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V-man

Member Since 02 Mar 2002
Offline Last Active Feb 06 2013 09:01 AM

#5029026 Trouble with very slow rendering with nvidia under Linux

Posted by V-man on 05 February 2013 - 08:15 AM

You should get information with glGetString and also, make sure you have the drivers from nvidia installed and not MESA3D or some other software junk.




#4973465 My first C++ game

Posted by V-man on 26 August 2012 - 07:12 AM

1. You can start out with freeGLUT to get off the ground. It hides the OS specific stuff like creation a window and GL context, user input.
2. There is Nehe but it is ancient and just teaches GL 1.1 and few things like VBO.
There is the Wiki for GL 3 stuff
http://www.opengl.org/wiki/Tutorials

and all this
http://www.opengl.org/wiki/Getting_started#Tutorials_and_How_To_Guides

3. The same way you learn the syntax for any other API
4. 2D tic tac toe or Pac Man.


#4973374 Fullscreen mode not working with signle buffer

Posted by V-man on 25 August 2012 - 06:33 PM

The code looks fine. It is probably some system issue. BTW, what OS, gpu are you using. Do you have the latest graphics drivers?


#4972972 OpenGL = Trying to start

Posted by V-man on 24 August 2012 - 07:19 AM

SDK?
http://www.opengl.org/wiki/FAQ#Is_there_an_OpenGL_SDK.3F


#4972335 FrameBuffer mixing with BackBuffer

Posted by V-man on 22 August 2012 - 01:37 PM

So you are saying you are rendering to a texture (FBO) that doesn't have a depth buffer, but it appears that it is using the depth buffer from the window? That should not be possible. If it is working, there is no guarantee that it will work on other hardware.

Also, if you don't have a depth buffer attached to your FBO, you should should disable depth testing. http://www.opengl.org/wiki/Framebuffer_Object_Examples#Color_only


#4951298 How To Solve Z buffer Fighting

Posted by V-man on 21 June 2012 - 05:28 AM

Use a 24 bit depth buffer for better precision. It is supported on everything.
http://www.opengl.org/wiki/Common_Mistakes#Depth_Buffer_Precision


#4944939 Does the OpenGL fixed function pipeline compute lighting in view-space?

Posted by V-man on 31 May 2012 - 05:14 AM

It sounds like you aren't a OpenGL user.
GL doesn't have a view matrix and it doesn't have a world matrix. GL only has a modelview matrix.
GL transforms vertices by the modelview matrix to get eye space vertices. It also transform normals by the inverse transpose of the modelview matrix to get eye space normal vectors. Lighting is computed in eye space. In order to deal with non uniform scale, you can glEnable(GL_NORMALIZE). If you only have a uniform scale, you can glEnable(GL_RESCALE) which is "faster" than GL_NORMALIZE.

Of course, all of the above is relevant to the year 2002 and before. It's time to move to the world of shaders.


#4944104 Strange GLSL issue

Posted by V-man on 28 May 2012 - 12:48 PM

I see this problem come up often on these forums. Perhaps you aren't NULL terminating the string you send to GL or you aren't reading in the shader text file properly.


#4936731 GLSL spotlight problem [SOLVED]

Posted by V-man on 02 May 2012 - 05:35 AM

The shader look fine.
You should probably verify your "LightDirection" that you send to
glLightfv( GL_LIGHT0, GL_SPOT_DIRECTION, LightDirection );


#4913742 How to process texture indices properly

Posted by V-man on 16 February 2012 - 02:49 PM

If you are going to use glVertexAttribPointer, then you need shaders.
Otherwise, use glVertexPointer, glNormalPointer and the like.


#4911643 Perspective in opengl 3.3

Posted by V-man on 10 February 2012 - 07:16 AM

You create the matrix and upload it to the shader. Use a matrix library such as
http://www.opengl.org/wiki/Related_toolkits_and_APIs#Math_Libraries


#4911421 Clarification about GL_LINE_STRIP and Vertex Arrays

Posted by V-man on 09 February 2012 - 02:33 PM

The number of indices is number of strips + 1


#4907019 realistic minimum GL version support in a year?

Posted by V-man on 28 January 2012 - 08:40 AM

Any card that does GL 3.0 has a driver that does GL 3.3 (on Windows anyway) so why not use that?
Doom3 can run on GL 1.1 apparently http://liamm.com/tech/voodoo-2-sli-doom-3-kit
All id engines are GL 1.1 + a load and tons of extensions.


#4906137 need help with rotation, transformation and scaling in opengl mathematics

Posted by V-man on 25 January 2012 - 11:02 AM

http://en.wikipedia.org/wiki/Shader


#4904737 Preventing vertex duplication when loading triangle indexes into index arrays?

Posted by V-man on 20 January 2012 - 07:59 PM

There is no way around it
http://www.opengl.org/wiki/FAQ#Multi_indexed_rendering




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