How can I use a .bmp file and create a Texture in Unity at runtime?

Question

I'm working in a Unity Project where the user choose image files (in .bmp format) that is used to make a Texture2D and pasted to a model, I create the next code, I work fine with .png and .jpg file, but when I try load .bmp I got only a (I assume) default texture with a red "?" symbol, so I think is for the image format, how can I create a Texture using .bmp files at run-time?

this is my code:

public static Texture2D LoadTexture(string filePath)
{
    Texture2D tex = null;
    byte[] fileData;

    if (File.Exists(filePath))
    {
        fileData = File.ReadAllBytes(filePath);
        tex = new Texture2D(2, 2);
        tex.LoadImage(fileData);
    }

    return tex;
}

Answer 1

The Texture2D.LoadImage function is only used to load PNG/JPG image byte array into a Texture. It doesn't support .bmp so the red symbol which usually means corrupted or unknown image is expected.

To load .bmp image format in Unity, you have to read and understand the .bmp format specification then implement a method that converts its byte array into Unity's Texture. Luckily, this has already been done by another person. Grab the BMPLoader plugin here.

To use it, include the using B83.Image.BMP namespace:

public static Texture2D LoadTexture(string filePath)
{
    Texture2D tex = null;
    byte[] fileData;

    if (File.Exists(filePath))
    {
        fileData = File.ReadAllBytes(filePath);

        BMPLoader bmpLoader = new BMPLoader();
        //bmpLoader.ForceAlphaReadWhenPossible = true; //Uncomment to read alpha too

        //Load the BMP data
        BMPImage bmpImg = bmpLoader.LoadBMP(fileData);

        //Convert the Color32 array into a Texture2D
        tex = bmpImg.ToTexture2D();
    }
    return tex;
}

You can also skip the File.ReadAllBytes(filePath); part and pass the .bmp image path directly to the BMPLoader.LoadBMP function:

public static Texture2D LoadTexture(string filePath)
{
    Texture2D tex = null;

    if (File.Exists(filePath))
    {
        BMPLoader bmpLoader = new BMPLoader();
        //bmpLoader.ForceAlphaReadWhenPossible = true; //Uncomment to read alpha too

        //Load the BMP data
        BMPImage bmpImg = bmpLoader.LoadBMP(filePath);

        //Convert the Color32 array into a Texture2D
        tex = bmpImg.ToTexture2D();
    }
    return tex;
}