al_get_opengl_texture http://www.allegro.cc/forums/view/606722 Allegro.cc Forum Thread matthew@allegro.cc (Matthew Leverton) Wed, 23 Mar 2011 12:59:51 +0000

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

]]> no-reply@allegro.cc (azerty_damned) Wed, 16 Mar 2011 00:59:35 +0000

What is it supposed to look like?

]]> no-reply@allegro.cc (Elias) Wed, 16 Mar 2011 02:35:23 +0000

Hi,

Here is the original texture...

]]> no-reply@allegro.cc (azerty_damned) Wed, 16 Mar 2011 16:09:25 +0000

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?

]]> no-reply@allegro.cc (Elias) Wed, 16 Mar 2011 16:41:12 +0000

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

]]> no-reply@allegro.cc (azerty_damned) Thu, 17 Mar 2011 00:59:27 +0000

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?

]]> no-reply@allegro.cc (Elias) Thu, 17 Mar 2011 02:16:56 +0000

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...

]]> no-reply@allegro.cc (azerty_damned) Thu, 17 Mar 2011 12:35:51 +0000
azerty_damned said:

I also have the problem when I use al_draw_bitmap()

Is ex_bitmap also broken?

]]> no-reply@allegro.cc (Elias) Thu, 17 Mar 2011 16:58:04 +0000

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)

]]> no-reply@allegro.cc (azerty_damned) Thu, 17 Mar 2011 19:01:31 +0000

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.

]]> no-reply@allegro.cc (Evert) Thu, 17 Mar 2011 19:47:46 +0000

.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.

]]> no-reply@allegro.cc (Elias) Thu, 17 Mar 2011 19:51:25 +0000
Elias said:

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?

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).

]]> no-reply@allegro.cc (Evert) Thu, 17 Mar 2011 20:44:49 +0000

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.

]]> no-reply@allegro.cc (Matthew Leverton) Thu, 17 Mar 2011 23:25:58 +0000

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...

]]> no-reply@allegro.cc (azerty_damned) Wed, 23 Mar 2011 12:05:17 +0000

Grep the cmake log or txt files or something like:

cmake .. -DWANT_NATIVE_IMAGE_LOADER=off

]]> no-reply@allegro.cc (Matthew Leverton) Wed, 23 Mar 2011 12:12:34 +0000

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?

]]> no-reply@allegro.cc (azerty_damned) Wed, 23 Mar 2011 12:59:51 +0000