[gcompris] intro gravity, improved with a tutorial

[Bruno Coudoin <bcoudoin src gnome org>]

commit bbbd46085574ce93bf7fbd214a8f784533e35795
Author: Bruno Coudoin <bruno coudoin free fr>
Date:   Mon Oct 8 00:40:57 2012 +0200

    intro gravity, improved with a tutorial
    
    I added all the instructions from the manual in the game itself.
    The instructions are given by sentences. In some cases, the children
    can play and then the tutorial continues.

 src/intro_gravity-activity/intro_gravity.py     |  174 ++++++++++++++++-------
 src/intro_gravity-activity/intro_gravity.xml.in |   13 +--
 2 files changed, 124 insertions(+), 63 deletions(-)
---
diff --git a/src/intro_gravity-activity/intro_gravity.py b/src/intro_gravity-activity/intro_gravity.py
index 8ccf82e..7b95be7 100644
--- a/src/intro_gravity-activity/intro_gravity.py
+++ b/src/intro_gravity-activity/intro_gravity.py
@@ -63,12 +63,12 @@ class Gcompris_intro_gravity:
     # Load planet on the left (saturn) and it's slider
     planet_left = Fixed_planet(self.rootitem,
                                     70, 200, "saturn.png")
-    Slider(self.rootitem, 20, 200, planet_left)
+    Slider(self.rootitem, self, 20, 200, planet_left)
 
     # Planet on right (neptune) and it's slider
     planet_right = Fixed_planet(self.rootitem,
                                      680, 200, "neptune.png")
-    Slider(self.rootitem, 780, 200, planet_right)
+    Slider(self.rootitem, self, 780, 200, planet_right)
 
     # Load the tux_ship
     self.ship_instance = Spaceship(self, self.rootitem,
@@ -80,39 +80,57 @@ class Gcompris_intro_gravity:
     gcompris.bar_set(0)
     gcompris.bar_location(2,-1,0.5)
 
-    # Ready button
-    self.ready_text = goocanvas.Text(
-      parent = self.rootitem,
-      x = 395,
-      y = 100,
-      fill_color = "white",
-      anchor = gtk.ANCHOR_CENTER,
-      alignment = pango.ALIGN_CENTER,
-      text = _("I'm ready") )
-    self.ready_text.connect('button_press_event', self.ready_event, False)
-    bounds = self.ready_text.get_bounds()
-    gap = 20
-
-    self.ready_back = goocanvas.Rect(
-      parent = self.rootitem,
-      radius_x = 6,
-      radius_y = 6,
-      x = bounds.x1 - gap,
-      y = bounds.y1 - gap,
-      width = bounds.x2 - bounds.x1 + gap * 2,
-      height = bounds.y2 - bounds.y1 + gap * 2,
-      stroke_color_rgba = 0xFFFFFFFFL,
-      fill_color_rgba = 0xCCCCCC44L)
-    gcompris.utils.item_focus_init(self.ready_back, None)
-    gcompris.utils.item_focus_init(self.ready_text, self.ready_back)
-    self.ready_back.connect('button_press_event', self.ready_event)
-
-  def ready_event(self, widget, target, event):
-    self.ready_back.props.visibility = goocanvas.ITEM_INVISIBLE
-    self.ready_text.props.visibility = goocanvas.ITEM_INVISIBLE
+    # Message button
+    self.message = Message(self.rootitem, 400, 320, 20, self.tuto_event)
+
+    self.tuto_step = 0
+    self.tutorial(self.tuto_step)
+
+  def tuto_event(self, widget = None, target = None, event = None):
+    self.tuto_step += 1
+    self.tutorial(self.tuto_step)
+
+  def tutorial(self, step):
+    """Display a tutorial message for the given step"""
+    if step == 0:
+      self.board_paused = True
+      self.message.show(
+        _("Gravity is universal and Newton's law of universal gravitation extends gravity beyond earth."
+          " This force of gravitational attraction is directly dependent upon the masses of both objects"
+          " and inversely proportional to the square of the distance that separates their centers.")
+        )
+    elif step == 1:
+      self.board_paused = True
+      self.message.show(
+        _("Since the gravitational force is directly proportional to the"
+          " mass of both interacting objects, more massive objects will"
+          " attract each other with a greater gravitational force."
+          " So as the mass of either object increases, the force of"
+          " gravitational attraction between them also increases but"
+          " this force is inversely proportional to the square of the"
+          " separation distance between the two interacting objects,"
+          " more separation distance will result in weaker gravitational"
+          " forces.")
+        )
+    elif step == 2:
+      self.board_paused = True
+      self.message.show(
+        _("You goal is to let Tux's spaceship move by changing the mass"
+          " of its surrounding planets. Don't get too close to the planets"
+          " or you will crash on them."
+          " The arrow indicates the direction of the force on your ship.")
+        )
+    elif step == 3:
+      self.board_paused = False
+      self.message.hide()
+    elif step == 4:
+      self.board_paused = True
+      self.message.show( _("Take care you an in danger, avoid the asteroids.") )
+    elif step == 5:
+      self.board_paused = False
+      self.message.hide()
+      Asteroids(self.ship_instance, self.rootitem)
 
