engine/src/flutter/impeller/renderer/compute_pass.h

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef FLUTTER_IMPELLER_RENDERER_COMPUTE_PASS_H_
#define FLUTTER_IMPELLER_RENDERER_COMPUTE_PASS_H_

#include <array>
#include <cstdint>
#include <string>

#include "fml/status.h"
#include "impeller/core/resource_binder.h"
#include "impeller/renderer/compute_pipeline_descriptor.h"
#include "impeller/renderer/pipeline_descriptor.h"

namespace impeller {

//------------------------------------------------------------------------------
/// @brief      Compute passes encode compute shader into the underlying command
///             buffer.
///
/// @see        `CommandBuffer`
///
class ComputePass : public ResourceBinder {
 public:
  virtual ~ComputePass();

  virtual bool IsValid() const = 0;

  void SetLabel(const std::string& label);

  virtual void SetCommandLabel(std::string_view label) = 0;

  virtual void SetPipeline(
      const std::shared_ptr<Pipeline<ComputePipelineDescriptor>>& pipeline) = 0;

  //----------------------------------------------------------------------------
  /// @brief      Dispatch a grid of compute workgroups.
  ///
  ///             The components of `workgroup_count` are workgroup
  ///             (threadgroup) counts, not invocation counts. The number of
  ///             invocations per workgroup (the local size) is declared by the
  ///             shader. The total invocations along an axis is therefore the
  ///             workgroup count times the shader's local size.
  ///
  /// @return     A cancelled status if any dimension is zero.
  ///
  virtual fml::Status Compute(std::array<uint32_t, 3> workgroup_count) = 0;

  /// @brief Ensures all previously encoded compute command's buffer writes are
  ///        visible to any subsequent compute commands.
  ///
  ///        On Vulkan, it does not matter if the compute command is in a
  ///        different command buffer, only that it is executed later in queue
  ///        order.
  virtual void AddBufferMemoryBarrier() = 0;

  /// @brief Ensures all previously encoded compute command's texture writes are
  ///        visible to any subsequent compute commands.
  ///
  ///        On Vulkan, it does not matter if the compute command is in a
  ///        different command buffer, only that it is executed later in queue
  ///        order.
  virtual void AddTextureMemoryBarrier() = 0;

  //----------------------------------------------------------------------------
  /// @brief      Encode the recorded commands to the underlying command buffer.
  ///
  /// @return     If the commands were encoded to the underlying command
  ///             buffer.
  ///
  virtual bool EncodeCommands() const = 0;

  const Context& GetContext() const { return *context_; }

 protected:
  const std::shared_ptr<const Context> context_;

  explicit ComputePass(std::shared_ptr<const Context> context);

  virtual void OnSetLabel(const std::string& label) = 0;

 private:
  ComputePass(const ComputePass&) = delete;

  ComputePass& operator=(const ComputePass&) = delete;
};

}  // namespace impeller

#endif  // FLUTTER_IMPELLER_RENDERER_COMPUTE_PASS_H_