From 750df62bd38c2430e109f39e8cf9861805788a24 Mon Sep 17 00:00:00 2001
From: Florian Forster <supertux@octo.it>
Date: Mon, 15 Mar 2010 20:21:03 +0000
Subject: [PATCH] Unstable tile: Implement a "slow fall" phase for sprites
 without "shake" and "dissolve" actions.

Sprites with neither a "shake" nor a "dissolve" action now start to fall down
immediately. For the first 0.5 seconds, the gravity modifier is set to 10%
though, so that the movement is *very* slow at first. It is noticable however
and hints at the instability of the tile. Hopefully, players won't be surprised
by a falling platform anymore now.

SVN-Revision: 6612
---
 .../objects/unstable_tile/iceplatform.sprite       |  9 +-----
 src/object/unstable_tile.cpp                       | 34 ++++++++++++++++++++--
 src/object/unstable_tile.hpp                       |  3 ++
 3 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/data/images/objects/unstable_tile/iceplatform.sprite b/data/images/objects/unstable_tile/iceplatform.sprite
index 076933285..51c691b5e 100644
--- a/data/images/objects/unstable_tile/iceplatform.sprite
+++ b/data/images/objects/unstable_tile/iceplatform.sprite
@@ -6,15 +6,8 @@
     )
   )
   (action
-    (name "shake")
-    (fps 2)
-    (images 
-      "iceplatform.png"
-    )
-  )
-  (action
     (name "fall-down")
-    (fps 1)
+    (fps 0.2)
     (images 
       "iceplatform.png"
     )
diff --git a/src/object/unstable_tile.cpp b/src/object/unstable_tile.cpp
index f83d71614..d31d5e625 100644
--- a/src/object/unstable_tile.cpp
+++ b/src/object/unstable_tile.cpp
@@ -75,7 +75,27 @@ void UnstableTile::dissolve (void)
     this->set_action ("dissolve", /* loops = */ 1);
   }
   else {
-    fall_down ();
+    slow_fall ();
+  }
+}
+
+void UnstableTile::slow_fall (void)
+{
+  /* Only enter slow-fall if neither shake nor dissolve is available. */
+  if (state != STATE_NORMAL) {
+    this->fall_down ();
+    return;
+  }
+
+  if (sprite->has_action ("fall-down")) {
+    state = STATE_SLOWFALL;
+    this->set_action ("fall-down", /* loops = */ 1);
+    physic.set_gravity_modifier (.10);
+    physic.enable_gravity (true);
+    slowfall_timer = 0.5; /* Fall slowly for half a second. */
+  }
+  else {
+    remove_me ();
   }
 }
 
@@ -83,12 +103,14 @@ void UnstableTile::fall_down (void)
 {
   if ((state != STATE_NORMAL)
       && (state != STATE_SHAKE)
-      && (state != STATE_DISSOLVE))
+      && (state != STATE_DISSOLVE)
+      && (state != STATE_SLOWFALL))
     return;
 
   if (sprite->has_action ("fall-down")) {
     state = STATE_FALL;
     this->set_action ("fall-down", /* loops = */ 1);
+    physic.set_gravity_modifier (.98);
     physic.enable_gravity (true);
   }
   else {
@@ -117,6 +139,14 @@ UnstableTile::update(float elapsed_time)
       }
       break;
 
+    case STATE_SLOWFALL:
+      if (slowfall_timer >= elapsed_time)
+	slowfall_timer -= elapsed_time;
+      else /* Switch to normal falling procedure */
+	fall_down ();
+      movement = physic.get_movement (elapsed_time);
+      break;
+
     case STATE_FALL:
       if (sprite->animation_done())
         remove_me ();
diff --git a/src/object/unstable_tile.hpp b/src/object/unstable_tile.hpp
index aea657ddf..d041d9574 100644
--- a/src/object/unstable_tile.hpp
+++ b/src/object/unstable_tile.hpp
@@ -39,6 +39,7 @@ private:
     STATE_NORMAL,   /**< default state */
     STATE_SHAKE,    /**< shaking, still solid */
     STATE_DISSOLVE, /**< dissolving, will turn non-solid after this */
+    STATE_SLOWFALL, /**< slow fall phase (used when neither shaking nor dissolving exist */
     STATE_FALL      /**< falling down */
   };
 
@@ -48,9 +49,11 @@ private:
   void shake (void);
   void dissolve (void);
   void fall_down (void);
+  void slow_fall (void);
 
   Physic physic;
   State state;
+  float slowfall_timer;
 };
 
 #endif
-- 
2.11.0