dispose method
Releases everything: the textures and buffers handed out, the arenas, the caches, the canvas's configuration and the device itself.
This backend can finish the job, and the WebGL2 one cannot. There the
canvas is the drawing surface and the platform view registry pins it for
the life of the application; the most that backend can do is remove the
element and ask WEBGL_lose_context to free the context behind it. Here
the canvas is a copy target, the factory holds an emptiable slot rather
than the element, unconfigure gives back the swap chain and
GPUDevice.destroy gives back the device — so what is left afterwards is
a closure over a null.
Call once. A second call is a caller mistake worth surfacing rather than one this device quietly absorbs.
Implementation
@override
void dispose() {
if (_disposed) {
throw StateError('WebGpuDevice.dispose() was already called');
}
_disposed = true;
webgpuDisposePersistentResources(_textures, _buffers);
_blankImage = null;
_blankCube = null;
uniformArena.dispose();
vertexArena.dispose();
indexArena.dispose();
_zeroBlock.destroy();
// Pipelines, layouts, samplers and bind groups have no `destroy` of their
// own: they belong to the device and die with it. Forgetting them is what
// makes the resource count fall to zero, and what stops a caller holding
// this device from holding them too.
pipelines.clear();
_bindingLayouts.clear();
_samplers.clear();
_bindGroups.clear();
_conversionLayouts.clear();
_conversionPipelines.clear();
_library.forget();
_context.unconfigure();
_canvas.remove();
_slot.element = null;
gpuDevice.destroy();
}