src/ui/scenic/lib/flatland/global_image_data.h

// Copyright 2020 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.

#ifndef SRC_UI_SCENIC_LIB_FLATLAND_GLOBAL_IMAGE_DATA_H_
#define SRC_UI_SCENIC_LIB_FLATLAND_GLOBAL_IMAGE_DATA_H_

#include "src/ui/scenic/lib/allocation/buffer_collection_importer.h"
#include "src/ui/scenic/lib/flatland/global_topology_data.h"
#include "src/ui/scenic/lib/flatland/uber_struct.h"

namespace flatland {

// The list of Images for a particular global topology. Entries in the list are sorted in the order
// they should be rendered.
using GlobalImageVector = std::vector<allocation::ImageMetadata>;

// The list of global opacity values for a particular global topology. Each entry is the global
// opacity value (i.e. relative to the root TransformHandle) of the transform in the corresponding
// position of the |topology_vector| supplied to ComputeGlobalOpacityValues().
using GlobalOpacityVector = std::vector<float>;

// Struct combining a vector of sorted images and a vector of indices corresponding to the
// transforms each image is paired with. Both vectors should be the same length.
struct GlobalImageData {
  GlobalIndexVector indices;
  GlobalImageVector images;
};

// Computes a list of global opacity values for the global topology.
//
// TODO(fxbug.dev/73516): This is nearly identical to |ComputeGlobalMatrices|. See
// if we want to consolidate these functions.
GlobalOpacityVector ComputeGlobalOpacityValues(
    const GlobalTopologyData::TopologyVector& global_topology,
    const GlobalTopologyData::ParentIndexVector& parent_indices,
    const UberStruct::InstanceMap& uber_structs);

// Computes the list of Images given a |global_topology| and the |uber_structs| used to generate
// that topology. Note that not all TransformHandles will have Images, so the return value will
// have fewer entries than there are in the global topology.
GlobalImageData ComputeGlobalImageData(const GlobalTopologyData::TopologyVector& global_topology,
                                       const GlobalTopologyData::ParentIndexVector& parent_indices,
                                       const UberStruct::InstanceMap& uber_structs);

}  // namespace flatland

#endif  // SRC_UI_SCENIC_LIB_FLATLAND_GLOBAL_IMAGE_DATA_H_