From d4ef778cc8bb2aab4ecd7a992926d3c11ef69cd4 Mon Sep 17 00:00:00 2001
From: Paolo Capriotti <p.capriotti@gmail.com>
Date: Fri, 19 Jun 2009 11:55:18 +0200
Subject: [PATCH] Add path specification for movement animations.

Paths are functions that compute the increment in position at time i. A linear
path and an L-shaped path have been added. The L-shaped path has been mapped
to the chess knight movement.
---
 lib/animations.rb            | 36 ++++++++++++++++++++++++++++++++----
 lib/animator_helper.rb       |  4 ++--
 lib/{games => }/factory.rb   |  0
 lib/games/chess/animator.rb  | 13 +++++++++++--
 lib/games/chess/chess.rb     |  1 -
 lib/games/games.rb           |  2 ++
 test/test_animations.rb      |  2 +-
 test/test_animator_helper.rb |  2 +-
 8 files changed, 49 insertions(+), 11 deletions(-)
 rename lib/{games => }/factory.rb (100%)

diff --git a/lib/animations.rb b/lib/animations.rb
index 7f66308..8321b91 100644
--- a/lib/animations.rb
+++ b/lib/animations.rb
@@ -1,4 +1,5 @@
 require 'animation_field'
+require 'factory'
 
 module Animations
   LENGTH = 100
@@ -24,18 +25,18 @@ module Animations
     end
   end
   
-  def movement(item, src, dst)
+  def movement(item, src, dst, path_factory)
     if item
       src = board.to_real(src)
       dst = board.to_real(dst)
-      delta = dst - src
+      path = path_factory.new(src, dst)
       
       SimpleAnimation.new "move to #{dst}", LENGTH, nil,
-        lambda {|i| item.pos = src + delta * i },
+        lambda {|i| item.pos = src + path[i] },
         lambda { item.pos = dst }
     end
   end
-  
+
   def disappear(item, name = "disappear")
     if item
       SimpleAnimation.new name, LENGTH,
@@ -60,3 +61,30 @@ module Animations
     Animation.new(name) { board.remove_item p }
   end
 end
+
+module Path
+  Linear = Factory.new do |src, dst|
+    delta = dst - src
+    lambda {|i| delta * i }
+  end
+
+  class LShape
+    FACTOR = Math.exp(3.0) - 1
+    def initialize(src, dst)
+      @delta = dst - src
+      nonlin = lambda{|i| (Math.exp(3.0 * i) - 1) / FACTOR }
+      lin = lambda {|i| i }
+      if @delta.x.abs < @delta.y.abs
+        @x = lin
+        @y = nonlin
+      else
+        @y = lin
+        @x = nonlin
+      end
+    end
+    
+    def [](i)
+      Qt::PointF.new(@delta.x * @x[i], @delta.y * @y[i])
+    end
+  end
+end
diff --git a/lib/animator_helper.rb b/lib/animator_helper.rb
index 390dad2..40ea8fd 100644
--- a/lib/animator_helper.rb
+++ b/lib/animator_helper.rb
@@ -3,9 +3,9 @@ require 'animations'
 module AnimatorHelper
   include Animations
   
-  def move!(src, dst)
+  def move!(src, dst, path)
     piece = board.move_item(src, dst)
-    movement(piece, src, dst)
+    movement(piece, src, dst, path)
   end
   
   def disappear_on!(p, opts = {})
diff --git a/lib/games/factory.rb b/lib/factory.rb
similarity index 100%
rename from lib/games/factory.rb
rename to lib/factory.rb
diff --git a/lib/games/chess/animator.rb b/lib/games/chess/animator.rb
index bdbdff0..719dbb1 100644
--- a/lib/games/chess/animator.rb
+++ b/lib/games/chess/animator.rb
@@ -8,7 +8,16 @@ module Chess
     def initialize(board)
       @board = board
     end
-  
+
+    def specific_move!(piece, src, dst)
+      path = if piece.type == :knight
+        Path::LShape
+      else
+        Path::Linear
+      end
+      move!(src, dst, path)
+    end
+
     def warp(state, opts = { :instant => true })
       res = []
       
@@ -32,7 +41,7 @@ module Chess
     
     def forward(state, move)
       capture = disappear_on! move.dst
-      actual_move = move! move.src, move.dst
+      actual_move = specific_move! state.board[move.dst], move.src, move.dst
       extra = if move.type == :king_side_castling
         move! move.dst + Point.new(1, 0), move.dst - Point.new(1, 0)
       elsif move.type == :queen_side_castling
diff --git a/lib/games/chess/chess.rb b/lib/games/chess/chess.rb
index dbc626b..c180f0c 100644
--- a/lib/games/chess/chess.rb
+++ b/lib/games/chess/chess.rb
@@ -6,7 +6,6 @@ require 'games/chess/policy'
 require 'games/chess/animator'
 require 'games/chess/validator'
 require 'games/chess/serializer'
-require 'games/factory'
 
 module Chess
 
diff --git a/lib/games/games.rb b/lib/games/games.rb
index 9d65921..3a5c4ed 100644
--- a/lib/games/games.rb
+++ b/lib/games/games.rb
@@ -1,3 +1,5 @@
+require 'factory'
+
 class Game
   GAMES = { }
 
diff --git a/test/test_animations.rb b/test/test_animations.rb
index c1df617..4f166e9 100644
--- a/test/test_animations.rb
+++ b/test/test_animations.rb
@@ -72,7 +72,7 @@ class TestAnimations < Test::Unit::TestCase
   
   def test_movement
     item = GeneralMock.new
-    @field.run @c.movement(item, Point.new(3, 4), Point.new(5, 6))
+    @field.run @c.movement(item, Point.new(3, 4), Point.new(5, 6), Path::Linear)
     @field.run_test
     
     old_p = nil
diff --git a/test/test_animator_helper.rb b/test/test_animator_helper.rb
index ee5694d..980f6b2 100644
--- a/test/test_animator_helper.rb
+++ b/test/test_animator_helper.rb
@@ -44,7 +44,7 @@ class TestAnimatorHelper < Test::Unit::TestCase
   
   def test_move
     @items[Point.new(3, 3)] = "white knight"
-    anim = @animator.move!(Point.new(3, 3), Point.new(5, 4))
+    anim = @animator.move!(Point.new(3, 3), Point.new(5, 4), Path::Linear)
     assert_animation(:movement, anim) do |args|
       piece, src, dst = args
       assert_equal "white knight", piece
-- 
2.11.4.GIT