Mouselook

#Blender Game Engine 2.55 Simple Camera Look
#Created by Mike Pan: mikepan.com

# Use mouse to look around
# W,A,S,D key to walk around
# E and C key to ascend and decend

from bge import logic as G
from bge import render as R
from bge import events
from mathutils import *

scene = G.getCurrentScene()
yaw = scene.objects["Empty"]

speed = 0.08                # walk speed
sensitivity = 0.002     # mouse sensitivity
smooth = 0.7            # mouse smoothing (0.0 - 0.99)

cont = G.getCurrentController()
owner = cont.owner
Mouse = cont.sensors["Mouse"]

w = R.getWindowWidth()//2
h = R.getWindowHeight()//2
screen_center = (w, h)

# center mouse on first frame, create temp variables
if "oldX" not in owner:
    #R.setMousePosition(w , h )
    R.setMousePosition(w + 1, h + 1)
    owner["oldX"] = 0.0
    owner["oldY"] = 0.0
else:
    scrc = Vector(screen_center)
    mpos = Vector(Mouse.position)
    x = scrc.x-mpos.x
    y = scrc.y-mpos.y
    # Smooth movement
    owner['oldX'] = (owner['oldX']*smooth + x*(1.0-smooth))
    owner['oldY'] = (owner['oldY']*smooth + y*(1.0-smooth))
    x = owner['oldX']* sensitivity
    y = owner['oldY']* sensitivity
    rotation_y = yaw.localOrientation
    rotation_y = rotation_y[0]
    rotation_y = rotation_y[1]

    if rotation_y < -0.89:
        if y > 0:
            y = 0
        else:
            y = y
    elif rotation_y > 0.86:
        if y < 0:
            y = 0
        else:
            y = y

    # set the values
    owner.applyRotation([0, 0, x], False)

    yaw.applyRotation([y, 0, 0], True)

    # Center mouse in game window
    R.setMousePosition(*screen_center)

keyboard = G.keyboard.events

# KEY BINDINGS

kbleft = events.AKEY # Replace these with others, if you wish
kbright = events.DKEY # An example would be 'events.WKEY, DKEY, SKEY, and AKEY
kbup = events.WKEY
kbdown = events.SKEY #

##################

if not 'moveinit' in owner:
    owner['moveinit'] = 1
    owner['mx'] = 0.0
    owner['my'] = 0.0

    #
    #
    #
    # ~~SETTINGS~~ #
    #
    #
    #
    # Tweak these settings to fit your needs

    owner['accel'] = 2.0      # Acceleration
    owner['maxspd'] = 1.0    # Top speed
    owner['friction'] = 0.75   # Friction percentage; set to 0.0 for immediate stop
    owner['movelocal'] = 1    # Move on local axis?

if keyboard[kbleft]:
    owner['mx'] += owner['accel']
elif keyboard[kbright]:
    owner['mx'] -= owner['accel']
else:
    owner['mx'] *= owner['friction']

if keyboard[kbup]:
    owner['my'] += owner['accel']
elif keyboard[kbdown]:
    owner['my'] -= owner['accel']
else:
    owner['my'] *= owner['friction']

# Clamping

if owner['mx'] > owner['maxspd']:
    owner['mx'] = owner['maxspd']
elif owner['mx'] < -owner['maxspd']:
    owner['mx'] = -owner['maxspd']

if owner['my'] > owner['maxspd']:
    owner['my'] = owner['maxspd']
elif owner['my'] < -owner['maxspd']:
    owner['my'] = -owner['maxspd']

# Actual movement

owner.setLinearVelocity([owner['my'], owner['mx'], owner.getLinearVelocity()[2]], owner['movelocal'])