sdk/fidl/fuchsia.ui.gfx/resources.fidl - fuchsia - Git at Google

 // Copyright 2017 The Fuchsia Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 library fuchsia.ui.gfx;

 using fuchsia.images;
 using fuchsia.ui.composition;
 using fuchsia.ui.views;
 using zx;

 /// These are all of the types of resources that can be created within a
 /// `Session`. Add new fields only to the bottom of the list.
 type ResourceArgs = strict resource union {
     // Memory resources.
     1: memory MemoryArgs;
     2: image ImageArgs;
     3: reserved;
     4: buffer BufferArgs;

     // Views.
     5: view ViewArgs;
     6: view_holder ViewHolderArgs;

     // Shapes (see shapes.fidl).
     7: rectangle RectangleArgs;
     8: rounded_rectangle RoundedRectangleArgs;
     9: circle CircleArgs;
    10: mesh MeshArgs;

     // Nodes (see nodes.fidl).
    11: shape_node ShapeNodeArgs;
    12: clip_node ClipNodeArgs;
    13: entity_node EntityNodeArgs;
    14: opacity_node OpacityNodeArgsHACK;

     // Materials.
    15: material MaterialArgs;

     // Layers.
    16: compositor CompositorArgs;
    17: display_compositor DisplayCompositorArgs;
    18: reserved;
    19: layer_stack LayerStackArgs;
    20: layer LayerArgs;

     // Scene representation and display.
    21: scene SceneArgs;
    22: camera CameraArgs;
    23: stereo_camera StereoCameraArgs;
    24: renderer RendererArgs;

     // Lighting.
    25: ambient_light AmbientLightArgs;
    26: directional_light DirectionalLightArgs;

     // A value that can be used in place of a constant value.
    27: variable VariableArgs;

     // TODO(fxbug.dev/24428): Move these where they belong.  They're added to the end
     // of the struct temporarily until we transition to xunions.
    28: point_light PointLightArgs;
    29: reserved;
    30: reserved;
    31: view3 ViewArgs3;
    32: image_pipe2 ImagePipe2Args;
    33: image2 ImageArgs2;
    34: image3 ImageArgs3;
 };

 /// `ImagePipe2` is a `Resource` that can be used as a `Texture` for a `Material`.
 type ImagePipe2Args = resource struct {
     image_pipe_request server_end:fuchsia.images.ImagePipe2;
 };

 /// `Memory` is a `Resource` that wraps a client-provided Zircon vmo to register
 /// it with Scenic.
 // TODO: specify resizing behavior.  Who can resize?  Client/Scenic/both/none?
 type MemoryArgs = resource struct {
     /// The VMO which backs this memory.
     vmo zx.handle:VMO;

     /// The amount of memory from `vmo` that should be utilized.
     allocation_size uint64;

     /// The type of memory stored in the VMO, namely whether it's GPU memory or
     /// host memory.
     memory_type fuchsia.images.MemoryType;
 };

 /// An image mapped to a range of a `Memory` resource.
 // TODO: more precise and extensive docs.
 @deprecated
 type ImageArgs = struct {
     info fuchsia.images.ImageInfo;

     memory_id uint32; // id of a `Memory` resource
     memory_offset uint32; // byte offset of image within `Memory` resource
 };

 /// An image mapped to a range of a `Memory` resource.
 @deprecated
 type ImageArgs2 = struct {
     width uint32;
     height uint32;

     /// The id of a `BufferCollection`. Before creating this resource, the
     /// buffer collection should be registered on the same `Session` with
     /// `RegisterBufferCollection` and it should have its contraints set.
     /// Once the buffers are allocated successfully (e.g. after calling
     /// `WaitForBuffersAllocated`), the collection's id can be used to create
     /// the image resource.
     buffer_collection_id uint32;
     /// The index of the VMO from the `BufferCollection` that backs this image.
     buffer_collection_index uint32;
 };

