Asset
Extends: EventHandler
An asset record of a file or data resource that can be loaded by the engine. The asset contains four important fields:
file
: contains the details of a file (filename, url) which contains the resource data, e.g. an image file for a texture asset.data
: contains a JSON blob which contains either the resource data for the asset (e.g. material data) or additional data for the file (e.g. material mappings for a model).options
: contains a JSON blob with handler-specific load options.resource
: contains the final resource when it is loaded. (e.g. a StandardMaterial or a Texture).
See the AssetRegistry for details on loading resources from assets.
const asset = new pc.Asset("a texture", "texture", {
url: "http://example.com/my/assets/here/texture.png"
});
Summary
Properties
data | Optional JSON data that contains either the complete resource data. |
file | The file details or null if no file. |
id | The asset id. |
loaded | True if the asset has finished attempting to load the resource. |
loading | True if the resource is currently being loaded. |
name | The asset name. |
options | Optional JSON data that contains the asset handler options. |
preload | If true the asset will be loaded during the preload phase of application set up. |
registry | The asset registry that this Asset belongs to. |
resource | A reference to the resource when the asset is loaded. |
resources | A reference to the resources of the asset when it's loaded. |
tags | Asset tags. |
type | The type of the asset. |
Methods
getFileUrl | Return the URL required to fetch the file for this asset. |
ready | Take a callback which is called as soon as the asset is loaded. |
unload | Destroys the associated resource and marks asset as unloaded. |
Events
add:localized | Fired when we add a new localized asset id to the asset. |
change | Fired when one of the asset properties |
error | Fired if the asset encounters an error while loading. |
load | Fired when the asset has completed loading. |
remove | Fired when the asset is removed from the asset registry. |
unload | Fired just before the asset unloads the resource. |
remove:localized | Fired when we remove a localized asset id from the asset. |
Inherited
Methods
fire | Fire an event, all additional arguments are passed on to the event listener. |
hasEvent | Test if there are any handlers bound to an event name. |
off | Detach an event handler from an event. |
on | Attach an event handler to an event. |
once | Attach an event handler to an event. |
Details
Constructor
Asset(name, type, [file], [data], [options])
Create a new Asset record. Generally, Assets are created in the loading process and you won't need to create them by hand.
const asset = new pc.Asset("a texture", "texture", {
url: "http://example.com/my/assets/here/texture.png"
});
Parameters
name | string | A non-unique but human-readable name which can be later used to retrieve the asset. |
type | string | Type of asset. One of ["animation", "audio", "binary", "container", "cubemap", "css", "font", "json", "html", "material", "model", "script", "shader", "sprite", "template", text", "texture", "textureatlas"] |
file | object | Details about the file the asset is made from. At the least must contain the 'url' field. For assets that don't contain file data use null. |
file.url | string | The URL of the resource file that contains the asset data. |
file.filename | string | The filename of the resource file or null if no filename was set (e.g from using AssetRegistry#loadFromUrl). |
file.size | number | The size of the resource file or null if no size was set (e.g. from using AssetRegistry#loadFromUrl). |
file.hash | string | The MD5 hash of the resource file data and the Asset data field or null if hash was set (e.g from using AssetRegistry#loadFromUrl). |
file.contents | ArrayBuffer | Optional file contents. This is faster than wrapping the data in a (base64 encoded) blob. Currently only used by container assets. |
data | object, string | JSON object or string with additional data about the asset. (e.g. for texture and model assets) or contains the asset data itself (e.g. in the case of materials). |
options | object | The asset handler options. For container options see ContainerHandler. |
options.crossOrigin | 'anonymous', 'use-credentials', null | For use with texture assets that are loaded using the browser. This setting overrides the default crossOrigin specifier. For more details on crossOrigin and its use, see https://developer.mozilla.org/en-US/docs/Web/API/HTMLImageElement/crossOrigin. |
Properties
Optional JSON data that contains either the complete resource data. (e.g. in the case of a material) or additional data (e.g. in the case of a model it contains mappings from mesh to material).
True if the asset has finished attempting to load the resource. It is not guaranteed that the resources are available as there could have been a network error.
A reference to the resources of the asset when it's loaded. An asset can hold more runtime resources than one e.g. cubemaps.
