Attachment 82505 Details for Bug 66850 – Test program showing problem with glGetTexImage

Test program showing problem with glGetTexImage

test_program.c (text/plain), 2.17 KB, created by Mikko Juola on 2013-07-16 20:55:06 UTC

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Creator: Mikko Juola

Created: 2013-07-16 20:55:06 UTC

Size: 2.17 KB

patch

obsolete

>/* 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;
>}
>

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Attachments on bug 66850: 82363 | 82480 | 82481 | 82482 | 82505 | 82506

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