 /// An image that is backed by a `BufferCollection` registered with `Allocator`.
 type ImageArgs3 = resource struct {
     width uint32;
     height uint32;

     /// Image creation requires an allocated `BufferCollection` registered with Allocator.
     /// `import_token` should be the other end of a BufferCollectionExportToken that is
     /// successfully registered. All clients of the specified BufferCollection must have set
     /// their constraints and buffers should be allocated before calling.
     import_token fuchsia.ui.composition.BufferCollectionImportToken;
     /// The index of the VMO from the `BufferCollection` that backs this image.
     buffer_collection_index uint32;
 };

 /// A buffer mapped to a range of `Memory`.
 // TODO: replace BufferArgs with BufferArgs2 that supports sysmem.
 type BufferArgs = struct {
     memory_id uint32; // id of a `Memory` resource
     memory_offset uint32; // byte offset of buffer within `Memory` resource
     num_bytes uint32;
 };

 /// Represents the root of a subgraph within a larger scene graph.  Nodes can be
 /// attached to the `View` as children, and these Nodes will have the `View`s'
 /// coordinate transform applied to their own, in addition to being clipped to
 /// the `View`s' bounding box.
 /// See `ViewProperties`.
 ///
 /// Each `View` is linked to a paired `ViewHolder` via a shared token pair.
 ///
 /// Usually the `View` and its associated `ViewHolder` exist in separate
 /// processes.  By combining them, the UI for an entire system can be built
 /// using content contributed from many different processes.
 type ViewArgs = resource struct {
     token fuchsia.ui.views.ViewToken;
     debug_name string:optional;
 };

 /// Represents the root of a subgraph within a larger scene graph.  Nodes can be
 /// attached to the `View` as children, and these Nodes will have the `View`s'
 /// coordinate transform applied to their own, in addition to being clipped to
 /// the `View`s' bounding box.
 /// See `ViewProperties`.
 ///
 /// Each `View` is linked to a paired `ViewHolder` via a shared token pair.
 ///
 /// Usually the `View` and its associated `ViewHolder` exist in separate
 /// processes.  By combining them, the UI for an entire system can be built
 /// using content contributed from many different processes.
 ///
 /// Clients self-identify their `View` with a `ViewRef`, which is a stable
 /// identifier that may be cloned and passed to other components in a
 /// feed-forward style. It is accompanied by a `ViewRefControl`, which Scenic
 /// uses to signal `View` destruction across the system; the `ViewRefControl`
 /// must be unique - do not clone it.
 type ViewArgs3 = resource struct {
     token fuchsia.ui.views.ViewToken;
     /// `control_ref.reference` must have default eventpair rights (i.e., with
     /// signaling), minus ZX_RIGHT_DUPLICATE.
     control_ref fuchsia.ui.views.ViewRefControl;
     /// `view_ref.reference` must have basic rights (i.e., no signaling).
     view_ref fuchsia.ui.views.ViewRef;
     debug_name string:optional;
 };

 /// Represents an attachment point for a subgraph within a larger scene graph.
 /// The `ViewHolder` can be attached to a Node as a child, and the contents of
 /// the linked `View` will become a child of the Node as well.
 ///
 /// Each `ViewHolder` is linked to a paired `View` via a shared token pair.
 ///
 /// Usually the `ViewHolder` and its associated `View` exist in separate
 /// processes.  By combining them, the UI for an entire system can be built
 /// using content contributed from many different processes.
 type ViewHolderArgs = resource struct {
     token fuchsia.ui.views.ViewHolderToken;
     debug_name string:optional;
 };

