From 7c37e211c705e644454faa8974d4018feeab855d Mon Sep 17 00:00:00 2001
From: Stephane Letz <letz@grame.fr>
Date: Fri, 10 Jul 2020 18:10:08 +0200
Subject: [PATCH] Implement sample-rate change.

---
 src/FaustEngine.cpp | 52 ++++++++++++++++++++++++++++-----------------
 1 file changed, 33 insertions(+), 19 deletions(-)

diff --git a/src/FaustEngine.cpp b/src/FaustEngine.cpp
index 4c51b27..32a9638 100644
--- a/src/FaustEngine.cpp
+++ b/src/FaustEngine.cpp
@@ -3,6 +3,8 @@
 #include <faust/dsp/llvm-dsp.h>
 #include <iostream>
 
+#define kBufferSize 64
+
 class FaustEngine : public ScriptEngine {
     
     public:
@@ -25,40 +27,41 @@ class FaustEngine : public ScriptEngine {
     
         int run(const std::string& path, const std::string& script) override
         {
-            display("Compiling...");
-            
             std::string error_msg;
             fFactory = createDSPFactoryFromString("FaustDSP", script, 0, NULL, "", error_msg, -1);
             if (!fFactory) {
-                display("Cannot create Faust factory");
+                display("ERROR: cannot create Faust factory !");
                 return -1;
             } else {
-                display("Compiling finished");
+                display("Compiling factory finished");
             }
             
             fDSP = fFactory->createDSPInstance();
             if (!fDSP) {
-                display("Cannot create Faust instance");
+                display("ERROR: cannot create Faust instance !");
                 return -1;
             } else {
-                display("Creating DSP");
+                display("Created DSP");
             }
             
-            fInputs = new FAUSTFLOAT*[fDSP->getNumInputs()];
-            fOutputs = new FAUSTFLOAT*[fDSP->getNumOutputs()];
+            // Prepare inputs/ouputs
+            if (fDSP->getNumInputs() > 6) {
+                display("ERROR: DSP has " + std::to_string(fDSP->getNumInputs()) + " inputs !");
+                return -1;
+            }
             
-            setFrameDivider(1);
-            setBufferSize(64);
+            if (fDSP->getNumOutputs() > 6) {
+                display("ERROR: DSP has " + std::to_string(fDSP->getNumInputs()) + " outputs !");
+                return -1;
+            }
             
-            // TODO
-            //ProcessBlock* block = getProcessBlock();
-            fDSP->init(44100);
-            return 0;
-        }
-    
-        int process() override
-        {
+            setFrameDivider(1);
+            setBufferSize(kBufferSize);
+        
+            // Prepare buffers for process
             ProcessBlock* block = getProcessBlock();
+            fInputs = new FAUSTFLOAT*[fDSP->getNumInputs()];
+            fOutputs = new FAUSTFLOAT*[fDSP->getNumOutputs()];
             
             for (int chan = 0; chan < fDSP->getNumInputs(); chan++) {
                 fInputs[chan] = block->inputs[chan];
@@ -67,7 +70,18 @@ class FaustEngine : public ScriptEngine {
                 fOutputs[chan] = block->outputs[chan];
             }
             
-            fDSP->compute(block->bufferSize, fInputs, fOutputs);
+            // Init DSP with default SR
+            fDSP->init(44100);
+            return 0;
+        }
+    
+        int process() override
+        {
+            // Possibly update SR
+            if (getProcessBlock()->sampleRate != fDSP->getSampleRate()) {
+                fDSP->init(getProcessBlock()->sampleRate);
+            }
+            fDSP->compute(kBufferSize, fInputs, fOutputs);
             return 0;
         }