Do not save/restore lv2 parameter-patch values, intercept restore

source/backend/CarlaBackend.h

@@ -341,6 +341,12 @@ static const uint PARAMETER_USES_CUSTOM_TEXT = 0x400;
  */
 static const uint PARAMETER_CAN_BE_CV_CONTROLLED = 0x800;
 
+/*!
+ * Parameter should not be saved as part of the project/session.
+ * @note only valid for parameter inputs.
+ */
+static const uint PARAMETER_IS_NOT_SAVED = 0x1000;
+
 /** @} */
 
 /* ------------------------------------------------------------------------------------------------------------

source/backend/plugin/CarlaPlugin.cpp

@@ -604,6 +604,8 @@ const CarlaStateSave& CarlaPlugin::getStateSave(const bool callPrepareForSave)
 
         if ((paramData.hints & PARAMETER_IS_ENABLED) == 0)
             continue;
+        if (paramData.hints & PARAMETER_IS_NOT_SAVED)
+            continue;
 
         const bool dummy = paramData.type != PARAMETER_INPUT || usingChunk;
 
@@ -750,6 +752,9 @@ void CarlaPlugin::loadStateSave(const CarlaStateSave& stateSave)
     {
         for (uint32_t i=0; i < pData->param.count; ++i)
         {
+            if (pData->param.data[i].hints & PARAMETER_IS_NOT_SAVED)
+                continue;
+
             if (getParameterSymbol(i, strBuf))
             {
                 ParamSymbol* const paramSymbol(new ParamSymbol(i, strBuf));

source/backend/plugin/CarlaPluginInternal.hpp

@@ -48,9 +48,9 @@ const ushort kPluginMaxMidiEvents = 512;
 // -----------------------------------------------------------------------
 // Extra parameter hints, hidden from backend
 
-const uint PARAMETER_MAPPED_RANGES_SET = 0x1000;
-const uint PARAMETER_IS_STRICT_BOUNDS  = 0x2000;
-const uint PARAMETER_IS_TRIGGER        = 0x4000;
+const uint PARAMETER_MAPPED_RANGES_SET = 0x10000;
+const uint PARAMETER_IS_STRICT_BOUNDS  = 0x20000;
+const uint PARAMETER_IS_TRIGGER        = 0x40000;
 
 // -----------------------------------------------------------------------
 // Extra plugin hints, hidden from backend

source/backend/plugin/CarlaPluginLV2.cpp

@@ -1512,6 +1512,72 @@ public:
         if (std::strcmp(type, CUSTOM_DATA_TYPE_PROPERTY) == 0)
             return CarlaPlugin::setCustomData(type, key, value, sendGui);
 
+        // See if this key is from a parameter exposed by carla, apply value if yes
+        for (uint32_t i=0; i < fRdfDescriptor->ParameterCount; ++i)
+        {
+            const LV2_RDF_Parameter& rdfParam(fRdfDescriptor->Parameters[i]);
+
+            if (std::strcmp(rdfParam.URI, key) == 0)
+            {
+                uint32_t parameterId = UINT32_MAX;
+                const int32_t rindex = static_cast<int32_t>(fRdfDescriptor->PortCount + i);
+
+                switch (rdfParam.Type)
+                {
+                case LV2_PARAMETER_BOOL:
+                case LV2_PARAMETER_INT:
+                // case LV2_PARAMETER_LONG:
+                case LV2_PARAMETER_FLOAT:
+                case LV2_PARAMETER_DOUBLE:
+                    for (uint32_t j=0; j < pData->param.count; ++j)
+                    {
+                        if (pData->param.data[j].rindex == rindex)
+                        {
+                            parameterId = j;
+                            break;
+                        }
+                    }
+                    break;
+                }
+
+                if (parameterId == UINT32_MAX)
+                    break;
+
+                std::vector<uint8_t> chunk(carla_getChunkFromBase64String(value));
+                CARLA_SAFE_ASSERT_RETURN(chunk.size() > 0,);
+
+#ifdef CARLA_PROPER_CPP11_SUPPORT
+                const uint8_t* const valueptr = chunk.data();
+#else
+                const uint8_t* const valueptr = &chunk.front();
+#endif
+                float rvalue;
+
+                switch (rdfParam.Type)
+                {
+                case LV2_PARAMETER_BOOL:
+                    rvalue = *(const int32_t*)valueptr != 0 ? 1.0f : 0.0f;
+                    break;
+                case LV2_PARAMETER_INT:
+                    rvalue = static_cast<float>(*(const int32_t*)valueptr);
+                    break;
+                case LV2_PARAMETER_FLOAT:
+                    rvalue = *(const float*)valueptr;
+                    break;
+                case LV2_PARAMETER_DOUBLE:
+                    rvalue = static_cast<float>(*(const double*)valueptr);
+                    break;
+                default:
+                    // making compilers happy
+                    rvalue = pData->param.ranges[parameterId].def;
+                    break;
+                }
+
+                fParamBuffers[parameterId] = pData->param.getFixedValue(parameterId, rvalue);
+                break;
+            }
+        }
+
         CarlaPlugin::setCustomData(type, key, value, sendGui);
     }
 
@@ -2965,6 +3031,7 @@ public:
                 pData->param.data[j].type   = PARAMETER_INPUT;
                 pData->param.data[j].hints |= PARAMETER_IS_ENABLED;
                 pData->param.data[j].hints |= PARAMETER_IS_AUTOMABLE;
+                pData->param.data[j].hints |= PARAMETER_IS_NOT_SAVED;
                 needsCtrlIn = true;
             }
             else

source/frontend/carla_backend.py

@@ -321,6 +321,10 @@ PARAMETER_USES_CUSTOM_TEXT = 0x400
 # Parameter can be turned into a CV control.
 PARAMETER_CAN_BE_CV_CONTROLLED = 0x800
 
+# Parameter should not be saved as part of the project/session.
+# @note only valid for parameter inputs.
+PARAMETER_IS_NOT_SAVED = 0x1000
+
 # ---------------------------------------------------------------------------------------------------------------------
 # Mapped Parameter Flags
 # Various flags for parameter mappings.