笔记：利用 Cocos2dx 3.2 与 Box2D制作一个跑酷游戏（上）
最近写lua写得没有力气了，所以想让脑袋放松一下，刚好看到有人在用swift做游戏：
于是脑子一短路，就想到了利用这些素材来做一个游戏。
本来不想记笔记的，但是由于选择物理引擎的时候遇到诸多问题，所以选择记录下来，目前只做了个雏形，需要再完善一点。
需要知识：
1 cocos2dx-3.2 基本知识
2 box2d有一定的了解。
由于比较简单，所以把所有代码给上了先，然后再简单介绍下遇到的问题之类的东西。
首先是主角，熊猫类：
Panda.h
#ifndef __PANDA_H__
#define __PANDA_H__ #include "cocos2d.h"
USING_NS_CC; class Panda : public cocos2d::Node
{
public:
Vector<SpriteFrame*> run_frames;
Vector<SpriteFrame*> jump_effect_frames;
Vector<SpriteFrame*> roll_frames;
Vector<SpriteFrame*> jump_frames;
Animation * run_anim;
Animation * jump_anim;
Animation * jump_effect_anim;
Animation * roll_anim;
Sprite * shape;
Animation * anim;
int cur_state;//current state
// Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
virtual bool init();
//play status RUM||ROLL||JUMP etc
void play(unsigned int state); void updateState();
// implement the "static create()" method manually
CREATE_FUNC(Panda); int getCurrentState();
//panda 4 states
enum {
RUN = ,
JUMP = ,
JUMP2 =
};
}; #endif // __PANDA_H__
#include "Panda.h"
#include "cocos2d.h" USING_NS_CC; bool Panda::init()
{
if(!Node::init())
return false; run_frames = Vector<SpriteFrame*>();
roll_frames = Vector<SpriteFrame*>();
jump_effect_frames = Vector<SpriteFrame*>();
jump_frames = Vector<SpriteFrame*>();
char str[] = {};
for(int i=; i<=;i++)
{
sprintf(str,"jump.atlas/panda_jump_0%d.png",i);
auto frame = SpriteFrameCache::getInstance()->getSpriteFrameByName(str);
if( frame != NULL )
{
jump_frames.pushBack(frame);
} sprintf(str,"roll.atlas/panda_roll_0%d.png",i);
auto frame_0 = SpriteFrameCache::getInstance()->getSpriteFrameByName(str);
if( frame_0 != NULL )
{
roll_frames.pushBack(frame_0);
} sprintf(str,"run.atlas/panda_run_0%d.png",i);
auto frame_1 = SpriteFrameCache::getInstance()->getSpriteFrameByName(str);
if( frame_1 != NULL )
{
run_frames.pushBack(frame_1);
} sprintf(str,"jump_effect.atlas/jump_effect_0%d.png",i);
auto frame_2 = SpriteFrameCache::getInstance()->getSpriteFrameByName(str);
if( frame_2 != NULL )
{
jump_effect_frames.pushBack(frame_2);
}
} run_anim = Animation::createWithSpriteFrames(run_frames,0.05f);
run_anim->retain();
roll_anim = Animation::createWithSpriteFrames(roll_frames,0.05f);
roll_anim->retain();
jump_anim = Animation::createWithSpriteFrames(jump_frames,0.05f);
jump_anim->retain();
jump_effect_anim = Animation::createWithSpriteFrames(jump_effect_frames,0.05f);
jump_effect_anim->retain();
shape= Sprite::createWithSpriteFrameName("run.atlas/panda_run_01.png");
addChild(shape);
return true;
} void Panda::play(unsigned int state)
{
Action * animate;
switch(state)
{
case RUN:
cur_state = Panda::RUN;
animate = RepeatForever::create(Animate::create(run_anim));
animate->setTag();
shape->runAction(animate);
break;
case JUMP:
cur_state = Panda::JUMP;
animate = Animate::create(jump_anim);
animate->setTag();
shape->stopActionByTag();
shape->runAction(animate);
break;
case JUMP2:
animate = Sequence::create(Animate::create(jump_effect_anim),Animate::create(roll_anim));
animate->setTag();
cur_state = Panda::JUMP2;
shape->runAction(animate);
break;
}
} int Panda::getCurrentState()
{
return cur_state;
} void Panda::updateState()
{
if (shape->getActionByTag() == nullptr && shape->getActionByTag() == nullptr)
{
play(Panda::RUN);
}
}
Panda.cpp
然后是场景类，里面有一些逻辑处理：
