source: orxonox.OLD/orxonox/trunk/src/lib/graphics/importer/texture.cc @ 3655

/* 
   orxonox - the future of 3D-vertical-scrollers

   Copyright (C) 2004 orx

   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, or (at your option)
   any later version.

   ### File Specific:
   main-programmer: Benjamin Grauer
   co-programmer: ...

   TGA-code: borrowed from nehe-Tutorials

*/


#define DEBUG_SPECIAL_MODULE DEBUG_MODULE_IMPORTER

#include "texture.h"

#include "graphics_engine.h"

// headers only for PathList
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <fstream>

/**
   \brief creates a ned PathList.
   
   It is a good idea to use this as an initial List,
   because if you give on a name the Path will not be checked for its existence.
*/
PathList::PathList()
{
  this->pathName = NULL;
  this->next = NULL;
}

/**
   \brief Creates a new PathList with a Name.
   \param pName the Name of The Path.

   This function just adds the Path without checking if it exists.
*/
PathList::PathList(char* pName)
{
  this->pathName = new char [strlen(pName)+1];
  strcpy (this->pathName, pName);
  this->next = NULL;
}

/**
   \brief destroys a PathList

   It does this by deleting the Name and then delete its preceding PathList.
*/
PathList::~PathList()
{
  if (this->pathName)
    delete []this->pathName;
  if (this->next)
    delete this->next;
}

PathList* PathList::firstPath = NULL;

/**
   \returns A Pointer to the first Path of the Pathlist
*/
PathList* PathList::getInstance(void)
{
  if (firstPath)
    return firstPath;
  firstPath = new PathList();
}
/**
   \brief Adds a new Pathlist Element.
   \param pName
   
   Adding a Path automatically checks if the Path exists,
   and if it does not it will not add it to the List.
*/
void PathList::addPath (char* pName)
{
  if (pName[0] == '\0')
    {
      PRINTF(2)("not Adding empty Path to the List.\n");
      return;
    }
  char* tmpPName = new char[strlen(pName)];
  strncpy(tmpPName, pName, strlen(pName)-1);
  tmpPName[strlen(pName)-1] = '\0';
  if (access (tmpPName, F_OK) == 0)
    {
      struct stat status;
      stat(tmpPName, &status);
      if (status.st_mode & S_IFDIR)
        {
          PRINTF(4)("Adding Path %s to the PathList.\n", pName);
          PathList* tmpPathList = this;
          while (tmpPathList->next)
            tmpPathList = tmpPathList->next;
          tmpPathList->next = new PathList(pName);
        }
      else
        PRINTF(2)("You tried to add non-folder %s to a PathList.\n", tmpPName);
    }
  else
      PRINTF(2)("You tried to add non-existing folder %s to a PathList.\n", tmpPName);
  delete []tmpPName;
}



/**
   \brief Constructor for a Texture
*/
Texture::Texture(void)
{
  this->pImage = new Image;
  this->pImage->data = NULL;
  this->map = NULL;
  this->texture = 0;
}

/**
   \brief Constructor for a Texture
*/
Texture::Texture(const char* imageName)
{
  this->pImage = new Image;
  this->pImage->data = NULL;
  this->map = NULL;
  this->texture = 0;
  this->loadImage(imageName);
}  

/**
   \brief Destructor of a Texture
   
   Frees Data, and deletes the textures from GL
*/
Texture::~Texture(void)
{
  if (this->pImage->data)
    delete []this->pImage->data;
  delete pImage;
  if (this->texture)
    glDeleteTextures(1, &this->texture);
}

/**
   \brief Searches for a Texture inside one of the defined Paths
   \param texName The name of the texture o search for.
   \returns pathName+texName if texName was found in the pathList. NULL if the Texture is not found.
*/
char* Texture::searchTextureInPaths(const char* texName) const
{
  char* tmpName = NULL;
  PathList* pList = PathList::getInstance();
  while (pList)
    {
      if (pList->pathName)
        {
          tmpName = new char [strlen(pList->pathName)+strlen(texName)+1];
          strcpy(tmpName, pList->pathName);
        }
      else
        {
          tmpName = new char [strlen(texName)+1];
          tmpName[0]='\0';
        }
      strcat(tmpName, texName);
      if (access (tmpName, F_OK) == 0)
        return tmpName;
      
      if (tmpName)
        delete []tmpName;
      tmpName = NULL;
      pList = pList->next;
    }
  return NULL;
}

