# I3DExBackdrop Struct Reference
[External Interfaces]

Inheritance diagram for I3DExBackdrop:

List of all members.

## Public Member Functions
virtual MCCOMErr MCCOMAPI | GetBackdropColor (TMCColorRGB &color, boolean &fullAreaDone, const TBBox2D &screenMinMax, const TVector2 &uv)=0

## Detailed Description

Backdrops are image at infinity (behind every objects) in the axis of the camera. Remember that backdrops are like composing the rendered image with another background image. Backdrops are not reflected on reflective objects. Use backgrounds for this. You need to use the screenMinMax coordinates because the uv coordinates that are given to you might be outside the production frame (for example when the marquee rendering tools are used in the interactive preview).

There are two interfaces to access a component: The shell interface (ISh. or I3DSh.) and the external interface (IEx. or I3DEx.) . You can get one from the other using QueryInterface.

Whenever it is possible you should use the Shell interface to access the component because the Shell will make sure that the parameter map of the external component is valid. This is especially important if the component is animated. For more information on components see the Overview of the SDK.

## Member Function Documentation

virtual MCCOMErr MCCOMAPI I3DExBackdrop::GetBackdropColor | ( | TMCColorRGB & | color,
|  | boolean & | fullAreaDone,
|  | const TBBox2D & | screenMinMax,
|  | const TVector2 & | uv |
| ) |  |  | `[pure virtual]`

Returns the color of the backdrop at a particular location of the screen.

Parameters:

  | color | The color that is returned.
  | fullAreaDone | For future use.
  | screenMinMax | The coordinates of the production frame in screen coordinates
  | uv | The coordinates of the point on the screen

Implemented in TBasicBackdrop.

The documentation for this struct was generated from the following file:

- I3dExEnvironment.h