Add reverb node to examples.

This uses https://github.com/blastbay/verblib to achieve the effect.

research/_extras/nodes/ma_reverb_node/ma_reverb_node.c

+
+#define VERBLIB_IMPLEMENTATION
+#include "ma_reverb_node.h"
+
+MA_API ma_reverb_node_config ma_reverb_node_config_init(ma_uint32 channels, ma_uint32 sampleRate)
+{
+    ma_reverb_node_config config;
+
+    MA_ZERO_OBJECT(&config);
+    config.nodeConfig = ma_node_config_init();  /* Input and output channels will be set in ma_reverb_node_init(). */
+    config.channels   = channels;
+    config.sampleRate = sampleRate;
+    config.roomSize   = verblib_initialroom;
+    config.damping    = verblib_initialdamp;
+    config.width      = verblib_initialwidth;
+    config.wetVolume  = verblib_initialwet;
+    config.dryVolume  = verblib_initialdry;
+    config.mode       = verblib_initialmode;
+
+    return config;
+}
+
+
+static void ma_reverb_node_process_pcm_frames(ma_node* pNode, const float** ppFramesIn, ma_uint32* pFrameCountIn, float** ppFramesOut, ma_uint32* pFrameCountOut)
+{
+    ma_reverb_node* pReverbNode = (ma_reverb_node*)pNode;
+
+    (void)pFrameCountIn;
+
+    verblib_process(&pReverbNode->reverb, ppFramesIn[0], ppFramesOut[0], *pFrameCountOut);
+}
+
+static ma_node_vtable g_ma_reverb_node_vtable =
+{
+    ma_reverb_node_process_pcm_frames,
+    NULL,
+    1,  /* 1 input channels. */
+    1,  /* 1 output channel. */
+    MA_NODE_FLAG_CONTINUOUS_PROCESSING  /* Reverb requires continuous processing to ensure the tail get's processed. */
+};
+
+MA_API ma_result ma_reverb_node_init(ma_node_graph* pNodeGraph, const ma_reverb_node_config* pConfig, const ma_allocation_callbacks* pAllocationCallbacks, ma_reverb_node* pReverbNode)
+{
+    ma_result result;
+    ma_node_config baseConfig;
+
+    if (pReverbNode == NULL) {
+        return MA_INVALID_ARGS;
+    }
+
+    MA_ZERO_OBJECT(pReverbNode);
+
+    if (pConfig == NULL) {
+        return MA_INVALID_ARGS;
+    }
+
+    if (verblib_initialize(&pReverbNode->reverb, (unsigned long)pConfig->sampleRate, (unsigned int)pConfig->channels) == 0) {
+        return MA_INVALID_ARGS;
+    }
+
+    baseConfig = pConfig->nodeConfig;
+    baseConfig.vtable            = &g_ma_reverb_node_vtable;
+    baseConfig.inputChannels [0] = pConfig->channels;
+    baseConfig.inputChannels [1] = 0;                   /* Unused. */
+    baseConfig.outputChannels[0] = pConfig->channels;
+    baseConfig.outputChannels[1] = 0;                   /* Unused. */
+
+    result = ma_node_init(pNodeGraph, &baseConfig, pAllocationCallbacks, &pReverbNode->baseNode);
+    if (result != MA_SUCCESS) {
+        return result;
+    }
+
+    return MA_SUCCESS;
+}
+
+MA_API void ma_reverb_node_uninit(ma_reverb_node* pReverbNode, const ma_allocation_callbacks* pAllocationCallbacks)
+{
+    /* The base node is always uninitialized first. */
+    ma_node_uninit(pReverbNode, pAllocationCallbacks);
+}

research/_extras/nodes/ma_reverb_node/ma_reverb_node.h

+/* Include ma_vocoder_node.h after miniaudio.h */
+#ifndef ma_reverb_node_h
+#define ma_reverb_node_h
+
+#include "verblib.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+The reverb node has one input and one output.
+*/
+typedef struct
+{
+    ma_node_config nodeConfig;
+    ma_uint32 channels;         /* The number of channels of the source, which will be the same as the output. Must be 1 or 2. The excite bus must always have one channel. */
+    ma_uint32 sampleRate;
+    float roomSize;
+    float damping;
+    float width;
+    float wetVolume;
+    float dryVolume;
+    float mode;
+} ma_reverb_node_config;
+
+MA_API ma_reverb_node_config ma_reverb_node_config_init(ma_uint32 channels, ma_uint32 sampleRate);
+
+
+typedef struct
+{
+    ma_node_base baseNode;
+    verblib reverb;
+} ma_reverb_node;
+
+MA_API ma_result ma_reverb_node_init(ma_node_graph* pNodeGraph, const ma_reverb_node_config* pConfig, const ma_allocation_callbacks* pAllocationCallbacks, ma_reverb_node* pReverbNode);
+MA_API void ma_reverb_node_uninit(ma_reverb_node* pReverbNode, const ma_allocation_callbacks* pAllocationCallbacks);
+
+#ifdef __cplusplus
+}
+#endif
+#endif  /* ma_reverb_node_h */