-    self.ship_instance.initiate()
-    asteroid_instance = Asteroids(self.ship_instance, self.rootitem)
 
   def end(self):
     # Remove the root item removes all the others inside it
@@ -199,7 +217,6 @@ class Spaceship(Gcompris_intro_gravity):
     self.done = False
     self.move = 0
 
-  def initiate(self):
     gobject.timeout_add(30, self.calculate)
 
   def calculate(self):
@@ -248,9 +265,10 @@ class Spaceship(Gcompris_intro_gravity):
       self.crash()
     # Manage the success case
     self.trip_distance += abs(self.move)
-    if self.trip_distance > 500 * self.level:
-      self.done = True
-      self.game.win()
+
+    if self.trip_distance > 100:
+      # Let's move to the next step in the tutorial
+      self.game.tuto_event()
 
     return True
 
@@ -261,7 +279,6 @@ class Spaceship(Gcompris_intro_gravity):
 class Asteroids:
   """Class for the asteroids"""
 
-
   def __init__(self, ship_instance, rootitem):
     self.ship_instance = ship_instance
     self.rootitem = rootitem
@@ -301,32 +318,36 @@ class Asteroids:
     self.asteroid_rootitem.lower(self.ship_instance.tux_spaceship)
     gobject.timeout_add(30, self.check_asteroid)
 
+  def get_real_bounds_center(self, item):
+    b = item.get_bounds()
+    return (b.x1 + (b.x2 - b.x1) / 2, b.y1 + (b.y2 - b.y1) / 2)
+
   def check_asteroid(self):
     if self.ship_instance.game.board_paused:
       return True
 
-    bound1 = self.asteroid1.get_bounds()
-    bound2 = self.asteroid2.get_bounds()
-
     # Move asteroids
     self.asteroid1.translate(0, -0.05)
     self.asteroid2.translate(0, 0.09)
 
     # Check whether ship and asteroid have collided
-    bound_ship = self.ship_instance.tux_spaceship.get_bounds()
-
-    bound1_x = (bound1.x1 + bound1.x2) / 2
-    bound2_x = (bound2.x1 + bound2.x2) / 2
-    bound1_y = (bound1.y1 + bound1.y2) / 2
-    bound2_y = (bound2.y1 + bound2.y2) / 2
-    bound_ship_x = (bound_ship.x1 + bound_ship.x2) / 2
-    bound_ship_y = (bound_ship.y1 + bound_ship.y2) / 2
+    (bound1_x, bound1_y) = self.get_real_bounds_center(self.asteroid1)
+    (bound2_x, bound2_y) = self.get_real_bounds_center(self.asteroid2)
+    (bound_ship_x, bound_ship_y) = self.get_real_bounds_center(self.ship_instance.tux_spaceship)
+
     if abs(bound1_x - bound_ship_x) < 40 and abs(bound1_y - bound_ship_y) < 40:
       self.crash_image(bound_ship_x, bound_ship_y)
+      return False
     elif abs(bound2_x - bound_ship_x) < 40 and abs(bound2_y - bound_ship_y) < 40:
       self.crash_image(bound_ship_x, bound_ship_y)
+      return False
     else:
-      return True
+      if bound2_y > 300:
+        self.ship_instance.done = True
+        self.ship_instance.game.win()
+        return False
+
+    return True
 
   def crash_image(self, x, y):
     image = goocanvas.Image(
@@ -370,7 +391,8 @@ class Slider:
   """ class for scale slider"""
 
