added setter/getter for bundler-style focal length

include/ACGL/Scene/GenericCamera.hh

@@ -117,7 +117,7 @@ class GenericCamera
         Eye getEye() const { return mCurrentEye; }
 	
 		/**
-		 * Set the horizontal field of view of the camera.
+         * Set the horizontal field of view of the camera in degree.
          * vertical FoV will get (implicitly) changed!
          * @param _fovh         New horizontal field of view of the camera.
 		 */
@@ -125,7 +125,7 @@ class GenericCamera
         double getHorizontalFieldOfView() const { return mHorizontalFieldOfView; }
 
 		/**
-		 * Set the vertical field of view of the camera.
+         * Set the vertical field of view of the camera in degree.
          * Aspect ratio will get changed!
          * @param _fovv         New vertical field of view of the camera.
 		 */
@@ -281,6 +281,17 @@ class GenericCamera
         /// Sets all internal state from a string
         void setStateFromString( const std::string &_state );
 
+        /// The focal length is coupled to the sensor size in real cameras. As this camera does not model a
+        /// sensor size, the focal length is given in pixels and is in relation to the viewports resolution.
+        /// This model is also used by bundler.
+        /// Note that this gives only useful results if the viewports aspect ratio is the same as the
+        /// projections aspect ratio!
+        float getFocalLenght();
+
+        /// Sets the focal length in pixel relative to the viewport dimension. This will change the FoV.
+        /// See getFocalLenght() for more information.
+        void setFocalLength( float _focalLengthInPixel );
+
 	private:
 		/// the Matrix with the camera position/orientation.
 		/// eyeShift is the half of the eyeDistance (can be 0 if we don't want stereo)

src/ACGL/Scene/GenericCamera.cc

@@ -485,6 +485,16 @@ void GenericCamera::setStateFromString( const std::string &_state )
     mViewportSize      = toUvec2( token[pos++] );
 }
 
+float GenericCamera::getFocalLenght()
+{
+    return ( (float) mViewportSize.y ) / ( 2.0f * tan( calcDegToRad(0.5f * mHorizontalFieldOfView) ) );
+}
+
+void GenericCamera::setFocalLength( float _focalLengthInPixel )
+{
+    float hFoVrad = 2.0f * atan( ( 0.5f * mViewportSize.y ) * (1.0f / _focalLengthInPixel ) );
+    setHorizontalFieldOfView( calcRadToDeg( hFoVrad ) );
+}
 
 
 /////////////// TESTS /////////////