irrlicht 游戏编程 有用的数学之faceTarget 旋转角色朝向目标

作用：旋转角色朝向目标。 

比如玩家靠近怪物。。怪物还没有朝向玩家，怪物发现了玩家，怪物转身朝向玩家并追赶。

以前用小画家画的草图。

模拟怪物旋转Y轴朝向角色

 

下面用irrlicht引擎做代码演示。

//朝向目标.只旋转y轴
core::vector3df faceTarget(IAnimatedMeshSceneNode* playerNode,irr::core::vector3df targetpos,f32 fixrot) 
{ 
	 

 
	vector3df nodepos=playerNode->getPosition();
	core::vector3df posDiff = targetpos - nodepos; //向量.角色->目标
	f32 degree = nodepos.Y; //keep current rotation if nothing to do 
	posDiff.normalize(); 


	//printf("dir %3.1f %3.1f %3.1f\n",posDiff.X,posDiff.Y,posDiff.Z);


	if (posDiff.X != 0.0f || posDiff.Z != 0.0f) 
		degree = atan2(posDiff.X,posDiff.Z) * core::RADTODEG; 

	playerNode->setRotation( core::vector3df( 0,degree+fixrot,0) ); //有个模型修复角度 
 
	return core::vector3df(0,degree,0); 
}

//完整的旋转朝向目标.xyz3轴都旋转了
core::vector3df  faceTarget2(IAnimatedMeshSceneNode* playerNode,irr::core::vector3df targetpos,f32 fixrot)
{
	// rotate to face target Node 
	vector3df nodePos = playerNode->getPosition(); 
	vector3df diff = targetpos - nodePos; //求得朝向目标的向量

	diff.normalize();
	vector3df rot=diff.getHorizontalAngle();
	rot.Y+=fixrot;
	playerNode->setRotation( rot ); 
	playerNode->updateAbsolutePosition(); 
	rot.Y-=fixrot;
	return rot;
}
 

 

来源：oschina

链接：https://my.oschina.net/simawei/blog/4267730