View Full Version : opengl2 support
I am quite a newbie. I am not very familiar with the concept of extensions.
I installed Glew, and executed
glewIsSupported("GL_VERSION_2_0")which returned false!
I also tried
GLEW_ARB_vertex_shader && GLEW_ARB_fragment_shaderand both failed.
Now, is this the end of the road for me? Is there any way to add support to those things? I really want to write a vertex shader. I have no idea how to do it now!
Thanks a lot
02-13-2006, 08:48 PM
what card, driver, OS do you have? did you create a context? did you call glewInit()? etc...
you gave us very little info...
Results of both glGetString (GL_VERSION) and glGetString (GL_RENDERER) could also help.
Hi, thanks a lot for the replies, and sorry for not being clear about the points you mentioned...
Here are some more info..
OS: Windows XP Home Edition
Graphics card: Intel 915 GM
glGetString (GL_VERSION): 1.4.0 - Build 220.127.116.1120
glGetString (GL_RENDERER): Intel 915GM
I did call glewInit, but I am not sure what a context is!
Thanks a lot for all the help
So, I discovered my card supports
Is there a big difference? What features do I lose?
Thanks a lot for all your help
Originally posted by <someone22>:
Is there a big difference? What features do I lose?Short answer: everything! :(
ARB_vtx_prog is really assembly like. You have a certain number of instruction slots which can only be processed in sequential order.
There are some NV extensions which I could point you to, but I guess they are not an option for you.
The bottom line is that you're using an assembly-like language. Think at how the programs written in assembly were.
ARB_vtx_shader is like C. You have loops, conditional execution and such (although they may not be supported by the hardware) and you get access to vertex textures (also hardware dependant).
The bottom line is that shaders can be much more complex, just as programs written in C usually have far more features than ASM.
If you want to know more, I'm pretty sure others will tell you the rest... but those are the hard facts.
I'm sorry but I fear you're out of GL2 at all.
If you need cheap options, NV 6600GT rocks. Avoid Radeons below X1300 since this is the first supporting shader model 3.
You still can do pretty things with GL 1.4. You won't have shaders but as you said you still have vertex/fragment programs. Like Obli said it's more like assembly like C but you can do pretty much the same things like with shaders: I don't really know if there are things you can't do, but I think there aren't.
Theoretically, maybe a day you'll have shaders available (was on since GL 1.5 on my card) as this is just a matter of implementation - hope I'm not wrong here -. But you might lack some other things like FBO, PBO... (don't really remember the version in which they appear).
A context, for beeing simple, will allow your window to do GL stuffs. You need different contexts per thread/process.
One last thing, maybe you can try the latest drivers, hopefully they will support shaders if you didn't already have done that.
Hope that could help a bit.
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