feat(tesseratos): add play pause plugin

tools/tesseratos/CMakeLists.txt

@@ -18,6 +18,7 @@ set(TESSERATOS_SOURCE
 	"src/tesseratos/transform_gizmo/plugin.cpp"
 	"src/tesseratos/metrics_panel/plugin.cpp"
 	"src/tesseratos/collider_gizmos/plugin.cpp"
+	"src/tesseratos/play_pause/plugin.cpp"
 )
 
 add_library(tesseratos ${TESSERATOS_SOURCE})

tools/tesseratos/include/tesseratos/play_pause/plugin.hpp

@@ -0,0 +1,26 @@
+/// @dir
+/// @brief @ref tesseratos-play-pause-plugin plugin directory.
+
+/// @file
+/// @brief Plugin entry point.
+/// @ingroup tesseratos-play-pause-plugin
+
+#pragma once
+
+#include <cubos/engine/prelude.hpp>
+
+namespace tesseratos
+{
+    /// @defgroup tesseratos-play-pause-plugin Play Pause
+    /// @ingroup tesseratos
+    /// @brief Allows changing the current simulation speed, or even pause it.
+    ///
+    /// ## Dependencies
+    /// - @ref imgui-plugin
+    /// - @ref tesseratos-toolbox-plugin
+
+    /// @brief Plugin entry function.
+    /// @param cubos @b CUBOS. main class
+    /// @ingroup tesseratos-play-pause-plugin
+    void playPausePlugin(cubos::engine::Cubos& cubos);
+} // namespace tesseratos

tools/tesseratos/src/tesseratos/play_pause/plugin.cpp

@@ -0,0 +1,70 @@
+#include <imgui.h>
+
+#include <cubos/engine/imgui/plugin.hpp>
+
+#include <tesseratos/play_pause/plugin.hpp>
+#include <tesseratos/toolbox/plugin.hpp>
+
+using cubos::core::reflection::reflect;
+
+using cubos::engine::Cubos;
+using cubos::engine::DeltaTime;
+
+namespace
+{
+    struct State
+    {
+        bool paused{false};
+        float multiplier{1.0F};
+    };
+} // namespace
+
+void tesseratos::playPausePlugin(Cubos& cubos)
+{
+    cubos.addPlugin(cubos::engine::imguiPlugin);
+    cubos.addPlugin(toolboxPlugin);
+
+    cubos.addResource<State>();
+
+    cubos.system("show Play Pause UI").tagged("cubos.imgui").call([](State& state, Toolbox& toolbox, DeltaTime& dt) {
+        if (!toolbox.isOpen("Play Pause"))
+        {
+            return;
+        }
+
+        if (ImGui::Begin("Play Pause"))
+        {
+            if (ImGui::Button("Play"))
+            {
+                state.paused = false;
+                dt.multiplier = state.multiplier;
+            }
+
+            ImGui::SameLine();
+
+            if (ImGui::Button("Pause"))
+            {
+                state.paused = true;
+                dt.multiplier = 0.0;
+            }
+
+            ImGui::SameLine();
+
+            ImGui::Text(state.paused ? "(Paused)" : "(Running)");
+
+            ImGui::SliderFloat("Speed Multiplier", &state.multiplier, 0.0F, 5.0F);
+
+            if (ImGui::Button("Reset"))
+            {
+                state.multiplier = 1.0F;
+            }
+
+            ImGui::End();
+        }
+
+        if (!state.paused)
+        {
+            dt.multiplier = state.multiplier;
+        }
+    });
+}

tools/tesseratos/src/tesseratos/plugin.cpp

@@ -3,6 +3,7 @@
 #include <tesseratos/debug_camera/plugin.hpp>
 #include <tesseratos/entity_inspector/plugin.hpp>
 #include <tesseratos/metrics_panel/plugin.hpp>
+#include <tesseratos/play_pause/plugin.hpp>
 #include <tesseratos/plugin.hpp>
 #include <tesseratos/scene_editor/plugin.hpp>
 #include <tesseratos/settings_inspector/plugin.hpp>
@@ -22,4 +23,5 @@ void tesseratos::plugin(cubos::engine::Cubos& cubos)
     cubos.addPlugin(metricsPanelPlugin);
     cubos.addPlugin(transformGizmoPlugin);
     cubos.addPlugin(colliderGizmosPlugin);
+    cubos.addPlugin(playPausePlugin);
 }