ogre 世界坐标、本地坐标、屏幕坐标之间的转换

1.本地坐标转为世界坐标

void local2World(const Vector3 locP, Vector3 &worldP, const SceneNode* node)
{
	Matrix4 worldMat;
	node->getWorldTransforms(&worldMat); //获取该物体的世界坐标矩阵
	worldP = worldMat * locP;
}           

2.世界坐标转为屏幕坐标

#define EPSILON 0.000001
bool world2Screen(Vector3 objPos, Vector2& screenPos)
{
	Matrix4 viewMat = mCamera->getViewMatrix();
	Matrix4 projMat = mCamera->getProjectionMatrix();


	Vector4 inP = Vector4(objPos.x, objPos.y, objPos.z ,1.0);
	Vector4 outP = viewMat * inP;
	outP = projMat * outP;

	if(outP.w <= EPSILON)
		return false;

	outP.x /= outP.w;
	outP.y /= outP.w;
	outP.z /= outP.w;

       //[-1,1]->[0,1]
	outP.x = outP.x*0.5 + 0.5;
	outP.y = outP.y*0.5 + 0.5;
	outP.z = outP.z*0.5 + 0.5;

	outP.x = outP.x * mWindow->getWidth();
	outP.y = (1-outP.y) * mWindow->getHeight();

	screenPos.x = outP.x;
	screenPos.y = outP.y;
	return true;
}