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Source/Engine/Render2D/FontTextureAtlas.h

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+// Copyright (c) 2012-2020 Wojciech Figat. All rights reserved.
+
+#pragma once
+
+#include "Engine/Core/Collections/Array.h"
+#include "Engine/Content/Assets/Texture.h"
+#include "Engine/Graphics/Textures/GPUTexture.h"
+#include "Engine/Utilities/RectPack.h"
+
+/// <summary>
+/// Texture resource that contains an atlas of cached font glyphs.
+/// </summary>
+API_CLASS(NoSpawn) class FLAXENGINE_API FontTextureAtlas : public Texture
+{
+DECLARE_BINARY_ASSET_HEADER(FontTextureAtlas, TexturesSerializedVersion);
+private:
+
+    struct CopyRowData
+    {
+        // Source data to copy
+        const byte* SrcData;
+
+        // Place to copy data to
+        uint8* DestData;
+
+        // The row number to copy
+        uint32 SrcRow;
+
+        // The row number to copy to
+        uint32 DestRow;
+
+        // The width of a source row
+        uint32 RowWidth;
+
+        // The width of the source texture
+        uint32 SrcTextureWidth;
+
+        // The width of the dest texture
+        uint32 DestTextureWidth;
+    };
+
+public:
+
+    /// <summary>
+    /// Contains information about single texture atlas slot.
+    /// </summary>
+    struct Slot : RectPack<Slot>
+    {
+        Slot(uint32 x, uint32 y, uint32 width, uint32 height)
+            : RectPack<Slot>(x, y, width, height)
+        {
+        }
+
+        void OnInsert()
+        {
+        }
+    };
+
+    /// <summary>
+    /// Describes how to handle texture atlas padding
+    /// </summary>
+    enum PaddingStyle
+    {
+        /// <summary>
+        /// Don't pad the atlas.
+        /// </summary>
+        NoPadding,
+
+        /// <summary>
+        /// Dilate the texture by one pixel to pad the atlas.
+        /// </summary>
+        DilateBorder,
+
+        /// <summary>
+        /// One pixel uniform padding border filled with zeros.
+        /// </summary>
+        PadWithZero,
+    };
+
+private:
+
+    Array<byte> _data;
+    uint32 _width;
+    uint32 _height;
+    PixelFormat _format;
+    uint32 _bytesPerPixel;
+    PaddingStyle _paddingStyle;
+    bool _isDirty;
+    Slot* _root;
+    Array<Slot*> _freeSlots;
+
+public:
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="FontTextureAtlas"/> class.
+    /// </summary>
+    /// <param name="format">The texture pixels format.</param>
+    /// <param name="paddingStyle">The texture entries padding style.</param>
+    /// <param name="index">The atlas index.</param>
+    FontTextureAtlas(PixelFormat format, PaddingStyle paddingStyle, int32 index);
+
+public:
+
+    /// <summary>
+    /// Gets the atlas width.
+    /// </summary>
+    /// <returns>The width.</returns>
+    FORCE_INLINE uint32 GetWidth() const
+    {
+        return _width;
+    }
+
+    /// <summary>
+    /// Gets the atlas height.
+    /// </summary>
+    /// <returns>The height.</returns>
+    FORCE_INLINE uint32 GetHeight() const
+    {
+        return _height;
+    }
+
+    /// <summary>
+    /// Gets the atlas size.
+    /// </summary>
+    /// <returns>The size.</returns>
+    FORCE_INLINE Vector2 GetSize() const
+    {
+        return Vector2(static_cast<float>(_width), static_cast<float>(_height));
+    }
+
+    /// <summary>
+    /// Determines whether this atlas is dirty and data need to be flushed.
+    /// </summary>
+    /// <returns>
+    ///   <c>true</c> if this atlas is dirty; otherwise, <c>false</c>.
+    /// </returns>
+    FORCE_INLINE bool IsDirty() const
+    {
+        return _isDirty;
+    }
+
+    /// <summary>
+    /// Gets padding style for textures in the atlas.
+    /// </summary>
+    /// <returns>The padding style.</returns>
+    FORCE_INLINE PaddingStyle GetPaddingStyle() const
+    {
+        return _paddingStyle;
+    }
+
+    /// <summary>
+    /// Gets amount of pixels to pad textures inside an atlas.
+    /// </summary>
+    /// <returns>The padding amount.</returns>
+    uint32 GetPaddingAmount() const;
+
+public:
+
+    /// <summary>
+    /// Setups the atlas after creation.
+    /// </summary>
+    /// <param name="format">The pixel format.</param>
+    /// <param name="paddingStyle">The padding style.</param>
+    void Setup(PixelFormat format, PaddingStyle paddingStyle);
+
+    /// <summary>
+    /// Initializes the atlas.
+    /// </summary>
+    /// <param name="width">The width.</param>
+    /// <param name="height">The height.</param>
+    void Init(uint32 width, uint32 height);
+
+    /// <summary>
+    /// Adds the new entry to the atlas
+    /// </summary>
+    /// <param name="targetWidth">Width of the entry.</param>
+    /// <param name="targetHeight">Height of the entry.</param>
+    /// <param name="data">The data.</param>
+    /// <returns>The atlas slot occupied by the new entry.</returns>
+    Slot* AddEntry(uint32 targetWidth, uint32 targetHeight, const Array<byte>& data);
+
+    /// <summary>
+    /// Invalidates the cached dynamic entry from the atlas.
+    /// </summary>
+    /// <param name="x">The slot location (X coordinate in atlas pixels).</param>
+    /// <param name="y">The slot location (Y coordinate in atlas pixels).</param>
+    /// <param name="width">The slot width (size in atlas pixels).</param>
+    /// <param name="height">The slot height (size in atlas pixels).</param>
+    /// <returns>True if slot has been freed, otherwise false.</returns>
+    bool Invalidate(uint32 x, uint32 y, uint32 width, uint32 height);
+
+    /// <summary>
+    /// Copies the data into the slot.
+    /// </summary>
+    /// <param name="slot">The slot.</param>
+    /// <param name="data">The data.</param>
+    void CopyDataIntoSlot(const Slot* slot, const Array<byte>& data);
+
+    /// <summary>
+    /// Clears this atlas entries data (doesn't change size/texture etc.).
+    /// </summary>
+    void Clear();
+
+    /// <summary>
+    /// Disposed whole atlas data (texture, nodes etc.).
+    /// </summary>
+    void Dispose();
+
+    /// <summary>
+    /// Flushes this atlas data to the GPU
+    /// </summary>
+    void Flush();
+
+    /// <summary>
+    /// Ensures that texture has been created for that atlas.
+    /// </summary>
+    void EnsureTextureCreated() const;
+
+    /// <summary>
+    /// Determines whether atlas has data synchronized with the GPU.
+    /// </summary>
+    /// <returns><c>true</c> if atlas has data synchronized with the GPU; otherwise, <c>false</c>.</returns>
+    bool HasDataSyncWithGPU() const;
+
+private:
+
+    Slot* invalidate(Slot* parent, uint32 x, uint32 y, uint32 width, uint32 height);
+    void markAsDirty();
+    void copyRow(const CopyRowData& copyRowData) const;
+    void zeroRow(const CopyRowData& copyRowData) const;
+
+protected:
+
+    // [Texture]
+    void unload(bool isReloading) override;
+};