Box2d的HelloWorld范例

box2d版本：2.4.0

cmake版本:3.16

vs版本：2017

 

1. 编写cmakeLists.txt

cmake_minimum_required(VERSION 3.10)

project(box2d_helloWorld)

# 指定box2d模块的cmake文件
set(box2d_DIR "X:/development/box2d/lib/cmake/box2d"

find_package(box2d REQUIRED)

set(DEMO_SRC
main.cpp)

add_executable(HelloWorld ${DEMO_SRC})

# 添加box2d的依赖库
target_link_libraries(HelloWorld box2d::box2d)

 2. 编写main.cpp文件，根据box2d的文档，编写helloWorld，最简单的范例

#include <iostream>

#include <box2d/box2d.h>
int main(int argc, char* argv[])
{
	b2Vec2 gravity(0.0f, -10.0f);

	b2World world(gravity);

	// groundbox
	b2BodyDef groundBodyDef;
	groundBodyDef.position.Set(0.0f, -10.0f);

	b2Body* groundBody = world.CreateBody(&groundBodyDef);

	b2PolygonShape groundBox;
	groundBox.SetAsBox(50.0f, 10.0f);
	groundBody->CreateFixture(&groundBox, 0.0f);

	// dynamic body
	b2BodyDef bodyDef;
	bodyDef.type = b2_dynamicBody;
	bodyDef.position.Set(0.0f, 4.0f);
	b2Body *body = world.CreateBody(&bodyDef);

	b2PolygonShape dynamicBox;
	dynamicBox.SetAsBox(1.0f, 1.0f);

	b2FixtureDef fixtureDef;
	fixtureDef.shape = &dynamicBox;
	fixtureDef.density = 1.0f;
	fixtureDef.friction = 0.3f;

	body->CreateFixture(&fixtureDef);

	// simullation.
	float timeStep = 1.0f / 60.0f;

	int32 velocityIterations = 6;
	int32 positionIterations =  2;


	// simulation
	for (int32 i = 0; i < 60; ++i)
	{
		world.Step(timeStep, velocityIterations, positionIterations);

		b2Vec2 position = body->GetPosition();
		float angle = body->GetAngle();

		printf("%4.2f %4.2f %4.2f\n", position.x, position.y, angle);
	}

	return 0;
}

 3. 使用cmake构建项目

>> cmake -S ./ -B ./build

在build目录下生成了vs的解决方案

 

4. 使用vs2017编译解决方案

>>devenv HelloWorld.sln /Build "Debug|win32"

 

5. 运行结果,得到输出结果

>>.\HelloWorld.exe

 

 

 

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