OpenGL texture depth (clipping textures)

Question

I am having an issue with textures showing through textures that are in front of it. I am building a maze, and textures on walls behind the walls closest to the camera are showing through. How do I go about fixing this?

http://imgur.com/1DPNj9L

Heres my code.

#include <windows.h>
#include <GL/gl.h>
#include <GL/glut.h>
#include <stdio.h>

GLuint texture; //the array for our texture
GLuint sky;

float cameraz = -1.0;


GLuint LoadTexture( const char * filename )
{

  GLuint texture;

  int width, height;

  unsigned char * data;

  FILE * file;
  int i;

  file = fopen( filename, "rb" );

  if ( file == NULL ) return 0;
  width = 512;
  height = 512;
  data = (unsigned char *)malloc( width * height * 3 );
  //int size = fseek(file,);
  fread( data, width * height * 3, 1, file );
  fclose( file );

 for(i = 0; i < width * height ; ++i)
{
   int index = i*3;
   unsigned char B,R;
   B = data[index];
   R = data[index+2];

   data[index] = R;
   data[index+2] = B;

}

glGenTextures( 1, &texture );
glBindTexture( GL_TEXTURE_2D, texture );
glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE,GL_MODULATE );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_NEAREST );


glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,GL_REPEAT );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,GL_REPEAT );
gluBuild2DMipmaps( GL_TEXTURE_2D, 3, width, height,GL_RGB, GL_UNSIGNED_BYTE, data );
free( data );

return texture;
}

void FreeTexture( GLuint texture )
{
  glDeleteTextures( 1, &texture );
}
/*
void drawBackground() 
      {
    glMatrixMode(GL_PROJECTION);
    glPushMatrix();
    glOrtho(0, 1, 0, 1, 0, 1);

    glMatrixMode(GL_MODELVIEW);
    glPushMatrix();
    glLoadIdentity();

    // No depth buffer writes for background.
    //glDepthMask( false );

    glBindTexture( GL_TEXTURE_2D,sky);
    glBegin( GL_QUADS ); {
      glTexCoord2f( 0.0f, 0.0f );
      glVertex2f( 0.0f, 0.0f );
      glTexCoord2f( 0.0f, 1.0f );
      glVertex2f( 0.0f, 1.0f );
      glTexCoord2f( 1.0f, 1.0f );
      glVertex2f( 1.0f, 1.0f );
      glTexCoord2f( 1.0f, 0.0f );
      glVertex2f( 1.0f, 0.0f );
    } glEnd();

    //glDepthMask( true );

    glPopMatrix();
    glMatrixMode(GL_PROJECTION);
    glPopMatrix();
    glMatrixMode(GL_MODELVIEW);
      }*/
void drawMaze (void) {