research/_extras/nodes/ma_reverb_node/ma_reverb_node_example.c

+#define MINIAUDIO_IMPLEMENTATION
+#include "../../../../miniaudio.h"
+#include "../../../miniaudio_engine.h"
+#include "ma_reverb_node.c"
+
+#include <stdio.h>
+
+#define DEVICE_FORMAT       ma_format_f32;      /* Must always be f32 for this example because the node graph system only works with this. */
+#define DEVICE_CHANNELS     1                   /* For this example, always set to 1. */
+#define DEVICE_SAMPLE_RATE  48000               /* Cannot be less than 22050 for this example. */
+
+static ma_audio_buffer_ref g_dataSupply;        /* The underlying data source of the source node. */
+static ma_data_source_node g_dataSupplyNode;    /* The node that will sit at the root level. Will be reading data from g_dataSupply. */
+static ma_reverb_node      g_reverbNode;        /* The reverb node. */
+static ma_node_graph       g_nodeGraph;         /* The main node graph that we'll be feeding data through. */
+
+void data_callback(ma_device* pDevice, void* pOutput, const void* pInput, ma_uint32 frameCount)
+{
+    MA_ASSERT(pDevice->capture.format == pDevice->playback.format && pDevice->capture.format == ma_format_f32);
+    MA_ASSERT(pDevice->capture.channels == pDevice->playback.channels);
+
+    /*
+    The node graph system is a pulling style of API. At the lowest level of the chain will be a 
+    node acting as a data source for the purpose of delivering the initial audio data. In our case,
+    the data source is our `pInput` buffer. We need to update the underlying data source so that it
+    read data from `pInput`.
+    */
+    ma_audio_buffer_ref_set_data(&g_dataSupply, pInput, frameCount);
+
+    /* With the source buffer configured we can now read directly from the node graph. */
+    ma_node_graph_read_pcm_frames(&g_nodeGraph, pOutput, frameCount, NULL);
+}
+
+int main(int argc, char** argv)
+{
+    ma_result result;
+    ma_device_config deviceConfig;
+    ma_device device;
+    ma_node_graph_config nodeGraphConfig;
+    ma_reverb_node_config reverbNodeConfig;
+    ma_data_source_node_config dataSupplyNodeConfig;
+
+    deviceConfig = ma_device_config_init(ma_device_type_duplex);
+    deviceConfig.capture.pDeviceID  = NULL;
+    deviceConfig.capture.format     = DEVICE_FORMAT;
+    deviceConfig.capture.channels   = DEVICE_CHANNELS;
+    deviceConfig.capture.shareMode  = ma_share_mode_shared;
+    deviceConfig.playback.pDeviceID = NULL;
+    deviceConfig.playback.format    = DEVICE_FORMAT;
+    deviceConfig.playback.channels  = DEVICE_CHANNELS;
+    deviceConfig.sampleRate         = DEVICE_SAMPLE_RATE;
+    deviceConfig.dataCallback       = data_callback;
+    result = ma_device_init(NULL, &deviceConfig, &device);
+    if (result != MA_SUCCESS) {
+        return result;
+    }
+
+
+    /* Node graph. */
+    nodeGraphConfig = ma_node_graph_config_init(device.capture.channels);
+
+    result = ma_node_graph_init(&nodeGraphConfig, NULL, &g_nodeGraph);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize node graph.");
+        goto done0;
+    }
+
+
+    /* Reverb. Attached straight to the endpoint. */
+    reverbNodeConfig = ma_reverb_node_config_init(device.capture.channels, device.sampleRate);
+
+    result = ma_reverb_node_init(&g_nodeGraph, &reverbNodeConfig, NULL, &g_reverbNode);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize vocoder node.");
+        goto done1;
+    }
+
+    ma_node_attach_output_bus(&g_reverbNode, 0, ma_node_graph_get_endpoint(&g_nodeGraph), 0);
+
+
+    /* Data supply. Attached to input bus 0 of the reverb node. */
+    result = ma_audio_buffer_ref_init(device.capture.format, device.capture.channels, NULL, 0, &g_dataSupply);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize audio buffer for source.");
+        goto done2;
+    }
+
+    dataSupplyNodeConfig = ma_data_source_node_config_init(&g_dataSupply, MA_FALSE);
+
+    result = ma_data_source_node_init(&g_nodeGraph, &dataSupplyNodeConfig, NULL, &g_dataSupplyNode);
+    if (result != MA_SUCCESS) {
+        printf("Failed to initialize source node.");
+        goto done2;
+    }
+
+    ma_node_attach_output_bus(&g_dataSupplyNode, 0, &g_reverbNode, 0);
+
+
+
+    /* Now we just start the device and wait for the user to terminate the program. */
+    ma_device_start(&device);
+
+    printf("Press Enter to quit...\n");
+    getchar();
+
+    /* It's important that we stop the device first or else we'll uninitialize the graph from under the device. */
+    ma_device_stop(&device);
+
+
+/*done3:*/ ma_data_source_node_uninit(&g_dataSupplyNode, NULL);
+done2: ma_reverb_node_uninit(&g_reverbNode, NULL);
+done1: ma_node_graph_uninit(&g_nodeGraph, NULL);
+done0: ma_device_uninit(&device);
+    
+    (void)argc;
+    (void)argv;
+
+    return 0;
+}
\ No newline at end of file