From 445dc0cc5770f9aa62264efb37c35d5964e41c0f Mon Sep 17 00:00:00 2001
From: Walter Bender <walter@sugarlabs.org>
Date: Wed, 11 Dec 2013 18:24:21 +0000
Subject: unpacking elements so as to be able to remove cjson dependency

---
(limited to 'elements/add_objects.py')

diff --git a/elements/add_objects.py b/elements/add_objects.py
new file mode 100644
index 0000000..49bf538
--- /dev/null
+++ b/elements/add_objects.py
@@ -0,0 +1,538 @@
+"""
+This file is part of the 'Elements' Project
+Elements is a 2D Physics API for Python (supporting Box2D2)
+
+Copyright (C) 2008, The Elements Team, <elements@linuxuser.at>
+
+Home:  http://elements.linuxuser.at
+IRC:   #elements on irc.freenode.org
+
+Code:  http://www.assembla.com/wiki/show/elements
+       svn co http://svn2.assembla.com/svn/elements                     
+
+License:  GPLv3 | See LICENSE for the full text
+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 3 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, see <http://www.gnu.org/licenses/>.              
+"""
+from locals import *
+from elements import box2d
+
+# Imports
+from math import pi
+from math import sqrt
+from math import asin
+
+import tools_poly
+
+class Add:
+    element_count = 0
+    
+    def __init__(self, parent):
+        self.parent = parent
+        
+    def ground(self):
+        """ Add a static ground to the scene
+        
+            Return: box2d.b2Body
+        """
+        return self._rect((-10.0, 0.0), 50.0, 0.1, dynamic=False)
+            
+    def triangle(self, pos, sidelength, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
+        """ Add a triangle | pos & a in the current input unit system (meters or pixels)
+        
+            Parameters:
+              pos .... position (x,y)
+              sidelength ...... sidelength
+              other .. see [physics parameters]
+            
+            Return: box2d.b2Body
+        """
+        vertices = [(-sidelength, 0.0), (sidelength, 0.0), (0.0, 2*sidelength)]
+        return self.poly(pos, vertices, dynamic, density, restitution, friction, screenCoord)
+
+    def ball(self, pos, radius, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
+        """ Add a dynamic ball at pos after correcting the positions and legths to the internal
+            meter system if neccessary (if INPUT_PIXELS), then call self._add_ball(...)
+            
+            Parameters:
+              pos ..... position (x,y)
+              radius .. circle radius
+              other ... see [physics parameters]
+              
+            Return: box2d.b2Body
+        """
+        # Bring coordinates into the world coordinate system (flip, camera offset, ...)
+        if screenCoord: x, y = self.parent.to_world(pos)
+        else: x, y = pos
+
+
+        if self.parent.input == INPUT_PIXELS:
+            x /= self.parent.ppm
+            y /= self.parent.ppm
+            radius /= self.parent.ppm
+            
+        return self._ball((x,y), radius, dynamic, density, restitution, friction)
+
+    def _ball(self, pos, radius, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
+        # Add a ball without correcting any settings
+        # meaning, pos and vertices are in meters
+        # Define the body
+        x, y = pos
+        bodyDef = box2d.b2BodyDef()
+        bodyDef.position=(x, y)
+
+        userData = { 'color' : self.parent.get_color() }
+        bodyDef.userData = userData
+
+        # Create the Body
+        if not dynamic:
+            density = 0
+
+        body = self.parent.world.CreateBody(bodyDef)
+                    
+        self.parent.element_count += 1
+
+        # Add a shape to the Body
+        circleDef = box2d.b2CircleDef()
+        circleDef.density = density
+        circleDef.radius = radius
+        circleDef.restitution = restitution
+        circleDef.friction = friction
+
+        body.CreateShape(circleDef)
+        body.SetMassFromShapes()    
+        
+        return body    
+
+    def rect(self, pos, width, height, angle=0, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
+        """ Add a dynamic rectangle with input unit according to self.input (INPUT_PIXELS or INPUT_METERS)
+            Correcting the positions to meters and calling self._add_rect()
+
+            Parameters:
+              pos ..... position (x,y)
+              width ....... horizontal line
+              height ....... vertical line
+              angle ........ in degrees (0 .. 360)
+              other ... see [physics parameters]
+
+            Return: box2d.b2Body
+        """
+        # Bring coordinates into the world coordinate system (flip, camera offset, ...)
