/* gcc -Wall -Wextra -g3 -lglut -lGL test_program.c -o test_program */

#define GL_GLEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/freeglut.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

int main(int argc, char* argv[])
{
    unsigned char* buf;
    GLuint tex;

    glutInitDisplayMode( GLUT_RGBA );
    glutInit( &argc, argv );
    glutCreateWindow( "glGenerateMipmap crash" );

    buf = calloc( 128*128*4*2, 1);
    memset( buf, 255, 128*128*4*2 ); /* set everything to white */

    glGenTextures( 1, &tex );
    glBindTexture( GL_TEXTURE_2D_ARRAY, tex );
    glTexImage3D( GL_TEXTURE_2D_ARRAY
                , 0
                , GL_COMPRESSED_RGBA
                , 128
                , 128
                , 2
                , 0
                , GL_RGBA
                , GL_UNSIGNED_BYTE
                , buf );
    glGenerateMipmap( GL_TEXTURE_2D_ARRAY );

    glGetTexImage( GL_TEXTURE_2D_ARRAY
                 , 1   /* get the second mipmap layer */
                 , GL_RGBA
                 , GL_UNSIGNED_BYTE
                 , buf );

    int layer_size = 64*64;
    int row_length = 64;

    /* Print the pixel value at (12, 12, 0).  '(x, y, layer)'
     *
     * Prints (255, 255, 255, 255), like expected. */
    printf("%d %d %d %d\n"
          , (int) buf[ 0 + (12 + 12*row_length + 0*layer_size)*4 ]
          , (int) buf[ 1 + (12 + 12*row_length + 0*layer_size)*4 ]
          , (int) buf[ 2 + (12 + 12*row_length + 0*layer_size)*4 ]
          , (int) buf[ 3 + (12 + 12*row_length + 0*layer_size)*4 ] );

    /* Print the pixel value at (12, 12, 1).
     *
     * This one returns (0, 0, 0, 0), even though I'd expect it returns
     * (255, 255, 255, 255) (or at least close as this is a compressed,
     * lossy format(?)).
     *
     * This returns (255, 255, 255, 255) if we use non-compressed internal
     * format or the nVidia proprietary drivers. */
    printf("%d %d %d %d\n"
         , (int) buf[ 0 + (12 + 12*row_length + 1*layer_size)*4 ]
         , (int) buf[ 1 + (12 + 12*row_length + 1*layer_size)*4 ]
         , (int) buf[ 2 + (12 + 12*row_length + 1*layer_size)*4 ]
         , (int) buf[ 3 + (12 + 12*row_length + 1*layer_size)*4 ] );

    return 0;
}