mycollision1view.cpp

本代码演示了在3D游戏编程中经常要使用的碰撞检测

				if (posi.dist(OldPos[j])<=40) 
				{
					point=posi;
					if (Timedummy>(MyTime-Add)) Timedummy=MyTime-Add;
					BallNr1=i;
					BallNr2=j;
					break;
				}
			}
		}
	}
	if (Timedummy!=10000) 
	{ 
		TimePoint=Timedummy;
		return 1;
	}
	return 0;
}

// 主函数,当前步长中运动所有的球,检查碰撞现象
void CMyCollision1View::idle()
{
	double rt,rt2,rt4,lamda=10000;
	CVector norm,uveloc;
	CVector normal,point,time;
	double RestTime,BallTime;
	CVector Pos2;
	int BallNr=0,dummy=0,BallColNr1,BallColNr2;
	CVector Nc;
	if (!hook_toball1)
	{
		camera_rotation+=0.1f;
		if (camera_rotation>360)
			camera_rotation=0;
	}
	RestTime=Time;
	lamda=1000;
	// 使用Euler方程计算下一步的速度
	for (int j=0;j<NrOfBalls;j++)
		ArrayVel[j]+=accel*RestTime;
	// 当时间没有结束
	while (RestTime>ZERO)
	{
		lamda=10000;
		// 对所有的球在球与平面/圆柱体之间找到最近的相交点
		for (int i=0;i<NrOfBalls;i++)
		{
			// 计算新的位置和距离
			OldPos[i]=ArrayPos[i];
			CVector::unit(ArrayVel[i],uveloc);
			ArrayPos[i]=ArrayPos[i]+ArrayVel[i]*RestTime;
			rt2=OldPos[i].dist(ArrayPos[i]);
			// 测试在球与5个平面之间是否发生碰撞
			if (TestIntersionPlane(pl1,OldPos[i],uveloc,rt,norm))
			{
				// 查找相交时间
				rt4=rt*RestTime/rt2;
				if (rt4<=lamda)
				{
					if (rt4<=RestTime+ZERO)
						if (! ((rt<=ZERO)&&(uveloc.dot(norm)>ZERO)) )
						{
							normal=norm;
							point=OldPos[i]+uveloc*rt;
							lamda=rt4;
							BallNr=i;
						}
				}
			}
			if (TestIntersionPlane(pl2,OldPos[i],uveloc,rt,norm))
			{
				rt4=rt*RestTime/rt2;
				if (rt4<=lamda)
				{
					if (rt4<=RestTime+ZERO)
						if(! ((rt<=ZERO)&&(uveloc.dot(norm)>ZERO)) )
						{
							normal=norm;
							point=OldPos[i]+uveloc*rt;
							lamda=rt4;
							BallNr=i;
							dummy=1;
						 }
				  }
				 
			  }

			  if (TestIntersionPlane(pl3,OldPos[i],uveloc,rt,norm))
			  {
			      rt4=rt*RestTime/rt2;

				  if (rt4<=lamda)
				  { 
				    if (rt4<=RestTime+ZERO)
						if (! ((rt<=ZERO)&&(uveloc.dot(norm)>ZERO)) )
						 {
							normal=norm;
							point=OldPos[i]+uveloc*rt;
							lamda=rt4;
							BallNr=i;
						 }
				  }
			  }

			  if (TestIntersionPlane(pl4,OldPos[i],uveloc,rt,norm))
			  {
				  rt4=rt*RestTime/rt2;

				  if (rt4<=lamda)
				  { 
				    if (rt4<=RestTime+ZERO)
						if (! ((rt<=ZERO)&&(uveloc.dot(norm)>ZERO)) )
						 {
							normal=norm;
							point=OldPos[i]+uveloc*rt;
							lamda=rt4;
							BallNr=i;
						 }
				  }
			  }

			  if (TestIntersionPlane(pl5,OldPos[i],uveloc,rt,norm))
			  {
				  rt4=rt*RestTime/rt2;

				  if (rt4<=lamda)
				  { 
				    if (rt4<=RestTime+ZERO)
						if (! ((rt<=ZERO)&&(uveloc.dot(norm)>ZERO)) )
						 {
							normal=norm;
							point=OldPos[i]+uveloc*rt;
							lamda=rt4;
							BallNr=i;
						 }
				  }
			  }