#ifndef __GAMEMAIN_H__
#define __GAMEMAIN_H__ #include "cocos2d.h"
#include "Panda.h"
#include "Box2D\Box2D.h"
#include "GLES-Render.h" USING_NS_CC;
//whether show assets
#define SHOW_DEBUG true
//draw scale of physics world
#define DRAW_SCALE 30.0f
#define ALL_ALHA 0.5f class GameMain : public cocos2d::Layer
{
public:
//physic engine related
b2World * world;
Map<b2Body,Sprite> * map;
b2Body * panda_body;
//objects move speed
float speed;
Sprite * far_bg;
Sprite * middle_bg_0;
Sprite * middle_bg_1;
Size cSize;
Size visibleSize;
Layer * platform_container;
Panda * panda;
GLESDebugDraw * debugDraw;
// there's no 'id' in cpp, so we recommend returning the class instance pointer
static cocos2d::Scene* createScene(); // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone
virtual bool init(); virtual void onEnter(); virtual void onExit(); void update(float dt); virtual bool onTouchBegan(Touch * touch, Event * event);
virtual void onTouchEnded(Touch * touch, Event * event);
virtual void onTouchMoved(Touch * touch, Event * event); virtual bool onContactBegin(const PhysicsContact& contact);
// implement the "static create()" method manually
CREATE_FUNC(GameMain); //
// Overrides
//
virtual void draw(Renderer *renderer, const Mat4 &transform, uint32_t flags) override;
private:
void create_ground();
void gen_step(const std::string& res, float posX, float posY);
void init_physics_world();
}; #endif // __HELLOWORLD_SCENE_H__
GameMain.h
#include "GameMain.h"
#include "cocos2d.h"
#include "Box2D\Box2D.h"
#include "GLES-Render.h"
USING_NS_CC; Scene* GameMain::createScene()
{
auto scene = Scene::create();
auto layer = GameMain::create();
scene->addChild(layer);
return scene;
} bool GameMain::init()
{
if ( !Layer::init() )
{
return false;
}
speed = 5.0f;
auto listener = EventListenerTouchOneByOne::create();
listener->onTouchBegan = CC_CALLBACK_2(GameMain::onTouchBegan,this);
listener->onTouchEnded = CC_CALLBACK_2(GameMain::onTouchEnded,this);
listener->onTouchMoved = CC_CALLBACK_2(GameMain::onTouchMoved,this); Director::getInstance()->getEventDispatcher()->addEventListenerWithSceneGraphPriority(listener, this); visibleSize = Director::getInstance()->getVisibleSize();
Vec2 origin = Director::getInstance()->getVisibleOrigin();
SpriteFrameCache::getInstance()->addSpriteFramesWithFile("panda.plist");//add panda animate
SpriteFrameCache::getInstance()->addSpriteFramesWithFile("scene.plist");//add scene resources middle_bg_0 = Sprite::create("bbg_snow_bone.jpg");
cSize = middle_bg_0->getContentSize();
middle_bg_0->setPosition(visibleSize.width*0.5, visibleSize.height*0.5);
middle_bg_0->setVisible(SHOW_DEBUG);
addChild(middle_bg_0); init_physics_world(); //gen_step();
create_ground(); //init panda and its physics data
Point p(visibleSize.width/,visibleSize.height/);
b2BodyDef bodyDef;
bodyDef.type = b2_dynamicBody;
bodyDef.position.Set(p.x/DRAW_SCALE, p.y/DRAW_SCALE);
panda_body = world->CreateBody(&bodyDef);
b2MassData massdata;
massdata.mass = 100.0f;
panda_body->SetMassData(&massdata); b2PolygonShape shape;
shape.SetAsBox(50.0f/DRAW_SCALE, 100.0f/DRAW_SCALE); b2FixtureDef fixtureDef;
fixtureDef.shape = &shape;
fixtureDef.density = 1.0f;
fixtureDef.friction = 0.3f;
panda_body->CreateFixture(&fixtureDef); panda = Panda::create();
