LASreadItemCompressed_RGB12_v2.cs

//===============================================================================
//
//  FILE:  lasreaditemcompressed_rgb12_v2.cs
//
//  CONTENTS:
//
//    Implementation of LASreadItemCompressed for RGB12 items (version 2).
//
//  PROGRAMMERS:
//
//    martin.isenburg@rapidlasso.com  -  http://rapidlasso.com
//
//  COPYRIGHT:
//
//    (c) 2005-2012, martin isenburg, rapidlasso - tools to catch reality
//    (c) of the C# port 2014 by Shinta <shintadono@googlemail.com>
//
//    This is free software; you can redistribute and/or modify it under the
//    terms of the GNU Lesser General Licence as published by the Free Software
//    Foundation. See the COPYING file for more information.
//
//    This software is distributed WITHOUT ANY WARRANTY and without even the
//    implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
//
//  CHANGE HISTORY: omitted for easier Copy&Paste (pls see the original)
//
//===============================================================================

using System;
using System.Diagnostics;

namespace laszip.net
{
	class LASreadItemCompressed_RGB12_v2 : LASreadItemCompressed
	{
		public LASreadItemCompressed_RGB12_v2(ArithmeticDecoder dec)
		{
			// set decoder
			Debug.Assert(dec!=null);
			this.dec=dec;

			// create models and integer compressors
			m_byte_used=dec.createSymbolModel(128);
			m_rgb_diff_0=dec.createSymbolModel(256);
			m_rgb_diff_1=dec.createSymbolModel(256);
			m_rgb_diff_2=dec.createSymbolModel(256);
			m_rgb_diff_3=dec.createSymbolModel(256);
			m_rgb_diff_4=dec.createSymbolModel(256);
			m_rgb_diff_5=dec.createSymbolModel(256);
		}

		public override bool init(laszip_point item)
		{
			// init state

			// init models and integer compressors
			dec.initSymbolModel(m_byte_used);
			dec.initSymbolModel(m_rgb_diff_0);
			dec.initSymbolModel(m_rgb_diff_1);
			dec.initSymbolModel(m_rgb_diff_2);
			dec.initSymbolModel(m_rgb_diff_3);
			dec.initSymbolModel(m_rgb_diff_4);
			dec.initSymbolModel(m_rgb_diff_5);

			// init last item
			Buffer.BlockCopy(item.rgb, 0, last_item, 0, 6);
			return true;
		}

		public override void read(laszip_point item)
		{
			int corr;
			int diff=0;

			uint sym=dec.decodeSymbol(m_byte_used);
			if((sym&(1<<0))!=0)
			{
				corr=(int)dec.decodeSymbol(m_rgb_diff_0);
				item.rgb[0]=(ushort)MyDefs.U8_FOLD(corr+(last_item[0]&255));
			}
			else
			{
				item.rgb[0]=(ushort)(last_item[0]&0xFF);
			}

			if((sym&(1<<1))!=0)
			{
				corr=(int)dec.decodeSymbol(m_rgb_diff_1);
				item.rgb[0]|=(ushort)((MyDefs.U8_FOLD(corr+(last_item[0]>>8)))<<8);
			}
			else
			{
				item.rgb[0]|=(ushort)(last_item[0]&0xFF00);
			}

			if((sym&(1<<6))!=0)
			{
				diff=(item.rgb[0]&0x00FF)-(last_item[0]&0x00FF);
				if((sym&(1<<2))!=0)
				{
					corr=(int)dec.decodeSymbol(m_rgb_diff_2);
					item.rgb[1]=(ushort)MyDefs.U8_FOLD(corr+MyDefs.U8_CLAMP(diff+(last_item[1]&255)));
				}
				else
				{
					item.rgb[1]=(ushort)(last_item[1]&0xFF);
				}

				if((sym&(1<<4))!=0)
				{
					corr=(int)dec.decodeSymbol(m_rgb_diff_4);
					diff=(diff+((item.rgb[1]&0x00FF)-(last_item[1]&0x00FF)))/2;
					item.rgb[2]=(ushort)MyDefs.U8_FOLD(corr+MyDefs.U8_CLAMP(diff+(last_item[2]&255)));
				}
				else
				{
					item.rgb[2]=(ushort)(last_item[2]&0xFF);
				}

				diff=(item.rgb[0]>>8)-(last_item[0]>>8);
				if((sym&(1<<3))!=0)
				{
					corr=(int)dec.decodeSymbol(m_rgb_diff_3);
					item.rgb[1]|=(ushort)((MyDefs.U8_FOLD(corr+MyDefs.U8_CLAMP(diff+(last_item[1]>>8))))<<8);
				}
				else
				{
					item.rgb[1]|=(ushort)(last_item[1]&0xFF00);
				}

				if((sym&(1<<5))!=0)
				{
					corr=(int)dec.decodeSymbol(m_rgb_diff_5);
					diff=(diff+((item.rgb[1]>>8)-(last_item[1]>>8)))/2;
					item.rgb[2]|=(ushort)((MyDefs.U8_FOLD(corr+MyDefs.U8_CLAMP(diff+(last_item[2]>>8))))<<8);
				}
				else
				{
					item.rgb[2]|=(ushort)(last_item[2]&0xFF00);
				}
			}
			else
			{
				item.rgb[1]=item.rgb[0];
				item.rgb[2]=item.rgb[0];
			}

			last_item[0]=item.rgb[0];
			last_item[1]=item.rgb[1];
			last_item[2]=item.rgb[2];
		}

		ArithmeticDecoder dec;
		ushort[] last_item=new ushort[3];

		ArithmeticModel m_byte_used;
		ArithmeticModel m_rgb_diff_0;
		ArithmeticModel m_rgb_diff_1;
		ArithmeticModel m_rgb_diff_2;
		ArithmeticModel m_rgb_diff_3;
		ArithmeticModel m_rgb_diff_4;
		ArithmeticModel m_rgb_diff_5;
	}
}