[osg-users] Structure in a Uniform Block

[Aurelien Albert]

Hi,

I would send parameters to my shaders using a structure, for example :


Code:

struct LightParameters
{
 vec4 position;
 int type;
 vec4 color;
 float someParameter;
 float someMoreParameter;
 ...
}





So I'm having a look at Uniform blocks and Uniform Buffer Object...

I've read this post : http://forum.openscenegraph.org/viewtopic.php?t=6775 and 
I've try the "osguniformbuffer" example, but I have some questions :

In the "osguniformbuffer", the block size is set to :

Code:
const unsigned blockSize = 20 * sizeof(GLfloat);



but in the GLSL code, the block is :


Code:
layout(std140) uniform colors0
{
 float DiffuseCool;
 float DiffuseWarm;
 vec3  SurfaceColor;
 vec3  WarmColor;
 vec3  CoolColor;
};



So I don't understand the "20 * sizeof(GLfloat)" in the computation of the 
block size.


How can I bind a C++ structure which mix vec4, float, int and other types to 
the Uniform Buffer Object ?



Thank you!

Cheers,
Aurelien[/code]

------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=44688#44688





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