Add support for using ma_node_graph as a node.

This allows the node graph to be connected to another node graph.

miniaudio.h

@@ -10364,6 +10364,7 @@ MA_API ma_node_graph_config ma_node_graph_config_init(ma_uint32 channels);
 struct ma_node_graph
 {
     /* Immutable. */
+    ma_node_base base;                  /* The node graph itself is a node so it can be connected as an input to different node graph. This has zero inputs and calls ma_node_graph_read_pcm_frames() to generate it's output. */
     ma_node_base endpoint;              /* Special node that all nodes eventually connect to. Data is read from this node in ma_node_graph_read_pcm_frames(). */
     ma_uint16 nodeCacheCapInFrames;
 
@@ -67733,6 +67734,28 @@ static ma_bool32 ma_node_graph_is_reading(ma_node_graph* pNodeGraph)
 #endif
 
 
+static void ma_node_graph_node_process_pcm_frames(ma_node* pNode, const float** ppFramesIn, ma_uint32* pFrameCountIn, float** ppFramesOut, ma_uint32* pFrameCountOut)
+{
+    ma_node_graph* pNodeGraph = (ma_node_graph*)pNode;
+    ma_uint64 framesRead;
+
+    ma_node_graph_read_pcm_frames(pNodeGraph, ppFramesOut[0], *pFrameCountOut, &framesRead);
+
+    *pFrameCountOut = (ma_uint32)framesRead;    /* Safe cast. */
+
+    (void)ppFramesIn;
+    (void)pFrameCountIn;
+}
+
+static ma_node_vtable g_node_graph_node_vtable =
+{
+    ma_node_graph_node_process_pcm_frames,
+    NULL,   /* onGetRequiredInputFrameCount */
+    0,      /* 1 input buses. */
+    1,      /* 1 output bus. */
+    0       /* Flags. */
+};
+
 static void ma_node_graph_endpoint_process_pcm_frames(ma_node* pNode, const float** ppFramesIn, ma_uint32* pFrameCountIn, float** ppFramesOut, ma_uint32* pFrameCountOut)
 {
     MA_ASSERT(pNode != NULL);
@@ -67769,7 +67792,9 @@ static ma_node_vtable g_node_graph_endpoint_vtable =
 MA_API ma_result ma_node_graph_init(const ma_node_graph_config* pConfig, const ma_allocation_callbacks* pAllocationCallbacks, ma_node_graph* pNodeGraph)
 {
     ma_result result;
+    ma_node_config baseConfig;
     ma_node_config endpointConfig;
+    ma_uint32 baseInputChannels = 0;
 
     if (pNodeGraph == NULL) {
         return MA_INVALID_ARGS;
@@ -67781,6 +67806,20 @@ MA_API ma_result ma_node_graph_init(const ma_node_graph_config* pConfig, const m
         pNodeGraph->nodeCacheCapInFrames = MA_DEFAULT_NODE_CACHE_CAP_IN_FRAMES_PER_BUS;
     }
 
+
+    /* Base node so we can use the node graph as a node into another graph. */
+    baseConfig = ma_node_config_init();
+    baseConfig.vtable = &g_node_graph_node_vtable;
+    baseConfig.pInputChannels  = &baseInputChannels;    /* <-- Always zero. */
+    baseConfig.pOutputChannels = &pConfig->channels;
+
+    result = ma_node_init(pNodeGraph, &baseConfig, pAllocationCallbacks, &pNodeGraph->base);
+    if (result != MA_SUCCESS) {
+        return result;
+    }
+
+
+    /* Endpoint. */
     endpointConfig = ma_node_config_init();
     endpointConfig.vtable          = &g_node_graph_endpoint_vtable;
     endpointConfig.pInputChannels  = &pConfig->channels;
@@ -67788,6 +67827,7 @@ MA_API ma_result ma_node_graph_init(const ma_node_graph_config* pConfig, const m
 
     result = ma_node_init(pNodeGraph, &endpointConfig, pAllocationCallbacks, &pNodeGraph->endpoint);
     if (result != MA_SUCCESS) {
+        ma_node_uninit(&pNodeGraph->base, pAllocationCallbacks);
         return result;
     }