Building G buffer

I found this example for storing normal, texture and position in three textures. What if I need multi texturing. Do I have to use

gl_FragData[3] = texture2D(Tex1, gl_TexCoord[1].st);

also, how does it work?

#extension GL_ARB_draw_buffers : enable

varying vec3 position, normal;
uniform sampler2D Tex0;

void main(void)
{
	gl_FragData[0] = vec4(position.xyz, 0.0);
	gl_FragData[1] = vec4(normalize(normal.xyz), 0.0);
	gl_FragData[2] = texture2D(Tex0, gl_TexCoord[0].st);
}

A) You don’t need position as you can always recover it from the depth buffer.
B) You can bake whatever consider to be useful into the G buffer.
I’m, for example, baking the following attributes:

  1. surface diffuse color (may be taken from multiple textures)
  2. surface specular color + shininess factor
  3. world-space normal

#extension GL_ARB_draw_buffers : enable

varying vec3 position, normal;
uniform sampler2D Tex0;
uniform sampler2D Tex1;

void main(void)
{
	vec4 color0 = texture2D(Tex0, gl_TexCoord[0].st);
	vec4 color1 = texture2D(Tex1, gl_TexCoord[1].st);

	gl_FragData[0] = vec4(position.xyz, 0.0); // you don't need this
	gl_FragData[1] = vec4(normalize(normal.xyz), 0.0);
	gl_FragData[2] = color0 * color1; // multiplicative blend
}