+        if screenCoord: x, y = self.parent.to_world(pos)
+        else: x, y = pos
+
+        # If required, translate pixel -> meters
+        if self.parent.input == INPUT_PIXELS:
+            x /= self.parent.ppm
+            y /= self.parent.ppm
+            width /= self.parent.ppm
+            height /= self.parent.ppm
+        
+        # grad -> radians
+        angle = (angle * pi) / 180
+        
+        return self._rect((x,y), width, height, angle, dynamic, density, restitution, friction)
+
+
+    def wall(self, pos1, pos2, width=5, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
+        """ Add a static rectangle between two arbitrary points with input unit according to self.input 
+            (INPUT_PIXELS or INPUT_METERS) Correcting the positions to meters and calling self._add_rect()
+
+            Return: box2d.b2Body
+        """
+        if width < 5: width = 5
+        
+        if (pos1[0] < pos2[0]):        
+            x1, y1 = pos1
+            x2, y2 = pos2
+        else:
+            x1, y1 = pos2
+            x2, y2 = pos1          
+
+        # Bring coordinates into the world coordinate system (flip, camera offset, ...)
+        if screenCoord: 
+           x1, y1 = self.parent.to_world((x1, y1))
+           x2, y2 = self.parent.to_world((x2, y2))
+
+        # If required, translate pixel -> meters
+        if self.parent.input == INPUT_PIXELS:
+            x1 /= self.parent.ppm
+            y1 /= self.parent.ppm
+            x2 /= self.parent.ppm
+            y2 /= self.parent.ppm
+            width /= self.parent.ppm
+                           
+        length = sqrt( (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2) )*0.5
+
+        if width > 0:
+            halfX = x1 + (x2-x1)*0.5
+            halfY = y1 + (y2-y1)*0.5
+
+            angle = asin( (y2-halfY)/length )
+            return self._rect((halfX, halfY), length, width, angle, False, density, restitution, friction)
+                    
+    def _rect(self, pos, width, height, angle=0, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
+        # Add a rect without correcting any settings
+        # meaning, pos and vertices are in meters
+        # angle is now in radians ((degrees * pi) / 180))
+        x, y = pos
+        bodyDef = box2d.b2BodyDef()
+        bodyDef.position=(x, y)
+
+        userData = { 'color' : self.parent.get_color() }
+        bodyDef.userData = userData
+
+        # Create the Body
+        if not dynamic:
+            density = 0
+
+        body = self.parent.world.CreateBody(bodyDef)
+                    
+        self.parent.element_count += 1
+
+        # Add a shape to the Body
+        boxDef = box2d.b2PolygonDef()
+        
+        boxDef.SetAsBox(width, height, (0,0), angle)
+        boxDef.density = density
+        boxDef.restitution = restitution
+        boxDef.friction = friction
+        body.CreateShape(boxDef)
+        
+        body.SetMassFromShapes()
+        
+        return body
+
+    def poly(self, pos, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
+        """ Add a dynamic polygon, which has the vertices arranged around the poly's center at pos
+            Correcting the positions to meters if INPUT_PIXELS, and calling self._add_poly()
+
+            Parameters:
+              pos ....... position (x,y)
+              vertices .. vertices arranged around the center
+              other ... see [physics parameters]
+
+            Return: box2d.b2Body
+        """        
+        # Bring coordinates into the world coordinate system (flip, camera offset, ...)
+        if screenCoord: x, y = self.parent.to_world(pos)
+        else: x, y = pos
+                    
+        # If required, translate pixel -> meters
+        if self.parent.input == INPUT_PIXELS:
+            # translate pixel -> meters
+            x /= self.parent.ppm
+            y /= self.parent.ppm
+            
+            # Translate vertices from pixels to meters
+            v_new = []
+            for v in vertices:
+                vx, vy = v
+                v_new.append((vx/self.parent.ppm, vy/self.parent.ppm))
+            vertices = v_new
+        
+        return self._poly((x,y), vertices, dynamic, density, restitution, friction)
+
+    def _poly(self, pos, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
+        # add a centered poly at pos without correcting any settings
+        # meaning, pos and vertices are in meters
+        x, y = pos
+        bodyDef = box2d.b2BodyDef()
+        bodyDef.position=(x, y)
+            
+        userData = { 'color' : self.parent.get_color() }
+        bodyDef.userData = userData
+
+        # Create the Body
+        if not dynamic:
+            density = 0
+
+        body = self.parent.world.CreateBody(bodyDef)
+        
+        self.parent.element_count += 1
+
+        # Add a shape to the Body
+        polyDef = box2d.b2PolygonDef()
+
+        polyDef.setVertices(vertices)
+        polyDef.density = density
+        polyDef.restitution = restitution
+        polyDef.friction = friction
+
+        body.CreateShape(polyDef)
+        body.SetMassFromShapes()
+                
+        return body
+   
+    def concavePoly(self, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5, screenCoord=True):
+        # 1. Step: Reduce        
+        # Detect if the polygon is closed or open
+        if vertices[0] != vertices[-1]:        
+            is_closed = False
+        else:
+            is_closed = True
+                            
+        # Continue reducing the vertecs
+        x, y = c = tools_poly.calc_center(vertices)
+        vertices = tools_poly.poly_center_vertices(vertices)
+        
+        # Bring coordinates into the world coordinate system (flip, camera offset, ...)
