glTexImage3DEXT crashed

[renaissance]

I am trying to use glTexImage3DEXT for volume rendering. In fact, I am using the code from the following link.
http://www.opengl.org/resources/code.../programs.html

However, after successful compilation, the program crashed when it entered glTexImage3DEXT function. I used
glewIsSupported("GL_EXT_texture3D");
to make diagnosis and I found the reture value is 0.

Can anyone give me some hints?

Thanks a lot.

[ZbuffeR]

Don't use it, if it is not available

[renaissance]

my system has the following config. Should the glTexImage3DEXT be supported and available?


GLEW version 1.5.1
Reporting capabilities of pixelformat 1
Running on a GeForce 8600 GT/PCI/SSE2 from NVIDIA Corporation
OpenGL version 2.1.1 is supported

[Korval]

OpenGL version 2.1.1 is supported

The implementation probably stopped exposing texture3D as an extension, as it supports a version of OpenGL that requires 3D textures. Just use the core function pointers.

[renaissance]

Hi Korval:

I do not quite understand what you posted. Can you give a little bit more explanationS?

Thanks a lot.

[Korval]

I do not quite understand what you posted. Can you give a little bit more explanationS?

OpenGL version 2.1 requires that implementations support 3D textures. The API to do this is part of the core OpenGL 2.1 specification.

However, support for 3D textures can also be exposed by an extension called "GL_EXT_texture3D". Because it is an extension, all of the function pointers for it end in "EXT" as do all of the #define enumerations.

OpenGL version 2.1 defines a function called "glTexImage3D" (note the lack of EXT at the end). The extension "GL_EXT_texture3D" defines a function called "glTexImage3DEXT". If an OpenGL version returns 2.1, it must expose "glTexImage3D" as a function. If an OpenGL implementation advertises the extension "GL_EXT_texture3D", then it must expose "glTexImage3DEXT".

Your GL implementation says that it does not support the "GL_EXT_texture3D" extension. However, your OpenGL version is 2.1, which means that it does expose "glTexImage3D". Therefore, you should stop looking for the extension and start looking for the core feature.

[Jan]

1) Did you call glewInit _after_ context creation?
2) Korval suggests to use glTexImage3D instead of glTexImage3DEXT.

[Jan]

Argh, too slow

[renaissance]

I tried using glTexImage3D before and it had the similar crashing result.

[renaissance]

Thank you for you advice, Jan and Korval.

For Jan, I do not understand the glewInit _after_ context suggestion. Can you come up with more details?