update headers

ios/include/filagui/ImGuiHelper.h

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+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef FILAGUI_IMGUIHELPER_H_
+#define FILAGUI_IMGUIHELPER_H_
+
+#include <vector>
+#include <functional>
+
+#include <filament/Engine.h>
+#include <filament/IndexBuffer.h>
+#include <filament/Material.h>
+#include <filament/MaterialInstance.h>
+#include <filament/Texture.h>
+#include <filament/TextureSampler.h>
+#include <filament/VertexBuffer.h>
+#include <filament/View.h>
+
+#include <utils/Entity.h>
+#include <utils/Path.h>
+
+struct ImDrawData;
+struct ImGuiIO;
+struct ImGuiContext;
+
+namespace filagui {
+
+// Translates ImGui's draw commands into Filament primitives, textures, vertex buffers, etc.
+// Creates a UI-specific Scene object and populates it with a Renderable. Does not handle
+// event processing; clients can simply call ImGui::GetIO() directly and set the mouse state.
+class UTILS_PUBLIC ImGuiHelper {
+public:
+    // Using std::function instead of a vanilla C callback to make it easy for clients to pass in
+    // lambdas that have captures.
+    using Callback = std::function<void(filament::Engine*, filament::View*)>;
+
+    // The constructor creates its own Scene and places it in the given View.
+    ImGuiHelper(filament::Engine* engine, filament::View* view, const utils::Path& fontPath,
+            ImGuiContext* imGuiContext = nullptr);
+    ~ImGuiHelper();
+
+    // Informs ImGui of the current display size, as well as a scaling factor when scissoring.
+    void setDisplaySize(int width, int height, float scaleX = 1.0f,
+            float scaleY = 1.0f, bool flipVertical = false);
+
+    // High-level utility method that takes a callback for creating all ImGui windows and widgets.
+    // Clients are responsible for rendering the View. This should be called on every frame,
+    // regardless of whether the Renderer wants to skip or not.
+    void render(float timeStepInSeconds, Callback imguiCommands);
+
+    // Low-level alternative to render() that consumes an ImGui command list and translates it into
+    // various Filament calls. This includes updating the vertex buffer, setting up material
+    // instances, and rebuilding the Renderable component that encompasses the entire UI. Since this
+    // makes Filament calls, it must be called from the main thread.
+    void processImGuiCommands(ImDrawData* commands, const ImGuiIO& io);
+
+    // Helper method called after resolving fontPath; public so fonts can be added by caller.
+    void createAtlasTexture(filament::Engine* engine);
+
+    // Returns the client-owned view, useful for drawing 2D overlays.
+    filament::View* getView() const { return mView; }
+
+  private:
+      void createBuffers(int numRequiredBuffers);
+      void populateVertexData(size_t bufferIndex, size_t vbSizeInBytes, void* vbData,
+                  size_t ibSizeInBytes, void* ibData);
+      void createVertexBuffer(size_t bufferIndex, size_t capacity);
+      void createIndexBuffer(size_t bufferIndex, size_t capacity);
+      void syncThreads();
+      filament::Engine* mEngine;
+      filament::View* mView; // The view is owned by the client.
+      filament::Scene* mScene;
+      filament::Material* mMaterial = nullptr;
+      filament::Camera* mCamera = nullptr;
+      std::vector<filament::VertexBuffer*> mVertexBuffers;
+      std::vector<filament::IndexBuffer*> mIndexBuffers;
+      std::vector<filament::MaterialInstance*> mMaterialInstances;
+      utils::Entity mRenderable;
+      utils::Entity mCameraEntity;
+      filament::Texture* mTexture = nullptr;
+      bool mHasSynced = false;
+      ImGuiContext* mImGuiContext;
+      filament::TextureSampler mSampler;
+      bool mFlipVertical = false;
+};
+
+} // namespace filagui
+
+#endif /* FILAGUI_IMGUIHELPER_H_ */