chromium/third_party/skia/src/gpu/graphite/compute/ComputeStep.h

/*
 * Copyright 2023 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef skgpu_graphite_compute_ComputeStep_DEFINED
#define skgpu_graphite_compute_ComputeStep_DEFINED

#include "include/core/SkColorType.h"
#include "include/core/SkSize.h"
#include "include/core/SkSpan.h"
#include "include/private/base/SkTArray.h"
#include "include/private/base/SkTo.h"
#include "src/base/SkEnumBitMask.h"
#include "src/gpu/graphite/ComputeTypes.h"

#include <optional>
#include <string>
#include <string_view>
#include <tuple>
#include <vector>

namespace skgpu::graphite {

class UniformManager;

/**
 * A `ComputeStep` represents a compute pass within a wider draw operation. A `ComputeStep`
 * implementation describes an invocation of a compute program and its data binding layout.
 *
 * A `ComputeStep` can perform arbitrary operations on the GPU over various types of data, including
 * geometry and image processing. The data processed by a `ComputeStep` can be inputs (textures or
 * buffers) populated on the CPU, data forwarded to and from other `ComputeStep` invocations (via
 * "slots"), transient storage buffers/textures that are only used within an individual dispatch,
 * geometry attribute (vertex/index/instance) and indirect draw parameters of a subsequent raster
 * pipeline stage, as well as texture outputs.
 *
 * The data flow between sequential `ComputeStep` invocations within a DispatchGroup is achieved by
 * operating over a shared "resource table". `ComputeStep`s can declare a resource with a slot
 * number. Multiple `ComputeStep`s in a group that declare a resource with the same slot number will
 * have access to the same backing resource object through that slot:
 *
 *      _______________                _______________
 *     |               |              |               |
 *     |                ---[Slot 0]---                |
 *     |               |              |               |
 *     |                ---[Slot 1]---                |
 *     | ComputeStep 1 |              | ComputeStep 2 |
 *     |                ---[Slot 2]   |               |
 *     |               |              |               |
 *     |               |   [Slot 3]---                |
 *     |               |              |               |
 *      ---------------                ---------------
 *
 * In the example above, slots 0 and 1 are accessed by both ComputeSteps, while slots 2 and 3 are
 * exclusively accessed by ComputeStep 1 and 2 respectively. Alternately, slots 2 and 3 could be
 * declared as "private" resources which are visible to a single ComputeStep.
 *
 * Similarly, raster stage geometry buffers that are specified as the output of a ComputeStep can be
 * used to assign the draw buffers of a RenderStep.
 *
 * It is the responsibility of the owning entity (e.g. a RendererProvider) to ensure that a chain of
 * ComputeStep and RenderStep invocations have a compatible resource and data-flow layout.
 */
class ComputeStep { … };
SK_MAKE_BITMASK_OPS(…)

}  // namespace skgpu::graphite

#endif  // skgpu_graphite_compute_ComputeStep_DEFINED