ImageLoaderTGA.cpp

Go to the documentation of this file.

#include "ImageLoaders.h"
#include "MercuryTextureManager.h"
#include "MercuryFiles.h"
#include "MercuryLog.h"

struct TGAHeader {
   char  IDLen;                 //String <<after>> header
   char  ColorMapType;          //Should be zero
   char  DataType;              //Describes pixel type
   short ColorMapOrgin;         //Ignore
   short ColorMapLength;        //Ignore
   //char  ColorMapDepth;           //Ignore
   short x_origin;              //Should be zero, ignore if not.
   short y_origin;              //Should be zero, ignore if not.
   short width;                 //Important
   short height;                //Important
   char  bitsperpixel;          //Bits per pixel
   char  imagedescriptor;       //
};

RawImageData* LoadTGA( MercuryFile * fp )
{
    TGAHeader MyHeader;
    char tc;
    int x;
    fp->Read( &MyHeader, sizeof( TGAHeader ) );

    if( MyHeader.ColorMapLength != 0 )
    {
        LOG.Warn( "TGA Loading failed on file:" + fp->GetName() + " Colormaps not supported." );
        return 0;
    }

    RawImageData * tmp = new RawImageData;

    switch( MyHeader.DataType )
    {
    case 2:
        switch( MyHeader.bitsperpixel ) 
        {
        case 24:
            tmp->attrs.m_ColorByteType = RGB;
            break;
        case 32:
            tmp->attrs.m_ColorByteType = RGBA;
            break;
        default:
            LOG.Warn( "TGA Loading failed on file:" + fp->GetName() + " invalid bpp on a RGB image (must be 24 or 32)." );
            delete tmp;
            return 0;
        }
        break;
    case 3:
        tmp->attrs.m_ColorByteType = LUMINANCE_ALPHA;
        if( MyHeader.bitsperpixel != 8 )
        {
            LOG.Warn( "TGA Loading failed on file:" + fp->GetName() + " invalid bpp on a grayscale image (must be 8)." );
            delete tmp;
            return 0;
        }
        break;
    default:
        LOG.Warn( "TGA Loading failed on file:" + fp->GetName() + " invalid data type." );
        delete tmp;
        return 0;
    }

    tmp->attrs.m_dpi_x = tmp->attrs.m_dpi_y = 0;

    tmp->attrs.m_height = MyHeader.height;
    tmp->attrs.m_width = MyHeader.width;

    //Read comment
    char * comment = new char[MyHeader.IDLen + 1];
    fp->Read( comment, MyHeader.IDLen );
    comment[MyHeader.IDLen] = 0;
    if( MyHeader.IDLen )
        LOG.Log( "Tag on TGA file: " + MString( comment ) );
    delete comment;

    //There will be no color table.

    int iImageSize = MyHeader.width * MyHeader.height * MyHeader.bitsperpixel / 8;
    if( tmp->attrs.m_ColorByteType == LUMINANCE_ALPHA )
        tmp->data = new unsigned char[iImageSize*2];
    else
        tmp->data = new unsigned char[iImageSize];
    fp->Read( tmp->data, iImageSize );

    //Swap red with blue
    if( tmp->attrs.m_ColorByteType == RGB )
        for( x = 0; x < iImageSize; x+=3 )
        {
            tc = tmp->data[x];
            tmp->data[x] = tmp->data[x+2];
            tmp->data[x+2] = tc;
        }
    else if( tmp->attrs.m_ColorByteType == RGBA )
        for( x = 0; x < iImageSize; x+=4 )
        {
            tc = tmp->data[x];
            tmp->data[x] = tmp->data[x+2];
            tmp->data[x+2] = tc;
            tmp->data[x+3] = tmp->data[x+3]; //huh? This is zero on virtually all images.
        }
    else if( tmp->attrs.m_ColorByteType == LUMINANCE_ALPHA )
        for( x = (iImageSize*2)-1; x > 0; x-=2 )
        {
            tmp->data[x] = tmp->data[x/2];
            tmp->data[x-1] = 255;
        }

    return tmp;
}

RUN_STATEMENT_AT_BOOT( include_tga1, IMAGEREADERREGISTER.AddDecoder( LoadTGA, "\0\0\2" ); ) //RGB uncompressed
RUN_STATEMENT_AT_BOOT( include_tga2, IMAGEREADERREGISTER.AddDecoder( LoadTGA, "\0\0\3" ); ) //grayscale uncompressed


/* 
 * Copyright (c) 2006 Charles Lohr
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the following
 * conditions are met:
 *  -   Redistributions of source code must retain the above
 *      copyright notice, this list of conditions and the following disclaimer.
 *  -   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.
 *  -   Neither the name of the Mercury Engine nor the names of its
 *      contributors may be used to endorse or promote products derived from
 *      this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT OWNER OR CONTRIBUTORS 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.
 */

---

Hosted by