Invisible vertex attributes

Hello. I’m trying to write a vertex shader for skinning, so I have to pass some per-vertex attributes to the shader.

This is the shader I’m writing:

 varying vec3 normal;
attribute vec4 attr_boneRelPos1;
attribute vec4 attr_boneRelPos0;
attribute vec4 attr_boneIdx;
uniform vec4 in_bonesMat[84];
void main()
        // first bone weight
        int idx = int(attr_boneIdx.x);
        vec3 pos1;
        pos1.x = dot(in_bonesMat[idx],attr_boneRelPos0);
        pos1.y = dot(in_bonesMat[idx+1],attr_boneRelPos0);
        pos1.z = dot(in_bonesMat[idx+2],attr_boneRelPos0);
        pos1 = pos1 * attr_boneIdx.y;
        idx = int(attr_boneIdx.z);
        vec3 pos2;
        pos2.x = dot(in_bonesMat[idx],attr_boneRelPos1);
        pos2.y = dot(in_bonesMat[idx+1],attr_boneRelPos1);
        pos2.z = dot(in_bonesMat[idx+2],attr_boneRelPos1);
        vec4 vertexBonePosition = vec4((pos2 * attr_boneIdx.w) + pos1,1.0);
	gl_Position = ftransform();
	normal = gl_Normal;
	gl_TexCoord[0] = gl_MultiTexCoord0;

I’m setting up 3 custom attribute variables to bind them to some buffers where I have the necessary data.

The shader compiles and links perfectly, but unfortunately, I’m not able to retrieve the location of those attributes, since glGetAttribLocation always return -1.

Using glGetActiveAttribARB I can get the active attributes, which are:
gl_Vertex, gl_Normal and gl_MultiTexCoord0.

Why I’m not able to “see” my custom attributes? Is every thing ok? Any ideas are appreciated?

Thanks in advance.

since you aren’t using the ‘vertexBonePosition’ variable to anything, the compiler will remove everything you use to calculate that. No need to input parameters that you aren’t using.

Bone animations are very easy to implement. Here are some examples:

Thank you! that was exactly the problem :wink:

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