/**
   \brief a Simple function that switches two char values
   \param a The first value
   \param b The second value
*/
inline void Texture::swap (unsigned char &a, unsigned char &b)
{
  unsigned char temp;
  temp = a;
  a    = b;
  b    = temp;
}


/**
   \brief Loads a Texture to the openGL-environment.
   \param pImage The Image to load to openGL
*/
bool Texture::loadTexToGL (Image* pImage)
{
  if (GraphicsEngine::texturesEnabled)
    {
      PRINTF(4)("Loading texture to OpenGL-Environment.\n");
      glGenTextures(1, &this->texture);
      glBindTexture(GL_TEXTURE_2D, this->texture);
      /* not Working, and not needed. 
         glTexImage2D( GL_TEXTURE_2D, 0, 3, width,
         height, 0, GL_BGR,
         GL_UNSIGNED_BYTE, map->pixels );
      */ 
      gluBuild2DMipmaps(GL_TEXTURE_2D, 3, pImage->width, pImage->height, pImage->format, GL_UNSIGNED_BYTE, pImage->data);
      
      glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST);
      glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR_MIPMAP_LINEAR);     
    }
}

#ifdef HAVE_SDL_SDL_IMAGE_H
bool Texture::loadImage(const char* imageName)
{
  if (GraphicsEngine::texturesEnabled)
    {
      char* imgNameWithPath = searchTextureInPaths(imageName);
      if (imgNameWithPath)
        {
          this->map=IMG_Load(imgNameWithPath);
          if(!map)
            {
              PRINTF(1)("IMG_Load: %s\n", IMG_GetError());
              return false;
            }
          pImage->height = map->h;
          pImage->width  = map->w;
          pImage->data   = (GLubyte*)map->pixels;
          pImage->bpp    = map->format->BytesPerPixel;
          if (pImage->bpp == 3)
            pImage->format = GL_RGB;
          else if (pImage->bpp == 4)
            pImage->format = GL_RGBA;
          
          if( !IMG_isPNG(SDL_RWFromFile(imgNameWithPath, "rb")) && !IMG_isJPG(SDL_RWFromFile(imgNameWithPath, "rb")))
            for (int i=0;i<map->h * map->w *3;i+=3)
              { 
                GLuint temp = pImage->data[i];
                pImage->data[i] = pImage->data[i+2];
                pImage->data[i+2] = temp;
              }
          /* this is the real swapping algorithm */
          for( int i = 0 ; i < (pImage->height / 2) ; ++i )
            for( int j = 0 ; j < pImage->width * pImage->bpp; j += pImage->bpp )
              for(int k = 0; k < pImage->bpp; ++k)
                swap( pImage->data[ (i * pImage->width * pImage->bpp) + j + k], pImage->data[ ( (pImage->height - i - 1) * pImage->width * pImage->bpp ) + j + k]);
          
          this->loadTexToGL (this->pImage);
          SDL_FreeSurface(map);
          this->pImage->data = NULL;
        }
      else
        {
          PRINTF(2)("Image not Found: %s\n", imgNameWithPath);
          return false;
        }
    }
}


#else /* HAVE_SDL_SDL_IMAGE_H */
/**
   \brief Makes the Programm ready to Read-in a texture-File
   1. Checks what type of Image should be imported
   \todo Checks where to find the Image
*/
bool Texture::loadImage(const char* imageName)
{
  if (GraphicsEngine::texturesEnabled)
    {
      char* imgNameWithPath = searchTextureInPaths(imageName);
      if (imgNameWithPath)
        {
          if (!strncmp(imgNameWithPath+strlen(imgNameWithPath)-4, ".bmp", 4))
            {
              PRINTF(4)("Requested bmp-image. Trying to Import.\n");
              return this->loadBMP(imgNameWithPath);
            }
          