    glBegin(GL_QUADS);
    glVertex3d(-500.0, 0, -500.0);
    glVertex3d(500.0, 0, -500.0);
    glVertex3d(500.0, 0, 500.0);
    glVertex3d(-500.0, 0, 500.0);
    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(0.0, 0.0, 0.0);
    glTexCoord2d(7.0,0.0); glVertex3d(0.0, 0.0, 7.0);
    glTexCoord2d(7.0,1.0); glVertex3d(0.0, 1.0, 7.0);
    glTexCoord2d(0.0,1.0); glVertex3d(0.0, 1.0, 0.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(0.0, 0.0, 7.0);
    glTexCoord2d(4.0,0.0); glVertex3d(4.0, 0.0, 7.0);
    glTexCoord2d(4.0,1.0); glVertex3d(4.0, 1.0, 7.0);
    glTexCoord2d(0.0,1.0); glVertex3d(0.0, 1.0, 7.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(5.0, 0.0, 7.0);
    glTexCoord2d(1.0,0.0); glVertex3d(6.0, 0.0, 7.0);
    glTexCoord2d(1.0,1.0); glVertex3d(6.0, 1.0, 7.0);
    glTexCoord2d(0.0,1.0); glVertex3d(5.0, 1.0, 7.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(6.0, 0.0, 0.0);
    glTexCoord2d(7.0,0.0); glVertex3d(6.0, 0.0, 7.0);
    glTexCoord2d(7.0,1.0); glVertex3d(6.0, 1.0, 7.0);
    glTexCoord2d(0.0,1.0); glVertex3d(6.0, 1.0, 0.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(1.0, 0.0, 0.0);
    glTexCoord2d(5.0,0.0); glVertex3d(6.0, 0.0, 0.0);
    glTexCoord2d(5.0,1.0); glVertex3d(6.0, 1.0, 0.0);
    glTexCoord2d(0.0,1.0); glVertex3d(1.0, 1.0, 0.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(1.0, 0.0, 0.0);
    glTexCoord2d(2.0,0.0); glVertex3d(1.0, 0.0, 2.0);
    glTexCoord2d(2.0,1.0); glVertex3d(1.0, 1.0, 2.0);
    glTexCoord2d(0.0,1.0); glVertex3d(1.0, 1.0, 0.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(1.0, 0.0, 2.0);
    glTexCoord2d(2.0,0.0); glVertex3d(2.0, 0.0, 2.0);
    glTexCoord2d(2.0,1.0); glVertex3d(2.0, 1.0, 2.0);
    glTexCoord2d(0.0,1.0); glVertex3d(1.0, 1.0, 2.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(3.0, 0.0, 0.0);
    glTexCoord2d(1.0,0.0); glVertex3d(3.0, 0.0, 1.0);
    glTexCoord2d(1.0,1.0); glVertex3d(3.0, 1.0, 1.0);
    glTexCoord2d(0.0,1.0); glVertex3d(3.0, 1.0, 0.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(2.0, 0.0, 1.0);
    glTexCoord2d(1.0,0.0); glVertex3d(3.0, 0.0, 1.0);
    glTexCoord2d(1.0,1.0); glVertex3d(3.0, 1.0, 1.0);
    glTexCoord2d(0.0,1.0); glVertex3d(2.0, 1.0, 1.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(4.0, 0.0, 1.0);
    glTexCoord2d(2.0,0.0); glVertex3d(6.0, 0.0, 1.0);
    glTexCoord2d(2.0,1.0); glVertex3d(6.0, 1.0, 1.0);
    glTexCoord2d(0.0,1.0); glVertex3d(4.0, 1.0, 1.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(3.0, 0.0, 2.0);
    glTexCoord2d(2.0,0.0); glVertex3d(5.0, 0.0, 2.0);
    glTexCoord2d(2.0,1.0); glVertex3d(5.0, 1.0, 2.0);
    glTexCoord2d(0.0,1.0); glVertex3d(3.0, 1.0, 2.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(3.0, 0.0, 2.0);
    glTexCoord2d(1.0,0.0); glVertex3d(3.0, 0.0, 3.0);
    glTexCoord2d(1.0,1.0); glVertex3d(3.0, 1.0, 3.0);
    glTexCoord2d(0.0,1.0); glVertex3d(3.0, 1.0, 2.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(2.0, 0.0, 3.0);
    glTexCoord2d(1.0,0.0); glVertex3d(3.0, 0.0, 3.0);
    glTexCoord2d(1.0,1.0); glVertex3d(3.0, 1.0, 3.0);
    glTexCoord2d(0.0,1.0); glVertex3d(2.0, 1.0, 3.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(2.0, 0.0, 3.0);
    glTexCoord2d(1.0,0.0); glVertex3d(2.0, 0.0, 4.0);
    glTexCoord2d(1.0,1.0); glVertex3d(2.0, 1.0, 4.0);
    glTexCoord2d(0.0,1.0); glVertex3d(2.0, 1.0, 3.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(2.0, 0.0, 4.0);
    glTexCoord2d(1.0,0.0); glVertex3d(3.0, 0.0, 4.0);
    glTexCoord2d(1.0,1.0); glVertex3d(3.0, 1.0, 4.0);
    glTexCoord2d(0.0,1.0); glVertex3d(2.0, 1.0, 4.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(3.0, 0.0, 4.0);
    glTexCoord2d(1.0,0.0); glVertex3d(3.0, 0.0, 5.0);
    glTexCoord2d(1.0,1.0); glVertex3d(3.0, 1.0, 5.0);
    glTexCoord2d(0.0,1.0); glVertex3d(3.0, 1.0, 4.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(1.0, 0.0, 5.0);
    glTexCoord2d(2.0,0.0); glVertex3d(3.0, 0.0, 5.0);
    glTexCoord2d(2.0,1.0); glVertex3d(3.0, 1.0, 5.0);
    glTexCoord2d(0.0,1.0); glVertex3d(1.0, 1.0, 5.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(1.0, 0.0, 3.0);
    glTexCoord2d(3.0,0.0); glVertex3d(1.0, 0.0, 6.0);
    glTexCoord2d(3.0,1.0); glVertex3d(1.0, 1.0, 6.0);
    glTexCoord2d(0.0,1.0); glVertex3d(1.0, 1.0, 3.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(0.0, 0.0, 3.0);
    glTexCoord2d(1.0,0.0); glVertex3d(1.0, 0.0, 3.0);
    glTexCoord2d(1.0,1.0); glVertex3d(1.0, 1.0, 3.0);
    glTexCoord2d(0.0,1.0); glVertex3d(0.0, 1.0, 3.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(4.0, 0.0, 3.0);
    glTexCoord2d(2.0,0.0); glVertex3d(6.0, 0.0, 3.0);
    glTexCoord2d(2.0,1.0); glVertex3d(6.0, 1.0, 3.0);
    glTexCoord2d(0.0,1.0); glVertex3d(4.0, 1.0, 3.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(4.0, 0.0, 3.0);
    glTexCoord2d(2.0,0.0); glVertex3d(4.0, 0.0, 5.0);
    glTexCoord2d(2.0,1.0); glVertex3d(4.0, 1.0, 5.0);
    glTexCoord2d(0.0,1.0); glVertex3d(4.0, 1.0, 3.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(4.0, 0.0, 5.0);
    glTexCoord2d(1.0,0.0); glVertex3d(5.0, 0.0, 5.0);
    glTexCoord2d(1.0,1.0); glVertex3d(5.0, 1.0, 5.0);
    glTexCoord2d(0.0,1.0); glVertex3d(4.0, 1.0, 5.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(5.0, 0.0, 4.0);
    glTexCoord2d(1.0,0.0); glVertex3d(6.0, 0.0, 4.0);
    glTexCoord2d(1.0,1.0); glVertex3d(6.0, 1.0, 4.0);
    glTexCoord2d(0.0,1.0); glVertex3d(5.0, 1.0, 4.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(2.0, 0.0, 6.0);
    glTexCoord2d(3.0,0.0); glVertex3d(5.0, 0.0, 6.0);
    glTexCoord2d(3.0,1.0); glVertex3d(5.0, 1.0, 6.0);
    glTexCoord2d(0.0,1.0); glVertex3d(2.0, 1.0, 6.0);
    glEnd();
    glPopMatrix();