 /// A Compositor draws its `LayerStack` into a framebuffer provided by its
 /// attached `Display`, if any.  If no display is attached, nothing is rendered.
 // TODO(fxbug.dev/23686): there is currently no way to create/attach a display.
 type CompositorArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// A DisplayCompositor draws its attached `LayerStack` into an image that is
 /// presented on a display.
 type DisplayCompositorArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// A LayerStack is a stack of layers that are attached to a Compositor, which
 /// draws them in order of increasing Z-order (or rather, presents the illusion
 /// of drawing them in that order: it may apply any optimizations that don't
 /// affect the output).
 ///
 /// Supported commands:
 /// - AddLayer
 type LayerStackArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// A Layer is a 2-dimensional image that is drawn by a Compositor.  The
 /// contents of each Layer in a Layerstack are independent of each other.
 /// A layer is not drawn unless it has a camera, texture, or color.
 ///
 /// Supported commands:
 /// - Detach
 /// - SetCamera
 /// - SetColor
 /// - SetTexture
 /// - SetSize (depth must be zero)
 /// - SetSize
 /// - SetTranslation (z component determines the relative Z-ordering of layers)
 /// - SetRotation (must rotate around Z-axis)
 /// - SetScale
 type LayerArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// A Scene is the root of a scene-graph, and defines the rendering environment
 /// (lighting, etc.) for the tree of nodes beneath it.
 ///
 /// Supported commands:
 /// - Add/RemoveLight
 /// - AddChild
 type SceneArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// A Camera is used to render a Scene from a particular viewpoint.  This is
 /// achieved by setting a Renderer to use the camera.
 ///
 /// The following commands may be applied to a Camera:
 /// - SetCameraTransform
 /// - SetCameraProjection
 /// - SetCameraPoseBuffer
 type CameraArgs = struct {
     /// The scene that the camera is viewing.
     scene_id uint32;
 };

 /// A StereoCamera is a Camera that renders the scene in side-by-side stereo.
 ///
 /// Any command which can be applied to a Camera can also be applied to a
 /// StereoCamera.
 /// Additional supported commands:
 /// - SetStereoCameraProjection
 type StereoCameraArgs = struct {
     /// The scene that the camera is viewing.
     scene_id uint32;
 };

 /// A Renderer renders a Scene via a Camera.
 ///
 /// Supported commands:
 /// - SetCamera
 /// - SetRendererParam
 type RendererArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// An AmbientLight is a Light that is is assumed to be everywhere in the scene,
 /// in all directions.
 ///
 /// Supported commands:
 /// - SetLightColor
 type AmbientLightArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// A DirectionalLight is a Light that is emitted from a point at infinity.
 ///
 /// Although the light is directional, the light has some amount of angular
 /// dispersion (i.e., the light is not fully columnated). For simplicity, we
 /// assume the dispersion of the light source is symmetric about the light's
 /// primary direction.
 ///
 /// Supported commands:
 /// - SetLightColor
 /// - SetLightDirection
 type DirectionalLightArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// A PointLight is a Light that emits light in all directions.  By default, the
 /// intensity of the light falls off according to the physically based
 /// "inverse-square law" (see Wikipedia), although it can be adjusted to other
 /// values for artistic effect.
 ///
 /// Supported commands:
 /// - SetLightColor
 /// - SetPointLightPosition
 /// - SetPointLightFalloff
 type PointLightArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// Simple texture-mapped material.
 ///
 /// Supported commands:
 /// - SetTextureCmd: sets the texture, or it can be left as zero (no texture).
 ///   The texture can be an Image or ImagePipe2.
 /// - SetColorCmd: sets the color.
 type MaterialArgs = struct {
     // TODO(fxbug.dev/23916): Clean up dummy args.
     @allow_deprecated_struct_defaults
     dummy uint32 = 0;
 };

 /// Describes a typed, client-modifiable value.
 type VariableArgs = struct {
     type ValueType;
     initial_value Value; // Must match type.  Must not be a variable_id.
 };