          else if (!strncmp(imgNameWithPath+strlen(imgNameWithPath)-4, ".jpg", 4) || !strncmp(imgNameWithPath+strlen(imgNameWithPath)-5, ".jpg", 5))
            {
              PRINTF(4)("Requested jpeg-image. Trying to Import\n");
              return this->loadJPG(imgNameWithPath);
            }
          else if (!strncmp(imgNameWithPath+strlen(imgNameWithPath)-4, ".tga", 4))
            {
              PRINTF(4)("Requested tga-image. Trying to Import\n");
              return this->loadTGA(imgNameWithPath);
            }
          else if (!strncmp(imgNameWithPath+strlen(imgNameWithPath)-4, ".png", 4))
            {
              PRINTF(4)("Requested png-image. Trying to Import\n");
              return this->loadPNG(imgNameWithPath);
            }
          else
            {
              PRINTF(2)("Requested Image was not recognized in its type. (Maybe a type-Cast-error.)\n FileName: %s", imgNameWithPath);
              return false;
            }
        }
      else
        {
          PRINTF(2)("Image not Found: %s\n", imgNameWithPath);
          return false;
        }
    }
}
/**
   \brief reads in a Windows BMP-file, and imports it to openGL.
   \param bmpName The name of the Image to load.
*/
bool Texture::loadBMP (char* bmpName)
{
  FILE *file;
  unsigned long size;                 // size of the image in bytes.
  unsigned long i;                    // standard counter.
  unsigned short int planes;          // number of planes in image (must be 1) 
  unsigned short int bpp;             // number of bits per pixel (must be 24)
  GLuint temp;                          // temporary color storage for bgr-rgb conversion.

  // make sure the file is there.
  if ((file = fopen(bmpName, "rb"))==NULL)
    {
      PRINTF(2)("File Not Found : %s\n",bmpName);
      return false;
    }
  // seek through the bmp header, up to the width/height:
  fseek(file, 18, SEEK_CUR);
  
  // read the width
  if ((i = fread(&pImage->width, 4, 1, file)) != 1) 
    {
      PRINTF(2)("Error reading width from %s.\n", bmpName);
      return false;
    }
  // read the height 
  if ((i = fread(&pImage->height, 4, 1, file)) != 1) 
    {
      PRINTF(2)("Error reading height from %s.\n", bmpName);
      return false;
    }
  
  // calculate the size (assuming 24 bits or 3 bytes per pixel).
  size = pImage->width * pImage->height * 3;
  
  // read the planes
  if ((fread(&planes, 2, 1, file)) != 1) 
    {
      PRINTF(2)("Error reading planes from %s.\n", bmpName);
      return false;
    }
  if (planes != 1) 
    {
      PRINTF(1)("Planes from %s is not 1: %u\n", bmpName, planes);
      return false;
    }
  
  // read the bpp
  if ((i = fread(&bpp, 2, 1, file)) != 1) 
    {
      PRINTF(2)("Error reading bpp from %s.\n", bmpName);
      return false;
    }
  if (bpp != 24) 
    {
      PRINTF(2)("Bpp from %s is not 24: %u\n", bmpName, bpp);
      return false;
    }
  
  // seek past the rest of the bitmap header.
  fseek(file, 24, SEEK_CUR);
  
  // read the data. 
  pImage->data = (GLubyte *) malloc(size);
  if (pImage->data == NULL) 
    {
      PRINTF(2)("Error allocating memory for color-corrected image data");
      return false;     
    }
  
  if ((i = fread(pImage->data, size, 1, file)) != 1) 
    {
      PRINTF(2)("Error reading image data from %s.\n", bmpName);
      return false;
    }
  fclose(file);

  // reverse all of the colors. (bgr -> rgb)
  for (i=0;i<size;i+=3) 
    { 
      temp = pImage->data[i];
      pImage->data[i] = pImage->data[i+2];
      pImage->data[i+2] = temp;
    }
  this->loadTexToGL (pImage);
  

  if (pImage)
    {
      if (pImage->data)
        {
          free(pImage->data);
        }
      
      free(pImage);
    }
  return true;

