Added mouse picking for selecting entities

- Added entity id uniform to the gbuffer
- Added entity id to RenderList
- Added selecting when clicking on an entity

Editor/src/Windows/EditorInterface.cpp

@@ -231,11 +231,29 @@ namespace Nuake {
                     tc.SetGlobalTransform(transform);
                 }
             }
+
+            if (m_IsHoveringViewport && Input::IsMouseButtonPressed(GLFW_MOUSE_BUTTON_1) && !ImGuizmo::IsUsing())
+            {
+                const auto windowPosNuake = Vector2(windowPos.x, windowPos.y);
+                auto& gbuffer = Engine::GetCurrentScene()->mSceneRenderer->GetGBuffer();
+                auto pixelPos = Input::GetMousePosition() - windowPosNuake;
+                pixelPos.y = gbuffer.GetSize().y - pixelPos.y; // imgui coords are inverted on the Y axis
+
+                gbuffer.Bind();
+
+                if (const int result = gbuffer.ReadPixel(3, pixelPos); result >= 0)
+                {
+                    Selection = EditorSelection(Entity{ (entt::entity)result, Engine::GetCurrentScene().get() });
+                }
+
+                gbuffer.Unbind();
+            }
         }
         else
         {
             ImGui::PopStyleVar();
         }
+
         ImGui::End();
     }