DirectAnimation API Reference - DirectX

Introduction to DirectAnimation

DirectAnimation is a multimedia animation library for Microsoft Windows that allows developers to create sophisticated animated visual effects and user interfaces. It provides a high-level abstraction over the underlying graphics and timing mechanisms, making it easier to manage complex animation sequences.

DirectAnimation offers:

Object-based animation: Animate properties of various graphical objects.
Timeline management: Control the timing and sequencing of animations.
Event handling: Respond to animation start, end, and other events.
Integration with DirectX: Seamlessly works with other DirectX components.

Core Concepts

Animation Groups

Animations are organized into groups, which can be played, paused, or stopped collectively. This allows for synchronized playback of multiple animated elements.

Key interfaces:

IAnimationGroup

Animation Elements

Individual animations that target specific properties of objects. These can be simple value transitions, path-based animations, or event-driven animations.

Key interfaces:

IAnimationElement
IAnimationPath
ITimingFunction

Properties

DirectAnimation can animate a wide range of properties, including position, rotation, scale, color, opacity, and custom user-defined properties.

Key Interfaces and Functions

`IDirectAnimation`

The primary interface for creating and managing animation groups.

Methods:

Method	Description
`CreateAnimationGroup`	Creates a new animation group.
`GetAnimationGroup`	Retrieves an existing animation group by its identifier.
`Cleanup`	Releases all resources held by DirectAnimation.

`IAnimationGroup`

Represents a collection of animations that can be controlled as a single unit.

Methods:

Method	Description
`AddAnimationElement`	Adds an animation element to the group.
`Play`	Starts playback of the animation group.
`Pause`	Pauses the animation group.
`Stop`	Stops the animation group.
`SetLoopCount`	Sets the number of times the group should loop.
`SetCompletionHandler`	Registers a callback function to be executed when the group completes.

`IAnimationElement`

Defines a single animation for a specific property.

Methods:

Method	Description
`SetPath`	Specifies the animation path.
`SetDuration`	Sets the duration of the animation.
`SetTimingFunction`	Applies a timing function to control the animation's easing.
`SetStartValue`	Defines the initial value for the animation.
`SetEndValue`	Defines the final value for the animation.

Example Usage (Conceptual C++)

This is a conceptual example demonstrating how DirectAnimation might be used in C++.


#include <d3d9.h> // Assuming DirectX 9 context
#include <DirectAnimation.h>

// Assume a DirectAnimation object (pDAnimation) and a target object (pTargetObject) exist

// Create an animation group
IAnimationGroup* pAnimGroup;
pDAnimation->CreateAnimationGroup(&pAnimGroup);

// Create an animation element for a position property
IAnimationElement* pPosElement;
pDAnimation->CreateAnimationElement(&pPosElement);

// Define an animation path (e.g., linear interpolation)
IAnimationPath* pPath;
pDAnimation->CreateAnimationPath(&pPath);
pPath->SetType(ANIMATION_PATH_LINEAR);
pPath->AddKeyframe(0.0f, 0.0f);  // Start at time 0, value 0
pPath->AddKeyframe(1.0f, 100.0f); // End at time 1, value 100

// Set the path and duration for the element
pPosElement->SetPath(pPath);
pPosElement->SetDuration(1.0f); // 1 second duration

// Add the element to the group
pAnimGroup->AddAnimationElement(pPosElement, TARGET_PROPERTY_POSITION_X); // Assuming a constant for X position

// Set loop count and start the animation
pAnimGroup->SetLoopCount(-1); // Loop indefinitely
pAnimGroup->Play();

// ... animation loop to update and render ...

// Release interfaces when done
pAnimGroup->Release();
pPosElement->Release();
pPath->Release();