EditorLayer.h

        void OnScenePlay();
        void OnSceneStop();
        // UI Panels
        void UI_Toolbar();
    private:
        enum class SceneState
        {
            Edit = 0, Play = 1
        };

        SceneState m_SceneState = SceneState::Edit;

        //编辑器资源
        Ref<Texture2D> m_IconPlay, m_IconStop;

EditorLayer.cpp

OnAttach

        m_IconPlay = Texture2D::Create("Resources/Icons/PlayButton.png");
        m_IconStop = Texture2D::Create("Resources/Icons/StopButton.png");

删去场景相机和控制器以及编辑器的更新逻辑

        // Update
        if (m_ViewportFocused)
            m_CameraController.OnUpdate(ts);
        //场景相机
        m_EditorCamera.OnUpdate(ts)
                // Update scene 拿到scene后，使用场景相机不断更新
        m_ActiveScene->OnUpdateEditor(ts, m_EditorCamera);

换成这个条件判断

        switch (m_SceneState)
        {
            case SceneState::Edit:
            {
                if (m_ViewportFocused)
                    m_CameraController.OnUpdate(ts);
                m_EditorCamera.OnUpdate(ts);
                m_ActiveScene->OnUpdateEditor(ts, m_EditorCamera);
                break;
            }
            case SceneState::Play:
            {
                m_ActiveScene->OnUpdateRuntime(ts);
                break;
            }
        }

单独写个uitoolbars函数

void EditorLayer::UI_Toolbar()
    {
        ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0, 2));
        ImGui::PushStyleVar(ImGuiStyleVar_ItemInnerSpacing, ImVec2(0, 0));
        ImGui::PushStyleColor(ImGuiCol_Button, ImVec4(0, 0, 0, 0));
        auto& colors = ImGui::GetStyle().Colors;
        const auto& buttonHovered = colors[ImGuiCol_ButtonHovered];
        ImGui::PushStyleColor(ImGuiCol_ButtonHovered, ImVec4(buttonHovered.x, buttonHovered.y, buttonHovered.z, 0.5f));
        const auto& buttonActive = colors[ImGuiCol_ButtonActive];
        ImGui::PushStyleColor(ImGuiCol_ButtonActive, ImVec4(buttonActive.x, buttonActive.y, buttonActive.z, 0.5f));
        ImGui::Begin("##toolbar", nullptr, ImGuiWindowFlags_NoDecoration | ImGuiWindowFlags_NoScrollbar | ImGuiWindowFlags_NoScrollWithMouse);
        float size = ImGui::GetWindowHeight() - 4.0f;
        Ref<Texture2D> icon = m_SceneState == SceneState::Edit ? m_IconPlay : m_IconStop;
        ImGui::SetCursorPosX((ImGui::GetWindowContentRegionMax().x * 0.5f) - (size * 0.5f));
        if (ImGui::ImageButton((ImTextureID)icon->GetRendererID(), ImVec2(size, size), ImVec2(0, 0), ImVec2(1, 1), 0))
        {
            if (m_SceneState == SceneState::Edit)
                OnScenePlay();
            else if (m_SceneState == SceneState::Play)
                OnSceneStop();
        }
        ImGui::PopStyleVar(2);
        ImGui::PopStyleColor(3);
        ImGui::End();
    }

实现效果

切换按钮切换到主相机渲染