Constructor
new Scratch3VideoSensingBlocks(runtime)
Parameters:
| Name | Type | Description |
|---|---|---|
runtime |
Runtime | the runtime instantiating this block package. |
Members
(static) DEFAULT_MOTION_STATE :MotionState
The default motion-related state, to be used when a target has no existing motion state.
Type:
- MotionState
(static) DIMENSIONS :Array.<number>
Dimensions the video stream is analyzed at after its rendered to the sample canvas.
Type:
- Array.<number>
(static) INTERVAL :number
After analyzing a frame the amount of milliseconds until another frame is analyzed.
Type:
- number
(static) STATE_KEY :string
The key to load & store a target's motion-related state.
Type:
- string
(static, readonly) VideoState :string
States the video sensing activity can be set to.
Type:
- string
_lastUpdate :number
The last millisecond epoch timestamp that the video stream was analyzed.
Type:
- number
ATTRIBUTE_INFO :Array.<object>
An array of choices of whether a reporter should return the frame's motion amount or direction.
Type:
- Array.<object>
detect :VideoMotion
The motion detection algoritm used to power the motion amount and direction values.
Type:
firstInstall :boolean
A flag to determine if this extension has been installed in a project. It is set to false the first time getInfo is run.
Type:
- boolean
globalVideoState :number
The video state of the video preview stored in a value accessible by any object connected to the virtual machine.
Type:
- number
globalVideoTransparency :number
The transparency setting of the video preview stored in a value accessible by any object connected to the virtual machine.
Type:
- number
runtime :Runtime
The runtime instantiating this block package.
Type:
SUBJECT_INFO :Array.<object>
An array of info about the subject choices.
Type:
- Array.<object>
VIDEO_STATE_INFO :Array.<object>
An array of info on video state options for the "turn video [STATE]" block.
Type:
- Array.<object>
Methods
_analyzeLocalMotion(target) → {MotionState}
Analyze a part of the frame that a target overlaps.
Parameters:
| Name | Type | Description |
|---|---|---|
target |
Target | a target to determine where to analyze |
Returns:
the motion state for the given target
- Type
- MotionState
(private) _buildMenu(info) → {array}
Create data for a menu in scratch-blocks format, consisting of an array of objects with text and value properties. The text is a translated string, and the value is one-indexed.
Parameters:
| Name | Type | Description |
|---|---|---|
info |
Array.<object> | An array of info objects each having a name property. |
Returns:
- An array of objects with text and value properties.
- Type
- array
(private) _getMotionState(target) → {MotionState}
Parameters:
| Name | Type | Description |
|---|---|---|
target |
Target | collect motion state for this target. |
Returns:
the mutable motion state associated with that target. This will be created if necessary.
- Type
- MotionState
(private) _loop()
Occasionally step a loop to sample the video, stamp it to the preview skin, and add a TypedArray copy of the canvas's pixel data.
getInfo() → {object}
Returns:
metadata for this extension and its blocks.
- Type
- object
reset()
Reset the extension's data motion detection data. This will clear out for example old frames, so the first analyzed frame will not be compared against a frame from before reset was called.
setVideoTransparency(args)
A scratch command block handle that configures the video preview's transparency from passed arguments.
Parameters:
| Name | Type | Description | ||||||
|---|---|---|---|---|---|---|---|---|
args |
object | the block arguments Properties
|
updateVideoDisplay()
Get the latest values for video transparency and state, and set the video device to use them.
videoOn(args, util) → {number}
A scratch reporter block handle that analyzes the last two frames and depending on the arguments, returns the motion or direction for the whole stage or just the target sprite.
Parameters:
| Name | Type | Description |
|---|---|---|
args |
object | the block arguments |
util |
BlockUtility | the block utility |
Returns:
the motion amount or direction of the stage or sprite
- Type
- number
videoToggle(args)
A scratch command block handle that configures the video state from passed arguments.
Parameters:
| Name | Type | Description | ||||||
|---|---|---|---|---|---|---|---|---|
args |
object | the block arguments Properties
|
whenMotionGreaterThan(args, util) → {boolean}
A scratch hat block edge handle that analyzes the last two frames where the target sprite overlaps and if it has more motion than the given reference value.
Parameters:
| Name | Type | Description |
|---|---|---|
args |
object | the block arguments |
util |
BlockUtility | the block utility |
Returns:
true if the sprite overlaps more motion than the reference
- Type
- boolean