Re: [Opensg-users] single point geometry not visible

[Carsten N. <car...@gm...>]

On 11/11/2014 10:47 AM, Carsten Neumann wrote:
> On 11/10/2014 11:41 PM, Victor Haefner wrote:
>>  > Would you happen to have a trace of GL calls issued (e.g. apitrace or
>>  > gDEBugger)? Thanks!
>
> thanks for sending the info, it confirms that the draw call is actually
> issued and I suspect that this is a similar problem to the one you are
> having with gl_Color.

hmm, digging some more it turns out the difference between having a 
geometry where all properties contain just a single value vs. properties 
with multiple values is that in the former case:

glVertexAttribN{f,d,i,ui}v family of functions is used to pass the 
vertex data and in the latter case buffer objects are filled with the 
data and glVertexAttribPointer is used to make the GL take vertex data 
out of those buffers.

Also interesting is that it is sufficient to add a second position to 
the positions property and leave everything else as is (including the 
index) - that puts the positions into a buffer and seems to make 
everything work. The other properties arrive at the shader even though 
they are set with glVertexAttrib*. This is on linux x86_64 with nvidia 
331.89.
I'm not sure if the spec makes position special in this regard, or if 
OpenSG is missing a setting here, or if this is a driver bug?

	Cheers,
		Carsten