LoadTexture.cpp

#include "LoadTexture.h"
#include "stdio.h"
#include <iostream>
#include <stdlib.h>

using namespace std;

Image *TextureImage;
RGB myimage[64][64];
RGB* g_pixel;

// texture with alpha
GLvoid LoadTextureAlpha(const char* image_file, int texID) {
  TextureImage = (Image *) malloc(sizeof(Image));
  if (TextureImage == NULL) {
    printf("Error allocating space for image");
    exit(1);
  }
  //cout << "trying to load " << image_file << endl;
  if (!ImageLoad32bpp(image_file, TextureImage)) {
    exit(1);
  }  

  /*  2d texture, level of detail 0 (normal), 3 components (red, green, blue),            */
  /*  x size from image, y size from image,                                              */    
  /*  border 0 (normal), rgb color data, unsigned byte data, data  */ 
  glBindTexture(GL_TEXTURE_2D, texID);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA,
    TextureImage->sizeX, TextureImage->sizeY,
    0, GL_RGBA, GL_UNSIGNED_BYTE, TextureImage->data);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); /*  cheap scaling when image bigger than texture */    
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); /*  cheap scaling when image smalled than texture*/
  
}


//routines to load in a bmp files - must be 2^nx2^m and a 24bit bmp
GLvoid LoadTexture(const char* image_file, int texID) {
  
  TextureImage = (Image *) malloc(sizeof(Image));
  if (TextureImage == NULL) {
    printf("Error allocating space for image");
    exit(1);
  }
  //cout << "trying to load " << image_file << endl;
  if (!ImageLoad(image_file, TextureImage)) {
    exit(1);
  }  
  /*  2d texture, level of detail 0 (normal), 3 components (red, green, blue),            */
  /*  x size from image, y size from image,                                              */    
  /*  border 0 (normal), rgb color data, unsigned byte data, data  */ 
  glBindTexture(GL_TEXTURE_2D, texID);
  glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB,
    TextureImage->sizeX, TextureImage->sizeY,
    0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage->data);
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); /*  cheap scaling when image bigger than texture */    
  glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); /*  cheap scaling when image smalled than texture*/
 
  
}


//code to create a checker board texture...
void makeCheckerBoard ( int nRows, int nCols )
{
  g_pixel = new RGB[nRows * nCols];
  int c;
  
  long count = 0;
  for ( int i=0; i < nRows; i++ ) {
    for ( int j=0; j < nCols; j++ ) {
      count = j*nCols +i;
      c = (((i/8) + (j/8)) %2) * 255;
      g_pixel[count].r = c;
      g_pixel[count].g = c;
      g_pixel[count].b = c;
      
    }
  }
  /* set up the checker board texture as well */ 
  glBindTexture(GL_TEXTURE_2D, 2);
  glTexImage2D(GL_TEXTURE_2D, 0, 3, 64, 64, 0, GL_RGB, GL_UNSIGNED_BYTE, g_pixel);
}


/* BMP file loader loads a 24-bit bmp file only */

/*
* getint and getshort are help functions to load the bitmap byte by byte
*/
static unsigned int getint(FILE *fp) {
  int c, c1, c2, c3;
  
  /*  get 4 bytes */ 
  c = getc(fp);  
  c1 = getc(fp);  
  c2 = getc(fp);  
  c3 = getc(fp);
  
  return ((unsigned int) c) +   
    (((unsigned int) c1) << 8) + 
    (((unsigned int) c2) << 16) +
    (((unsigned int) c3) << 24);
}

static unsigned int getshort(FILE *fp){
  int c, c1;
  
  /* get 2 bytes*/
  c = getc(fp);  
  c1 = getc(fp);
  
  return ((unsigned int) c) + (((unsigned int) c1) << 8);
}

/*  quick and dirty bitmap loader...for 24 bit bitmaps with 1 plane only.  */

int ImageLoad(const char *filename, Image *image) {
  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) */
  char temp;                          /*  used to convert bgr to rgb color. */
  