panda->setPosition(visibleSize.width/, visibleSize.height/);
Size panda_size = Size(50.0f,100.0f);
panda->play(Panda::RUN);
this->addChild(panda);
panda_body->SetUserData(panda);
panda->setVisible(SHOW_DEBUG); gen_step("platform_l.png",51.0,100.0f);
gen_step("platform_m.png",196.0f,100.0f);
gen_step("platform_r.png",392.0f,100.0f);
return true;
} void GameMain::init_physics_world()
{
b2Vec2 gravity;
gravity.Set(0.0f,-10.0f);
world = new b2World(gravity);
world->SetAllowSleeping(true);
world->SetContinuousPhysics(true);
debugDraw = new GLESDebugDraw(DRAW_SCALE);
uint32 flags = ;
flags += GLESDebugDraw::e_shapeBit;
flags += GLESDebugDraw::e_aabbBit;
flags += GLESDebugDraw::e_centerOfMassBit;
debugDraw->SetFlags(flags);
world->SetDebugDraw(debugDraw);
} void GameMain::draw(Renderer *renderer, const Mat4 &transform, uint32_t flags)
{
world->DrawDebugData();
Layer::draw(renderer,transform,flags);
} void GameMain::create_ground()
{
b2BodyDef ground_def;
ground_def.position.Set(visibleSize.width//DRAW_SCALE, visibleSize.height//DRAW_SCALE); b2Body * ground_body = world->CreateBody(&ground_def); /***/
//bottom
b2PolygonShape ground_shape;
ground_shape.SetAsBox(visibleSize.width//DRAW_SCALE,,b2Vec2(,-visibleSize.height//DRAW_SCALE),);
ground_body->CreateFixture(&ground_shape,);
//top
ground_shape.SetAsBox(visibleSize.width//DRAW_SCALE,,b2Vec2(,visibleSize.height//DRAW_SCALE),);
ground_body->CreateFixture(&ground_shape,);
//left
ground_shape.SetAsBox(,visibleSize.height//DRAW_SCALE,b2Vec2(-visibleSize.width//DRAW_SCALE,),);
ground_body->CreateFixture(&ground_shape,);
//right
ground_shape.SetAsBox(,visibleSize.height//DRAW_SCALE,b2Vec2(visibleSize.width//DRAW_SCALE,),);
ground_body->CreateFixture(&ground_shape,);
} bool GameMain::onTouchBegan(Touch * touch, Event * event)
{
Sprite * ball = Sprite::create("apple.png");
ball->setVisible(SHOW_DEBUG);
Size contentSize = ball->getContentSize();
addChild(ball);
b2BodyDef ballDef;
ballDef.type = b2_dynamicBody;
ballDef.position.Set(touch->getLocation().x/DRAW_SCALE, touch->getLocation().y/DRAW_SCALE);
b2Body * ballBody = world->CreateBody(&ballDef);
ballBody->SetUserData(ball);
b2MassData massData;
massData.center = b2Vec2(contentSize.width//DRAW_SCALE,contentSize.height//DRAW_SCALE);
massData.mass = ;
b2CircleShape ballShape;
ballShape.ComputeMass(&massData,1.5f);
ballShape.m_radius=45.0f/DRAW_SCALE;
b2FixtureDef ballFixture;
ballFixture.density = 10.0f;
ballFixture.friction = 1.0f;
ballFixture.restitution = 0.6f;
ballFixture.shape = &ballShape; ballBody->CreateFixture(&ballFixture);
ballBody->SetGravityScale();
/**
float vx = touch->getLocation().x > panda->getPositionX() ? 100.0f : -100.0f;
panda->updateState();
int cur_state = panda->getCurrentState();
if( cur_state == Panda::RUN )
{
panda_body->ApplyForce(b2Vec2(vx,1000),panda_body->GetPosition(),true);
panda->play(Panda::JUMP);
}else if(cur_state == Panda::JUMP)
{
panda_body->ApplyForce(b2Vec2(vx,800),panda_body->GetPosition(),true);
panda->play(Panda::JUMP2);
}*/
return true;
} void GameMain::update(float dt)
{
world->Step(dt,,);
b2Body* b = world->GetBodyList();
while (b)
{
b2Body* bNext = b->GetNext();
Sprite * sp = (Sprite *)b->GetUserData();
if( sp != nullptr )
sp->setPosition(b->GetPosition().x*DRAW_SCALE,b->GetPosition().y*DRAW_SCALE); b = bNext;
