Re: [Freeglut-developer] gl 2+ codepath demos - shapes

[Sylvain <be...@be...>]

Btw we're going off-topic.

The question at hand is about demos bargains :

- Real-world/reusable samples vs. FreeGLUT "test cases":
  externals dependencies (libs, C++...) vs. standalone code

- Portable demos that run anywhere vs. Android-specific demo:
  GLES2 (more strict) vs. GL2 code

John T.: don't let your hatred against trimmed-down GL3 and GLES2
affect your arguments ;)

Cheers!
- Sylvain

On Sat, Jun 09, 2012 at 09:34:18AM +0200, Sylvain wrote:
> Hi,
> 
> On Sat, Jun 09, 2012 at 08:40:30AM +0300, John Tsiombikas wrote:
> > On Fri, Jun 08, 2012 at 07:23:19PM +0200, Sylvain wrote:
> > > Hi John,
> > > 
> > > On Fri, Jun 08, 2012 at 04:52:05PM +0300, John Tsiombikas wrote:
> > > > On Fri, Jun 08, 2012 at 08:35:22PM +0800, Diederick C. Niehorster wrote:
> > > > > - con: shading calculations are done in view space, which is
> > > > > (apparently) not current practice.
> > > > > ...
> > > > > - pro: shading calculations done in object space, and shaders
> > > > > otherwise demonstrate best practices.
> > > > 
> > > > "current practice" ? Shading calculations are much simpler in view
> > > > space, what's the argument for doing them in object space?
> > > 
> > > World space, not object space.
> > 
> > Ok world space, go on... are you going to present the benefit of doing
> > lighting in world space then, instead of view space where it's much
> > simpler and efficient?
> 
> I don't know, when I discussed best practices off-line with Diederick,
> it was about GPU-side vs. CPU-side matrix computations.
> 
> I personnaly prefer world space because I find it easier to understand
> and debug, when everything is done in a reference space that doesn't
> move.  AFAIK the Unity 3D framework does that.  I would be interested
> in knowing why it is more efficient to compute in view space.
> 
> I don't have a strong opinion about this.
> 
> > > > > Anyone doing serious work will use one matrix API or another, and glm
> > > > > is a common and simple one.
> > > > 
> > > > Everyone I know has his own vector/matrix code lying around and being
> > > > reused for ever. Glm, I never even heard about.
> > > 
> > > It brings the GLSL matrix syntax to C++.  I suggest you have a look :)
> > 
> > I have my own, thanks :)
> > Been using it for about a decade now, and it has both a C++ and a plain
> > C interface, so I can use it in all of my projects (most of them are C):
> > http://gfxtools.svn.sourceforge.net/viewvc/gfxtools/libvmath/
> 
> In my tutorials I chose GLM because this brought a unified matrix
> syntax, easier to understand and use.  It also has decent
> documentation, support for Android, and a number of extensions
> (transformations, perlin noise...), which I also needed in the
> tutorial series.  There are a number of other matrix libs out there,
> and I can imagine everybody has its preference, though it makes sense
> to me to check the alternatives from time to time.
> 
> -- 
> Sylvain