              // 测试球与3个圆柱体是否发生碰撞
			  if (TestIntersionCylinder(cyl1,OldPos[i],uveloc,rt,norm,Nc))
			  {
				  rt4=rt*RestTime/rt2;

				  if (rt4<=lamda)
				  { 
				    if (rt4<=RestTime+ZERO)
						if (! ((rt<=ZERO)&&(uveloc.dot(norm)>ZERO)) )
						 {
							normal=norm;
							point=Nc;
							lamda=rt4;
							BallNr=i;
						 }
				  }
				 
			  }
			  if (TestIntersionCylinder(cyl2,OldPos[i],uveloc,rt,norm,Nc))
			  {
				  rt4=rt*RestTime/rt2;

				  if (rt4<=lamda)
				  { 
				    if (rt4<=RestTime+ZERO)
						if (! ((rt<=ZERO)&&(uveloc.dot(norm)>ZERO)) )
						 {
							normal=norm;
							point=Nc;
							lamda=rt4;
							BallNr=i;
						 }
				  }
				 
			  }
			  if (TestIntersionCylinder(cyl3,OldPos[i],uveloc,rt,norm,Nc))
			  {
				  rt4=rt*RestTime/rt2;

				  if (rt4<=lamda)
				  { 
				    if (rt4<=RestTime+ZERO)
						if (! ((rt<=ZERO)&&(uveloc.dot(norm)>ZERO)) )
						 {
							normal=norm;
							point=Nc;
							lamda=rt4;
							BallNr=i;
						 }
				  }
				 
			  }
	   }

	   // 检查球之间是否发生碰撞
	   if (FindBallCol(Pos2,BallTime,RestTime,BallColNr1,BallColNr2))
			  {
				  if (sounds)
					  PlaySound("Data/Explode.wav",NULL,SND_FILENAME|SND_ASYNC);
			      
				  if ( (lamda==10000) || (lamda>BallTime) )
				  {
					  RestTime=RestTime-BallTime;

					  CVector pb1,pb2,xaxis,U1x,U1y,U2x,U2y,V1x,V1y,V2x,V2y;
					  double a,b;

					  pb1=OldPos[BallColNr1]+ArrayVel[BallColNr1]*BallTime;
					  pb2=OldPos[BallColNr2]+ArrayVel[BallColNr2]*BallTime;
					  xaxis=(pb2-pb1).unit();

					  a=xaxis.dot(ArrayVel[BallColNr1]);
					  U1x=xaxis*a;
					  U1y=ArrayVel[BallColNr1]-U1x;

					  xaxis=(pb1-pb2).unit();
					  b=xaxis.dot(ArrayVel[BallColNr2]);
      				  U2x=xaxis*b;
					  U2y=ArrayVel[BallColNr2]-U2x;

					  V1x=(U1x+U2x-(U1x-U2x))*0.5;
					  V2x=(U1x+U2x-(U2x-U1x))*0.5;
					  V1y=U1y;
					  V2y=U2y;

					  for (j=0;j<NrOfBalls;j++)
					  ArrayPos[j]=OldPos[j]+ArrayVel[j]*BallTime;

					  ArrayVel[BallColNr1]=V1x+V1y;
					  ArrayVel[BallColNr2]=V2x+V2y;