+        if screenCoord: x, y = self.parent.to_world(c)
+        else: x, y = c
+
+        # If required, translate pixel -> meters
+        if self.parent.input == INPUT_PIXELS:
+            # translate pixel -> meters
+            x /= self.parent.ppm
+            y /= self.parent.ppm
+        
+        # Let's add the body
+        bodyDef = box2d.b2BodyDef()
+        bodyDef.position=(x, y)
+
+        userData = { 'color' : self.parent.get_color() }
+        bodyDef.userData = userData
+
+        # Create the Body
+        if not dynamic:
+            density = 0
+
+        body = self.parent.world.CreateBody(bodyDef)
+                    
+        self.parent.element_count += 1
+
+        # Create the reusable Box2D polygon and circle definitions
+        polyDef = box2d.b2PolygonDef()
+        polyDef.vertexCount = 4 # rectangle
+        polyDef.density = density
+        polyDef.restitution = restitution
+        polyDef.friction = friction
+
+        circleDef = box2d.b2CircleDef()
+        circleDef.density = density
+        circleDef.radius = 0.086
+        circleDef.restitution = restitution
+        circleDef.friction = friction
+
+        # Set the scale factor 
+        factor = 8.0
+
+        v2 = box2d.b2Vec2(*vertices[0])
+        for v in vertices[1:]:
+            v1    = v2.copy()
+            v2    = box2d.b2Vec2(*v)
+             
+            vdir = v2-v1 # (v2x-v1x, v2y-v1y)
+            vdir.Normalize()
+            
+            # we need a little size for the end part
+            vn = box2d.b2Vec2(-vdir.y*factor, vdir.x*factor)
+
+            v = [ v1+vn, v1-vn, v2-vn, v2+vn ] 
+
+            # Create a line (rect) for each part of the polygon, 
+            # and attach it to the body                
+            polyDef.setVertices( [vi / self.parent.ppm for vi in v] )
+
+            try:
+                polyDef.checkValues()
+            except ValueError:
+                print "concavePoly: Created an invalid polygon!"
+                return None
+
+            body.CreateShape(polyDef)
+
+            # Now add a circle to the points between the rects
+            # to avoid sharp edges and gaps
+            if not is_closed and v2.tuple() == vertices[-1]:
+                # Don't add a circle at the end
+                break
+
+            circleDef.localPosition = v2 / self.parent.ppm
+            body.CreateShape(circleDef)            
+                                 
+        # Now, all shapes have been attached
+        body.SetMassFromShapes()                
+        
+        # Return hard and soft reduced vertices
+        return body
+
+    def complexPoly(self, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
+        # 1. Step: Reduce
+        # 2. Step: See if start and end are close, if so then close the polygon
+        # 3. Step: Detect if convex or concave
+        # 4. Step: Start self.convexPoly or self.concavePoly
+        vertices, is_convex = tools_poly.reduce_poly_by_angle(vertices)            
+        #print "->", is_convex
+
+        # If start and endpoints are close to each other, close polygon
+        x1, y1 = vertices[0]
+        x2, y2 = vertices[-1]
+        dx = x2 - x1
+        dy = y2 - y1
+        l = sqrt((dx*dx)+(dy*dy))
+
+        if l < 50:
+            vertices[-1] = vertices[0]
+        else:
+            # Never convex if open (we decide so :)
+            is_convex = False
+
+        if tools_poly.is_line(vertices):
+            # Lines shall be drawn by self.concavePoly(...)
+            print "is line"
+            is_convex = False
+                    
+        if is_convex:
+            print "convex"
+            return self.convexPoly(vertices, dynamic, density, restitution, friction), vertices
+        else:
+            print "concave"
+            return self.concavePoly(vertices, dynamic, density, restitution, friction), vertices        
+        
+
+    def convexPoly(self, vertices, dynamic=True, density=1.0, restitution=0.16, friction=0.5):
+        """ Add a complex polygon with vertices in absolute positions (meters or pixels, according
+            to INPUT_PIXELS or INPUT_METERS). This function does the reduction and convec hulling 
+            of the poly, and calls add_poly(...) 
