Multiwindow hold each instance's context and switch them and example

example-multiwindow/addons.make

+ofxImGui
+ofxXmlSettings
\ No newline at end of file

example-multiwindow/src/main.cpp

+#include "ofMain.h"
+#include "ofApp.h"
+#include "ofAppGLFWWindow.h"
+
+//========================================================================
+int main( ){
+	ofGLFWWindowSettings settings;
+	settings.setSize(300, 300);
+	settings.setPosition(ofVec2f(0, 100));
+	auto window1 = ofCreateWindow(settings);
+
+	settings.setPosition(ofVec2f(300, 100));
+	auto window2 = ofCreateWindow(settings);
+
+	auto app1 = std::make_shared<ofApp>();
+	auto app2 = std::make_shared<ofApp>();
+
+	ofRunApp(window1, app1);
+	ofRunApp(window2, app2);
+
+	ofRunMainLoop();
+}

example-multiwindow/src/ofApp.cpp

+#include "ofApp.h"
\ No newline at end of file

example-multiwindow/src/ofApp.h

+#pragma once
+
+#include "ofMain.h"
+#include "ofxImGui.h"
+
+class ofApp : public ofBaseApp{
+
+	public:
+		ofApp() : v(0) {}
+
+		void setup() {
+			gui.setup();
+		}
+		void draw() {
+			gui.begin();
+			ImGui::SliderFloat("slider", &v, 0.f, 10.f);
+			gui.end();
+		}
+
+	private:
+		ofxImGui::Gui gui;
+		float v;
+};

src/Gui.cpp

@@ -12,19 +12,19 @@ namespace ofxImGui
 		: lastTime(0.0f)
 		, theme(nullptr)
 	{
-		ImGui::CreateContext();
+		context = ImGui::CreateContext();
 	}
 
 	//--------------------------------------------------------------
 	Gui::~Gui()
 	{
 		exit();
-		ImGui::DestroyContext();
+		ImGui::DestroyContext(context);
 	}
 
 	//--------------------------------------------------------------
 	void Gui::setup(BaseTheme* theme_, bool autoDraw_) {
-		ImGui::CreateContext();
+		ImGui::SetCurrentContext(context);
 		ImGuiIO& io = ImGui::GetIO();
 
 		io.DisplaySize = ImVec2((float)ofGetWidth(), (float)ofGetHeight());
@@ -66,7 +66,7 @@ namespace ofxImGui
 		}
 		loadedTextures.clear();
 
-		ImGui::DestroyContext();
+		ImGui::DestroyContext(context);
 	}
 
 	//--------------------------------------------------------------
@@ -165,6 +165,7 @@ namespace ofxImGui
 
 	//--------------------------------------------------------------
 	void Gui::begin() {
+		ImGui::SetCurrentContext(context);
 		ImGuiIO& io = ImGui::GetIO();
 
 		float currentTime = ofGetElapsedTimef();

src/Gui.h

@@ -63,5 +63,6 @@ namespace ofxImGui
 		BaseTheme* theme;
 
 		std::vector<ofTexture*> loadedTextures;
+		ImGuiContext* context;
 	};
 }