initial work to split into dart_filament and flutter_filament

flutter_filament/windows/include/filament/backend/Platform.h

@@ -0,0 +1,86 @@
+/*
+ * 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.
+ */
+
+//! \file
+
+#ifndef TNT_FILAMENT_BACKEND_PLATFORM_H
+#define TNT_FILAMENT_BACKEND_PLATFORM_H
+
+#include <backend/DriverEnums.h>
+
+#include <utils/compiler.h>
+
+namespace filament::backend {
+
+class Driver;
+
+/**
+ * Platform is an interface that abstracts how the backend (also referred to as Driver) is
+ * created. The backend provides several common Platform concrete implementations, which are
+ * selected automatically. It is possible however to provide a custom Platform when creating
+ * the filament Engine.
+ */
+class UTILS_PUBLIC Platform {
+public:
+    struct SwapChain {};
+    struct Fence {};
+    struct Stream {};
+
+    struct DriverConfig {
+        /*
+         * size of handle arena in bytes. Setting to 0 indicates default value is to be used.
+         * Driver clamps to valid values.
+         */
+        size_t handleArenaSize = 0;
+    };
+
+    virtual ~Platform() noexcept;
+
+    /**
+     * Queries the underlying OS version.
+     * @return The OS version.
+     */
+    virtual int getOSVersion() const noexcept = 0;
+
+    /**
+     * Creates and initializes the low-level API (e.g. an OpenGL context or Vulkan instance),
+     * then creates the concrete Driver.
+     * The caller takes ownership of the returned Driver* and must destroy it with delete.
+     *
+     * @param sharedContext an optional shared context. This is not meaningful with all graphic
+     *                      APIs and platforms.
+     *                      For EGL platforms, this is an EGLContext.
+     * 
+     * @param driverConfig  specifies driver initialization parameters
+     *
+     * @return nullptr on failure, or a pointer to the newly created driver.
+     */
+    virtual backend::Driver* createDriver(void* sharedContext,
+            const DriverConfig& driverConfig) noexcept = 0;
+
+    /**
+     * Processes the platform's event queue when called from its primary event-handling thread.
+     *
+     * Internally, Filament might need to call this when waiting on a fence. It is only implemented
+     * on platforms that need it, such as macOS + OpenGL. Returns false if this is not the main
+     * thread, or if the platform does not need to perform any special processing.
+     */
+    virtual bool pumpEvents() noexcept;
+};
+
+} // namespace filament
+
+#endif // TNT_FILAMENT_BACKEND_PLATFORM_H