Improve Y16 color setup

Currently the colors for the Y16 and Y16_BE pixelformats are in the range 0x0000-0xff00. So pure white (0xffff) is never created.

Improve this by using the same byte for both LSB and MSB so the full range is achieved.

index b1147f2..e28f32b 100644
@@ -896,16 +896,12 @@ static void gen_twopix(struct tpg_data *tpg,
 	b_v = tpg->colors[color][2]; /* B or precalculated V */
 
 	switch (tpg->fourcc) {
-	case V4L2_PIX_FMT_GREY:
-		buf[0][offset] = r_y;
-		break;
 	case V4L2_PIX_FMT_Y16:
-		buf[0][offset] = 0;
-		buf[0][offset+1] = r_y;
-		break;
 	case V4L2_PIX_FMT_Y16_BE:
+		buf[0][offset+1] = r_y;
+		/* fall through */
+	case V4L2_PIX_FMT_GREY:
 		buf[0][offset] = r_y;
-		buf[0][offset+1] = 0;
 		break;
 	case V4L2_PIX_FMT_YUV422P:
 	case V4L2_PIX_FMT_YUV420:

Hello Hans

If someone uses vivid as reference (I sometimes do), this could lead to incorrect implementations. If the user don't implement the endianess right he will never notice. I have carried out an endianness bug for some months, until gstreamer was showing "funny" ;) images.

If the problem is that you want to reach saturation, I would rather setting the lsb to 0xff all the time. (i.e. going from 0x00ff to 0xffff).

If we want saturation and zero, we could set the lsb to val?0xff:0;

Regards!