bmpLoader.c

//#include <vector.h>
#include <iostream>

#include <GL/gl.h>
#include <GL/glu.h>


typedef union PixelInfo
{
    std::uint32_t Colour;
    struct
    {
        std::uint8_t B, G, R, A;
    };
} *PPixelInfo;


class BMP
{
private:
    std::uint32_t width, height;
    std::uint16_t BitsPerPixel;
    std::vector<std::uint8_t> Pixels;

public:
    BMP(const char* FilePath);
    std::vector<std::uint8_t> GetPixels() const {return this->Pixels;}
    std::uint32_t GetWidth() const {return this->width;}
    std::uint32_t GetHeight() const {return this->height;}
    bool HasAlphaChannel() {return BitsPerPixel == 32;}
};

BMP::BMP(const char* FilePath)
{
    std::fstream hFile(FilePath, std::ios::in | std::ios::binary);
    if (!hFile.is_open()) throw std::invalid_argument("Error: File Not Found.");

    hFile.seekg(0, std::ios::end);
    std::size_t Length = hFile.tellg();
    hFile.seekg(0, std::ios::beg);
    std::vector<std::uint8_t> FileInfo(Length);
    hFile.read(reinterpret_cast<char*>(FileInfo.data()), 54);

    if(FileInfo[0] != 'B' && FileInfo[1] != 'M')
    {
        hFile.close();
        throw std::invalid_argument("Error: Invalid File Format. Bitmap Required.");
    }

    if (FileInfo[28] != 24 && FileInfo[28] != 32)
    {
        hFile.close();
        throw std::invalid_argument("Error: Invalid File Format. 24 or 32 bit Image Required.");
    }

    BitsPerPixel = FileInfo[28];
    width = FileInfo[18] + (FileInfo[19] << 8);
    height = FileInfo[22] + (FileInfo[23] << 8);
    std::uint32_t PixelsOffset = FileInfo[10] + (FileInfo[11] << 8);
    std::uint32_t size = ((width * BitsPerPixel + 31) / 32) * 4 * height;
    Pixels.resize(size);

    hFile.seekg (PixelsOffset, std::ios::beg);
    hFile.read(reinterpret_cast<char*>(Pixels.data()), size);
    hFile.close();
}