atlasbook.h

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/***************************************************************************
 *   Copyright (C) 2005-2019 by the FIFE team                              *
 *   http://www.fifengine.net                                              *
 *   This file is part of FIFE.                                            *
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 *   FIFE is free software; you can redistribute it and/or                 *
 *   modify it under the terms of the GNU Lesser General Public            *
 *   License as published by the Free Software Foundation; either          *
 *   version 2.1 of the License, or (at your option) any later version.    *
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 *   This library 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     *
 *   Lesser General Public License for more details.                       *
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 *   Free Software Foundation, Inc.,                                       *
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#ifndef FIFE_VIDEO_ATLASBOOK_H
#define FIFE_VIDEO_ATLASBOOK_H

// Standard C++ library includes
#include <vector>
#include <cassert>
#include <cmath>
#include <algorithm>

// 3rd party library includes

// FIFE includes
// These includes are split up in two parts, separated by one empty line
// First block: files included from the FIFE root src directory
// Second block: files included from the same folder
#include "util/structures/rect.h"

namespace FIFE {

    class AtlasBlock {
    public:
        uint32_t page;
        uint32_t left, right, top, bottom;

        AtlasBlock(const Rect& rect, uint32_t page)
            : page(page),
            left(rect.x), right(rect.right()),
            top(rect.y), bottom(rect.bottom()){
        }

        AtlasBlock() {
        }

        //        (0,0) [left]   [right]
        //           +--------------------
        //           |
        //   [top]   |    +---------+
        //           |    |         |
        //           |    |         |
        //           |    |         |
        //           |    |         |
        //  [bottom] |    +---------+
        //           |

        // bottom > top
        // right > left

        void setTrivial() {
            left = right = top = bottom = 0;
        }

        bool isTrivial() const {
            return getWidth() == 0 || getHeight() == 0;
        }

        uint32_t getWidth() const { return right - left; }
        uint32_t getHeight() const { return bottom - top; }

        AtlasBlock intersects(AtlasBlock const& rect) const;
        void merge(AtlasBlock const& rect);
    };

    class AtlasPage {
    public:
        AtlasPage(uint32_t width, uint32_t height,
            uint32_t pixelSize, uint32_t page)
            : width(width), height(height), pixelSize(pixelSize),
            page(page), freePixels(width*height*pixelSize){
        }

        AtlasBlock* getBlock(uint32_t width, uint32_t height);
        void shrink(bool pot);

        uint32_t getWidth() const {
            return width;
        }

        uint32_t getHeight() const {
            return height;
        }

    private:
        AtlasBlock const* intersects(AtlasBlock const* block) const;

        uint32_t width, height;
        uint32_t pixelSize;
        uint32_t page;
        int32_t freePixels;

        typedef std::vector<AtlasBlock> Blocks;
        Blocks blocks;
    };

    class AtlasBook {
    public:

        AtlasBook(uint32_t pageWidth, uint32_t pageHeight,
            uint32_t pixelSize = 4)
            : pageWidth(pageWidth), pageHeight(pageHeight),
            pixelSize(pixelSize) {
        }

        AtlasBlock* getBlock(uint32_t width, uint32_t height);

        // try to shrink every atlas page
        void shrink(bool pot);

        AtlasPage& getPage(size_t index) {
            return pages[index];
        }

    private:
        // add new atlas to atlas container
        AtlasPage* extendCache(uint32_t minPageWidth, uint32_t minPageHeight);

        // How big the new atlases should be
        uint32_t pageWidth, pageHeight;
        uint32_t pixelSize;

        typedef std::vector<AtlasPage> Pages;
        Pages pages;
    };
}

#endif