little help with shaders

[devsh]

excuse me but i don't quite get the normals from vectors like the viewproj and stuff in shaders.

it's a GLSL question

I know where the camera is vec3(0.0,0.0,1.0) but for example how do i get a vector to vec3(0.0,0.0,1.0) from every single vertex???

I need it to implement a FAKED fresnel effect


And one more, how do i project textures??

like shadows and water caustics???

[Nimrod]

If you are wondering about how to send a variable to your GLSL codes, the answer is in example/tutorial 10.
In short, set the variable with setVertexShaderConstant in the callback.
for example if this is in the callback:

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irr::core::vector3df pos(0,0,1);
services->setVertexShaderConstant("mLightPos", reinterpret_cast<irr::f32*>(&pos), 3);

the variable can be "retrieved" in the GLSL code like this:

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uniform vec3 mLightPos;

As to your particular application, reflection and refraction are common topics for shaders;
a quick google would yield a lot of useful results.

[devsh]

oh well i know about passing these but i think for you to under stand i would need to draw a diagram

the fact of the matter is that...

lets take a look at this the | symbolises normal
the / symbolises the vector towards the camera vec3(0.0,0.0,1.0)
C is the cam

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                                        C
 / / / /  /  /  /  / /  /  /  /  /  / /  / / /  /
/ / / /  /  /  /  / /  /  /  /  /  / /  /  / /  /
|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|_|

as you can see only on vector towards the camera meets it, all the others shooting from other vertexes are parallel but miss it

What I am trying to achieve is to get a vector for each vertex, that meets the camera i.e.

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  C
 /|\
/_|_\

[/code]

[omaremad]

google vector math...

2 position vectors....
make one direction vector
do something to it
do something with it and the normal.


That should be enough hints....

[devsh]

i just cant get it in my head how to get a vector from gl_Position to the camera and then compare it to the normal vector

[omaremad]

Search these topics...

1-vector math (hint subtraction)
2-normalisation
3-dot product

Shaders have built in functions for all of them but you must understand what they do.