 /// Describes an exported resource that is to be imported by an
 /// ImportResourceCmd.
 ///
 /// NOTE: Currently just an enum of importable resource types, but may later be
 /// expanded to express concepts like "meshes with a particular vertex format".
 type ImportSpec = strict enum {
     NODE = 0;
 };
	// Copyright 2017 The Fuchsia Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.
	library fuchsia.ui.gfx;

	using fuchsia.images;
	using fuchsia.ui.composition;
	using fuchsia.ui.views;
	using zx;

	/// These are all of the types of resources that can be created within a
	/// `Session`. Add new fields only to the bottom of the list.
	type ResourceArgs = strict resource union {
	// Memory resources.
	1: memory MemoryArgs;
	2: image ImageArgs;
	3: reserved;
	4: buffer BufferArgs;

	// Views.
	5: view ViewArgs;
	6: view_holder ViewHolderArgs;

	// Shapes (see shapes.fidl).
	7: rectangle RectangleArgs;
	8: rounded_rectangle RoundedRectangleArgs;
	9: circle CircleArgs;
	10: mesh MeshArgs;

	// Nodes (see nodes.fidl).
	11: shape_node ShapeNodeArgs;
	12: clip_node ClipNodeArgs;
	13: entity_node EntityNodeArgs;
	14: opacity_node OpacityNodeArgsHACK;

	// Materials.
	15: material MaterialArgs;

	// Layers.
	16: compositor CompositorArgs;
	17: display_compositor DisplayCompositorArgs;
	18: reserved;
	19: layer_stack LayerStackArgs;
	20: layer LayerArgs;

	// Scene representation and display.
	21: scene SceneArgs;
	22: camera CameraArgs;
	23: stereo_camera StereoCameraArgs;
	24: renderer RendererArgs;

	// Lighting.
	25: ambient_light AmbientLightArgs;
	26: directional_light DirectionalLightArgs;

	// A value that can be used in place of a constant value.
	27: variable VariableArgs;

	// TODO(fxbug.dev/24428): Move these where they belong. They're added to the end
	// of the struct temporarily until we transition to xunions.
	28: point_light PointLightArgs;
	29: reserved;
	30: reserved;
	31: view3 ViewArgs3;
	32: image_pipe2 ImagePipe2Args;
	33: image2 ImageArgs2;
	34: image3 ImageArgs3;
	};

	/// `ImagePipe2` is a `Resource` that can be used as a `Texture` for a `Material`.
	type ImagePipe2Args = resource struct {
	image_pipe_request server_end:fuchsia.images.ImagePipe2;
	};

	/// `Memory` is a `Resource` that wraps a client-provided Zircon vmo to register
	/// it with Scenic.
	// TODO: specify resizing behavior. Who can resize? Client/Scenic/both/none?
	type MemoryArgs = resource struct {
	/// The VMO which backs this memory.
	vmo zx.handle:VMO;

	/// The amount of memory from `vmo` that should be utilized.
	allocation_size uint64;

	/// The type of memory stored in the VMO, namely whether it's GPU memory or
	/// host memory.
	memory_type fuchsia.images.MemoryType;
	};

	/// An image mapped to a range of a `Memory` resource.
	// TODO: more precise and extensive docs.
	@deprecated
	type ImageArgs = struct {
	info fuchsia.images.ImageInfo;

	memory_id uint32; // id of a `Memory` resource
	memory_offset uint32; // byte offset of image within `Memory` resource
	};

	/// An image mapped to a range of a `Memory` resource.
	@deprecated
	type ImageArgs2 = struct {
	width uint32;
	height uint32;

	/// The id of a `BufferCollection`. Before creating this resource, the
	/// buffer collection should be registered on the same `Session` with
	/// `RegisterBufferCollection` and it should have its contraints set.
	/// Once the buffers are allocated successfully (e.g. after calling
	/// `WaitForBuffersAllocated`), the collection's id can be used to create
	/// the image resource.
	buffer_collection_id uint32;
	/// The index of the VMO from the `BufferCollection` that backs this image.
	buffer_collection_index uint32;
	};