}

/**
   \brief reads in a jpg-file
   \param jpgName the Name of the Image to load
*/
bool Texture::loadJPG (char* jpgName)
{
#ifdef HAVE_JPEGLIB_H
  struct jpeg_decompress_struct cinfo;
  Image *pImage = NULL;
  FILE *pFile;
  
  // Open a file pointer to the jpeg file and check if it was found and opened 
  if((pFile = fopen(jpgName, "rb")) == NULL) 
    {
      // Display an error message saying the file was not found, then return NULL
      PRINTF(2)("Unable to load JPG File %s.\n", jpgName);
      return false;
    }
  
  // Create an error handler
  jpeg_error_mgr jerr;
  
  // Have our compression info object point to the error handler address
  cinfo.err = jpeg_std_error(&jerr);
  
  // Initialize the decompression object
  jpeg_create_decompress(&cinfo);
  
  // Specify the data source (Our file pointer) 
  jpeg_stdio_src(&cinfo, pFile);
  
  // Allocate the structure that will hold our eventual jpeg data (must free it!)
  pImage = (Image*)malloc(sizeof(Image));
  
  // DECOFING
  // Read in the header of the jpeg file
  jpeg_read_header(&cinfo, TRUE);
  
  // Start to decompress the jpeg file with our compression info
  jpeg_start_decompress(&cinfo);
  
  // Get the image dimensions and row span to read in the pixel data
  pImage->rowSpan = cinfo.image_width * cinfo.num_components;
  pImage->width   = cinfo.image_width;
  pImage->height   = cinfo.image_height;
  
  // Allocate memory for the pixel buffer
  pImage->data = new unsigned char[pImage->rowSpan * pImage->height];
  
  // Here we use the library's state variable cinfo.output_scanline as the
  // loop counter, so that we don't have to keep track ourselves.
  
  // Create an array of row pointers
  unsigned char** rowPtr = new unsigned char*[pImage->height];
  for (int i = 0; i < pImage->height; i++)
    rowPtr[i] = &(pImage->data[i*pImage->rowSpan]);
  
  // Now comes the juice of our work, here we extract all the pixel data
  int rowsRead = 0;
  while (cinfo.output_scanline < cinfo.output_height) 
    {
      // Read in the current row of pixels and increase the rowsRead count
      rowsRead += jpeg_read_scanlines(&cinfo, &rowPtr[rowsRead], cinfo.output_height - rowsRead);
    }
  
  // Delete the temporary row pointers
  delete [] rowPtr;
  
  // Finish decompressing the data
  jpeg_finish_decompress(&cinfo);//  decodeJPG(&cinfo, pImage);
  
  // This releases all the stored memory for reading and decoding the jpeg
  jpeg_destroy_decompress(&cinfo);
  
  // Close the file pointer that opened the file
  fclose(pFile);
  

  if(pImage == NULL)
    exit(0);
  
  this->loadTexToGL (pImage);
  if (pImage)
    {
      if (pImage->data)
        {
          free(pImage->data);
        }
      
      free(pImage);
    }
  return true;
#else /* HAVE_JPEGLIB_H */
  PRINTF(1)("sorry, but you did not compile with jpeg-support.\nEither install SDL_image or jpeglib, and recompile to see the image\n");
  return false;
#endif /* HAVE_JPEGLIB_H */

}

/**
   \brief reads in a tga-file
   \param tgaName the Name of the Image to load
*/
bool Texture::loadTGA(const char * tgaName)
{
  typedef struct
  {
    GLubyte Header[12];
  } TGAHeader;
  TGAHeader tgaHeader;                  
  
  GLubyte uTGAcompare[12] = {0,0,2, 0,0,0,0,0,0,0,0,0}; // Uncompressed TGA Header 
  GLubyte cTGAcompare[12] = {0,0,10,0,0,0,0,0,0,0,0,0}; // Compressed TGA Header 
  FILE * fTGA;
  fTGA = fopen(tgaName, "rb");

  if(fTGA == NULL)
    {
      PRINTF(2)("Error could not open texture file: %s\n", tgaName);
      return false;
    }
  
  if(fread(&tgaHeader, sizeof(TGAHeader), 1, fTGA) == 0)
    {
      PRINTF(2)("Error could not read file header of %s\n", tgaName);
      if(fTGA != NULL)
        {
          fclose(fTGA);
        }
      return false;
    }
  
