Box2D Hello World (C++)
Description
This is a C++Builder port of the Hello World example that the chapter 2 of the Box2D manual features.
Select File > New > Other > C++Builder Projects > Console Application to create a new C++Builder console application, and use the code below.
Code
/*
* Copyright (c) 2006-2007 Erin Catto http://www.box2d.org
*
* This software is provided 'as-is', without any express or implied
* warranty. In no event will the authors be held liable for any damages
* arising from the use of this software.
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software. If you use this software
* in a product, an acknowledgment in the product documentation would be
* appreciated but is not required.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
*/
#pragma hdrstop
#pragma argsused
#pragma comment(lib, "Box2D")
#ifdef _WIN32
#include <tchar.h>
#else
typedef char _TCHAR;
#define _tmain main
#endif
#include <stdio.h>
#include <iostream>
#include <Box2D/Box2D.h>
// This is a simple example of building and running a simulation
// using Box2D. Here we create a large ground box and a small dynamic
// box.
// There are no graphics for this example. Box2D is meant to be used
// with your rendering engine in your game engine.
int _tmain(int argc, _TCHAR* argv[])
{
B2_NOT_USED(argc);
B2_NOT_USED(argv);
// Define the gravity vector.
b2Vec2 gravity(0.0f, -10.0f);
// Construct a world object, which will hold and simulate the rigid bodies.
b2World world(gravity);
// Define the ground body.
b2BodyDef groundBodyDef;
groundBodyDef.position.Set(0.0f, -10.0f);
// Call the body factory which allocates memory for the ground body
// from a pool and creates the ground box shape (also from a pool).
// The body is also added to the world.
b2Body* groundBody = world.CreateBody(&groundBodyDef);
// Define the ground box shape.
b2PolygonShape groundBox;
// The extents are the half-widths of the box.
groundBox.SetAsBox(50.0f, 10.0f);
// Add the ground fixture to the ground body.
groundBody->CreateFixture(&groundBox, 0.0f);
// Define the dynamic body. We set its position and call the body factory.
b2BodyDef bodyDef;
bodyDef.type = b2_dynamicBody;
bodyDef.position.Set(0.0f, 4.0f);
b2Body* body = world.CreateBody(&bodyDef);
// Define another box shape for our dynamic body.
b2PolygonShape dynamicBox;
dynamicBox.SetAsBox(1.0f, 1.0f);
// Define the dynamic body fixture.
b2FixtureDef fixtureDef;
fixtureDef.shape = &dynamicBox;
// Set the box density to be non-zero, so it will be dynamic.
fixtureDef.density = 1.0f;
// Override the default friction.
fixtureDef.friction = 0.3f;
// Add the shape to the body.
body->CreateFixture(&fixtureDef);
// Prepare for simulation. Typically we use a time step of 1/60 of a
// second (60Hz) and 10 iterations. This provides a high quality simulation
// in most game scenarios.
float32 timeStep = 1.0f / 60.0f;
int32 velocityIterations = 6;
int32 positionIterations = 2;
// This is our little game loop.
for (int32 i = 0; i < 60; ++i)
{
// Instruct the world to perform a single step of simulation.
// It is generally best to keep the time step and iterations fixed.
world.Step(timeStep, velocityIterations, positionIterations);
// Now print the position and angle of the body.
b2Vec2 position = body->GetPosition();
float32 angle = body->GetAngle();
printf("%4.2f %4.2f %4.2f\n", position.x, position.y, angle);
}
// When the world destructor is called, all bodies and joints are freed. This can
// create orphaned pointers, so be careful about your world management.
getchar();
return 0;
}