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/cygdrive/d/Eigene Dateien/!DProcs/code_gen/src/tga.cpp

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/*
   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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

   See gpl.txt for more information regarding the GNU General Public License.


    File    : tga.c
    Date    : 05/05/1999
    Author  : Nate Miller
    Contact : vandals1@home.com

    Change Log
    **********
    8/07/99 - made the code portable
    7/26/99 - added code to fclose () a file when there is an error
    6/11/99 - added support for 8bit images, changed commenting

    2/04/04 - added createTexture(), modified getRGBA and getGray
*/
#include "tga.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef _WIN32
#include <windows.h>
#endif
#include <GL/gl.h>
#include <GL/glu.h>

#include <iostream>
using namespace std;

GLenum texFormat;

typedef unsigned char BYTE ;

/*
=============
checkSize

Make sure its a power of 2.
=============
*/
int checkSize (int x)
{
    if (x == 2   || x == 4 || 
        x == 8   || x == 16 || 
        x == 32  || x == 64 ||
        x == 128 || x == 256 || x == 512)
        return 1;
    else return 0;
}
/*
=============
getRGBA

Reads in RGBA data for a 32bit image. 
=============
*/
unsigned char *getRGBA (FILE *s, int size)
{
    BYTE *rgba;
    BYTE temp;
    int bread;
    int i;

    rgba = new BYTE[size*4]; //malloc (size * 4);

    if (rgba == NULL)
        return 0;

    bread = fread (rgba, sizeof (unsigned char), size * 4, s); 

    if (bread != size * 4)
    {
        delete[] rgba; //free (rgba);
        return 0;
    }

    /* TGA is stored in BGRA, make it RGBA */
    /* transparent color is magenta (1,0,1), which is set to (1,1,1,1) */
    for (i = 0; i < size * 4; i += 4 )
    {
        temp = rgba[i];
        rgba[i] = rgba[i + 2];
        rgba[i + 2] = temp;
        if ((rgba[i] == 255) && (rgba[i+1] == 0) && (rgba[i+2] == 255))
        {
           // set alpha to 0
           rgba[i+3] = 0;
           rgba[i+1] = 255;
        }
        else
        {
           // else alpha is set to full opaque
           rgba[i+3] = 255;
        }

    }

    texFormat = GL_RGBA;
    return rgba;
}
/*
=============
getRGB

Reads in RGB data for a 24bit image. 
=============
*/
unsigned char *getRGB (FILE *s, int size)
{
    BYTE *rgb;
    BYTE temp;
    int bread;
    int i;

    rgb = new BYTE[size*3]; // malloc (size * 3);

    if (rgb == NULL)
        return 0;

    bread = fread (rgb, sizeof (unsigned char), size * 3, s);

    if (bread != size * 3)
    {
        delete[] rgb; //free (rgb);
        return 0;
    }

    /* TGA is stored in BGR, make it RGB */
    for (i = 0; i < size * 3; i += 3)
    {
        temp = rgb[i];
        rgb[i] = rgb[i + 2];
        rgb[i + 2] = temp;
    }

    texFormat = GL_RGB;

    return rgb;
}
/*
=============
getGray

Gets the grayscale image data.  Used as an alpha channel.
=============
*/
unsigned char *getGray (FILE *s, int size)
{
    BYTE *grayData;
    int bread;

    grayData = new BYTE[size]; //malloc (size);

    if (grayData == NULL)
        return 0;

    bread = fread (grayData, sizeof (unsigned char), size, s);

    if (bread != size)
    {
        delete[] grayData; //free (grayData);
        return 0;
    }

    //texFormat = GL_ALPHA;
     texFormat = GL_LUMINANCE;
    //texFormat = GL_INTENSITY8;

    return grayData;
}
/*
=============
getData

Gets the image data for the specified bit depth.
=============
*/
unsigned char *getData (FILE *s, int sz, int iBits)
{
    if (iBits == 32)
        return getRGBA (s, sz);
    else if (iBits == 24)
        return getRGB (s, sz);  
    else if (iBits == 8)
        return getGray (s, sz);
    return NULL;
}
/*
=============
returnError
=============
Called when there is an error loading the .tga file.
*/
int returnError (FILE *s, int error)
{
    fclose (s);
    return error;
}
/*
=============
loadTGA

Loads up a targa file.  Supported types are 8,24 and 32 uncompressed images.  
id is the texture ID to bind too.
=============
*/
int loadTGA (char *name, int id)
{
    unsigned char type[4];
    unsigned char info[7];
    unsigned char *imageData = NULL;
    int imageWidth, imageHeight;
    int imageBits, size;
    FILE *s;

    if (!(s = fopen (name, "r+bt")))
        return TGA_FILE_NOT_FOUND;

    fread (&type, sizeof (char), 3, s); // read in colormap info and image type, byte 0 ignored
    fseek (s, 12, SEEK_SET);            // seek past the header and useless info
    fread (&info, sizeof (char), 6, s);

    if (type[1] != 0 || (type[2] != 2 && type[2] != 3))
        returnError (s, TGA_BAD_IMAGE_TYPE);

    imageWidth = info[0] + info[1] * 256; 
    imageHeight = info[2] + info[3] * 256;
    imageBits = info[4]; 

    size = imageWidth * imageHeight; 

    /* make sure dimension is a power of 2 */
    if (!checkSize (imageWidth) || !checkSize (imageHeight))
        returnError (s, TGA_BAD_DIMENSION);

    /* make sure we are loading a supported type */
    if (imageBits != 32 && imageBits != 24 && imageBits != 8)
        returnError (s, TGA_BAD_BITS);

    imageData = getData (s, size, imageBits);

    /* no image data */
    if (imageData == NULL)
        returnError (s, TGA_BAD_DATA);

    fclose (s);

    glBindTexture (GL_TEXTURE_2D, id);
    glPixelStorei (GL_UNPACK_ALIGNMENT, 1);
    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
    /* glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); */
    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    /* glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); */
    glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);


    if (texFormat == GL_LUMINANCE)
    {
         glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
         glTexImage2D (GL_TEXTURE_2D, 0, GL_INTENSITY, imageWidth, imageHeight, 0,
                  GL_LUMINANCE, GL_UNSIGNED_BYTE, imageData);

    }
    else
    {
           glTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
           glTexImage2D (GL_TEXTURE_2D, 0, texFormat, imageWidth, imageHeight, 0,
                  texFormat, GL_UNSIGNED_BYTE, imageData);
   }


    /* release data, its been uploaded */
    free (imageData);

    return 1;
}




unsigned int createTexture( char  *  filename )
{
  #define CHECK_GL_ERROR(msg) {const GLint e = glGetError(); if ((e != 0) && (e != GL_NO_ERROR)) {cerr\
  << endl << "OpenGL-ERROR <0x" << e <<  "> in " __FILE__ "(" << __LINE__ << ")!" << endl << msg << endl;cerr << gluErrorString(e) << endl;}}

  GLuint texid = 0;
  glGenTextures(1,&texid);
  CHECK_GL_ERROR("glGenTextures failed");
  if (loadTGA(filename,texid) != 1)
   {
     cout << "Error occured while tried to load TGA texture from " << filename << endl;
   }

  CHECK_GL_ERROR(filename);

  return texid;

  #undef CHECK_GL_ERROR
} // end of createTexture()

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