  if(memcmp(uTGAcompare, &tgaHeader, sizeof(TGAHeader)) == 0)
    {
      loadUncompressedTGA(tgaName, fTGA);
      if (fTGA)
        fclose (fTGA);
    }
  else if(memcmp(cTGAcompare, &tgaHeader, sizeof(TGAHeader)) == 0)
    {
      loadCompressedTGA(tgaName, fTGA);
        if (fTGA)
          fclose (fTGA);
    }
  else
    {
      PRINTF(2)("Error TGA file be type 2 or type 10\n");
      if (fTGA)
        fclose(fTGA);
      return false;
    }
  return true;
}

/**
   \brief reads in an uncompressed tga-file
   \param filename the Name of the Image to load
   \param fTGA a Pointer to a File, that should be read
*/
bool Texture::loadUncompressedTGA(const char * filename, FILE * fTGA)
{
  GLubyte header[6];      // First 6 Useful Bytes From The Header 
  GLuint  bytesPerPixel;  // Holds Number Of Bytes Per Pixel Used In The TGA File 
  GLuint  imageSize;      // Used To Store The Image Size When Setting Aside Ram 
  GLuint  temp;           // Temporary Variable
  GLuint  type;
  GLuint  Height;         // Height of Image 
  GLuint  Width;          // Width of Image 
  GLuint  Bpp;            // Bits Per Pixel 

  GLuint cswap;
  if(fread(header, sizeof(header), 1, fTGA) == 0)
    {
      PRINTF(2)("Error could not read info header\n");
      return false;
    }
  
  Width = pImage->width  = header[1] * 256 + header[0];
  Height =  pImage->height = header[3] * 256 + header[2];
  Bpp = pImage->bpp = header[4];
  // Make sure all information is valid
  if((pImage->width <= 0) || (pImage->height <= 0) || ((pImage->bpp != 24) && (pImage->bpp !=32)))
    {
      PRINTF(2)("Error invalid texture information\n");
      return false;
    }
  
  if(pImage->bpp == 24) 
    {
      pImage->type = GL_RGB;
    }
  else
    {
      pImage->type = GL_RGBA;
    }
  
  bytesPerPixel = (Bpp / 8);
  imageSize = (bytesPerPixel * Width * Height);
  pImage->data = (GLubyte*) malloc(imageSize);
  
  if(pImage->data == NULL)
    {
      PRINTF(2)("Error could not allocate memory for image\n");
      return false;
    }
  
  if(fread(pImage->data, 1, imageSize, fTGA) != imageSize)
    {
      PRINTF(2)("Error could not read image data\n");
      if(pImage->data != NULL)
        {
          free(pImage->data);
        }
      return false;
    }
  
  for(cswap = 0; cswap < (int)imageSize; cswap += bytesPerPixel)
    {
      pImage->data[cswap] ^= pImage->data[cswap+2] ^=
        pImage->data[cswap] ^= pImage->data[cswap+2];
    }
  
  this->loadTexToGL (pImage);

  return true;
}

/**
   \brief reads in a compressed tga-file
   \param filename the Name of the Image to load
   \param fTGA a Pointer to a File, that should be read
*/
bool Texture::loadCompressedTGA(const char * filename, FILE * fTGA)
{
  GLubyte header[6];      // First 6 Useful Bytes From The Header 
  GLuint  bytesPerPixel;  // Holds Number Of Bytes Per Pixel Used In The TGA File 
  GLuint  imageSize;      // Used To Store The Image Size When Setting Aside Ram 
  GLuint  temp;           // Temporary Variable
  GLuint  type;
  GLuint  Height;         // Height of Image 
  GLuint  Width;          // Width of Image 
  GLuint  Bpp;            // Bits Per Pixel 

  if(fread(header, sizeof(header), 1, fTGA) == 0)
    {
      PRINTF(2)("Error could not read info header\n");
      return false;
    }
  
  Width = pImage->width  = header[1] * 256 + header[0];
  Height = pImage->height = header[3] * 256 + header[2];
  Bpp = pImage->bpp     = header[4];