}
} //generate floors
void GameMain::gen_step(const std::string& res, float posX, float posY)
{
Sprite * sp = Sprite::create(res);
sp->setPosition(posX, posY);
addChild(sp); Size contentSize = sp->getContentSize(); b2BodyDef bodyDef;
bodyDef.position.Set(posX/DRAW_SCALE, posY/DRAW_SCALE);
b2Body * body = world->CreateBody(&bodyDef); b2PolygonShape shape;
shape.SetAsBox(contentSize.width/DRAW_SCALE, contentSize.height/DRAW_SCALE); b2FixtureDef fixtureDef;
fixtureDef.shape = &shape;
fixtureDef.density = 1.0f;
fixtureDef.friction = 0.3f;
body->CreateFixture(&fixtureDef);
sp->setVisible(SHOW_DEBUG);
} bool GameMain::onContactBegin(const PhysicsContact& contact)
{
log("Contacted...");
return true;
} void GameMain::onTouchEnded(Touch * touch, Event * event)
{ } void GameMain::onTouchMoved(Touch * touch, Event * event)
{ } void GameMain::onEnter()
{
Layer::onEnter();
this->schedule(schedule_selector(GameMain::update),0.03f);
} void GameMain::onExit()
{
delete world;
delete debugDraw;
Layer::onExit();
this->unschedule(schedule_selector(GameMain::update));
}
GameMain.cpp
需要注意：
1 所有的熊猫动作打包成一个plist，所有的场景素材打包到另一个plist
这就是我们在场景类的init方法里面预加载的两个文件：
SpriteFrameCache::getInstance()->addSpriteFramesWithFile("panda.plist");//add panda animate
SpriteFrameCache::getInstance()->addSpriteFramesWithFile("scene.plist");//add scene resources
资源目录应该是这样的：
2 去cocos2d-x-3.2\tests\cpp-tests\Classes\Box2DTestBed下面将GLES-Render.h和GLES-Render.cpp拷到项目里面来，因为Box2d没有b2Debug的实现，这个是我们手头上需要的实现。
3 使用Box2d的时候极有可能会出现编译连接错误，找不到Box2d相关的类，这个时候需要将cocos2d-x-3.2\external\Box2D编译一下，然后在项目的连接器中加入引用：
4 通过b2World::SetDebugDraw(b2Draw * draw)将GLESDebugDraw实例设置为world的debugDraw之后，每帧调用world->DrawDebugData()是不会生效的，只有复写Layer::draw()方法并在其中调用此方法才会显示debugDraw。
由于debugDraw是调用显卡去渲染的，所以debugDraw是位于场景最底层的，当你把所有场景内的显示对象的通过setVisible设置为false的时候，你就可以看到了。
可以设置SHOW_DEBUG的值来设置显示对象的visible。
如下：
可以看到下面的debugDraw有点测漏了。
5 cocos2dx 3.2内置了chipmunk物理引擎，用起来比较简单，但是我之前学习ActionScript的时候有用过Box2d，并且Box2d的功能比较强大一些，所以选择了Box2d。ActionScript还有一个效率比Box2d稍强的无力引擎：Nape
以下是一开始用chipmunk实现的一些功能的代码：
#include "GameMain.h"
#include "cocos2d.h" USING_NS_CC; Scene* GameMain::createScene()
{
auto scene = Scene::createWithPhysics();
scene->getPhysicsWorld()->setDebugDrawMask(PhysicsWorld::DEBUGDRAW_ALL);
scene->getPhysicsWorld()->setUpdateRate(0.5);
auto layer = GameMain::create();
scene->addChild(layer);
return scene;
} bool GameMain::init()
{
if ( !Layer::init() )
{
return false;
} speed = 5.0f; auto listener = EventListenerTouchOneByOne::create();
listener->onTouchBegan = CC_CALLBACK_2(GameMain::onTouchBegan,this);
listener->onTouchEnded = CC_CALLBACK_2(GameMain::onTouchEnded,this);
listener->onTouchMoved = CC_CALLBACK_2(GameMain::onTouchMoved,this); auto contact_listener = EventListenerPhysicsContact::create();
contact_listener->onContactBegin = CC_CALLBACK_1(GameMain::onContactBegin,this); Director::getInstance()->getEventDispatcher()->addEventListenerWithSceneGraphPriority(listener, this);
Director::getInstance()->getEventDispatcher()->addEventListenerWithFixedPriority(contact_listener,); visibleSize = Director::getInstance()->getVisibleSize();
Vec2 origin = Director::getInstance()->getVisibleOrigin();
SpriteFrameCache::getInstance()->addSpriteFramesWithFile("panda.plist");//add panda animate