	/// An image that is backed by a `BufferCollection` registered with `Allocator`.
	type ImageArgs3 = resource struct {
	width uint32;
	height uint32;

	/// Image creation requires an allocated `BufferCollection` registered with Allocator.
	/// `import_token` should be the other end of a BufferCollectionExportToken that is
	/// successfully registered. All clients of the specified BufferCollection must have set
	/// their constraints and buffers should be allocated before calling.
	import_token fuchsia.ui.composition.BufferCollectionImportToken;
	/// The index of the VMO from the `BufferCollection` that backs this image.
	buffer_collection_index uint32;
	};

	/// A buffer mapped to a range of `Memory`.
	// TODO: replace BufferArgs with BufferArgs2 that supports sysmem.
	type BufferArgs = struct {
	memory_id uint32; // id of a `Memory` resource
	memory_offset uint32; // byte offset of buffer within `Memory` resource
	num_bytes uint32;
	};

	/// Represents the root of a subgraph within a larger scene graph. Nodes can be
	/// attached to the `View` as children, and these Nodes will have the `View`s'
	/// coordinate transform applied to their own, in addition to being clipped to
	/// the `View`s' bounding box.
	/// See `ViewProperties`.
	///
	/// Each `View` is linked to a paired `ViewHolder` via a shared token pair.
	///
	/// Usually the `View` and its associated `ViewHolder` exist in separate
	/// processes. By combining them, the UI for an entire system can be built
	/// using content contributed from many different processes.
	type ViewArgs = resource struct {
	token fuchsia.ui.views.ViewToken;
	debug_name string:optional;
	};

	/// Represents the root of a subgraph within a larger scene graph. Nodes can be
	/// attached to the `View` as children, and these Nodes will have the `View`s'
	/// coordinate transform applied to their own, in addition to being clipped to
	/// the `View`s' bounding box.
	/// See `ViewProperties`.
	///
	/// Each `View` is linked to a paired `ViewHolder` via a shared token pair.
	///
	/// Usually the `View` and its associated `ViewHolder` exist in separate
	/// processes. By combining them, the UI for an entire system can be built
	/// using content contributed from many different processes.
	///
	/// Clients self-identify their `View` with a `ViewRef`, which is a stable
	/// identifier that may be cloned and passed to other components in a
	/// feed-forward style. It is accompanied by a `ViewRefControl`, which Scenic
	/// uses to signal `View` destruction across the system; the `ViewRefControl`
	/// must be unique - do not clone it.
	type ViewArgs3 = resource struct {
	token fuchsia.ui.views.ViewToken;
	/// `control_ref.reference` must have default eventpair rights (i.e., with
	/// signaling), minus ZX_RIGHT_DUPLICATE.
	control_ref fuchsia.ui.views.ViewRefControl;
	/// `view_ref.reference` must have basic rights (i.e., no signaling).
	view_ref fuchsia.ui.views.ViewRef;
	debug_name string:optional;
	};

	/// Represents an attachment point for a subgraph within a larger scene graph.
	/// The `ViewHolder` can be attached to a Node as a child, and the contents of
	/// the linked `View` will become a child of the Node as well.
	///
	/// Each `ViewHolder` is linked to a paired `View` via a shared token pair.
	///
	/// Usually the `ViewHolder` and its associated `View` exist in separate
	/// processes. By combining them, the UI for an entire system can be built
	/// using content contributed from many different processes.
	type ViewHolderArgs = resource struct {
	token fuchsia.ui.views.ViewHolderToken;
	debug_name string:optional;
	};