The type of the asset. One of ["animation", "audio", "binary", "container", "cubemap", "css", "font", "json", "html", "material", "model", "render", "script", "shader", "sprite", "template", "text", "texture", "textureatlas"]
Methods
getFileUrl()
Return the URL required to fetch the file for this asset.
const assets = app.assets.find("My Image", "texture");
const img = "<img src='" + assets[0].getFileUrl() + "'>";
Returns
string, nullThe URL. Returns null if the asset has no associated file.
ready(callback, [scope])
Take a callback which is called as soon as the asset is loaded. If the asset is already loaded the callback is called straight away.
const asset = app.assets.find("My Asset");
asset.ready(function (asset) {
// asset loaded
});
app.assets.load(asset);
Parameters
callback | AssetReadyCallback | The function called when the asset is ready. Passed the (asset) arguments. |
scope | object | Scope object to use when calling the callback. |
unload()
Destroys the associated resource and marks asset as unloaded.
const asset = app.assets.find("My Asset");
asset.unload();
// asset.resource is null
Events
add:localized
Fired when we add a new localized asset id to the asset.
Parameters
locale | string | The locale. |
assetId | number | The asset id we added. |
change
Fired when one of the asset properties file
, data
, resource
or resources
is changed.
Parameters
asset | Asset | The asset that was loaded. |
property | string | The name of the property that changed. |
value | * | The new property value. |
oldValue | * | The old property value. |
error
Fired if the asset encounters an error while loading.
Parameters
err | string | The error message. |
asset | Asset | The asset that generated the error. |
remove
Fired when the asset is removed from the asset registry.
Parameters
asset | Asset | The asset that was removed. |
unload
Fired just before the asset unloads the resource. This allows for the opportunity to prepare for an asset that will be unloaded. E.g. Changing the texture of a model to a default before the one it was using is unloaded.
Parameters
asset | Asset | The asset that is due to be unloaded. |
remove:localized
Fired when we remove a localized asset id from the asset.
Parameters
locale | string | The locale. |
assetId | number | The asset id we removed. |
Inherited
Methods
fire(name, [arg1], [arg2], [arg3], [arg4], [arg5], [arg6], [arg7], [arg8])
Fire an event, all additional arguments are passed on to the event listener.
obj.fire('test', 'This is the message');
Parameters
name | string | Name of event to fire. |
arg1 | * | First argument that is passed to the event handler. |
arg2 | * | Second argument that is passed to the event handler. |
arg3 | * | Third argument that is passed to the event handler. |
arg4 | * | Fourth argument that is passed to the event handler. |
arg5 | * | Fifth argument that is passed to the event handler. |
arg6 | * | Sixth argument that is passed to the event handler. |
arg7 | * | Seventh argument that is passed to the event handler. |
arg8 | * | Eighth argument that is passed to the event handler. |
Returns
EventHandlerSelf for chaining.
hasEvent(name)
Test if there are any handlers bound to an event name.
obj.on('test', function () { }); // bind an event to 'test'
obj.hasEvent('test'); // returns true
obj.hasEvent('hello'); // returns false
Parameters
name | string | The name of the event to test. |
Returns
booleanTrue if the object has handlers bound to the specified event name.
off([name], [callback], [scope])
Detach an event handler from an event. If callback is not provided then all callbacks are unbound from the event, if scope is not provided then all events with the callback will be unbound.
const handler = function () {
};
obj.on('test', handler);
obj.off(); // Removes all events
obj.off('test'); // Removes all events called 'test'
obj.off('test', handler); // Removes all handler functions, called 'test'
obj.off('test', handler, this); // Removes all handler functions, called 'test' with scope this
Parameters
name | string | Name of the event to unbind. |
callback | HandleEventCallback | Function to be unbound. |
scope | object | Scope that was used as the this when the event is fired. |
Returns
EventHandlerSelf for chaining.
on(name, callback, [scope])
Attach an event handler to an event.
obj.on('test', function (a, b) {
console.log(a + b);
});
obj.fire('test', 1, 2); // prints 3 to the console
Parameters
name | string | Name of the event to bind the callback to. |
callback | HandleEventCallback | Function that is called when event is fired. Note the callback is limited to 8 arguments. |
scope | object | Object to use as 'this' when the event is fired, defaults to current this. |
Returns
EventHandlerSelf for chaining.
once(name, callback, [scope])
Attach an event handler to an event. This handler will be removed after being fired once.
obj.once('test', function (a, b) {
console.log(a + b);
});
obj.fire('test', 1, 2); // prints 3 to the console
obj.fire('test', 1, 2); // not going to get handled
Parameters
name | string | Name of the event to bind the callback to. |
callback | HandleEventCallback | Function that is called when event is fired. Note the callback is limited to 8 arguments. |
scope | object | Object to use as 'this' when the event is fired, defaults to current this. |
Returns
EventHandlerSelf for chaining.