LWJGL shader normal's alias - opengl

Question

I'm writing my app with LWJGL and on some graphic cards (AMD Radeon series) I can not change the normal's name in vertex shader because something goes wrong and only one big triangle appears on the screen. Here is my code:
#version 150
//our attributes
in vec3 a_position;
in vec2 a_textureCoords;
in vec3 a_normal; //Here is an error
//send the color out to the fragment shader
out vec2 vTextureCoords;
void main(void)
{
a_normal;
gl_Position = vec4(a_position, 1.0);
vTextureCoords = a_textureCoords;
}
if I change shader to this:
#version 150
//our attributes
in vec3 a_position;
in vec2 a_textureCoords;
in vec3 normal;
//send the color out to the fragment shader
out vec2 vTextureCoords;
void main(void)
{
normal;
gl_Position = vec4(a_position, 1.0);
vTextureCoords = a_textureCoords;
}
Everything works fine and mesh appear as it should be. Is it normal?
And my bind attribute function:
//Before
GL20.glBindAttribLocation(s_programID, 2, "a_normal");
//After
GL20.glBindAttribLocation(s_programID, 2, "normal");
edit
Attributes locations in shader:
//Before
a_normal 0
a_position 1
a_textureCoords 2
//After
a_position 0
a_textureCoords 1
normal 2

Answer 1

I'd suggest you to write something like this:
#version 150
#define POSITION 0
#define TEX_COORD 1
#define NORMAL 2
//our attributes
layout (location = POSITION) in vec3 a_position;
layout (location = TEX_COORD) in vec2 a_textureCoords;
layout (location = NORMAL) in vec3 a_normal;
//send the color out to the fragment shader
out vec2 vTextureCoords;
void main(void)
{
a_normal;
gl_Position = vec4(a_position, 1.0);
vTextureCoords = a_textureCoords;
}
And then on java you have something like:
interface Semantic {
interface Attr {
int POSITION = 0;
int TEX_COORD = 1;
int NORMAL = 2;
}
}
that you will use in your glVertexAttribPointer and glEnableVertexAttribute functions
Otherwise, remember to glBindAttribLocation before or glGetAttribLocation after linking the program
Ps: remember to do something useful with that a_normal otherwise the glsl compiler will optimize it out by removing it completely