al_get_opengl

azerty_damned

Hi,

al_get_opengl_texture() returns a texture with garbage in data
(see screenshot). I've tried with .bmp and .tiff files.

I'm using Allegro 5.0.1 with MacOS X 10.5.8.

Here is my method to load a bitmap and return its OpenGL id:

#SelectExpand
  1void Texture::load(const char *filename)
  2{
  3    pBmp = al_load_bitmap(absoluteBundleResourcePath(filename));
  4    if (pBmp == NULL)
  5        throw Exception("*** Can't load image!");
  6
  7    if (!al_is_compatible_bitmap((ALLEGRO_BITMAP *) pBmp))
  8    {
  9        al_destroy_bitmap((ALLEGRO_BITMAP *) pBmp);
 10        throw Exception("*** Image not compatible with OpenGL!");
 11    }
 12
 13    iID = al_get_opengl_texture((ALLEGRO_BITMAP *) pBmp);
 14    if (iID == 0)
 15    {
 16        al_destroy_bitmap((ALLEGRO_BITMAP *) pBmp);
 17        throw Exception("*** Can't get OpenGL id!");
 18    }
 19
 20    bLoaded = true;
 21}
 22
 23void Texture::bind() const
 24{
 25    glBindTexture(GL_TEXTURE_2D, iID);
 26}

So, what is going (am I doing) wrong?

Thanks in advance for any answer,
azerty

Elias

What is it supposed to look like?

azerty_damned

Hi,

Here is the original texture...

Elias

Hm, does the picture work fine if you draw it with al_draw_bitmap? Else can you make a small example program reproducing the problem?

azerty_damned

Hi,

Here is the program that reproduces the problem.

I hope it is clear enough.

#SelectExpand
   1/*
   2 *  Bitmap used as OpenGL texture problem
   3 */
   4#include <cstdlib>
   5#include <allegro5/allegro.h>
   6#include <allegro5/allegro_image.h>
   7#include <allegro5/allegro_opengl.h>
   8#include <OpenGL/glu.h>
   9
  10static int SCR_W = 1024;
  11static int SCR_H =  768;
  12
  13int main(int argc, char **argv)
  14{
  15  (void) argc;
  16  (void) argv;
  17
  18  if (!al_init()) exit(1);
  19
  20  //  Configure display
  21  al_set_new_display_flags(ALLEGRO_OPENGL | ALLEGRO_WINDOWED);
  22  al_set_new_display_option(ALLEGRO_VSYNC, 1, ALLEGRO_REQUIRE);
  23  al_set_new_display_option(ALLEGRO_DEPTH_SIZE, 8, ALLEGRO_REQUIRE);
  24  al_set_new_display_option(ALLEGRO_FLOAT_DEPTH, 1, ALLEGRO_REQUIRE);
  25
  26  ALLEGRO_DISPLAY *pDisplay;
  27  pDisplay = al_create_display(SCR_W, SCR_H);
  28  if (pDisplay == NULL) exit(1);
  29
  30  //  Mandatory 
  31  al_install_keyboard();
  32  al_init_image_addon();
  33
  34  //  Configure OpenGL
  35  glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
  36  glEnable(GL_DEPTH_TEST);
  37  glDepthMask(GL_TRUE);
  38  glDepthFunc(GL_LEQUAL);
  39  glEnable(GL_CULL_FACE);
  40  glCullFace(GL_BACK);
  41  glEnable(GL_TEXTURE_2D);
  42
  43  //  Load bitmap
  44  ALLEGRO_BITMAP *pBmp = al_load_bitmap("reflect.tiff");
  45  GLuint iID = al_get_opengl_texture(pBmp);
  46
  47  //  Prepare event queue
  48  ALLEGRO_EVENT event;
  49  ALLEGRO_EVENT_QUEUE *pQueue = al_create_event_queue();
  50  al_register_event_source(pQueue, al_get_keyboard_event_source());
  51  al_register_event_source(pQueue, al_get_display_event_source(pDisplay));
  52
  53  //  Enter main loop
  54  bool bLeave = false;
  55  while (!bLeave)
  56  {
  57    //  Clear buffers
  58    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  59
  60    //  2D mode
  61    glMatrixMode(GL_PROJECTION);
  62    glLoadIdentity();
  63    gluOrtho2D(0, SCR_W, SCR_H, 0);
  64
  65    glMatrixMode(GL_MODELVIEW);
  66    glLoadIdentity();
  67
  68    //  Blit 2D texture
  69    GLint w = al_get_bitmap_width(pBmp);
  70    GLint h = al_get_bitmap_height(pBmp);
  71    glBindTexture(GL_TEXTURE_2D, iID);
  72    glBegin(GL_QUADS);
  73      glNormal3f(0.0f, 0.0f, 1.0f);
  74      glTexCoord2f(0.0f, 0.0f); glVertex2i(0, h);
  75      glTexCoord2f(1.0f, 0.0f); glVertex2i(w, h);
  76      glTexCoord2f(1.0f, 1.0f); glVertex2i(w, 0);
  77      glTexCoord2f(0.0f, 1.0f); glVertex2i(0, 0);
  78    glEnd();
  79
  80    //  Show backbuffer
  81    al_flip_display();
  82
  83    //  Check events
  84    if (!al_is_event_queue_empty(pQueue))
  85    {
  86      while (al_get_next_event(pQueue, &event))
  87      {
  88        switch (event.type)
  89        {
  90          case ALLEGRO_EVENT_DISPLAY_CLOSE:
  91            bLeave = true;
  92          break;
  93        }
  94      }
  95    }
  96  }
  97
  98  //  Properly leave program
  99  al_destroy_event_queue(pQueue);
 100
 101  al_destroy_bitmap(pBmp);
 102
 103  al_shutdown_image_addon();
 104
 105  if (al_is_keyboard_installed())
 106        al_uninstall_keyboard();
 107
 108  if (al_is_system_installed())
 109        al_uninstall_system();
 110
 111  //  Be done
 112  exit(0);
 113}
 114
 115//  EOF

