12.04 - Ubuntu is using Intel Compatible controller instead of NVidia

I'm trying to run Minecraft on my Ubuntu 12.04 but I'm having the following error:

[08:04:00 INFO]: Client> org.lwjgl.LWJGLException: Could not init GLX

[08:04:00 INFO]: Client> at
org.lwjgl.opengl.LinuxDisplayPeerInfo.initDefaultPeerInfo(Native
Method) ~[lwjgl-2.9.1.jar:?]
[08:04:00 INFO]: Client> at org.lwjgl.opengl.LinuxDisplayPeerInfo.(LinuxDisplayPeerInfo.java:61)

~[lwjgl-2.9.1.jar:?] [08:04:00 INFO]: Client> at
org.lwjgl.opengl.LinuxDisplay.createPeerInfo(LinuxDisplay.java:818)

~[lwjgl-2.9.1.jar:?] [08:04:00 INFO]: Client> at
org.lwjgl.opengl.DrawableGL.setPixelFormat(DrawableGL.java:61)

~[lwjgl-2.9.1.jar:?] [08:04:00 INFO]: Client> at
org.lwjgl.opengl.Display.create(Display.java:846)

~[lwjgl-2.9.1.jar:?] [08:04:00 INFO]: Client> at
org.lwjgl.opengl.Display.create(Display.java:757)

~[lwjgl-2.9.1.jar:?] [08:04:00 INFO]: Client> at azl.ad(SourceFile:312) [1.7.5.jar:?]

[08:04:00 INFO]: Client> at azl.f(SourceFile:696) [1.7.5.jar:?]

[08:04:00 INFO]: Client> at
net.minecraft.client.main.Main.main(SourceFile:148) [1.7.5.jar:?]

[08:04:01 INFO]: Client> Xlib: extension "GLX" missing on display
":0".

Looking around the net, I found out my nvidia drivers are not being used, using the following command:

lsb_release -a && lspci -vmk | grep -A 8 -B 2 VGA && lspci | grep VGA && glxinfo | grep -w 'direct\|OpenGL'

I get:

No LSB modules are available. Distributor ID: Ubuntu

Description: Ubuntu 12.04.4 LTS Release: 12.04 Codename: precise

Device: 00:02.0 Class: VGA compatible controller Vendor: Intel

Corporation Device: 4th Gen Core Processor Integrated Graphics

Controller SVendor: Hewlett-Packard Company SDevice: Device 1966

Rev: 06 Driver: i915 Module: i915

00:02.0 VGA compatible controller: Intel Corporation 4th Gen Core

Processor Integrated Graphics Controller (rev 06) Xlib: extension

"GLX" missing on display ":0". Xlib: extension "GLX" missing on

display ":0". Xlib: extension "GLX" missing on display ":0". Xlib:

extension "GLX" missing on display ":0". Xlib: extension "GLX"

missing on display ":0". Error: couldn't find RGB GLX visual or

fbconfig Xlib: extension "GLX" missing on display ":0". Xlib:

extension "GLX" missing on display ":0". Xlib: extension "GLX"

missing on display ":0". Xlib: extension "GLX" missing on display

":0". Xlib: extension "GLX" missing on display ":0". Xlib: extension

"GLX" missing on display ":0". Xlib: extension "GLX" missing on

display ":0".

How can I get the right driver installed and used by default?

BTW, in the Additional Drivers section I see the nvidia driver, but it says that the driver is installed but not being used.

Well, installing Bumblebee solved my issues.

Here are the steps I followed:

https://wiki.ubuntu.com/Bumblebee