Passing Vec2 to fragment shader

[neseir]

Hi

 

I'm trying to modify one of the standard shaders to accept one more Vec2 parameter. In the fragment part of the shader I have added :

 

in vec2 my_offset;

 

Settings this vector to different values changes the offset drawing the texture from the material (offset values added to the texture coordinates) in the material editor works fine.

 

The problem is how to access this input Vector from the lua code. I have added a part witch loads a material and connects the same shader i used in the material editor (from the Start function after the map is loaded) :

 --Load a material
 local material = Material:Load("Materials/Mine/greystuff.mat")
 self.shader = Shader:Load("Shaders/Model/mydefault.shader")
 material:SetShader(self.shader)
--	 self.shader:Release()

--Create a model
local model = Model:Sphere()
model:SetMaterial(material)
model:SetPosition(0,3,0)

self.roll = Vec2(0.0, 0.0)

 

In the app function i have added (before the world:Update()) :

self.roll.y = self.roll.y + 0.001
self.shader:SetVec2("my_offset", self.roll)

 

But the texture is not moving.

 

Is this the proper way of doing this ? I found some code doing this in an earlier relase of Leadwerks but it was in C and I'm not sure if I got this wrong trying to translate to lua (think he was using SetShaderVec2 instead of Shader:SetVec2).

 

BR

Eirik

[shadmar]

Hard to tell without seeing mydefault.shader

[Rastar]

If you specify that variable as "in vec2" it is supposed to be a vertex attribute, ie have a different value per vertex. However, the Shader:SetXY() methods set shader uniforms. So I guess, in your case you should define that as

 

uniform vec2 my_offset;

[neseir]

Hi

 

Thanks, I did not notice that when I tested this. Will check this and update with more information when I'm home again.

 

Regards

Eirik

[neseir]

Hi

 

@Rastar: Did as You said and it worked perfectly. Thanks

 

BR

Eirik