[PD] question about glsl

[cyrille henry]

hello,

i copy this to the mailling list, as other could be interested.

oyuki a écrit :
> hello i was trying you gem examples of glsl, i got surprised about the
> speed of this stuff, i was experimenting with the sphere example and  i
> can have more than 400 iterations(with repeat) of this object .
> why this object(with a lot of complexity in its shape) is faster than a
> normal geo ? 
how many normal geo could you have if you don't load the shader?

on a generic point, using shader mean bypassing some graphic card fonctionality, that you have to implement yourself.
by exemple, lighting computation is not done anymore automaticaly. in this exemple, i did not compute a complex light, so maybe computing the shape deformation could be faster than computing standard lighting.


> 
> is there any tutorial for learning glsl for making stuff in gem?
there is 1 exemple in gem doc that explain how to use a shader.
then, you have to look for generic glsl information.
you can find a lot on the web. 
also, the orange book is a must have reference book.

> or do i
> need to learn before c ?
glsl syntax is close to C syntax, but glsl is not C.
i dont think you need to learn C in order to learn glsl.
but glsl is a programing language that ou have to learn anyway.

cyrille

> 
> many thanks
> 
> 
> oyuki