro@180: 		}
giuliomoro@180: 	}
andrewm@13: }
andrewm@13: 
andrewm@56: // cleanup() is called once at the end, after the audio has stopped.
andrewm@56: // Release any resources that were allocated in setup().
andrewm@13: 
giuliomoro@301: void cleanup(BelaContext *context, void *userData)
andrewm@13: {
andrewm@13: 
andrewm@13: }