SpriteFrameCache::getInstance()->addSpriteFramesWithFile("scene.plist");//add scene resources middle_bg_0 = Sprite::create("bbg_snow_bone.jpg");
cSize = middle_bg_0->getContentSize();
middle_bg_0->setPosition(visibleSize.width*0.5, visibleSize.height*0.5);
middle_bg_1 = Sprite::create("bbg_snow_bone.jpg");
middle_bg_1->setPosition(visibleSize.width*1.5, visibleSize.height*0.5);
addChild(middle_bg_0);
addChild(middle_bg_1); gen_floor(); panda = Panda::create();
panda->setPosition(visibleSize.width/, visibleSize.height/);
Size panda_size = Size(50.0f,100.0f);
panda->play(Panda::RUN);
auto panda_body = PhysicsBody::createBox(panda_size);
panda_body->retain();
panda->setPhysicsBody(panda_body);
this->addChild(panda); auto edge_sp = Sprite::create();
auto edge_body = PhysicsBody::createEdgeBox(visibleSize,PHYSICSBODY_MATERIAL_DEFAULT,);
edge_sp->setPosition(visibleSize.width/, visibleSize.height/);
edge_sp->setPhysicsBody(edge_body);
edge_sp->setTag();
addChild(edge_sp);
return true;
} bool GameMain::onContactBegin(const PhysicsContact& contact)
{
log("Contacted...");
return true;
} bool GameMain::onTouchBegan(Touch * touch, Event * event)
{
log("Touched.....");
int cur_state = panda->getCurrentState();
panda->getPhysicsBody()->applyForce(Vect(500.0f,500.0f));
if( cur_state == Panda::RUN )
{
panda->play(Panda::JUMP);
}else if(cur_state == Panda::JUMP)
{
panda->play(Panda::JUMP2);
}
return true;
} void GameMain::onTouchEnded(Touch * touch, Event * event)
{ } void GameMain::onTouchMoved(Touch * touch, Event * event)
{ } void GameMain::update(float dt)
{
/**
middle_bg_0->setPositionX(middle_bg_0->getPositionX()-speed); if(middle_bg_0->getPositionX() < -cSize.width*0.5)
{
middle_bg_0->setPositionX(cSize.width*1.5);
} middle_bg_1->setPositionX(middle_bg_1->getPositionX()-speed);
if(middle_bg_1->getPositionX() < -cSize.width*0.5)
{
middle_bg_1->setPositionX(cSize.width*1.5);
}*/
} void GameMain::onEnter()
{
Layer::onEnter();
this->schedule(schedule_selector(GameMain::update),0.05f);
} void GameMain::onExit()
{
Layer::onExit();
this->unschedule(schedule_selector(GameMain::update));
} void GameMain::createFloor(int posx,int posy,int w,int h)
{ }
//generate floors
void GameMain::gen_floor()
{
Sprite * sp_l = Sprite::create("platform_l.png");
auto body_l = PhysicsBody::createBox(sp_l->getContentSize());
body_l->setDynamic(false);
sp_l->setPhysicsBody(body_l);
sp_l->setPosition(50.0f,);
addChild(sp_l); Sprite * sp_m = Sprite::create("platform_m.png");
auto body_m = PhysicsBody::createBox(sp_m->getContentSize());
body_m->setDynamic(false);
sp_m->setPhysicsBody(body_m);
sp_m->setPosition(sp_l->getPositionX() + (sp_l->getContentSize().width+sp_m->getContentSize().width)/,);
addChild(sp_m); Sprite * sp_r = Sprite::create("platform_r.png");
auto body_r = PhysicsBody::createBox(sp_r->getContentSize());
body_r->setDynamic(false);
sp_r->setPhysicsBody(body_r);
sp_r->setPosition(sp_m->getPositionX() + (sp_m->getContentSize().width+sp_r->getContentSize().width)/,);
addChild(sp_r);
}
GameMain.cpp
建议：
不想吐槽搜索引擎，建议大家遇到问题先尝试自己解决，解决不了的然后可以用国外的搜索引擎搜索一下，或者可以直接去StackFlow去搜索
参考文章：
（翻译）介绍Box2D的Cocos2D 2.X教程：弹球 [Cocos2D-x For WP8]Box2D物理引擎 How to enable Box2d debug draw with Coco2d-x 3.0 beta 2笔记：利用 Cocos2dx 3.2 与 Box2D制作一个跑酷游戏（上）的更多相关文章
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