convertBitmap.kt

 private fun convertBitmapToByteBuffer(bitmap: Bitmap): ByteBuffer {
        val byteBuffer = ByteBuffer.allocateDirect(4 * INPUT_SIZE * INPUT_SIZE * PIXEL_SIZE)
        byteBuffer.order(ByteOrder.nativeOrder())
        val intValues = IntArray(INPUT_SIZE * INPUT_SIZE)

        bitmap.getPixels(intValues, 0, bitmap.width, 0, 0, bitmap.width, bitmap.height)
        var pixel = 0
        for (i in 0 until INPUT_SIZE) {
            for (j in 0 until INPUT_SIZE) {
                val `val` = intValues[pixel++]

                byteBuffer.putFloat((((`val`.shr(16)  and 0xFF) - IMAGE_MEAN) / IMAGE_STD))
                byteBuffer.putFloat((((`val`.shr(8) and 0xFF) - IMAGE_MEAN) / IMAGE_STD))
                byteBuffer.putFloat((((`val` and 0xFF) - IMAGE_MEAN) / IMAGE_STD))
            }
        }
        return byteBuffer
    }