/*
** imgztexture.cpp
** Texture class for IMGZ style images
**
**---------------------------------------------------------------------------
** Copyright 2004-2006 Randy Heit
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
**
*/

#include "doomtype.h"
#include "files.h"
#include "r_data.h"
#include "w_wad.h"

// [RH] Just a format I invented to avoid WinTex's palette remapping
// when I wanted to insert some alpha maps.

struct FIMGZTexture::ImageHeader
{
	BYTE Magic[4];
	WORD Width;
	WORD Height;
	SWORD LeftOffset;
	SWORD TopOffset;
	BYTE Compression;
	BYTE Reserved[11];
};


bool FIMGZTexture::Check(FileReader & file)
{
	DWORD id;
	file.Seek(0, SEEK_SET);
	return file.Read(&id, 4) == 4 && id == MAKE_ID('I','M','G','Z');
}

FTexture *FIMGZTexture::Create(FileReader & file, int lumpnum)
{
	DWORD magic;
	WORD w, h;
	SWORD l, t;

	file.Seek(0, SEEK_SET);
	file >> magic >> w >> h >> l >> t;
	return new FIMGZTexture(lumpnum, w, h, l, t);
}

FIMGZTexture::FIMGZTexture (int lumpnum, WORD w, WORD h, SWORD l, SWORD t)
	: SourceLump(lumpnum), Pixels(0), Spans(0)
{
	Wads.GetLumpName (Name, lumpnum);
	Name[8] = 0;
	Width = w;
	Height = h;
	LeftOffset = l;
	TopOffset = t;
	CalcBitSize ();
}

FIMGZTexture::~FIMGZTexture ()
{
	Unload ();
	if (Spans != NULL)
	{
		FreeSpans (Spans);
		Spans = NULL;
	}
}

void FIMGZTexture::Unload ()
{
	if (Pixels != NULL)
	{
		delete[] Pixels;
		Pixels = NULL;
	}
}

const BYTE *FIMGZTexture::GetColumn (unsigned int column, const Span **spans_out)
{
	if (Pixels == NULL)
	{
		MakeTexture ();
	}
	if ((unsigned)column >= (unsigned)Width)
	{
		if (WidthMask + 1 == Width)
		{
			column &= WidthMask;
		}
		else
		{
			column %= Width;
		}
	}
	if (spans_out != NULL)
	{
		if (Spans == NULL)
		{
			Spans = CreateSpans (Pixels);
		}
		*spans_out = Spans[column];
	}
	return Pixels + column*Height;
}

const BYTE *FIMGZTexture::GetPixels ()
{
	if (Pixels == NULL)
	{
		MakeTexture ();
	}
	return Pixels;
}

void FIMGZTexture::MakeTexture ()
{
	FMemLump lump = Wads.ReadLump (SourceLump);
	const ImageHeader *imgz = (const ImageHeader *)lump.GetMem();
	const BYTE *data = (const BYTE *)&imgz[1];

	if (Width != 0xFFFF)
	{
		Width = LittleShort(imgz->Width);
		Height = LittleShort(imgz->Height);
		LeftOffset = LittleShort(imgz->LeftOffset);
		TopOffset = LittleShort(imgz->TopOffset);
	}

	BYTE *dest_p;
	int dest_adv = Height;
	int dest_rew = Width * Height - 1;

	CalcBitSize ();
	Pixels = new BYTE[Width*Height];
	dest_p = Pixels;

	// Convert the source image from row-major to column-major format
	if (!imgz->Compression)
	{
		for (int y = Height; y != 0; --y)
		{
			for (int x = Width; x != 0; --x)
			{
				*dest_p = *data;
				dest_p += dest_adv;
				data++;
			}
			dest_p -= dest_rew;
		}
	}
	else
	{
		// IMGZ compression is the same RLE used by IFF ILBM files
		int runlen = 0, setlen = 0;
		BYTE setval = 0;  // Shut up, GCC

		for (int y = Height; y != 0; --y)
		{
			for (int x = Width; x != 0; )
			{
				if (runlen != 0)
				{
					BYTE color = *data;
					*dest_p = color;
					dest_p += dest_adv;
					data++;
					x--;
					runlen--;
				}
				else if (setlen != 0)
				{
					*dest_p = setval;
					dest_p += dest_adv;
					x--;
					setlen--;
				}
				else
				{
					SBYTE code = *data++;
					if (code >= 0)
					{
						runlen = code + 1;
					}
					else if (code != -128)
					{
						setlen = (-code) + 1;
						setval = *data++;
					}
				}
			}
			dest_p -= dest_rew;
		}
	}
}