					  // 更新爆炸序列
                      for(j=0;j<20;j++)
					  {
						  if (ExplosionArray[j]._Alpha<=0)
						  {
							  ExplosionArray[j]._Alpha=1;
                              ExplosionArray[j]._Position=ArrayPos[BallColNr1];
							  ExplosionArray[j]._Scale=1;
							  break;
						  }
					  }

					  continue;
				  }
			  }
 
			if (lamda!=10000)
			{		 
				      RestTime-=lamda;

					  for (j=0;j<NrOfBalls;j++)
					  ArrayPos[j]=OldPos[j]+ArrayVel[j]*lamda;

					  rt2=ArrayVel[BallNr].mag();
					  ArrayVel[BallNr].unit();
					  ArrayVel[BallNr]=CVector::unit( (normal*(2*normal.dot(-ArrayVel[BallNr]))) + ArrayVel[BallNr] );
					  ArrayVel[BallNr]=ArrayVel[BallNr]*rt2;
							
					  for(j=0;j<20;j++)
					  {
						  if (ExplosionArray[j]._Alpha<=0)
						  {
							  ExplosionArray[j]._Alpha=1;
                              ExplosionArray[j]._Position=point;
							  ExplosionArray[j]._Scale=1;
							  break;
						  }
					  }
			}
			else RestTime=0;

	}

}

// 初始化各种变量
void CMyCollision1View::InitVars()
{
	 //create palnes
	pl1._Position=CVector(0,-300,0);
	pl1._Normal=CVector(0,1,0);
	pl2._Position=CVector(300,0,0);
	pl2._Normal=CVector(-1,0,0);
	pl3._Position=CVector(-300,0,0);
	pl3._Normal=CVector(1,0,0);
	pl4._Position=CVector(0,0,300);
	pl4._Normal=CVector(0,0,-1);
	pl5._Position=CVector(0,0,-300);
	pl5._Normal=CVector(0,0,1);
	// 创建圆柱体
	cyl1._Position=CVector(0,0,0);
	cyl1._Axis=CVector(0,1,0);
	cyl1._Radius=60+20;
	cyl2._Position=CVector(200,-300,0);
	cyl2._Axis=CVector(0,0,1);
	cyl2._Radius=60+20;
	cyl3._Position=CVector(-200,0,0);
	cyl3._Axis=CVector(0,1,1);
    cyl3._Axis.unit();
	cyl3._Radius=30+20;
	cylinder_obj= gluNewQuadric();
	gluQuadricTexture(cylinder_obj, GL_TRUE);
    // 设置球的最初位置和运动速度
	NrOfBalls=10;
	ArrayVel[0]=veloc;
	ArrayPos[0]=CVector(199,180,10);
	ExplosionArray[0]._Alpha=0;
	ExplosionArray[0]._Scale=1;
	ArrayVel[1]=veloc;
	ArrayPos[1]=CVector(0,150,100);
	ExplosionArray[1]._Alpha=0;
	ExplosionArray[1]._Scale=1;
	ArrayVel[2]=veloc;
	ArrayPos[2]=CVector(-100,180,-100);
	ExplosionArray[2]._Alpha=0;
	ExplosionArray[2]._Scale=1;
	for (int i=3; i<10; i++)
	{
         ArrayVel[i]=veloc;
	     ArrayPos[i]=CVector(-500+i*75, 300, -500+i*50);
		 ExplosionArray[i]._Alpha=0;
	     ExplosionArray[i]._Scale=1;
	}
	for (i=10; i<20; i++)
	{
         ExplosionArray[i]._Alpha=0;
	     ExplosionArray[i]._Scale=1;
	}
}

// 测试直线是否与平面相交函数 
int CMyCollision1View::TestIntersionPlane(const Plane& plane,const CVector& position,const CVector& direction, double& lamda, CVector& pNormal)
{
    double DotProduct=direction.dot(plane._Normal);
	double l2;
    // 检查直线是否与平面平行
    if ((DotProduct<ZERO)&&(DotProduct>-ZERO)) 
		return 0;

    l2=(plane._Normal.dot(plane._Position-position))/DotProduct;

    if (l2<-ZERO) 
		return 0;

    pNormal=plane._Normal;
	lamda=l2;
    return 1;

