Add initial prototype.

4-high/gel/applet/demo/game/box2d_test/box2d_HelloWorld.cpp

@@ -0,0 +1,75 @@
+#include <box2d/box2d.h>
+#include <stdio.h>
+
+int main(int argc, char** argv)
+{
+  B2_NOT_USED(argc);
+  B2_NOT_USED(argv);
+
+  // Construct a world object, which will hold and simulate the rigid bodies.
+  b2World world (b2Vec2 (0.0f, 0.0f));      // Does not bounce.
+//  b2World world (b2Vec2 (0.0f, 0.017f));    // Bounces.
+
+  // Define the dynamic ball body. We set its position and call the body factory.
+  b2BodyDef bodyDef;
+  bodyDef.type = b2_dynamicBody;
+  bodyDef.position.Set(0.0f, 0.0f);
+  b2Body* body = world.CreateBody(&bodyDef);
+
+  // Define a ball shape for our dynamic body.
+  b2CircleShape Ball;
+  Ball.m_radius = 0.5f;
+
+  // Define the dynamic body fixture.
+  b2FixtureDef fixtureDef;
+
+  fixtureDef.shape = &Ball;
+  fixtureDef.density = 1.0f;
+  fixtureDef.friction = 0.0f;
+  fixtureDef.restitution = 1.0f;
+
+  // Add the shape to the body.
+  body->CreateFixture(&fixtureDef);
+
+
+  // Define the statoc box body.
+
+  float   stadium_Width     = 300.0;
+  float   stadium_Height    = 10.0;
+  float   Thickness         =  2.0;
+  float   top_wall_Y_Offset = stadium_Height + (Thickness / 2.0);
+
+  // Define the ground box shape.
+  b2PolygonShape groundBox;
+  groundBox.SetAsBox(stadium_Width, Thickness);
+
+  b2BodyDef groundBodyDef;
+  groundBodyDef.type = b2_staticBody;
+  groundBodyDef.position.Set (0.0f, top_wall_Y_Offset);
+  b2Body* groundBody = world.CreateBody(&groundBodyDef);
+
+  b2FixtureDef GfixtureDef;
+  GfixtureDef.shape = &groundBox;
+  GfixtureDef.density = 0.0f;
+  GfixtureDef.friction = 0.0f;
+  GfixtureDef.restitution = 1.0f;
+  groundBody->CreateFixture(&GfixtureDef);
+
+  body->ApplyForceToCenter(b2Vec2 (45.0, 40.0), 1);
+
+  float   timeStep = 1.0f / 60.0f;
+  int32   velocityIterations = 6;
+  int32   positionIterations = 2;
+
+  for (int32 i = 0; i < 700; ++i)
+    {
+      world.Step(timeStep, velocityIterations, positionIterations);
+
+      b2Vec2   position = body->GetPosition();
+      float    angle    = body->GetAngle();
+
+      printf("%d   %4.2f %4.2f    %4.2f\n", i, position.x, position.y, angle);
+    }
+
+  return 0;
+}

4-high/gel/applet/demo/game/box2d_test/gel_box2d_test.gpr

@@ -0,0 +1,31 @@
+with
+     "box2d_contrib";
+
+
+project gel_box2d_Test
+is
+   for Source_Dirs use (".");
+   for Object_Dir  use "obj";
+   for Exec_Dir    use ".";
+   for Main        use ("box2d_HelloWorld.cpp");
+   for Languages   use ("C++");
+
+   package Naming is
+      for Spec_Suffix ("C++") use ".h";
+      for Body_Suffix ("C++") use ".cpp";
+   end Naming;
+
+   package Compiler is
+      for Default_Switches ("c++") use ("-g", 
+                                        "-Wno-return-type-c-linkage",
+                                        "-I../../../c_math/source/c",
+                                        "-I" & External ("LACE") & "/3-mid/physics/implement/c_math/source/c",
+                                        "-I" & External ("LACE") & "/3-mid/physics/implement/box2d/contrib/include",
+                                        "-I../contrib/box2d-2.4.1/include");
+   end Compiler;
+
+   package Linker is
+      for Switches ("c++") use ("-lbox2d");
+   end Linker;
+
+end gel_box2d_Test;