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sky-raven
08-16-2002, 06:52 AM
Hello ,
I have recently tried one of your exercises called mutitex.c. This I tried on a Suse 7.2 linux running Glu version 1.1 with Mesa 3.4.1 with OpenGL 1.2 version under X Windows. The number of texturing units available were 2 from running
glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB,)
Also extensions available with this implementation were found out by running
glGetString(GL_EXTENSIONS)
And gave the following listing of

GL_ARB_multitexture
GL_ARB_texture_cube_map
GL_ARB_tranpose_matrix
GL_EXT_abgr
GL_EXT_blend_color
GL_EXT_blend_func_separate
GL_EXT_blend_logic_op
GL_EXT_blend_minmax
GL_EXT_blend_subtract
GL_EXT_clip_volume_hint
GL_EXT_compiled_vertex_array
GL_EXT_histogram
GL_EXT_packed_pixels
GL_EXT_paletted_texture
GL_EXT_point_parameters
GL_EXT_polygon_offset
GL_EXT_rescale_normal
GL_EXT_shared_texture_palette
GL_EXT_stencil_wrap
GL_EXT_texture3D
GL_EXT_texture_env_add
GL_EXT_texture_env_combine
GL_EXT_texture_env_dot3
GL_EXT_texture_object
GL_EXT_texture_lod_bias
GL_EXT_vertex_array
GL_HP_occlusion_test
GL_INGR_blend_func_separate
GL_MESA_window_pos
GL_MESA_resize_buffers
GL_NV_texgen_reflection
GL_PGI_misc_hints
GL_SGI_color_matrix
GL_SGI_color_table
GL_SGIS_pixel_texture
GL_SGIS_texture_edge_clamp
GL_SGIX_pixel_texture

You will notice that GL_ARB_imaging is not included. When I compiled and ran multitex.c, (see below), I only got a black screen. Why is this? Have I done something wrong?

I look forward to your reply.


David Olivieri

multitex.c programme was taken from Redbook OpenGL Programming Guide 1.2.
See below :-
/*
* Copyright (c) 1993-1999, Silicon Graphics, Inc.
* ALL RIGHTS RESERVED
* Permission to use, copy, modify, and distribute this software for
* any purpose and without fee is hereby granted, provided that the above
* copyright notice appear in all copies and that both the copyright notice
* and this permission notice appear in supporting documentation, and that
* the name of Silicon Graphics, Inc. not be used in advertising
* or publicity pertaining to distribution of the software without specific,
* written prior permission.
*
* THE MATERIAL EMBODIED ON THIS SOFTWARE IS PROVIDED TO YOU "AS-IS"
* AND WITHOUT WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR OTHERWISE,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR
* FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
* GRAPHICS, INC. BE LIABLE TO YOU OR ANYONE ELSE FOR ANY DIRECT,
* SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY
* KIND, OR ANY DAMAGES WHATSOEVER, INCLUDING WITHOUT LIMITATION,
* LOSS OF PROFIT, LOSS OF USE, SAVINGS OR REVENUE, OR THE CLAIMS OF
* THIRD PARTIES, WHETHER OR NOT SILICON GRAPHICS, INC. HAS BEEN
* ADVISED OF THE POSSIBILITY OF SUCH LOSS, HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE
* POSSESSION, USE OR PERFORMANCE OF THIS SOFTWARE.
*
* US Government Users Restricted Rights
* Use, duplication, or disclosure by the Government is subject to
* restrictions set forth in FAR 52.227.19(c)(2) or subparagraph
* (c)(1)(ii) of the Rights in Technical Data and Computer Software
* clause at DFARS 252.227-7013 and/or in similar or successor
* clauses in the FAR or the DOD or NASA FAR Supplement.
* Unpublished-- rights reserved under the copyright laws of the
* United States. Contractor/manufacturer is Silicon Graphics,
* Inc., 2011 N. Shoreline Blvd., Mountain View, CA 94039-7311.
*
* OpenGL(R) is a registered trademark of Silicon Graphics, Inc.
*/

/* multitex.c
*/
#include <GL/glut.h>
#include <stdlib.h>
#include <stdio.h>

#ifdef GL_VERSION_1_2

static GLubyte texels0[32][32][4];
static GLubyte texels1[16][16][4];

void makeCheckImages(void)
{
int i, j;

for (i = 0; i < 32; i++) {
for (j = 0; j < 32; j++) {
texels0[i][j][0] = (GLubyte) i;
texels0[i][j][1] = (GLubyte) j;
texels0[i][j][2] = (GLubyte) (i*j)/255;
texels0[i][j][3] = (GLubyte) 255;
}
}

