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diff --git a/plugins/gpu_senquack/gpu_inner_quantization.h b/plugins/gpu_senquack/gpu_inner_quantization.h
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+/***************************************************************************
+*   Copyright (C) 2016 PCSX4ALL Team                                      *
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+*   This program is distributed in the hope that it will be useful,       *
+*   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+*   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+*   GNU General Public License for more details.                          *
+*                                                                         *
+*   You should have received a copy of the GNU General Public License     *
+*   along with this program; if not, write to the                         *
+*   Free Software Foundation, Inc.,                                       *
+*   51 Franklin Street, Fifth Floor, Boston, MA 02111-1307 USA.           *
+***************************************************************************/
+
+#ifndef _OP_DITHER_H_
+#define _OP_DITHER_H_
+
+static void SetupDitheringConstants()
+{
+	// Initialize Dithering Constants
+	// The screen is divided into 8x8 chunks and sub-unitary noise is applied
+	// using the following matrix. This ensures that data lost in color
+	// quantization will be added back to the image 'by chance' in predictable
+	// patterns that are naturally 'smoothed' by your sight when viewed from a
+	// certain distance.
+	//
+	// http://caca.zoy.org/study/index.html
+	//
+	// Shading colors are encoded in 4.5, and then are quantitized to 5.0,
+	// DitherMatrix constants reflect that.
+
+	static const u8 DitherMatrix[] = {
+		 0, 32,  8, 40,  2, 34, 10, 42,
+		48, 16, 56, 24, 50, 18, 58, 26,
+		12, 44,  4, 36, 14, 46,  6, 38,
+		60, 28, 52, 20, 62, 30, 54, 22,
+		 3, 35, 11, 43,  1, 33,  9, 41,
+		51, 19, 59, 27, 49, 17, 57, 25,
+		15, 47,  7, 39, 13, 45,  5, 37,
+		63, 31, 55, 23, 61, 29, 53, 21
+	};
+
+	int i, j;
+	for (i = 0; i < 8; i++)
+	{
+		for (j = 0; j < 8; j++)
+		{
+			u16 offset = (i << 3) | j;
+
+			u32 component = ((DitherMatrix[offset] + 1) << 4) / 65; //[5.5] -> [5]
+
+			// XXX - senquack - hack Dec 2016
+			//  Until JohnnyF gets the time to work further on dithering,
+			//   force lower bit of component to 0. This fixes grid pattern
+			//   affecting quality of dithered image, as well as loss of
+			//   detail in dark areas. With lower bit unset like this, existing
+			//   27-bit accuracy of dithering math is unneeded, could be 24-bit.
+			//   Is 8x8 matrix overkill as a result, can we use 4x4?
+			component &= ~1;
+
+			gpu_senquack.DitherMatrix[offset] = (component)
+			                              | (component << 10)
+			                              | (component << 20);
+		}
+	}
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Convert padded u32 5.4:5.4:5.4 bgr fixed-pt triplet to final bgr555 color,
+//  applying dithering if specified by template parameter.
+//
+// INPUT:
+//     'uSrc24' input: 000bbbbbXXXX0gggggXXXX0rrrrrXXXX
+//                     ^ bit 31
+//       'pDst' is a pointer to destination framebuffer pixel, used
+//         to determine which DitherMatrix[] entry to apply.
+// RETURNS:
+//         u16 output: 0bbbbbgggggrrrrr
+//                     ^ bit 16
+// Where 'X' are fixed-pt bits, '0' is zero-padding, and '-' is don't care
+////////////////////////////////////////////////////////////////////////////////
+template <int DITHER>
+GPU_INLINE u16 gpuColorQuantization24(u32 uSrc24, const u16 *pDst)
+{
+	if (DITHER)
+	{
+		u16 fbpos  = (u32)(pDst - gpu_senquack.vram);
+		u16 offset = ((fbpos & (0x7 << 10)) >> 7) | (fbpos & 0x7);
+
+		//clean overflow flags and add
+		uSrc24 = (uSrc24 & 0x1FF7FDFF) + gpu_senquack.DitherMatrix[offset];
+
+		if (uSrc24 & (1<< 9)) uSrc24 |= (0x1FF    );
+		if (uSrc24 & (1<<19)) uSrc24 |= (0x1FF<<10);
+		if (uSrc24 & (1<<29)) uSrc24 |= (0x1FF<<20);
+	}
+
+	return ((uSrc24>> 4) & (0x1F    ))
+	     | ((uSrc24>> 9) & (0x1F<<5 ))
+	     | ((uSrc24>>14) & (0x1F<<10));
+}
+
+#endif //_OP_DITHER_H_