Convert Eular Angles from World Axises to Local - algorithm

Question

I am trying to create a VR application using iPhone's motion manager object. By VR I mean an app to show places on camera.
I can successfully visualize iPhone orientation using yaw, pitch and roll with Z -> X -> Y rotational order.
Here is a picture of what I had done till now:
So I can rotate the device and it will do rotate correctly in my Windows app that I created for monitoring.
This is correct and I will show the code for it later. But this is not what I want to do.
What I want to do is actually opposite of this. I don't want device to move. I want the world around it to rotate. So if user point the device's camera to east, he should see the "east sign" and if he changed the direction to the north, he should see the "north sign" on the screen. But accurate. Not like other applications out there that removed the roll movement.
The problem is here that when I move the device from laying on the table to portrait mode, rotating to right and left result in incorrect rotation. And if I put it in landscape mode, then top to down rotation is incorrect. In other word, rotations are based on world axes and they only works correct when device in laying on the ground. Because it is the reference frame I think.
What I want to ask here is how to convert these angles so I see the result i expect. There should be a way based on trigonometry.
These are the function I use to calculate the rotation matrix:
private static Matrix4 CreateRotationMatrix(char axis, float radians, bool rightHanded = true)
{
float c = (float)Math.Cos(radians);
float s = (float)Math.Sin(radians) * (rightHanded ? 1 : -1);
switch (axis)
{
case 'X':
return new Matrix4(
new Vector4(1.0f, 0.0f, 0.0f, 0.0f),
new Vector4(0.0f, c, -s, 0.0f),
new Vector4(0.0f, s, c, 0.0f),
new Vector4(0.0f, 0.0f, 0.0f, 1.0f));
case 'Y':
return new Matrix4(
new Vector4(c, 0.0f, s, 0.0f),
new Vector4(0.0f, 1.0f, 0.0f, 0.0f),
new Vector4(-s, 0.0f, c, 0.0f),
new Vector4(0.0f, 0.0f, 0.0f, 1.0f));
case 'Z':
return new Matrix4(
new Vector4(c, -s, 0.0f, 0.0f),
new Vector4(s, c, 0.0f, 0.0f),
new Vector4(0.0f, 0.0f, 1.0f, 0.0f),
new Vector4(0.0f, 0.0f, 0.0f, 1.0f));
default:
return Matrix4.Identity;
}
}
public static Matrix4 MatrixFromEulerAngles(
Vector3 euler,
string order,
bool isRightHanded = true,
bool isIntrinsic = true)
{
if (order.Length != 3) throw new ArgumentOutOfRangeException("order", "String must have exactly 3 charecters");
// X = Pitch
// Y = Yaw
// Z = Roll
return isIntrinsic
? CreateRotationMatrix(order[2], GetEulerAngle(order[2], euler), isRightHanded)
* CreateRotationMatrix(order[1], GetEulerAngle(order[1], euler), isRightHanded)
* CreateRotationMatrix(order[0], GetEulerAngle(order[0], euler), isRightHanded)
: CreateRotationMatrix(order[0], GetEulerAngle(order[0], euler), isRightHanded)
* CreateRotationMatrix(order[1], GetEulerAngle(order[1], euler), isRightHanded)
* CreateRotationMatrix(order[2], GetEulerAngle(order[2], euler), isRightHanded);
}
private static float GetEulerAngle(char angle, Vector3 euler)
{
switch (angle)
{
case 'X':
return euler.X;
case 'Y':
return euler.Y;
case 'Z':
return euler.Z;
default:
return 0f;
}
}
And this is how I apply the matrix to OpenGL:
Matrix4 projectionMatrix = Helper.MatrixFromEulerAngles(new Vector3(pitch, yaw, roll), "YXZ", true, true);
GL.LoadMatrix(ref projectionMatrix);

Answer 1

Ok, inverting was part of the answer. It helped a lot. Thanks #dari and #Spektre for the suggestion.
But the complete answer was, change the rotation direction (right-handed -> left-handed), changing the rotation order (YXZ -> ZXY, in other word, Intrinsic to Extrinsic) and Inverting the result matrix.
Before asking, I had tried all of these three alone, but never thought of using them all together.
So:
Matrix4 projectionMatrix = Helper.MatrixFromEulerAngles(new Vector3(pitch, yaw, roll), "YXZ", false, false);
projectionMatrix.Invert();
GL.LoadMatrix(ref projectionMatrix);