 
-  def __init__(self, rootitem, x, y, planet_instance):
+  def __init__(self, rootitem, game, x, y, planet_instance):
+    self.game = game
     self.planet_instance = planet_instance
     self.height = 60
     self.button_width = 20
@@ -433,6 +455,9 @@ class Slider:
       line_width = 5.0)
 
   def move_bar(self, widget, target, event, move):
+    if self.game.board_paused:
+      return
+
     self.scale_value += move
     # Take care not to bypass bounds
     if self.scale_value > 1.0:
@@ -447,3 +472,48 @@ class Slider:
     # Change the planet mass
     self.planet_instance.set_scale(self.scale_value)
 
+class Message:
+  """Create a message on screen"""
+
+  def __init__(self, rootitem, x, y, gap, tuto_event):
+    self.rootitem = goocanvas.Group(parent = rootitem)
+    self.gap = gap
+    self.text = goocanvas.Text(
+      parent = self.rootitem,
+      x = x,
+      y = y,
+      width = 500,
+      fill_color = "white",
+      anchor = gtk.ANCHOR_CENTER,
+      alignment = pango.ALIGN_CENTER,
+      text = "")
+
+    self.back = goocanvas.Rect(
+      parent = self.rootitem,
+      radius_x = 6,
+      radius_y = 6,
+      stroke_color_rgba = 0xFFFFFFFFL,
+      fill_color_rgba = 0x666666AAL)
+    self.back.lower(None)
+    self.hide()
+    self.back.connect("button_press_event", tuto_event)
+    self.text.connect("button_press_event", tuto_event)
+
+  def _refreshBack(self):
+    bounds = self.text.get_bounds()
+    self.back.set_properties(
+      x = bounds.x1 - self.gap,
+      y = bounds.y1 - self.gap,
+      width = bounds.x2 - bounds.x1 + self.gap * 2,
+      height = bounds.y2 - bounds.y1 + self.gap * 2)
+    gcompris.utils.item_focus_init(self.back, None)
+    gcompris.utils.item_focus_init(self.text, self.back)
+
+  def hide(self):
+    self.rootitem.props.visibility = goocanvas.ITEM_INVISIBLE
+
+  def show(self, msg):
+    self.text.props.text = msg
+    self._refreshBack()
+    self.rootitem.props.visibility = goocanvas.ITEM_VISIBLE
+
diff --git a/src/intro_gravity-activity/intro_gravity.xml.in b/src/intro_gravity-activity/intro_gravity.xml.in
index 3899102..97218ea 100644
--- a/src/intro_gravity-activity/intro_gravity.xml.in
+++ b/src/intro_gravity-activity/intro_gravity.xml.in
@@ -12,17 +12,8 @@
         <_title>Intro gravity</_title>
         <_description>Introduction to the concept of gravity</_description>
         <_goal>Maintain the spaceship in the middle without crashing into the planets or the asteroids</_goal>
-        <_manual xml:space="preserve">
-Gravity is universal and Newton's law of universal gravitation extends gravity beyond earth.This force of gravitational attraction is directly dependent upon the masses of both objects and inversely proportional to the square of the distance that separates their centers.
-
-Since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. So as the mass of either object increases, the force of gravitational attraction between them also increases but this force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces.
-
-Increase and decrease the size of the planets at the two ends to see how the force on the spaceship changes with changes in the size and distance. This force results in acceleration of the spaceship.
-The arrow indicates the direction of force.
-
-With every level the speed of the spaceship will increase.
-        </_manual>
-        <_credit>www.openclipart.org</_credit>
+        <_manual>Follow the instructions when you run the activity.</_manual>
+        <_credit></_credit>
   </Board>
   <Data directory=""/>
 </GCompris>