Allow cancelling offline render

Source/PluginEditor.cpp

@@ -360,8 +360,9 @@ void PaulstretchpluginAudioProcessorEditor::showSettingsMenu()
 	menu.addItem(6, "Dump preset to clipboard", true, false);
 #endif
 	menu.addItem(7, "Show technical info", true, processor.m_show_technical_info);
-	menu.addItem(8, "Offline render...", 
-		processor.m_offline_render_state == 200 || processor.m_offline_render_state == -1, false);
+	if (processor.m_offline_render_state==-1 || processor.m_offline_render_state == 200)
+		menu.addItem(8, "Offline render...", true, false);
+	else menu.addItem(9, "Cancel render", true, false);
 	int r = menu.show();
 	if (r >= 200 && r < 210)
 	{
@@ -423,6 +424,10 @@ void PaulstretchpluginAudioProcessorEditor::showSettingsMenu()
 	{
 		processor.offlineRender(File("C:\\MusicAudio\\sourcesamples\\paultesmaus\\plugin_offline_test\\out.wav"));
 	}
+	if (r == 9)
+	{
+		processor.m_offline_render_cancel_requested = true;
+	}
 }
 
 WaveformComponent::WaveformComponent(AudioFormatManager* afm, AudioThumbnail* thumb)

Source/PluginProcessor.cpp

@@ -453,12 +453,15 @@ String PaulstretchpluginAudioProcessor::offlineRender(File outputfile)
 	auto rendertask = [ss,writer,blocksize,numoutchans, outsr, this]()
 	{
 		AudioBuffer<float> renderbuffer(numoutchans, blocksize);
-		int64_t outlen = 50 * outsr;
+		int64_t outlen = 250 * outsr;
 		int64_t outcounter = 0;
 		AudioSourceChannelInfo asci(renderbuffer);
 		m_offline_render_state = 0;
+		m_offline_render_cancel_requested = false;
 		while (outcounter < outlen)
 		{
+			if (m_offline_render_cancel_requested == true)
+				break;
 			ss->getNextAudioBlock(asci);
 			writer->writeFromAudioSampleBuffer(renderbuffer, 0, blocksize);
 			outcounter += blocksize;

Source/PluginProcessor.h

@@ -163,6 +163,7 @@ public:
 	void setStateFromTree(ValueTree tree);
 	String offlineRender(File outputfile);
 	std::atomic<int> m_offline_render_state{ -1 };
+	std::atomic<bool> m_offline_render_cancel_requested{ false };
 	bool m_state_dirty = false;
 	std::unique_ptr<AudioThumbnail> m_thumb;
 	bool m_show_technical_info = false;