	/// A Compositor draws its `LayerStack` into a framebuffer provided by its
	/// attached `Display`, if any. If no display is attached, nothing is rendered.
	// TODO(fxbug.dev/23686): there is currently no way to create/attach a display.
	type CompositorArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// A DisplayCompositor draws its attached `LayerStack` into an image that is
	/// presented on a display.
	type DisplayCompositorArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// A LayerStack is a stack of layers that are attached to a Compositor, which
	/// draws them in order of increasing Z-order (or rather, presents the illusion
	/// of drawing them in that order: it may apply any optimizations that don't
	/// affect the output).
	///
	/// Supported commands:
	/// - AddLayer
	type LayerStackArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// A Layer is a 2-dimensional image that is drawn by a Compositor. The
	/// contents of each Layer in a Layerstack are independent of each other.
	/// A layer is not drawn unless it has a camera, texture, or color.
	///
	/// Supported commands:
	/// - Detach
	/// - SetCamera
	/// - SetColor
	/// - SetTexture
	/// - SetSize (depth must be zero)
	/// - SetSize
	/// - SetTranslation (z component determines the relative Z-ordering of layers)
	/// - SetRotation (must rotate around Z-axis)
	/// - SetScale
	type LayerArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// A Scene is the root of a scene-graph, and defines the rendering environment
	/// (lighting, etc.) for the tree of nodes beneath it.
	///
	/// Supported commands:
	/// - Add/RemoveLight
	/// - AddChild
	type SceneArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// A Camera is used to render a Scene from a particular viewpoint. This is
	/// achieved by setting a Renderer to use the camera.
	///
	/// The following commands may be applied to a Camera:
	/// - SetCameraTransform
	/// - SetCameraProjection
	/// - SetCameraPoseBuffer
	type CameraArgs = struct {
	/// The scene that the camera is viewing.
	scene_id uint32;
	};

	/// A StereoCamera is a Camera that renders the scene in side-by-side stereo.
	///
	/// Any command which can be applied to a Camera can also be applied to a
	/// StereoCamera.
	/// Additional supported commands:
	/// - SetStereoCameraProjection
	type StereoCameraArgs = struct {
	/// The scene that the camera is viewing.
	scene_id uint32;
	};

	/// A Renderer renders a Scene via a Camera.
	///
	/// Supported commands:
	/// - SetCamera
	/// - SetRendererParam
	type RendererArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// An AmbientLight is a Light that is is assumed to be everywhere in the scene,
	/// in all directions.
	///
	/// Supported commands:
	/// - SetLightColor
	type AmbientLightArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// A DirectionalLight is a Light that is emitted from a point at infinity.
	///
	/// Although the light is directional, the light has some amount of angular
	/// dispersion (i.e., the light is not fully columnated). For simplicity, we
	/// assume the dispersion of the light source is symmetric about the light's
	/// primary direction.
	///
	/// Supported commands:
	/// - SetLightColor
	/// - SetLightDirection
	type DirectionalLightArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// A PointLight is a Light that emits light in all directions. By default, the
	/// intensity of the light falls off according to the physically based
	/// "inverse-square law" (see Wikipedia), although it can be adjusted to other
	/// values for artistic effect.
	///
	/// Supported commands:
	/// - SetLightColor
	/// - SetPointLightPosition
	/// - SetPointLightFalloff
	type PointLightArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// Simple texture-mapped material.
	///
	/// Supported commands:
	/// - SetTextureCmd: sets the texture, or it can be left as zero (no texture).
	/// The texture can be an Image or ImagePipe2.
	/// - SetColorCmd: sets the color.
	type MaterialArgs = struct {
	// TODO(fxbug.dev/23916): Clean up dummy args.
	@allow_deprecated_struct_defaults
	dummy uint32 = 0;
	};

	/// Describes a typed, client-modifiable value.
	type VariableArgs = struct {
	type ValueType;
	initial_value Value; // Must match type. Must not be a variable_id.
	};

	/// Describes an exported resource that is to be imported by an
	/// ImportResourceCmd.
	///
	/// NOTE: Currently just an enum of importable resource types, but may later be
	/// expanded to express concepts like "meshes with a particular vertex format".
	type ImportSpec = strict enum {
	NODE = 0;
	};