texture_atlas_maker.cpp

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#include "texture_atlas_maker.hpp"
#include <cmath>
#include "font_resources.hpp"
 
namespace rendering_engine
{
 
const Color TextureAtlasMaker::sDefaultPaletteBackgroundColor(0U, 0U, 0U);
 
TextureAtlasMaker::TextureAtlasMaker(std::map<char, ImageData> images)
{
    mImageCollection = images;
}
 
bool TextureAtlasMaker::CreateTextureAtlas(std::map<char, std::pair<unsigned int, unsigned int>>& texAtlasData, ImageData& texAtlasImage)
{
    if( mImageCollection.size() == 0 )
    {
        return false;
    }
 
    //Find palette specification
 
    //Find dimension of each cell
    unsigned int cellWidth;
    unsigned int cellHeight;
    FindCellDimensions(cellWidth, cellHeight);
 
    //Find number of rows and columns
    unsigned int numberOfColumns;
    unsigned int numberOfRows;
    CalculateGridDimensions(numberOfColumns, numberOfRows);
 
    //Create palette
    ImageData textureAtlasPalette(static_cast<unsigned int>(cellWidth * numberOfColumns), static_cast<unsigned int>(cellHeight * numberOfRows));
    textureAtlasPalette.Fill(sDefaultPaletteBackgroundColor);
 
    auto imageIterator = mImageCollection.begin();
 
    for(unsigned int y = 0; y < numberOfRows; y++)
    {
        for(unsigned int x = 0; x < numberOfColumns; x++)
        {
            if( imageIterator != mImageCollection.end() )
            {
                ImageData::DrawImageOnImageAtPos(x * cellWidth, y * cellHeight, textureAtlasPalette, imageIterator->second);
 
                texAtlasData.emplace(imageIterator->first, std::make_pair<unsigned int, unsigned int>(x * cellWidth, y * cellHeight));
 
 
                imageIterator++;
            }
        }
    }
    texAtlasImage = textureAtlasPalette;
 
    return true;
}
 
ImageData TextureAtlasMaker::CreateTextureAtlas(std::unordered_map<std::uint32_t, std::pair<GlyphMetrics, ImageData>>& ioFontAtlas)
{
    if (ioFontAtlas.size() == 0)
    {
        return ImageData();
    }
 
    //Find palette specification
 
    //Find dimension of each cell
    unsigned int cellWidth;
    unsigned int cellHeight;
    FindCellDimensions(cellWidth, cellHeight, ioFontAtlas);
 
    //Find number of rows and columns
    unsigned int numberOfColumns;
    unsigned int numberOfRows;
    CalculateGridDimensions(numberOfColumns, numberOfRows, ioFontAtlas);
 
    //Create palette
    ImageData textureAtlasPalette(static_cast<unsigned int>(cellWidth * numberOfColumns), static_cast<unsigned int>(cellHeight * numberOfRows));
    textureAtlasPalette.Fill(sDefaultPaletteBackgroundColor);
 
    auto imageIterator = ioFontAtlas.begin();
 
    for (unsigned int y = 0; y < numberOfRows; y++)
    {
        for (unsigned int x = 0; x < numberOfColumns; x++)
        {
            if (imageIterator != ioFontAtlas.end())
            {
                ImageData::DrawImageOnImageAtPos(x * cellWidth, y * cellHeight, textureAtlasPalette, imageIterator->second.second);
 
                imageIterator->second.first.atlasX = static_cast<std::uint32_t>(x * cellWidth) + imageIterator->second.first.padding;
                imageIterator->second.first.atlasY = static_cast<std::uint32_t>(y * cellHeight) + imageIterator->second.first.padding;
                
                imageIterator++;
            }
        }
    }
 
    return textureAtlasPalette;
}
 
void TextureAtlasMaker::FindCellDimensions(unsigned int& outputWidth, unsigned int& outputHeight)
{
    unsigned int height = 0U;
    unsigned int width = 0U;
    for( auto& it : mImageCollection )
    {
        if( it.second.GetHeight() >= height )
        {
            height = it.second.GetHeight();
        }
        if( it.second.GetWidth() >= width )
        {
            width = it.second.GetWidth();
        }
    }
 
    outputWidth = width;
    outputHeight = height;
}
 
void TextureAtlasMaker::FindCellDimensions(unsigned int& outputWidth, unsigned int& outputHeight, std::unordered_map<std::uint32_t, std::pair<GlyphMetrics, ImageData>>& fontAtlas)
{
    unsigned int height = 0U;
    unsigned int width = 0U;
    for (auto& it : fontAtlas)
    {
        if (it.second.second.GetHeight() >= height)
        {
            height = it.second.second.GetHeight();
        }
        if (it.second.second.GetWidth() >= width)
        {
            width = it.second.second.GetWidth();
        }
    }
 
    outputWidth = width;
    outputHeight = height;
}
 
void TextureAtlasMaker::CalculateGridDimensions(unsigned int& outputNumberOfColumns, unsigned int& outputNumberOfRows)
{
    unsigned int cellWidth;
    unsigned int cellHeight;
    FindCellDimensions(cellWidth, cellHeight);
 
    const std::size_t cellsNum = mImageCollection.size();
    const double totalSquare =
        static_cast<double>(cellWidth) *
        static_cast<double>(cellHeight) *
        static_cast<double>(cellsNum);
 
    const double rootSq = std::sqrt(totalSquare);
 
    outputNumberOfColumns = static_cast<unsigned int>(
        std::ceil(rootSq / static_cast<double>(cellWidth)));
 
    outputNumberOfRows = static_cast<unsigned int>(
        std::ceil(
            static_cast<double>(cellsNum) /
            static_cast<double>(outputNumberOfColumns)));
}
 
void TextureAtlasMaker::CalculateGridDimensions(unsigned int& outputNumberOfColumns, unsigned int& outputNumberOfRows, std::unordered_map<std::uint32_t, std::pair<GlyphMetrics, ImageData>>& fontAtlas)
{
    unsigned int cellWidth;
    unsigned int cellHeight;
    FindCellDimensions(cellWidth, cellHeight, fontAtlas);
 
    const std::size_t cellsNum = fontAtlas.size();
 
    const double totalSquare =
        static_cast<double>(cellWidth) *
        static_cast<double>(cellHeight) *
        static_cast<double>(cellsNum);
 
    const double rootSq = std::sqrt(totalSquare);
 
    outputNumberOfColumns = static_cast<unsigned int>(
        std::ceil(rootSq / static_cast<double>(cellWidth)));
 
    outputNumberOfRows = static_cast<unsigned int>(
        std::ceil(
            static_cast<double>(cellsNum) /
            static_cast<double>(outputNumberOfColumns)));
}
 
}// rendering_engine