screen_overlay.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

// ScreenOverlay is a simple sprite container with no advanced functions.
// Contains an id of a sprite, which may be either owned by overlay, or shared
// to whole game similar to how other objects use sprites.
// May logically exist either on UI or room layer.
// TODO: historically overlay objects contained an actual bitmap in them.
// This was remade into having a dynamic sprite allocated exclusively for
// overlay. But sprites do not have any kind of a ref count of their own
// (unless exported into script as DynamicSprite), so we have to keep an
// overlay's flag, which tells that the sprite it references must be deleted
// on overlay's disposal. This should be improved at some point, by devising
// a better kind of a sprite's ownership mechanic.

#ifndef AGS_ENGINE_AC_SCREEN_OVERLAY_H
#define AGS_ENGINE_AC_SCREEN_OVERLAY_H

#include "common/std/memory.h"
#include "ags/shared/core/types.h"
#include "ags/shared/util/geometry.h"

namespace AGS3 {

// Forward declaration
namespace AGS {
namespace Shared {
class Bitmap;
class Stream;
} // namespace Shared
} // namespace AGS

namespace AGS {
namespace Engine {
class IDriverDependantBitmap;
} // namespace Engine
} // namespace AGS

using namespace AGS; // FIXME later

enum OverlayFlags {
    kOver_AlphaChannel = 0x0001,
    kOver_PositionAtRoomXY = 0x0002, // room-relative position, may be in ui
    kOver_RoomLayer = 0x0004,        // work in room layer (as opposed to UI)
    kOver_SpriteShared = 0x0008   // reference shared sprite (as opposed to exclusive)
};

enum OverlaySvgVersion {
    kOverSvgVersion_Initial = 0,
    kOverSvgVersion_35028   = 1, // offset x,y
    kOverSvgVersion_36008   = 2, // z, transparency
    kOverSvgVersion_36025   = 3, // merged options into flags
    kOverSvgVersion_36108   = 4, // don't save owned sprites (use dynamic sprites)
};

struct ScreenOverlay {
    // Overlay's "type" is a merged special overlay ID and internal container index
    int type = -1;
    // Arbitrary creation order index, meant for resolving equal z-sorting
    int creation_id = 0;
    int timeout = 0;
    // Note that x,y are overlay's properties, that define its position in script;
    // but real drawn position is x + offsetX, y + offsetY;
    int x = 0, y = 0;
    // Border/padding offset for the tiled text windows
    int offsetX = 0, offsetY = 0;
    // Width and height to stretch the texture to
    int scaleWidth = 0, scaleHeight = 0;
    int bgSpeechForChar = -1;
    int associatedOverlayHandle = 0; // script obj handle
    int zorder = INT_MIN;
    int transparency = 0;

    ScreenOverlay() = default;
    ScreenOverlay(ScreenOverlay &&);
    ~ScreenOverlay();
    ScreenOverlay &operator=(ScreenOverlay &&);

    // FIXME: These are private in the upstream repo,
    // but Windows CI complains
    ScreenOverlay(const ScreenOverlay &) = default;
    ScreenOverlay &operator=(const ScreenOverlay &) = default;

    bool HasAlphaChannel() const {
        return (_flags & kOver_AlphaChannel) != 0;
    }
    bool IsSpriteShared() const {
        return (_flags & kOver_SpriteShared) != 0;
    }
    bool IsRoomRelative() const {
        return (_flags & kOver_PositionAtRoomXY) != 0;
    }
    bool IsRoomLayer() const {
        return (_flags & kOver_RoomLayer) != 0;
    }
    void SetAlphaChannel(bool on) {
        on ? _flags |= kOver_AlphaChannel : _flags &= ~kOver_AlphaChannel;
    }
    void SetRoomRelative(bool on) {
        on ? _flags |= kOver_PositionAtRoomXY : _flags &= ~kOver_PositionAtRoomXY;
    }
    void SetRoomLayer(bool on) {
        on ? _flags |= (kOver_RoomLayer | kOver_PositionAtRoomXY) :
            _flags &= ~(kOver_RoomLayer | kOver_PositionAtRoomXY);
    }
    // Gets actual overlay's image, whether owned by overlay or by a sprite reference
    Shared::Bitmap *GetImage() const;
    // Get sprite reference id, or 0 if none set
    int GetSpriteNum() const {
        return _sprnum;
    }
    Size GetGraphicSize() const;
    // Assigns an exclusive image to this overlay; the image will be stored as a dynamic sprite
    // in a sprite cache, but owned by this overlay and therefore disposed at its disposal
    void SetImage(std::unique_ptr<Shared::Bitmap> pic, bool has_alpha = false, int offx = 0, int offy = 0);
    // Assigns a shared sprite to this overlay
    void SetSpriteNum(int sprnum, int offx = 0, int offy = 0);
    // Tells if Overlay has graphically changed recently
    bool HasChanged() const {
        return _hasChanged;
    }
    // Manually marks GUI as graphically changed
    void MarkChanged() {
        _hasChanged = true;
    }
    // Clears changed flag
    void ClearChanged() {
        _hasChanged = false;
    }

    void ReadFromSavegame(Shared::Stream *in, bool &has_bitmap, int32_t cmp_ver);
    void WriteToSavegame(Shared::Stream *out) const;

private:
    void ResetImage();

    int _flags = 0;  // OverlayFlags
    int _sprnum = 0; // sprite id
    bool _hasChanged = false;
};

} // namespace AGS3

#endif