  /*  make sure the file is there. */
  if ((file = fopen(filename, "rb"))==NULL) {
    printf("File Not Found : %s\n",filename);
    return 0;
  }
  
  /*  seek through the bmp header, up to the width height: */
  fseek(file, 18, SEEK_CUR);
  
  /*  No 100% errorchecking anymore!!! */
  
  /*  read the width */
  image->sizeX = getint (file);
  
  /*  read the height */ 
  image->sizeY = getint (file);
  
  /*  calculate the size (assuming 24 bits or 3 bytes per pixel). */
  size = image->sizeX * image->sizeY * 3;
  
  /*  read the planes */    
  planes = getshort(file);
  if (planes != 1) {
    printf("Planes from %s is not 1: %u\n", filename, planes);
    return 0;
  }
  
  /*  read the bpp */    
  bpp = getshort(file);
  if (bpp != 24) {
    printf("Bpp from %s is not 24: %u\n", filename, bpp);
    return 0;
  }
  
  /*  seek past the rest of the bitmap header. */
  fseek(file, 24, SEEK_CUR);
  
  /*  read the data.  */
  image->data = (char *) malloc(size);
  if (image->data == NULL) {
    printf("Error allocating memory for color-corrected image data");
    return 0; 
  }
  
  if ((i = fread(image->data, size, 1, file)) != 1) {
    printf("Error reading image data from %s.\n", filename);
    return 0;
  }
  
  for (i=0;i<size;i+=3) { /*  reverse all of the colors. (bgr -> rgb) */
    temp = image->data[i];
    image->data[i] = image->data[i+2];
    image->data[i+2] = temp;
  }
  
  fclose(file); /* Close the file and release the filedes */
  
  /*  we're done. */
  return 1;
}


/* modified from 24bit by Mustafa Khafateh */
int ImageLoad32bpp(const char *filename, Image *image) {
  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) */
  char r,g,b;                       /*  used to convert bgr to rgb color. */

  
  /*  make sure the file is there. */
  if ((file = fopen(filename, "rb"))==NULL) {
    printf("File Not Found : %s\n",filename);
    return 0;
  }
  
  /*  seek through the bmp header, up to the width height: */
  fseek(file, 18, SEEK_CUR);
  
  /*  No 100% errorchecking anymore!!! */
  
  /*  read the width */
  image->sizeX = getint (file);
  
  /*  read the height */ 
  image->sizeY = getint (file);
  
  /*  calculate the size (assuming 32 bits or 4 bytes per pixel). */
  size = image->sizeX * image->sizeY * 4;
  
  /*  read the planes */    
  planes = getshort(file);
  if (planes != 1) {
    printf("Planes from %s is not 1: %u\n", filename, planes);
    return 0;
  }
  
  /*  read the bpp */    
  bpp = getshort(file);
  if (bpp != 32) {
    printf("Bpp from %s is not 32: %u\n", filename, bpp);
    return 0;
  }
  
  /*  seek past the rest of the bitmap header. */
  fseek(file, 24, SEEK_CUR);
  
  /*  read the data.  */
  image->data = (char *) malloc(size);
  if (image->data == NULL) {
    printf("Error allocating memory for color-corrected image data");
    return 0; 
  }
  
  if ((i = fread(image->data, size, 1, file)) != 1) {
    printf("Error reading image data from %s.\n", filename);
    return 0;
  }
  
  for (i=0;i<size;i+=4) { /*  reverse all of the colors. (bgr -> rgb) */
    b = image->data[i];
    g = image->data[i+1];
    r = image->data[i+2];
    // a = image->data[i+3];

    image->data[i] = r;
    image->data[i+1] = g;
    image->data[i+2] = b;
    //image->data[i+3] = a;
  }
  
  fclose(file); /* Close the file and release the filedes */
  
  /*  we're done. */
  return 1;
}