  GLuint pixelcount     = Height * Width;
  GLuint currentpixel   = 0;
  GLuint currentbyte    = 0;
  GLubyte * colorbuffer = (GLubyte *)malloc(bytesPerPixel);

  //Make sure all pImage info is ok 
  if((pImage->width <= 0) || (pImage->height <= 0) || ((pImage->bpp != 24) && (pImage->bpp !=32)))
    {
      PRINTF(2)("Error Invalid pImage information\n");
      return false;
    }
  
  bytesPerPixel = (Bpp / 8);
  imageSize             = (bytesPerPixel * Width * Height);
  pImage->data  = (GLubyte*) malloc(imageSize);
  
  if(pImage->data == NULL)
    {
      PRINTF(2)("Error could not allocate memory for image\n");
      return false;
    }
  
  do
    {
      GLubyte chunkheader = 0;
      
      if(fread(&chunkheader, sizeof(GLubyte), 1, fTGA) == 0)
        {
          PRINTF(2)("Error could not read RLE header\n");
          if(pImage->data != NULL)
            {
              free(pImage->data);
            }
          return false;
        }
      // If the ehader is < 128, it means the that is the number of RAW color packets minus 1 
      if(chunkheader < 128)
        {
          short counter;
          chunkheader++;
          // Read RAW color values
          for(counter = 0; counter < chunkheader; counter++)
            { 
              // Try to read 1 pixel 
              if(fread(colorbuffer, 1, bytesPerPixel, fTGA) != bytesPerPixel)
                {
                  PRINTF(2)("Error could not read image data\n");
                  if(colorbuffer != NULL)
                    {
                      free(colorbuffer);
                    }
                  
                  if(pImage->data != NULL)
                    {
                      free(pImage->data);
                    }
                  
                  return false; 
                }
              // write to memory 
              // Flip R and B vcolor values around in the process 
              pImage->data[currentbyte    ] = colorbuffer[2];                               
              pImage->data[currentbyte + 1] = colorbuffer[1];
              pImage->data[currentbyte + 2] = colorbuffer[0];
              
              if(bytesPerPixel == 4) // if its a 32 bpp image 
                {
                  pImage->data[currentbyte + 3] = colorbuffer[3];// copy the 4th byte 
                }
              
              currentbyte += bytesPerPixel;
              currentpixel++;

              // Make sure we haven't read too many pixels 
              if(currentpixel > pixelcount)     
                {
                  PRINTF(2)("Error too many pixels read\n");
                  if(colorbuffer != NULL)
                    {
                      free(colorbuffer);
                    }
                  
                  if(pImage->data != NULL)
                    {
                      free(pImage->data);
                    }
                  
                  return false;
                }
            }
        }
      // chunkheader > 128 RLE data, next color  reapeated chunkheader - 127 times
      else
        {
          short counter;
          chunkheader -= 127;   // Subteact 127 to get rid of the ID bit 
          if(fread(colorbuffer, 1, bytesPerPixel, fTGA) != bytesPerPixel) // Attempt to read following color values 
            {
              PRINTF(2)("Error could not read from file");
              if(colorbuffer != NULL)
                {
                  free(colorbuffer);
                }
              
              if(pImage->data != NULL)
                {
                  free(pImage->data);
                }
              
              return false;
            }
          
          for(counter = 0; counter < chunkheader; counter++) //copy the color into the image data as many times as dictated
            {                                                   
              // switch R and B bytes areound while copying
              pImage->data[currentbyte    ] = colorbuffer[2];
              pImage->data[currentbyte + 1] = colorbuffer[1];
              pImage->data[currentbyte + 2] = colorbuffer[0];
              
              if(bytesPerPixel == 4)
                {
                  pImage->data[currentbyte + 3] = colorbuffer[3];
                }
              
              currentbyte += bytesPerPixel;
              currentpixel++;
              
              if(currentpixel > pixelcount)
                {
                  PRINTF(2)("Error too many pixels read\n");
                  if(colorbuffer != NULL)
                    {
                      free(colorbuffer);
                    }
                  
                  if(pImage->data != NULL)
                    {
                      free(pImage->data);
                    }
                  
                  return false;
                }
            }
        }
    }
  
  while(currentpixel < pixelcount);     // Loop while there are still pixels left

  this->loadTexToGL (pImage);

  return true;
}


/**
   \brief reads in a png-file
   \param pngName the Name of the Image to load
*/
bool Texture::loadPNG(const char* pngName)
{
#ifdef HAVE_PNG_H

