[android-developers] Re: How can I get this two angel ? Please help me

Oh , finally this post comes out 3 days later.

I am new here, and thanks for group owner .

在 2012年6月21日星期四UTC+8上午12时24分20秒，CuGBabyBeaR写道：

I'm a Chinese and sorry about my English is not good .  

That is my problem:

How can I get two angel?

angel 1. angel between device surface and the level

angel 2. azimuth of device surface (azimuth of the projection of device surface normal vector)

I read the document on developer.android.com which part about class Sensor.Event , and have several questions.

1. Is sensor of type TYPE_ORIENTATION really physically exist ? 

   In the document , it told me that :"use getRotationMatrix() in conjunction with remapCoordinateSystem() and getOrientation() to compute these values instead."

(this is it http://developer.android.com/reference/android/hardware/Sensor.html#TYPE_ORIENTATION)

Since I can compute the orientation values by other two sensor values , why is there a redundant sensor exist?

2. I need to compute the normal vector of device surface?

  I want to get the angel between device surface and the level . 

In my mind , I put device in the world coordinate system : Y point to North , X point to East , Z point to sky 

Then for the two angel I want , I only need to get the normal vector of device surface .

3. How can I get the normal vector?

  Whether I use sensor of type TYPE_ORIENTATION  or use getRotationMatrix() plus getOrientation() , the values I can get are Azimuth Pitch and Roll ( differences are only on sign and 3 angels is in degree or radian ).

  I tried several different way to rotation vector (0,0,1) with this 3 angels to get the normal vector , but all of them seems do not work .Help me , make is work please. T T

Thank in advance.

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