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Member Since 16 May 2012
Offline Last Active Oct 25 2013 02:00 AM

Topics I've Started

UI Widget Library with OpenGL support

28 November 2012 - 06:26 PM

I've been trying to find a GUI library (Linux/Windows) that can render its widgets using OpenGL (no results so far). The main requirement: library should reuse existing OpenGL3 context. Second main requirement: library should be light weight. Do such libs exist? I am even ok to fork some stuff that can render widgets via OpenGL and adapt it to my needs.

http://www.opengl.org/registry/ABI relevance

15 September 2012 - 09:35 AM

Is http://www.opengl.org/registry/ABI still up to date? What confuses me is that:

3.4. The libraries must export all OpenGL 1.2, GLU 1.3, GLX 1.3, and ARB_multitexture entry points statically.
It's possible (but unlikely) that additional ARB or vendor extensions will be mandated before the ABI is finalized. Applications should not expect to link statically against any entry points not specified here.

Does that mean any core functionality for OpenGL 2 and higher should be accessed by glXGetProcAddress() (Yet its defined in gl.h/glext.h)?

Also should I explicitly load anything with glXGetProcAddress() if all the prototypes are actually defined in glext.h? I am not talking about checks for extention support but about linking.

Camera pointing to -Z

11 August 2012 - 06:02 PM

Why are cameras usualy implemented pointing to -Z direction, not Z? Is there any technical background behind this or its just an unformal convection?

convex/geometry transformation

20 June 2012 - 05:03 PM

How shold a game engine handle transformation for an entity that aggregates true geometry as, lets say, OpenGL VAO, and convex geometry? For instance I want to move the entity in world, so I get a translation matrix and pass it to shader + apply that matrix to convex verticies manually or something?

How to eliminate phong normal intepolation?

16 May 2012 - 09:32 AM

So I'm learning Phong illumination technique. I have an ambient + diffuse lighted cube with light directed orthogonally to one of the faces (see attachement). Neighbour faces are partially lighted which is technically correct due to normals interpolation but looks unnatural so I'm looking forward on how to eliminate such effect.
My thoughts on how to `eliminate' normals interpolation in partial cases are:
- duplicate mesh verticies and give them proper orthogonal normals (complicates asset creation/export steps and makes mesh larger);
- make mesh edges rounded (complicates geometry);
- add a `correction' normal map;
- add another vertex attribute to indicate if we should use existing normal or calculate a new orthogonal one (also makes mesh larger);
- write another shader to perform flat-shading (will affect all the mesh);
My goal is to correctly shade shapes like cylinder where top and bottom faces should be flat shaded and all other surface smooth shaded.