Creates a new Texture using the given source and dimensions.
| name | type | description |
|---|---|---|
| key | string |
The unique string-based key of the Texture. |
| source | HTMLImageElement |
The source Image element. |
| width | number |
The width of the Texture. |
| height | number |
The height of the Texture. |
The Texture that was created, or null if the key is already in use.