Preset parameter persistence

[thingfish47]

I am developing a plugin, and have handled all the VST 2.4 'programs and persistence' functions in the AudioEffect and AudioEffectX classes. When I save a project with my plugin, and reload it, setchunk is called, and the last set of parameters are loaded by the DAW. So far so good, but I note that other plugins will 'remember' any changes made to any of the preset parameters, and this is not happening with my plugin. Is there another function that can achieve this that I am unaware of, and therefore not handling?

[thingfish47]

I think what I really mean here is, does Reaper itself provide persistence for plugin pre-sets (and dumping out the project file leads me to believe this is true), or is the plugin responsible for this, in which case can I get advice on where to save them with Reaper?

Either way, I would appreciate some advice.

[Geoff Waddington]

Originally Posted by thingfish47

I think what I really mean here is, does Reaper itself provide persistence for plugin pre-sets (and dumping out the project file leads me to believe this is true), or is the plugin responsible for this, in which case can I get advice on where to save them with Reaper?

Here is a code excerpt that shows how for control surfaces, I'm not sure if VST Presets are supported this way, but it's likely very close to this, you'll have to substitute the EuCon stuff with equivalent code for your app, note that lenSurfacePayload is passed by reference:

static WDL_HeapBuf hb;

static void SaveExtensionConfig(ProjectStateContext *context, bool isUndo, struct project_config_extension_t *reg)
{
	// can optionally not save undo chunks, up to you (if it makes sense in
	// the undo state or not, etc)
	if(isUndo)
	{
		return;
	}

	if(!pEuConApplication)
	{
		return;
	}

	void *ptrSurfacePayload = 0;
	NEuCon::uint32 lenSurfacePayload = 0;

	tERR err = pEuConApplication->GetPayloadFromSurface(ptrSurfacePayload, lenSurfacePayload);

	if( err == kERR_OK)
	{
		context->AddLine("<EuConArtist");

		cfg_encode_binary(context, ptrSurfacePayload, lenSurfacePayload); // this is implemented in WDL/projectcontext.cpp

		context->AddLine(">");

		pEuConApplication->FreePayloadBuffer(ptrSurfacePayload);
	}
}

static bool ProcessExtensionLine(const char *line, ProjectStateContext *context, bool isUndo, struct project_config_extension_t *reg)
{
	if(isUndo)
	{
		return false;
	}

	if (strcmp(line,"<EuConArtist"))
	{
		return false;
	}

	hb.Resize(0);

	cfg_decode_binary(context, &hb); // this is implemented in WDL/projectcontext.cpp

	return true;
}

static void BeginLoadProjectState(bool isUndo, struct project_config_extension_t *reg)
{
}

project_config_extension_t csurf_eucon_projectconfig = 
{ 
	ProcessExtensionLine, 
	SaveExtensionConfig, 
	BeginLoadProjectState, 
	NULL 
};