CGUISprite.h

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/* Copyright (C) 2022 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
    A GUI Sprite, which is actually a collage of several
    sprites.
*/

#ifndef INCLUDED_CGUISPRITE
#define INCLUDED_CGUISPRITE

#include "gui/GUIRenderer.h"
#include "gui/SettingTypes/CGUISize.h"
#include "gui/SettingTypes/CGUIColor.h"
#include "lib/file/vfs/vfs_path.h"
#include "ps/CStr.h"
#include "renderer/backend/Sampler.h"

#include <map>
#include <memory>
#include <vector>

class CCanvas2D;

struct SGUIImageEffects
{
    SGUIImageEffects() : m_Greyscale(false) {}
    CGUIColor m_AddColor;
    CGUIColor m_SolidColor;
    bool m_Greyscale;
};

/**
 * A CGUISprite is actually a collage of several <b>real</b>
 * sprites, this struct represents is such real sprite.
 */
struct SGUIImage
{
    NONCOPYABLE(SGUIImage);
public:
    SGUIImage() :
        m_FixedHAspectRatio(0.f),
        m_RoundCoordinates(true),
        m_AddressMode(Renderer::Backend::Sampler::AddressMode::REPEAT),
        m_Effects(),
        m_Size(CGUISize::Full()),
        m_TextureSize(CGUISize::Full())
    {
    }

    // Filename of the texture
    VfsPath m_TextureName;

    // Image placement (relative to object)
    CGUISize m_Size;

    // Texture placement (relative to image placement)
    CGUISize m_TextureSize;

    // Because OpenGL wants textures in squares with a power of 2 (64x64, 256x256)
    //  it's sometimes tedious to adjust this. So this value simulates which area
    //  is the real texture
    CRect m_TexturePlacementInFile;

    /**
     * If non-zero, then the image's width will be adjusted when rendering so that
     * the width:height ratio equals this value.
     */
    float m_FixedHAspectRatio;

    /**
     * If true, the image's coordinates will be rounded to integer pixels when
     * rendering, to avoid blurry filtering.
     */
    bool m_RoundCoordinates;

    /**
     * Texture address mode (REPEAT, CLAMP_TO_EDGE, etc).
     */
    Renderer::Backend::Sampler::AddressMode m_AddressMode;

    // Visual effects (e.g. color modulation)
    std::shared_ptr<SGUIImageEffects> m_Effects;

    // Color
    CGUIColor m_BackColor;
};

/**
 * The GUI sprite, is actually several real sprites (images)
 * like a collage. View the section <sprites> in the GUI
 * TDD for more information.
 *
 * Drawing routine is located in CGUI
 *
 * @see CGUI#DrawSprite
 */
class CGUISprite
{
    NONCOPYABLE(CGUISprite);
public:
    CGUISprite() {}
    virtual ~CGUISprite();

    /**
     * Adds an image to the sprite collage.
     *
     * @param image Adds this image to the sprite collage.
     */
    void AddImage(std::unique_ptr<SGUIImage> image);

    /// List of images
    std::vector<std::unique_ptr<SGUIImage>> m_Images;
};

// An instance of a sprite, usually stored in IGUIObjects - basically a string
// giving the sprite's name, but with some extra data to cache rendering
// calculations between draw calls.
class CGUISpriteInstance
{
public:
    NONCOPYABLE(CGUISpriteInstance);
    MOVABLE(CGUISpriteInstance);

    CGUISpriteInstance();
    CGUISpriteInstance(const CStr& SpriteName);

    void Draw(CGUI& pGUI, CCanvas2D& canvas, const CRect& Size, std::map<CStr, std::unique_ptr<const CGUISprite>>& Sprites) const;

    /**
     * Whether this Sprite has no texture name set.
     */
    operator bool() const { return !m_SpriteName.empty(); };

    /**
     * Returns the sprite texture name.
     */
    const CStr& GetName() const { return m_SpriteName; }

    /**
     * Changes the texture name.
     * Use as rarely as possible, because it clears the draw cache.
     */
    void SetName(const CStr& SpriteName);

private:
    CStr m_SpriteName;

    // Stored drawing calls, for more efficient rendering
    mutable GUIRenderer::DrawCalls m_DrawCallCache;
    // Relevant details of previously rendered sprite; the cache is invalidated
    // whenever any of these values changes.
    mutable CRect m_CachedSize;
};

#endif // INCLUDED_CGUISPRITE