/*
 * Copyright (c) 1993-1997, Silicon Graphics, Inc
 * modified 11/10/97 to read image 

/*  texture2.c (taken from checker.c)
 *  This program texture maps a checkerboard image onto
 *  two rectangles.
 *
 *  ******** This program adds a second texture to the mix
    ******** Comments that show its difference from texture.c
    ******** are prefixed by several astericks ************

 */
#include <GL/gl.h>
#include <GL/glu.h>
#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>

/*	Create checkerboard and input images for texture	*/
/*  These have 4 as the last parameter for the Alpha channel */
#define	checkImageWidth 128
#define	checkImageHeight 128
static GLubyte checkImage[checkImageHeight][checkImageWidth][4];
static GLubyte Image[checkImageHeight][checkImageWidth][4];


/*********** This array holds system-generated texture names *******/
static GLuint texName[2];


/***********************************/
/* Read Photoshop image saved as raw, interleaved */
void ReadImage(void)
{
   int I,J;
   
   FILE *fptr; 

   fptr = fopen("Benedict:fruit", "r");    
      
   if (fptr == NULL)
     exit(1);
   else { 
            
      for ( I = 0; I < checkImageHeight; I++)
          for (J = 0; J < checkImageWidth; J++) {
              Image[I][J][0] = (GLubyte) fgetc(fptr);
              Image[I][J][1] = (GLubyte) fgetc(fptr);
              Image[I][J][2] = (GLubyte) fgetc(fptr);                                                 
              Image[I][J][3] = (GLubyte) 255;          
              }
      }
}
/***********************************/
/* Make a checkered texture image */

void makeCheckImage(void)
{
   int i, j, c;    
    
   for (i = 0; i < checkImageHeight; i++) {
      for (j = 0; j < checkImageWidth; j++) {
         c = ((((i&0x8)==0)^((j&0x8))==0))*255;
         checkImage[i][j][0] = (GLubyte) c;
         checkImage[i][j][1] = (GLubyte) c;
         checkImage[i][j][2] = (GLubyte) c;
         checkImage[i][j][3] = (GLubyte) 255;
      }
   }
}

/***********************************/
/* Initialize the shading model and texture */
void init(void)
{    
   glClearColor (0.0, 0.0, 0.0, 0.0);
   glShadeModel(GL_FLAT);
   glEnable(GL_DEPTH_TEST);

   /* If you want to make a checkered image, replace the line 
   below by MakeCheckImage */
   ReadImage();
   makeCheckImage();
   
   glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

   /********* Create two new texture names *************/
   glGenTextures(2, texName);
   
   /********* Create the first texture *****************/
   glBindTexture(GL_TEXTURE_2D, texName[0]);

   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth, checkImageHeight, 
                0, GL_RGBA, GL_UNSIGNED_BYTE, Image);
       
   
   /********* Create the second texture *****************/
   glBindTexture(GL_TEXTURE_2D, texName[1]);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, checkImageWidth, checkImageHeight, 
                0, GL_RGBA, GL_UNSIGNED_BYTE, checkImage);

}

/***********************************/
/* Display a quad with texture */
void display(void)
{
   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
   
   
   glEnable(GL_TEXTURE_2D);
   glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);


  /* Use the first texture */
  glBindTexture(GL_TEXTURE_2D, texName[0]);
  glBegin(GL_QUADS);
   glTexCoord2f(0.0, 0.0); glVertex3f(-2.0, -1.0, 0.0);
   glTexCoord2f(0.0, 1.0); glVertex3f(-2.0, 1.0, 0.0);
   glTexCoord2f(1.0, 1.0); glVertex3f(0.0, 1.0, 0.0);
   glTexCoord2f(1.0, 0.0); glVertex3f(0.0, -1.0, 0.0);
  glEnd();
  
  /* Use the second texture */
  glBindTexture(GL_TEXTURE_2D, texName[1]);
  glBegin(GL_QUADS);
  
   glTexCoord2f(0.0, 0.0); glVertex3f(1.0, -1.0, 0.0);
   glTexCoord2f(0.0, 1.0); glVertex3f(1.0, 1.0, 0.0);
   glTexCoord2f(1.0, 1.0); glVertex3f(2.41421, 1.0, -1.41421);
   glTexCoord2f(1.0, 0.0); glVertex3f(2.41421, -1.0, -1.41421);
   glEnd();
   
   glFlush();
   glDisable(GL_TEXTURE_2D);
}

/***********************************/
/* Basic reshape - nothing unique */

void reshape(int w, int h)
{
   glViewport(0, 0, (GLsizei) w, (GLsizei) h);
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
   gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 30.0);
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();
   glTranslatef(0.0, 0.0, -3.6);
}

/***********************************/
/* Only for exiting program */
void keyboard (unsigned char key, int x, int y)
{
   switch (key) {
      case 27:
         exit(0);
         break;
      default:
         break;
   }
}

/***********************************/
/* Basic main - nothing unique */

int main(int argc, char** argv)
{
   glutInit(&argc, argv);
   glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH);
   glutInitWindowSize(250, 250);
   glutInitWindowPosition(100, 100);
   glutCreateWindow(argv[0]);
   init();
   glutDisplayFunc(display);
   glutReshapeFunc(reshape);
   glutKeyboardFunc(keyboard);
   glutMainLoop();
   return 0; 
}