#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <math.h>

#define WINDSIZEX 100
#define WINDSIZEY 100


void
init (void)
{
    int i;
    GLfloat white[] = { 1.0, 1.0, 1.0, 1.0 };

    glClearColor (0.0, 0.0, 0.0, 1.0);
    glColor4fv (white);
    glDisable (GL_DITHER);

    if (!strstr(glGetString(GL_EXTENSIONS), "GL_EXT_packed_depth_stencil")) {
	printf("GL_EXT_packed_depth_stencil not support\n");
    }
    else {
	printf("GL_EXT_packed_depth_stencil supported\n");
    }
}


static void
test (void)
{
    GLuint depthstencil[4];
    static const GLuint image[4] = {
                0x00000000,
                0x00000012,
                0x12345678,
                0xffffffff
    };

    int i;
    int depthBits, stencilBits;
    glGetIntegerv(GL_DEPTH_BITS, &depthBits);
    glGetIntegerv(GL_STENCIL_BITS, &stencilBits);

    printf("depthBits = %d\n", depthBits);
    printf("stencilBits = %d\n", stencilBits);

    glWindowPos2iARB(0, 0);

    glDrawPixels (2, 2, GL_DEPTH_STENCIL_EXT, GL_UNSIGNED_INT_24_8_EXT, image);
 
    glReadPixels(0, 0, 2, 2, GL_DEPTH_STENCIL_EXT,
                     GL_UNSIGNED_INT_24_8_EXT, depthstencil);

    for (i = 0; i < 4; i++) {
	printf("depthstencil[%d] = %x\n", i, depthstencil[i]);
	if (image[i] != depthstencil[i])
		printf("wrong readback\n");
    }
}

void
display (void)
{
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity ();
    glOrtho (0, WINDSIZEX, 0, WINDSIZEY, 0, -1.0);
    test ();
}

int
main (int argc, char **argv)
{
    glutInit (&argc, argv);
    glutInitDisplayMode (GLUT_SINGLE | GLUT_RGBA | GLUT_DEPTH | GLUT_STENCIL);
    glutInitWindowSize (WINDSIZEX, WINDSIZEY);
    glutInitWindowPosition (100, 100);
    glutCreateWindow (argv[0]);
    init ();
    glutDisplayFunc (display);
    glutMainLoop ();
    return 0;
}