(svn r2712) Overhaul DirectMusic MIDI backend:

- Merge the .c and .cpp part into one file
- Properly deinitialize at the end
- Remove "experimental" status
- Miscellaneous smaller changes
-Fix: Volume control works now

music/dmusic.cpp

@@ -0,0 +1,226 @@
+/* $Id$ */
+
+#include "../stdafx.h"
+
+#ifdef WIN32_ENABLE_DIRECTMUSIC_SUPPORT
+
+extern "C" {
+	#include "../openttd.h"
+	#include "../debug.h"
+	#include "../win32.h"
+	#include "dmusic.h"
+}
+
+#include <windows.h>
+#include <dmksctrl.h>
+#include <dmusici.h>
+#include <dmusicc.h>
+#include <dmusicf.h>
+
+
+// the performance object controls manipulation of the segments
+static IDirectMusicPerformance* performance = NULL;
+
+// the loader object can load many types of DMusic related files
+static IDirectMusicLoader* loader = NULL;
+
+// the segment object is where the MIDI data is stored for playback
+static IDirectMusicSegment* segment = NULL;
+
+static bool seeking = false;
+
+
+#define M(x) x "\0"
+static const char ole_files[] =
+	M("ole32.dll")
+	M("CoCreateInstance")
+	M("CoInitialize")
+	M("CoUninitialize")
+	M("")
+;
+#undef M
+
+struct ProcPtrs {
+	unsigned long (WINAPI * CoCreateInstance)(REFCLSID rclsid, LPUNKNOWN pUnkOuter, DWORD dwClsContext, REFIID riid, LPVOID* ppv);
+	HRESULT (WINAPI * CoInitialize)(LPVOID pvReserved);
+	void (WINAPI * CoUninitialize)();
+};
+
+static ProcPtrs proc;
+
+
+static const char* DMusicMidiStart(const char* const* parm)
+{
+	if (performance != NULL) return NULL;
+
+	if (proc.CoCreateInstance == NULL) {
+		if (!LoadLibraryList((Function*)&proc, ole_files))
+			return "ole32.dll load failed";
+	}
+
+	// Initialize COM
+	if (FAILED(proc.CoInitialize(NULL))) {
+		return "COM initialization failed";
+	}
+
+	// create the performance object
+	if (FAILED(proc.CoCreateInstance(
+				CLSID_DirectMusicPerformance,
+				NULL,
+				CLSCTX_INPROC,
+				IID_IDirectMusicPerformance,
+				(LPVOID*)&performance
+			))) {
+		proc.CoUninitialize();
+		return "Failed to create the performance object";
+	}
+
+	// initialize it
+	if (FAILED(performance->Init(NULL, NULL, NULL))) {
+		performance->Release();
+		performance = NULL;
+		proc.CoUninitialize();
+		return "Failed to initialize performance object";
+	}
+
+	// choose default Windows synth
+	if (FAILED(performance->AddPort(NULL))) {
+		performance->CloseDown();
+		performance->Release();
+		performance = NULL;
+		proc.CoUninitialize();
+		return "AddPort failed";
+	}
+
+	// create the loader object; this will be used to load the MIDI file
+	if (FAILED(proc.CoCreateInstance(
+				CLSID_DirectMusicLoader,
+				NULL,
+				CLSCTX_INPROC,
+				IID_IDirectMusicLoader,
+				(LPVOID*)&loader
+			))) {
+		performance->CloseDown();
+		performance->Release();
+		performance = NULL;
+		proc.CoUninitialize();
+		return "Failed to create loader object";
+	}
+
+	return NULL;
+}
+
+
+static void DMusicMidiStop(void)
+{
+	/* release everything but the segment, which the performance
+	 * will release automatically (and it'll crash if it's been
+	 * released already) */
+
+	seeking = false;
+
+	loader->Release();
+	loader = NULL;
+
+	performance->CloseDown();
+	performance->Release();
+	performance = NULL;
+
+	segment = NULL;
+
+	proc.CoUninitialize();
+}
+
+
+static void DMusicMidiPlaySong(const char* filename)
+{
+	// set up the loader object info
+	DMUS_OBJECTDESC obj_desc;
+	ZeroMemory(&obj_desc, sizeof(obj_desc));
+	obj_desc.dwSize = sizeof(obj_desc);
+	obj_desc.guidClass = CLSID_DirectMusicSegment;
+	obj_desc.dwValidData = DMUS_OBJ_CLASS | DMUS_OBJ_FILENAME | DMUS_OBJ_FULLPATH;
+	MultiByteToWideChar(
+		CP_ACP, MB_PRECOMPOSED,
+		filename, -1,
+		obj_desc.wszFileName, lengthof(obj_desc.wszFileName)
+	);
+
+	// release the existing segment if we have any
+	if (segment != NULL) {
+		segment->Release();
+		segment = NULL;
+	}
+
+	// make a new segment
+	if (FAILED(loader->GetObject(
+				&obj_desc, IID_IDirectMusicSegment, (LPVOID*)&segment
+			))) {
+		DEBUG(misc, 0) ("DirectMusic: Get object failed");
+		return;
+	}
+
+	// tell the segment what kind of data it contains
+	if (FAILED(segment->SetParam(
+				GUID_StandardMIDIFile, 0xFFFFFFFF, 0, 0, performance
+			))) {
+		DEBUG(misc, 0) ("DirectMusic: SetParam (MIDI file) failed");
+		return;
+	}
+
+	// tell the segment to 'download' the instruments
+	if (FAILED(segment->SetParam(GUID_Download, 0xFFFFFFFF, 0, 0, performance))) {
+		DEBUG(misc, 0) ("DirectMusic: Failed to download instruments");
+		return;
+	}
+
+	// start playing the MIDI file
+	if (FAILED(performance->PlaySegment(segment, 0, 0, NULL))) {
+		DEBUG(misc, 0) ("DirectMusic: PlaySegment failed");
+		return;
+	}
+
+	seeking = true;
+}
+
+
+static void DMusicMidiStopSong(void)
+{
+	if (FAILED(performance->Stop(segment, NULL, 0, 0))) {
+		DEBUG(misc, 0) ("DirecMusic: StopSegment failed");
+	}
+	seeking = false;
+}
+
+
+static bool DMusicMidiIsSongPlaying(void)
+{
+	/* Not the nicest code, but there is a short delay before playing actually
+	 * starts. OpenTTD makes no provision for this. */
+	if (performance->IsPlaying(segment, NULL) == S_OK) {
+		seeking = false;
+		return true;
+	} else {
+		return seeking;
+	}
+}
+
+
+static void DMusicMidiSetVolume(byte vol)
+{
+	// 0 - 127 -> -2000 - 0
+	long db = vol * 2000 / 127 - 2000;
+	performance->SetGlobalParam(GUID_PerfMasterVolume, &db, sizeof(db));
+}
+
+
+extern "C" const HalMusicDriver _dmusic_midi_driver = {
+	DMusicMidiStart,
+	DMusicMidiStop,
+	DMusicMidiPlaySong,
+	DMusicMidiStopSong,
+	DMusicMidiIsSongPlaying,
+	DMusicMidiSetVolume,
+};
+
+#endif