    glPushMatrix();
    glBegin (GL_QUADS);
    glTexCoord2d(0.0,0.0); glVertex3d(4.0, 0.0, 6.0);
    glTexCoord2d(1.0,0.0); glVertex3d(4.0, 0.0, 7.0);
    glTexCoord2d(1.0,1.0); glVertex3d(4.0, 1.0, 7.0);
    glTexCoord2d(0.0,1.0); glVertex3d(4.0, 1.0, 6.0);
    glEnd();
    glPopMatrix();
}

void display (void) {
    glClearColor (0.0,0.0,0.0,1.0);
    glClear (GL_COLOR_BUFFER_BIT);
    glLoadIdentity();  
    glEnable( GL_TEXTURE_2D ); //enable texturing
    //glDepthMask(GL_TRUE);
    gluLookAt (0.5, 0.5, cameraz, 0.5, 1.0, cameraz + 1.0, 0.0, 1.0, 0.0);
    //drawBackground();
    drawMaze();
    glutSwapBuffers();
}
void reshape (int w, int h) {
    glViewport (0, 0, (GLsizei)w, (GLsizei)h);
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity ();
    gluPerspective (60, (GLfloat)w / (GLfloat)h, 1.0, 100.0);
    glMatrixMode (GL_MODELVIEW);
}
void arrow_keys ( int a_keys, int x, int y )  // Create Special Function (required for arrow keys)
{
  switch ( a_keys ) {
    case GLUT_KEY_UP:
        cameraz += 0.1;
      break;
    case GLUT_KEY_DOWN:
        cameraz -= 0.1;
      break;
    case GLUT_KEY_LEFT:
        cameraz += 0.1;
      break;
    case GLUT_KEY_RIGHT:
        cameraz += 0.1;
      break;
    default:
      break;
  }
}

void init(){
    texture = LoadTexture( "wall.bmp" );
    //sky = LoadTexture("sky.bmp");

}
int main (int argc, char **argv) {
    glutInit (&argc, argv);
    glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGBA);
    glutInitWindowSize (500, 500);
    glutInitWindowPosition (100, 100);
    glutCreateWindow ("Mipmaps example");
    init();
    glutDisplayFunc (display);
    glutIdleFunc (display);
    glutReshapeFunc (reshape);
    glutSpecialFunc     ( arrow_keys );
    texture = LoadTexture("texture.raw", 256, 256 );

    glutMainLoop ();

    FreeTexture( texture );

    return 0;
}

Thanks

Answer 1

Firstly you need to ask for a depth buffer when you initialize the display:

glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA | GLUT_DEPTH);

You also need to enable depth testing before drawing the maze:

glEnable(GL_DEPTH_TEST);

You could also uncomment glDepthMask(GL_TRUE);, but depth writing should be enabled by default.