mGUI: Improve loading speed (fixes #1957)

CHANGES

@@ -97,6 +97,7 @@ Misc:
  - FFmpeg: Add looping option for GIF/APNG
  - mGUI: Show battery percentage
  - mGUI: Skip second scan loop when possible
+ - mGUI: Improve loading speed (fixes mgba.io/i/1957)
  - Qt: Renderer can be changed while a game is running
  - Qt: Add hex index to palette view
  - Qt: Add transformation matrix info to sprite view

src/core/core.c

@@ -153,12 +153,23 @@ bool mCorePreloadVFCB(struct mCore* core, struct VFile* vf, void (cb)(size_t, si
 	vfm = VFileMemChunk(NULL, size);
 #endif
 
-	uint8_t buffer[2048];
+	size_t chunkSize;
+#ifdef FIXED_ROM_BUFFER
+	uint8_t* buffer = (uint8_t*) romBuffer;
+	chunkSize = 0x10000;
+#else
+	uint8_t buffer[0x4000];
+	chunkSize = sizeof(buffer);
+#endif
 	ssize_t read;
 	size_t total = 0;
 	vf->seek(vf, 0, SEEK_SET);
-	while ((read = vf->read(vf, buffer, sizeof(buffer))) > 0) {
+	while ((read = vf->read(vf, buffer, chunkSize)) > 0) {
+#ifdef FIXED_ROM_BUFFER
+		buffer += read;
+#else
 		vfm->write(vfm, buffer, read);
+#endif
 		total += read;
 		if (cb) {
 			cb(total, size, context);

src/feature/gui/gui-runner.c

@@ -296,10 +296,6 @@ static void _log(struct mLogger* logger, int category, enum mLogLevel level, con
 
 static void _updateLoading(size_t read, size_t size, void* context) {
 	struct mGUIRunner* runner = context;
-	if (read & 0x3FFFF) {
-		return;
-	}
-
 	runner->params.drawStart();
 	if (runner->params.guiPrepare) {
 		runner->params.guiPrepare();
@@ -388,7 +384,13 @@ void mGUIRun(struct mGUIRunner* runner, const char* path) {
 		mInputMapInit(&runner->core->inputMap, &GBAInputInfo);
 
 		struct VFile* rom = mDirectorySetOpenPath(&runner->core->dirs, path, runner->core->isROM);
+		if (runner->setFrameLimiter) {
+			runner->setFrameLimiter(runner, false);
+		}
 		found = mCorePreloadVFCB(runner->core, rom, _updateLoading, runner);
+		if (runner->setFrameLimiter) {
+			runner->setFrameLimiter(runner, true);
+		}
 
 #ifdef FIXED_ROM_BUFFER
 		extern size_t romBufferSize;