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ios/include/filament/BufferObject.h

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+/*
+ * Copyright (C) 2021 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_BUFFEROBJECT_H
+#define TNT_FILAMENT_BUFFEROBJECT_H
+
+#include <filament/FilamentAPI.h>
+
+#include <backend/DriverEnums.h>
+
+#include <backend/BufferDescriptor.h>
+
+#include <utils/compiler.h>
+
+namespace filament {
+
+class FBufferObject;
+
+class Engine;
+
+/**
+ * A generic GPU buffer containing data.
+ *
+ * Usage of this BufferObject is optional. For simple use cases it is not necessary. It is useful
+ * only when you need to share data between multiple VertexBuffer instances. It also allows you to
+ * efficiently swap-out the buffers in VertexBuffer.
+ *
+ * NOTE: For now this is only used for vertex data, but in the future we may use it for other things
+ * (e.g. compute).
+ *
+ * @see VertexBuffer
+ */
+class UTILS_PUBLIC BufferObject : public FilamentAPI {
+    struct BuilderDetails;
+
+public:
+    using BufferDescriptor = backend::BufferDescriptor;
+    using BindingType = backend::BufferObjectBinding;
+
+    class Builder : public BuilderBase<BuilderDetails> {
+        friend struct BuilderDetails;
+    public:
+        Builder() noexcept;
+        Builder(Builder const& rhs) noexcept;
+        Builder(Builder&& rhs) noexcept;
+        ~Builder() noexcept;
+        Builder& operator=(Builder const& rhs) noexcept;
+        Builder& operator=(Builder&& rhs) noexcept;
+
+        /**
+         * Size of the buffer in bytes.
+         * @param byteCount Maximum number of bytes the BufferObject can hold.
+         * @return A reference to this Builder for chaining calls.
+         */
+        Builder& size(uint32_t byteCount) noexcept;
+
+        /**
+         * The binding type for this buffer object. (defaults to VERTEX)
+         * @param BindingType Distinguishes between SSBO, VBO, etc. For now this must be VERTEX.
+         * @return A reference to this Builder for chaining calls.
+         */
+        Builder& bindingType(BindingType bindingType) noexcept;
+
+        /**
+         * Creates the BufferObject and returns a pointer to it. After creation, the buffer
+         * object is uninitialized. Use BufferObject::setBuffer() to initialize it.
+         *
+         * @param engine Reference to the filament::Engine to associate this BufferObject with.
+         *
+         * @return pointer to the newly created object or nullptr if exceptions are disabled and
+         *         an error occurred.
+         *
+         * @exception utils::PostConditionPanic if a runtime error occurred, such as running out of
+         *            memory or other resources.
+         * @exception utils::PreConditionPanic if a parameter to a builder function was invalid.
+         *
+         * @see IndexBuffer::setBuffer
+         */
+        BufferObject* build(Engine& engine);
+    private:
+        friend class FBufferObject;
+    };
+
+    /**
+     * Asynchronously copy-initializes a region of this BufferObject from the data provided.
+     *
+     * @param engine Reference to the filament::Engine associated with this BufferObject.
+     * @param buffer A BufferDescriptor representing the data used to initialize the BufferObject.
+     * @param byteOffset Offset in bytes into the BufferObject
+     */
+    void setBuffer(Engine& engine, BufferDescriptor&& buffer, uint32_t byteOffset = 0);
+
+    /**
+     * Returns the size of this BufferObject in elements.
+     * @return The maximum capacity of the BufferObject.
+     */
+    size_t getByteCount() const noexcept;
+};
+
+} // namespace filament
+
+#endif // TNT_FILAMENT_BUFFEROBJECT_H