Elias

Works fine here in Linux. I had to disable vsync, depth_size and float_depth though and convert the .tiff to a .png. Can you try making those changes and see if the problem is fixed?

azerty_damned

Hi Elias,

I've used a png file and removed all the calls to al_set_new_display_option() but the result is the same... Maybe this is a MacOS X specific issue? I also have the problem when I use al_draw_bitmap()...

Thanks for your help...

Elias

azerty_damned said:

I also have the problem when I use al_draw_bitmap()

Is ex_bitmap also broken?

azerty_damned

Hello Elias,

ex_bitmap works but not ex_draw_bitmap...

ex_bitmap uses a .pcx file; ex_draw_bitmap a .png, so I've saved my texture as .pcx and the problem has disappeared. But I don't want to use PCX, because of
transparency, so if you have another suggestion, please tell me.

I've compiled the Allegro library with this version of GCC:

Using built-in specs.
Target: powerpc-apple-darwin9
Thread model: posix
gcc version 4.0.1 (Apple Inc. build 5465)

Evert

Ok, PowerPC. That could be important.
Can you try toggling the option for the native image loader in the CMake options and recompile?
If you switch it off, you'll need libpng and zlib to load PNG images. If that works there's an endianess bug in the native image loader.

I can try your example later (on 10.6) to see if it works here.

Elias

.png (as well as .tiff) is handled by the OSX image loader. .pcx is read directly. So guess we have a good indication now that the OSX image loader is broken.

Since you are using 10.5 but all devs are using 10.6 I'm fairly certain that's the problem. OSX must somehow load images differently under 10.5. Is there a way to debug 10.5 specific problems under 10.6?

[edit:] Oh, didn't see PowerPC, that could be another reason of course, swapped byte order always can cause problems.

Evert

Elias said:

Probably. Just compile an executable that is designed to run under 10.5. I don't think that's the problem though.
In fact, it's probably possible to debug the PPC build on an Intel machine by just setting the target to PPC (and the OS X version to 10.5, if it doesn't do that automatically), recompile and run (you can run PPC binaries on Intel Macs through some sort of emulation, or maybe it actually JIT re-compiles it, I'm not entirely sure other than that it works).

Matthew Leverton

As I've reported many times, the native loader does not work properly on 10.4/PPC. The screenshot is the same type of results I get. I fixed some endian issues with the locking code, but that didn't fix the horizontal garbage of some images.

The libpng/libjpeg loaders work fine.

azerty_damned

Hi,

I've installed libpng15 and zlib (/usr/local/lib) but I don't know how to tell cmake to use them instead of native image loaders.

Can you help me?

Thanks...

Matthew Leverton

Grep the cmake log or txt files or something like:

cmake .. -DWANT_NATIVE_IMAGE_LOADER=off

azerty_damned

Hi Matthew,

It is working now, thank you. Is there any hope to see the problem with native loaders on ppc solved in the future?

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