Add a way to compare images

[bitwes]

This little function could be added to Gut with some modifications:

func compare_pixels(img1, img2):
    var are_the_same = true
    var start_pixel = Vector2(0, 0)
    var end_pixel = Vector2(img1.get_width(), img1.get_height())
    var pixel = start_pixel
    var same_count = 0

    img1.lock()
    img2.lock()
    while(pixel.x < end_pixel.x):
        pixel.y = start_pixel.y
        while(pixel.y < end_pixel.y):
            if(img1.get_pixel(pixel.x, pixel.y) == img2.get_pixel(pixel.x, pixel.y)):
                same_count += 1
            pixel.y += 1
        pixel.x += 1

    img1.unlock()
    img2.unlock()

    var num_pixels = end_pixel - start_pixel
    num_pixels = num_pixels.x * num_pixels.y
    return float(same_count) / float(num_pixels)

• It should take in an optional Rect2 to compare a part of two images.
• It should make sure both contain the Rect2 so that we don't go out of bounds
• When the Rect2 is not supplied then it should make sure that both images are the same size. If you need to compare a smaller image to a section of a larger image you would just pass the Rect2 for the smaller image sieze.
• Could maybe take two Rect2s, one for image1 and another for image2. In that case the method should verify the Rect2s are the same size.

[tom-knight]

What about using https://github.com/lihop/godot-pixelmatch?

[bitwes]

That's probably a WAY better approach.