}

// 测试直线是否与圆柱体相交
int CMyCollision1View::TestIntersionCylinder(const Cylinder& cylinder,const CVector& position,const CVector& direction, double& lamda, CVector& pNormal,CVector& newposition)
{
	CVector RC;
	double d;
	double t,s;
	CVector n,D,O;
	double ln;
	double in,out;

	CVector::subtract(position,cylinder._Position,RC);
	CVector::cross(direction,cylinder._Axis,n);

    ln=n.mag();

	if ( (ln<ZERO)&&(ln>-ZERO) ) return 0;

	n.unit();

	d= fabs( RC.dot(n) );

    if (d<=cylinder._Radius)
	{
		CVector::cross(RC,cylinder._Axis,O);
		t= - O.dot(n)/ln;
		CVector::cross(n,cylinder._Axis,O);
		O.unit();
		s= fabs( sqrt(cylinder._Radius*cylinder._Radius - d*d) / direction.dot(O) );

		in=t-s;
		out=t+s;

		if (in<-ZERO){
			if (out<-ZERO) return 0;
			else lamda=out;
		}
		else
        if (out<-ZERO) {
			      lamda=in;
		}
		else
		if (in<out) lamda=in;
		else lamda=out;

    	newposition=position+direction*lamda;
		CVector HB=newposition-cylinder._Position;
		pNormal=HB - cylinder._Axis*(HB.dot(cylinder._Axis));
		pNormal.unit();

		return 1;
	}
    
	return 0;
}

void CMyCollision1View::LoadGLTextures() 
{	
    // 装入纹理
    Image *image1, *image2, *image3, *image4;
    // 为纹理分配存储空间
    image1 = (Image *) malloc(sizeof(Image));
    if (image1 == NULL) {
	printf("Error allocating space for image");
	exit(0);
    }
	image2 = (Image *) malloc(sizeof(Image));
    if (image2 == NULL) {
	printf("Error allocating space for image");
	exit(0);
    }
	image3 = (Image *) malloc(sizeof(Image));
    if (image3 == NULL) {
	printf("Error allocating space for image");
	exit(0);
    }
	image4 = (Image *) malloc(sizeof(Image));
    if (image4 == NULL) {
	printf("Error allocating space for image");
	exit(0);
    }

    if (!m_MyImage.ImageLoad("data/marble.bmp", image1)) {
	exit(1);
    } 
	if (!m_MyImage.ImageLoad("data/spark.bmp", image2)) {
	exit(1);
    }
	if (!m_MyImage.ImageLoad("data/boden.bmp", image3)) {
	exit(1);
    } 
	if (!m_MyImage.ImageLoad("data/wand.bmp", image4)) {
	exit(1);
    }
    // 创建纹理
    glGenTextures(2, &texture[0]);
    glBindTexture(GL_TEXTURE_2D, texture[0]);   

    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); 
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); 
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T, GL_REPEAT);

    glTexImage2D(GL_TEXTURE_2D, 0, 3, image1->sizeX, image1->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image1->data);

    glBindTexture(GL_TEXTURE_2D, texture[1]);   

    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); 
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); 
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T, GL_REPEAT);

    glTexImage2D(GL_TEXTURE_2D, 0, 3, image2->sizeX, image2->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image2->data);

    glGenTextures(2, &texture[2]);
    glBindTexture(GL_TEXTURE_2D, texture[2]);   

    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); 
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); 
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T, GL_REPEAT);

    glTexImage2D(GL_TEXTURE_2D, 0, 3, image3->sizeX, image3->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image3->data);

    glBindTexture(GL_TEXTURE_2D, texture[3]);   

    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR); 
    glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR); 
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_WRAP_T, GL_REPEAT);

    glTexImage2D(GL_TEXTURE_2D, 0, 3, image4->sizeX, image4->sizeY, 0, GL_RGB, GL_UNSIGNED_BYTE, image4->data);

	free(image1->data);
	free(image1);
	free(image2->data);
	free(image2);
	free(image3->data);
	free(image3);
	free(image4->data);
	free(image4);

};