  FILE *PNG_file = fopen(pngName, "rb");
  if (PNG_file == NULL)
    {
      return 0;
    }
  
  GLubyte PNG_header[8];
  
  fread(PNG_header, 1, 8, PNG_file);
  if (png_sig_cmp(PNG_header, 0, 8) != 0)
    {
      PRINTF(2)("Not Recognized as a pngFile\n");
      fclose (PNG_file);
      return 0;
    }
  
  png_structp PNG_reader = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
  if (PNG_reader == NULL)
    {
      fclose(PNG_file);
      return 0;
    }
  
  png_infop PNG_info = png_create_info_struct(PNG_reader);
  if (PNG_info == NULL)
    {
      png_destroy_read_struct(&PNG_reader, NULL, NULL);
      fclose(PNG_file);
      return 0;
    }
  
  png_infop PNG_end_info = png_create_info_struct(PNG_reader);
  if (PNG_end_info == NULL)
    {
      png_destroy_read_struct(&PNG_reader, &PNG_info, NULL);
      fclose(PNG_file);
      return 0;
    }
  
  if (setjmp(png_jmpbuf(PNG_reader)))
    {
      png_destroy_read_struct(&PNG_reader, &PNG_info, &PNG_end_info);
      fclose(PNG_file);
      return (0);
    }
  
  png_init_io(PNG_reader, PNG_file);
  png_set_sig_bytes(PNG_reader, 8);
  
  png_read_info(PNG_reader, PNG_info);
  
  pImage->width = png_get_image_width(PNG_reader, PNG_info);
  pImage->height = png_get_image_height(PNG_reader, PNG_info);
  
  png_uint_32 bit_depth, color_type;
  bit_depth = png_get_bit_depth(PNG_reader, PNG_info);
  color_type = png_get_color_type(PNG_reader, PNG_info);
  
  if (color_type == PNG_COLOR_TYPE_PALETTE)
    {
      png_set_palette_to_rgb(PNG_reader);
    }
  
  if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
    {
      png_set_gray_1_2_4_to_8(PNG_reader);
    }
  
  if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
    {
      png_set_gray_to_rgb(PNG_reader);
    }
  
  if (png_get_valid(PNG_reader, PNG_info, PNG_INFO_tRNS))
    {
      png_set_tRNS_to_alpha(PNG_reader);
    }
  else
    {
      png_set_filler(PNG_reader, 0xff, PNG_FILLER_AFTER);
    }
  
  if (bit_depth == 16)
    {
      png_set_strip_16(PNG_reader);
    }
  
  png_read_update_info(PNG_reader, PNG_info);
  
  pImage->data = (png_byte*)malloc(4 * pImage->width * pImage->height);
  png_byte** PNG_rows = (png_byte**)malloc(pImage->height * sizeof(png_byte*));
  
  unsigned int row;
  for (row = 0; row < pImage->height; ++row)
    {
      PNG_rows[pImage->height - 1 - row] = pImage->data + (row * 4 * pImage->width);
    }
  
  png_read_image(PNG_reader, PNG_rows);
  
  free(PNG_rows);
  
  png_destroy_read_struct(&PNG_reader, &PNG_info, &PNG_end_info);
  fclose(PNG_file);
  
  /*  if (!ST_is_power_of_two(pImage->width) || !ST_is_power_of_two(pImage->height))
    {
      free(pImage->data);
      return 0;
    }
  */
  this->loadTexToGL (pImage);  
  
  free(pImage->data);
  
  return true;
#else /* HAVE_PNG_H */
  PRINTF(1)("sorry, but you did not compile with png-support.\nEither install SDL_image or libpng, and recompile to see the image\n");
  return false;
#endif /* HAVE_PNG_H */

}
#endif /* HAVE_SDL_SDL_IMAGE_H */