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