const char *GetClassName ()
	void FunctionInitialize (vtkRenderer * ,vtkVolume * ,vtkVolumeRayCastMapper * ,float * ,float * ,float * ,float ,float * ,float * ,int )
	void CastARay (int ,void * ,float ,float ,int ,float )
	float GetZeroOpacityThreshold (vtkVolume *)
	void SpecificFunctionInitialize (vtkRenderer * ,vtkVolume * ,vtkVolumeRayCastMapper *)

Do the basic initialization. This includes saving the parameters passed in into local variables, as well as grabbing some useful info from the volume property and normal encoder. This initialize routine is called once per render. It also calls the SpecificFunctionInitialize of the subclass function.

void FunctionInitialize (vtkRenderer * ,vtkVolume * ,vtkVolumeRayCastMapper * ,float * ,float * ,float * ,float ,float * ,float * ,int )

Give a ray type (0 = unsigned char, 1 = unsigned short, 2 = short) cast a ray through the scalar data starting at ray_position and taking num_steps of ray_increment size. Return the final compositing value in pixel_value where pixel_value[0] = red, pixel_value[1] = green, pixel_value[2] = blue, pixel_value[3] = alpha pixel_value[4] = depth, and pixel_value[5] = number of steps

void CastARay (int ,void * ,float ,float ,int ,float )

Get the value below which all scalar values are considered to have 0 opacity.

float GetZeroOpacityThreshold (vtkVolume *)

This method gives the subclass a chance to do any special initialization that it may need to do

void SpecificFunctionInitialize (vtkRenderer * ,vtkVolume * ,vtkVolumeRayCastMapper *)