From 77c95618683612ff9c79142daa0a45937ccac1bd Mon Sep 17 00:00:00 2001
From: redstrate <54911369+redstrate@users.noreply.github.com>
Date: Wed, 17 Feb 2021 01:09:12 -0500
Subject: [PATCH] Re-enable multiviewport

Also fixes a bunch of stuff to make multiviewport way more stable
---
 engine/core/include/engine.hpp    |  8 +++++---
 engine/core/src/engine.cpp        | 24 +++++++++++++++---------
 engine/core/src/imguilayer.cpp    |  6 ++----
 engine/renderer/src/imguipass.cpp |  6 ++++--
 platforms/mac/main.mm.in          |  2 ++
 5 files changed, 28 insertions(+), 18 deletions(-)

diff --git a/engine/core/include/engine.hpp b/engine/core/include/engine.hpp
index 1280c3e..657a8e1 100755
--- a/engine/core/include/engine.hpp
+++ b/engine/core/include/engine.hpp
@@ -76,6 +76,8 @@ public:
      @param index The index of the window to begin rendering for.
      */
     void render(const int index);
+    
+    void end_frame();
 
     /// Pause updating.
     void pause();
@@ -344,12 +346,12 @@ private:
         RenderTarget* render_target;
     };
 
-    std::vector<Window> _windows;
+    std::vector<std::unique_ptr<Window>> _windows;
 
     Window* get_window(const int identifier) {
         for(auto& window : _windows) {
-            if(window.identifier == identifier)
-                return &window;
+            if(window->identifier == identifier)
+                return window.get();
         }
         
         return nullptr;
diff --git a/engine/core/src/engine.cpp b/engine/core/src/engine.cpp
index 0ceb1a9..712a505 100755
--- a/engine/core/src/engine.cpp
+++ b/engine/core/src/engine.cpp
@@ -84,11 +84,11 @@ bool Engine::is_paused() const {
 }
 
 void Engine::quit() {
-    _windows[0].quitRequested = true;
+    _windows[0]->quitRequested = true;
 }
 
 bool Engine::is_quitting() const {
-    return _windows[0].quitRequested;
+    return _windows[0]->quitRequested;
 }
 
 void Engine::prepare_quit() {
@@ -193,7 +193,7 @@ ui::Screen* Engine::load_screen(const file::Path path) {
 void Engine::set_screen(ui::Screen* screen) {
     _current_screen = screen;
     
-    screen->extent = _windows[0].extent;
+    screen->extent = _windows[0]->extent;
     screen->calculate_sizes();
     
     get_renderer()->set_screen(screen);
@@ -414,10 +414,12 @@ void Engine::add_window(void* native_handle, const int identifier, const prism::
     
     _gfx->initialize_view(native_handle, identifier, drawable_extent.width, drawable_extent.height);
 
-    Window& window = _windows.emplace_back();
-    window.identifier = identifier;
-    window.extent = extent;
-    window.render_target = _renderer->allocate_render_target(drawable_extent);
+    _windows.push_back(std::move(std::make_unique<Window>()));
+    
+    Window* window = _windows.back().get();
+    window->identifier = identifier;
+    window->extent = extent;
+    window->render_target = _renderer->allocate_render_target(drawable_extent);
 
     render_ready = true;
 }
@@ -425,8 +427,8 @@ void Engine::add_window(void* native_handle, const int identifier, const prism::
 void Engine::remove_window(const int identifier) {
     Expects(identifier >= 0);
 
-    utility::erase_if(_windows, [identifier](Window& w) {
-        return w.identifier == identifier;
+    utility::erase_if(_windows, [identifier](std::unique_ptr<Window>& w) {
+        return w->identifier == identifier;
     });
 }
 
@@ -658,6 +660,10 @@ void Engine::begin_frame(const float delta_time) {
         _app->begin_frame();
 }
 
+void Engine::end_frame() {
+    ImGui::UpdatePlatformWindows();
+}
+
 int frame_delay = 0;
 const int frame_delay_between_resolution_change = 60;
 
diff --git a/engine/core/src/imguilayer.cpp b/engine/core/src/imguilayer.cpp
index c49d5f6..4351cc9 100755
--- a/engine/core/src/imguilayer.cpp
+++ b/engine/core/src/imguilayer.cpp
@@ -41,8 +41,8 @@ ImGuiLayer::ImGuiLayer() {
     io.BackendFlags |= ImGuiBackendFlags_PlatformHasViewports;
     io.BackendPlatformName = "Prism";
     
-    //if(platform::supports_feature(PlatformFeature::Windowing))
-    //    io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;
+    if(platform::supports_feature(PlatformFeature::Windowing))
+        io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;
     
     for (auto& [im, pl] : imToPl)
         io.KeyMap[im] = platform::get_keycode(pl);
@@ -196,8 +196,6 @@ void ImGuiLayer::render(int index) {
     if(index == 0) {
         ImGui::EndFrame();
         ImGui::Render();
-        
-        ImGui::UpdatePlatformWindows();
     }
 }
 
diff --git a/engine/renderer/src/imguipass.cpp b/engine/renderer/src/imguipass.cpp
index 9399eff..0143a58 100755
--- a/engine/renderer/src/imguipass.cpp
+++ b/engine/renderer/src/imguipass.cpp
@@ -75,9 +75,11 @@ void ImGuiPass::render_post(GFXCommandBuffer* command_buffer, const int index) {
     } else {
         auto& io = ImGui::GetPlatformIO();
         for(int i = 1; i < io.Viewports.size(); i++) {
-            if((io.Viewports[i]->Flags & ImGuiViewportFlags_Minimized) == 0)
-                if(*(int*)io.Viewports[i]->PlatformHandle == index)
+            if((io.Viewports[i]->Flags & ImGuiViewportFlags_Minimized) == 0) {
+                auto platform_handle = (int*)io.Viewports[i]->PlatformHandle;
+                if(platform_handle != nullptr && *platform_handle == index)
                     draw_data = io.Viewports[i]->DrawData;
+            }
         }
     }
     
diff --git a/platforms/mac/main.mm.in b/platforms/mac/main.mm.in
index 7cb6f18..fbf5a13 100755
--- a/platforms/mac/main.mm.in
+++ b/platforms/mac/main.mm.in
@@ -615,6 +615,8 @@ int main(int argc, char* argv[]) {
                 if(window != nullptr)
                     [window->delegate render];
             }
+
+            engine->end_frame();
             
             scrollX = 0.0f;
             scrollY = 0.0f;