From: Marek Moeckel <wansti@gmx.de>
Date: Fri, 15 Jul 2005 23:53:09 +0000 (+0000)
Subject: Patch by <balinor@pnxs.de>:
X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=1bfcf5a82ac306fa5380c4db2be5109b61fac58e;p=supertux.git

Patch by <balinor@pnxs.de>:
- implements an abstract path GameObject, which could be used to guide
  platforms, cameras etc. along a path.

SVN-Revision: 2720
---

diff --git a/src/object/path.cpp b/src/object/path.cpp
new file mode 100644
index 000000000..8fa5a1625
--- /dev/null
+++ b/src/object/path.cpp
@@ -0,0 +1,132 @@
+//  $Id:$
+// 
+//  SuperTux
+//  Copyright (C) 2005 Philipp <balinor@pnxs.de>
+//
+//  This program is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU General Public License
+//  as published by the Free Software Foundation; either version 2
+//  of the License, or (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+// 
+//  You should have received a copy of the GNU General Public License
+//  along with this program; if not, write to the Free Software
+//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+//  02111-1307, USA.
+
+#include "path.hpp"
+
+#include "lisp/lisp.hpp"
+#include "lisp/list_iterator.hpp"
+#include "object_factory.hpp"
+
+#include <assert.h>
+
+
+// some constants
+#define DEFAULT_PIXELS_PER_SECOND	50
+#define EPSILON				1.5
+
+Path::Path(const lisp::Lisp& reader)
+{
+  float x,y;
+
+  lisp::ListIterator iter(&reader);
+
+  assert (iter.next());
+  std::string token = iter.item();
+  assert(token == "name");
+  iter.value()->get(name);
+
+  pixels_per_second = DEFAULT_PIXELS_PER_SECOND;
+  assert (iter.next());
+  token = iter.item();
+  if (token == "speed") {
+    iter.value()->get(pixels_per_second);
+    iter.next();
+  }
+  do {
+    token = iter.item();
+    if(token == "x") {
+      iter.value()->get(x);
+    } else if(token == "y") {
+      iter.value()->get(y);
+      points.push_back(Vector(x,y));
+    }
+  } while(iter.next());
+
+  next_target = points.begin();
+  pos = *next_target;
+
+  calc_next_velocity();
+
+  // register this path for lookup:
+  registry[name] = this;
+}
+
+Path::~Path()
+{
+  registry.erase(name);
+}
+
+void
+Path::update(float elapsed_time)
+{
+  last_movement = velocity * elapsed_time;
+  pos += last_movement;
+  if ((pos - *next_target).norm() < EPSILON) {
+    pos = *next_target;
+    calc_next_velocity();
+  }
+}
+
+void
+Path::draw(DrawingContext& context)
+{
+  // NOOP ;-)
+}
+
+const Vector&
+Path::GetPosition() {
+  return pos;
+}
+
+const Vector&
+Path::GetStart() {
+  return *(points.begin());
+}
+
+const Vector&
+Path::GetLastMovement() {
+  return last_movement;
+}
+
+void
+Path::calc_next_velocity()
+{
+  Vector distance;
+
+  ++next_target;
+  if (next_target == points.end()) {
+    next_target = points.begin();
+  }
+
+  distance = *next_target - pos;
+  velocity = distance.unit() * pixels_per_second;
+}
+
+//////////////////////////////////////////////////////////////////////////////
+// static stuff
+
+PathRegistry Path::registry;
+
+Path*
+Path::GetByName(const std::string& name) {
+  return registry[name];
+}
+
+IMPLEMENT_FACTORY(Path, "path");
diff --git a/src/object/path.hpp b/src/object/path.hpp
new file mode 100644
index 000000000..3671ec0e0
--- /dev/null
+++ b/src/object/path.hpp
@@ -0,0 +1,70 @@
+//  $Id:$
+// 
+//  SuperTux
+//  Copyright (C) 2005 Philipp <balinor@pnxs.de>
+//
+//  This program is free software; you can redistribute it and/or
+//  modify it under the terms of the GNU General Public License
+//  as published by the Free Software Foundation; either version 2
+//  of the License, or (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+// 
+//  You should have received a copy of the GNU General Public License
+//  along with this program; if not, write to the Free Software
+//  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+//  02111-1307, USA.
+#ifndef __PATH_HPP__
+#define __PATH_HPP__
+
+#include <string>
+#include <list>
+#include <map>
+
+#include "math/vector.hpp"
+#include "game_object.hpp"
+#include "lisp/lisp.hpp"
+
+
+class   Path;
+typedef std::map<std::string,Path*>       PathRegistry;
+
+
+typedef std::list<Vector>                 PathPoints;
+typedef std::list<Vector>::const_iterator PathPointIter;
+
+
+class Path : public GameObject
+{
+public:
+  Path(const lisp::Lisp& reader);
+  ~Path();
+
+  virtual void update(float elapsed_time);
+  virtual void draw(DrawingContext& context);
+
+  const Vector& GetPosition();
+  const Vector& GetStart();
+  const Vector& GetLastMovement();
+
+  // WARNING: returns NULL if not found !
+  static Path* GetByName(const std::string& name);
+
+private:
+  std::string   name;
+  float         pixels_per_second;
+  PathPoints    points;	
+  PathPointIter next_target;
+  Vector        pos;
+  Vector        velocity;
+  Vector        last_movement;
+
+  void calc_next_velocity();
+
+  static PathRegistry registry;
+};
+
+#endif