PNGTextureReader.h

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#pragma once
 
#include <map>
#include <string>
#include <vector>
 
#include <tdme/tdme.h>
#include <tdme/engine/fileio/textures/fwd-tdme.h>
#include <tdme/engine/fwd-tdme.h>
#include <tdme/utilities/ByteBuffer.h>
 
#include <ext/libpng/png.h>
 
using std::map;
using std::string;
using std::vector;
 
using tdme::engine::Texture;
using tdme::utilities::ByteBuffer;
 
/**
 * PNG texture reader class
 * @author Andreas Drewke
 */
class tdme::engine::fileio::textures::PNGTextureReader final
{
    friend class tdme::engine::Texture;
 
public:
    /**
     * Read PNG header from memory
     * @param pngData png vector data to read PNG from
     * @param width width
     * @param height height
     * @param bytes per pixel
     * @return success
     */
    static bool readHeader(const vector<uint8_t>& pngData, int& width, int& height, uint8_t& bytesPerPixel);
 
    /**
     * Read PNG from memory into texture byte buffer
     * @param pngData png vector data to read PNG from
     * @param textureByteBuffer texture byte buffer
     * @return success
     */
    static bool read(const vector<uint8_t>& pngData, ByteBuffer& textureByteBuffer);
 
    /**
     * Read PNG from memory
     * @param textureId texture id
     * @param pngData png vector data to read PNG from
     * @param powerOfTwo scale image to fit power of two dimensions
     * @param idPrefix id prefix
     */
    static Texture* read(const string& textureId, const vector<uint8_t>& pngData, bool powerOfTwo = true, const string& idPrefix = string());
 
private:
    /**
     * PNG input stream
     */
    class PNGInputStream {
    public:
 
        /**
         * Public constructor
         * @param data data
         */
        PNGInputStream(const vector<uint8_t>* data): offset(0), data(data) {
        }
 
        /**
         * Destructor
         */
        ~PNGInputStream() {
        }
 
        /**
         * Read bytes
         * @param outBytes out bytes
         * @param outBytesToRead out bytes to read
         */
        void readBytes(int8_t* outBytes, int32_t outBytesToRead) {
            for (int32_t i = 0; i < outBytesToRead && offset < data->size(); i++) {
                outBytes[i] = (*data)[offset++];
            }
        }
 
    private:
        int offset;
        const vector<uint8_t>* data;
 
    };
 
    /**
     * Read PNG data from memory
     * @param png_ptr png structure
     * @param outBytes out bytes
     * @param outBytesToRead out bytes to read
     */
    static void readDataFromMemory(png_structp png_ptr, png_bytep outBytes, png_size_t outBytesToRead);
 
};