work towards getting imgui properly working in viewer

platform/imgui_backend/imgui_backend.go

@@ -60,7 +60,6 @@ func Init() error {
 		io.KeyMap(imguiKey, nativeKey)
 	}
 
-	singleton.fontTexture = createFontTexture()
 	singleton.isInit = true
 
 	return nil
@@ -87,6 +86,10 @@ func NewFrame(windowSize math.Vec2i) error {
 		return ErrWasNotInit
 	}
 
+	if singleton.fontTexture == 0 {
+		singleton.fontTexture = createFontTexture()
+	}
+
 	// Setup display size (every frame to accommodate for window resizing)
 	io := imgui.CurrentIO()
 	io.SetDisplaySize(imgui.Vec2{X: float32(windowSize.X), Y: float32(windowSize.Y)})

platform/platform.go

@@ -70,6 +70,21 @@ func Shutdown() error {
 	return nil
 }
 
+func CreateWindow(title string, width, height int, scene Scene) (*Window, error) {
+	if !state.isInit {
+		return nil, ErrWasNotInit
+	}
+
+	window, err := newWindow(title, width, height, scene)
+	if err != nil {
+		return nil, err
+	}
+
+	state.windows = append(state.windows, window)
+
+	return window, err
+}
+
 func ProcessEvents() error {
 	if !state.isInit {
 		return ErrWasNotInit
@@ -91,21 +106,6 @@ func ProcessEvents() error {
 	return nil
 }
 
-func CreateWindow(title string, width, height int, scene Scene) (*Window, error) {
-	if !state.isInit {
-		return nil, ErrWasNotInit
-	}
-
-	window, err := newWindow(title, width, height, scene)
-	if err != nil {
-		return nil, err
-	}
-
-	state.windows = append(state.windows, window)
-
-	return window, err
-}
-
 func advanceWindows() {
 	for _, window := range state.windows {
 		window.advance()

platform/window.go

@@ -29,13 +29,13 @@ func newWindow(title string, width, height int, scene Scene) (*Window, error) {
 		return nil, err
 	}
 
-	sdlGlContext, err := sdlWindow.GLCreateContext()
+	sdlRenderer, err := sdl.CreateRenderer(sdlWindow, -1, sdl.RENDERER_ACCELERATED)
 	if err != nil {
 		sdlWindow.Destroy()
 		return nil, err
 	}
 
-	sdlRenderer, err := sdl.CreateRenderer(sdlWindow, -1, sdl.RENDERER_ACCELERATED)
+	sdlGlContext, err := sdlWindow.GLCreateContext()
 	if err != nil {
 		sdlWindow.Destroy()
 		return nil, err
@@ -83,7 +83,9 @@ func (w *Window) RenderTexture(texture *Texture, srcRect, dstRect math.Rect4i) {
 func (w *Window) advance() {
 	imgui_backend.NewFrame(w.displaySize())
 	w.scene.Advance(w)
+
 	imgui.Render()
+
 	w.sdlWindow.GLMakeCurrent(w.sdlGlContext)
 	imgui_backend.Render(w.displaySize(), w.bufferSize(), imgui.RenderedDrawData())
 	w.sdlWindow.GLSwap()