for (i = 0; i < 16; i++) {
for (j = 0; j < 16; j++) {
texels1[i][j][0] = (GLubyte) 255;
texels1[i][j][1] = (GLubyte) i;
texels1[i][j][2] = (GLubyte) j;
texels1[i][j][3] = (GLubyte) 255;
}
}
}

void init(void)
{
GLuint texNames[2];

glClearColor (0.0, 0.0, 0.0, 0.0);
glShadeModel(GL_FLAT);
glEnable(GL_DEPTH_TEST);

makeCheckImages();
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

glGenTextures(2, texNames);
glBindTexture(GL_TEXTURE_2D, texNames[0]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 32, 32, 0, GL_RGBA,
GL_UNSIGNED_BYTE, texels0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

glBindTexture(GL_TEXTURE_2D, texNames[1]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 16, 16, 0, GL_RGBA,
GL_UNSIGNED_BYTE, texels1);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
/* Use the two texture objects to define two texture units
* for use in multitexturing */
glActiveTextureARB (GL_TEXTURE0_ARB);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texNames[0]);
glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glMatrixMode (GL_TEXTURE);
glLoadIdentity();
glTranslatef(0.5f, 0.5f, 0.0f);
glRotatef(45.0f, 0.0f, 0.0f, 1.0f);
glTranslatef(-0.5f, -0.5f, 0.0f);
glMatrixMode (GL_MODELVIEW);
glActiveTextureARB (GL_TEXTURE1_ARB);
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texNames[1]);
glTexEnvi (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
}

void display(void)
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glBegin(GL_TRIANGLES);
glMultiTexCoord2fARB (GL_TEXTURE0_ARB, 0.0, 0.0);
glMultiTexCoord2fARB (GL_TEXTURE1_ARB, 1.0, 0.0);
glVertex2f(0.0, 0.0);
glMultiTexCoord2fARB (GL_TEXTURE0_ARB, 0.5, 1.0);
glMultiTexCoord2fARB (GL_TEXTURE1_ARB, 0.5, 0.0);
glVertex2f(50.0, 100.0);
glMultiTexCoord2fARB (GL_TEXTURE0_ARB, 1.0, 0.0);
glMultiTexCoord2fARB (GL_TEXTURE1_ARB, 1.0, 1.0);
glVertex2f(100.0, 0.0);
glEnd();
glFlush();
}

void reshape(int w, int h)
{
glViewport(0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
if (w <= h)
gluOrtho2D(0.0, 100.0, 0.0, 100.0 * (GLdouble)h/(GLdouble)w);
else
gluOrtho2D(0.0, 100.0 * (GLdouble)w/(GLdouble)h, 0.0, 100.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

void keyboard(unsigned char key, int x, int y)
{
switch (key) {
case 27:
exit(0);
break;
}
}

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();
glutReshapeFunc(reshape);
glutDisplayFunc(display);
glutKeyboardFunc (keyboard);
glutMainLoop();
return 0;
}
#else
int main(int argc, char** argv)
{
fprintf (stderr, "This program demonstrates a feature which is not in OpenGL Version 1.0 or 1.1.\n");
fprintf (stderr, "If your implementation of OpenGL Version 1.0 has the right extensions,\n");
fprintf (stderr, "you may be able to modify this program to make it run.\n");
return 0;
}
#endif

Robbo
08-16-2002, 07:05 AM
At no point can I see you initialise the extensions. They are probably initialised by default on whatever version that source is written for.

You have to wglGetProcAddress etc. to get them to work.

zeckensack
08-16-2002, 07:31 AM
Make sure you link your application to the matching include library (same version as your mesa installation).


Originally posted by Robbo:

At no point can I see you initialise the extensions. They are probably initialised by default on whatever version that source is written for.

You have to wglGetProcAddress etc. to get them to work.

No, that shouldn't be required on non-Windows platforms where the GL stuff is kept up to date. It's a peculiarity of Win32 (due to de facto non-existant support) that core features have to be treated like extensions.

zeckensack
08-16-2002, 07:33 AM
Whoops!

Just noticed that you used eg glMultiTexCoord2fARB. Try leaving out the extension suffix, I believe that's the way to handle things correctly.

eg glMultiTexCoord2f(blabla)

Robbo
08-16-2002, 07:40 AM
Ah - just as I thought - Mesa what????

sky-raven
08-18-2002, 06:13 AM
I will try this

At no point can I see you initialise the extensions. They are probably initialised by default on whatever version that source is written for.

You have to wglGetProcAddress etc. to get them to work.[/QUOTE]

sky-raven
08-18-2002, 06:16 AM
Is Mesa a problem?
Originally posted by sky-raven:
I will try this

At no point can I see you initialise the extensions. They are probably initialised by default on whatever version that source is written for.

You have to wglGetProcAddress etc. to get them to work.
[/QUOTE]