+
+            Parameters:
+              vertices .. absolute vertices positions
+              other ..... see [physics parameters]
+
+            Return: box2d.b2Body
+        """
+        # NOTE: Box2D has a maximum poly vertex count, defined in Common/box2d.b2Settings.h (box2d.b2_maxPolygonVertices)
+        # We need to make sure, that we reach that by reducing the poly with increased tolerance
+        # Reduce Polygon
+        tolerance = 10 #5
+        v_new = vertices
+        while len(v_new) > box2d.b2_maxPolygonVertices:
+            tolerance += 1    
+            v_new = tools_poly.reduce_poly(vertices, tolerance)
+            
+        print "convexPoly: Polygon reduced from %i to %i vertices | tolerance: %i" % (len(vertices), len(v_new), tolerance)
+        vertices = v_new
+             
+        # So poly should be alright now
+        # Continue reducing the vertecs
+        vertices_orig_reduced = vertices    
+        vertices = tools_poly.poly_center_vertices(vertices)
+
+        vertices = tools_poly.convex_hull(vertices)
+
+        if len(vertices) < 3: 
+            return 
+        
+        # Define the body
+        x, y = c = tools_poly.calc_center(vertices_orig_reduced)
+        return self.poly((x,y), vertices, dynamic, density, restitution, friction)
+
+    def to_b2vec(self, pt):
+    # Convert vector to a b2vect
+        pt = self.parent.to_world(pt)
+        ptx, pty = pt
+        ptx /= self.parent.ppm
+        pty /= self.parent.ppm
+        pt = box2d.b2Vec2(ptx, pty)
+        return pt
+
+    def joint(self, *args):
+        print "* Add Joint:", args
+
+        if len(args) == 5:
+            # Tracking Joint
+            b1, b2, p1, p2, flag = args
+
+            p1 = self.to_b2vec(p1)
+            p2 = self.to_b2vec(p2)            
+           
+            jointDef = box2d.b2DistanceJointDef()
+            jointDef.Initialize(b1, b2, p1, p2)
+            jointDef.collideConnected = flag
+            
+            self.parent.world.CreateJoint(jointDef)           
+
+        elif len(args) == 4:
+            # Distance Joint
+            b1, b2, p1, p2 = args
+
+            p1 = self.to_b2vec(p1)
+            p2 = self.to_b2vec(p2)            
+           
+            jointDef = box2d.b2DistanceJointDef()
+            jointDef.Initialize(b1, b2, p1, p2)
+            jointDef.collideConnected = True
+            
+            self.parent.world.CreateJoint(jointDef)           
+             
+        elif len(args) == 3:
+            # Revolute Joint between two bodies (unimplemented)
+            pass
+
+        elif len(args) == 2:
+            # Revolute Joint to the Background, at point 
+            b1 = self.parent.world.GetGroundBody()
+            b2 = args[0]
+            p1 = self.to_b2vec(args[1])
+
+            jointDef = box2d.b2RevoluteJointDef()
+            jointDef.Initialize(b1, b2, p1)
+            self.parent.world.CreateJoint(jointDef)
+
+        elif len(args) == 1:
+            # Revolute Joint to the Background, body center
+            b1 = self.parent.world.GetGroundBody()
+            b2 = args[0]
+            p1 = b2.GetWorldCenter()
+            
+            jointDef = box2d.b2RevoluteJointDef()
+            jointDef.Initialize(b1, b2, p1)
+            
+            self.parent.world.CreateJoint(jointDef)
+
+    def motor(self, body, pt, torque=900, speed=-10):
+        # Revolute joint to the background with motor torque applied
+        b1 = self.parent.world.GetGroundBody()
+        pt = self.to_b2vec(pt)
+
+        jointDef = box2d.b2RevoluteJointDef()
+        jointDef.Initialize(b1, body, pt)
+        jointDef.maxMotorTorque = torque
+        jointDef.motorSpeed = speed
+        jointDef.enableMotor = True
+
+        self.parent.world.CreateJoint(jointDef)
+
+    def mouseJoint(self, body, pos, jointForce=100.0):
+        pos = self.parent.to_world(pos)
+        x, y = pos
+        x /= self.parent.ppm
+        y /= self.parent.ppm
+
+        mj = box2d.b2MouseJointDef()
+        mj.body1 = self.parent.world.GetGroundBody()
+        mj.body2 = body
+        mj.target = (x, y)
+        mj.maxForce = jointForce * body.GetMass()
+        if 'getAsType' in dir(box2d.b2Joint):
+            self.parent.mouseJoint = self.parent.world.CreateJoint(mj).getAsType()
+        else:
+            self.parent.mouseJoint = self.parent.world.CreateJoint(mj)
+        body.WakeUp()
+        
+    def remove_mouseJoint(self):
+        if self.parent.mouseJoint:
+            self.parent.world.DestroyJoint(self.parent.mouseJoint)
+            self.parent.mouseJoint = None
+
--
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