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ZHAO Peng

OpenGL Immature support of OpenGL core profile in freeglut?

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ZHAO Peng    108
Hello everyone, I am trying to build some demos using freeglut for learning OpenGL 3.2 core profile. When I try the latest stable release 2.6, there is a performance problem when call display function in idle call back. So I download the development source codes from SVN and build them by myself. Everything seems OK at the first. However, when I try to use uniform block, each related functions, such as glGetUniformBlockIndex, would make the program crash. When I switch the profile to GLUT_COMPATIBILITY_PROFILE, there is no problem. Core profile version: ... glutInitContextProfile(GLUT_CORE_PROFILE); ... GLint lightBlockIndex= glGetUniformBlockIndex(usedProgram, "colors0");//This call will crash ! .... Compatibility profile version: ... glutInitContextProfile(GLUT_COMPATIBILITY_PROFILE); ... GLint lightBlockIndex= glGetUniformBlockIndex(usedProgram, "colors0");//This is OK! .... These codes are tested on OpenSUSE 11.2 with GTX260 card (driver:195.36.07.04). The same problem also occurs on Radeon cards. I also test the uniform block functions using codes GLUS written by Nopper, and it is OK. So I am sure it is the problem of freeglut. Any suggestions or alternative solution? Thanks! ZHAO Peng

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Asem    154
i had the same problem with sdl. i ended up downloading the src code and addding the code to select the profile but that was not the problem. it seems to be able to use the core you must only have those core gl functions initialized. i found that to be odd and it probably not the real reasonn but it worked for me. use the gl3.h header file it might help.

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ZHAO Peng    108
Thanks for your reply!
I use glew 1.5.4 instead of gl3.h. I think the core functions should have been ready to be called. In my option, maybe there are some problems when freeglut creates core profile context. I will try to fix it by modifying the source codes of freeglut.
It seems that there is still no GUI library working with OpenGL core profile perfectly. This is really an annoying problem for programmer.

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ZHAO Peng    108
Finally, I have solved my problem. I should apologize to freeglut for the misunderstanding.
The real reason is that GLEW considers my Nvidia driver as experimental driver. So I should add "glewExperimental= GL_TRUE;" before "glewInit();";
But I don't know why GLEW regards "NVIDIA-Linux-x86_64-190.53" as experimental driver. Anyway it works.

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