Yingcai Xiao Chapter 4 The Visualization Pipeline

Visualization: Transformation & Representation Transformation: Converting data from its original form into graphics primitives. Data representation: including internal data structure for storing the original data and the graphics primitives for displaying the data. Visualization: transformating data from one representation to another representation.

Test Data Generation The Functional Model f=F(x) f=F(x,y) f=F(x,y,z) Given (x,y,z) of a grid node, compute the fake data value using F.

Visualization Pipeline

Pipeline Objects Data Objects (data structures) Process Objects (algorithms) Source (out only) Filter (in & out) Mapper (in only) Data Objects (data structures) Process Objects (algorithms) Source (out only) Filter (in & out) Mapper (in only)

Executing the Pipeline Efficiency: avoid unnecessary execution Execution: using a process object to operate Demand-driven: caused by output request Event-driven: caused by input parameter changes

Explicit Execution: Centralized Control

Implicit Execution: Decentralize Control

Programming Data Interface  Programming interface: function  File interface: I/O  System interface: Converts vtkVRMLExporter vtk3DSImporter

Put It All Together  C++, strong typed, implicit control, demand-driven  Filter2  SetInput(Filter1  GetOutput)  Intermediate data: Store: fast, more memory Don’t store: slower, less memory