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