OpenGL テクスチャ作成のために Golang で画像ピクセルをバイト配列に変換する方法

package main

import (
    "fmt"
    "image"
    "image/png"
    "os"
)

func main() {
    // Open the image file
    file, err := os.Open("./image.png")
    if err != nil {
        fmt.Println("Error: Unable to open the image file.")
        return
    }
    defer file.Close()

    // Decode the image
    img, _, err := image.Decode(file)
    if err != nil {
        fmt.Println("Error: Unable to decode the image.")
        return
    }

    // Get the pixel array
    pixelArray, err := GetPixelArray(img)
    if err != nil {
        fmt.Println("Error: Unable to get the pixel array.")
        return
    }

    fmt.Println("Pixel array:")
    fmt.Println(pixelArray)
}

// GetPixelArray converts an image to a byte array containing the RGBA values of its pixels.
func GetPixelArray(img image.Image) ([]byte, error) {
    bounds := img.Bounds()
    width, height := bounds.Max.X, bounds.Max.Y

    // Create a byte array to store the pixel values
    pixelArray := make([]byte, 0, width*height*4)

    // Iterate over the pixels and add their RGBA values to the byte array
    for y := 0; y < height; y++ {
        for x := 0; x < width; x++ {
            r, g, b, a := img.At(x, y).RGBA()

            pixelArray = append(pixelArray, byte(r/257))
            pixelArray = append(pixelArray, byte(g/257))
            pixelArray = append(pixelArray, byte(b/257))
            pixelArray = append(pixelArray, byte(a/257))
        }
    }

    return pixelArray, nil
}