133 lines
6.1 KiB
C++
133 lines
6.1 KiB
C++
#pragma once
|
|
|
|
#include <mbgl/renderer/tile_mask.hpp>
|
|
|
|
#include <vector>
|
|
#include <functional>
|
|
#include <algorithm>
|
|
|
|
namespace mbgl {
|
|
namespace algorithm {
|
|
|
|
template <typename T>
|
|
bool tileNeedsMask(const std::reference_wrapper<T>& tile) { return tile.get().usedByRenderedLayers; }
|
|
template <typename T>
|
|
void setTileMask(const std::reference_wrapper<T>& tile, TileMask&& mask ) { return tile.get().setMask(std::move(mask)); }
|
|
|
|
// Overloads for tests
|
|
template <typename T> bool tileNeedsMask(const T& tile) { return tile.usedByRenderedLayers; }
|
|
template <typename T> void setTileMask(T& tile, TileMask&& mask ) { return tile.setMask(std::move(mask)); }
|
|
|
|
template <typename Iterator>
|
|
void computeTileMasks(
|
|
const CanonicalTileID& root,
|
|
const UnwrappedTileID& ref,
|
|
const Iterator begin,
|
|
const Iterator end,
|
|
TileMask& mask) {
|
|
// If the reference or any of its children is found in the list, we need to recurse.
|
|
for (auto it = begin; it != end; ++it) {
|
|
const UnwrappedTileID& id = it->first;
|
|
if (!tileNeedsMask(it->second)) {
|
|
continue;
|
|
}
|
|
|
|
if (ref == id) {
|
|
// The current tile is masked out, so we don't need to add them to the mask set.
|
|
return;
|
|
}
|
|
|
|
if (id.isChildOf(ref)) {
|
|
// There's at least one child tile that is masked out, so recursively descend.
|
|
for (const auto& child : ref.children()) {
|
|
computeTileMasks(root, child, it, end, mask);
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
// We couldn't find a child, so it's definitely a masked part.
|
|
// Compute the difference between the root tile ID and the reference tile ID, since TileMask
|
|
// elements are always relative (see below for explanation).
|
|
const uint8_t diffZ = ref.canonical.z - root.z;
|
|
mask.emplace(diffZ, ref.canonical.x - (root.x << diffZ), ref.canonical.y - (root.y << diffZ));
|
|
}
|
|
|
|
// Updates the TileMasks for all renderable tiles. Each renderable tile has a corresponding UnwrappedTileID
|
|
// indicating where it should be rendered on the screen. A TileMask describes all regions
|
|
// within a renderable tile that are *not* covered by other renderable tiles.
|
|
// Example: Renderable tiles in our list are 2/1/3, 3/3/6, and 4/5/13. The schematic for creating the
|
|
// TileMask for 2/1/3 looks like this:
|
|
//
|
|
// ┌────────┬────────┬─────────────────┐
|
|
// │ │ │#################│
|
|
// │ 4/4/12 │ 4/5/12 │#################│
|
|
// │ │ │#################│
|
|
// ├──────3/2/6──────┤#####3/3/6#######│
|
|
// │ │########│#################│
|
|
// │ 4/4/13 │#4/5/13#│#################│
|
|
// │ │########│#################│
|
|
// ├────────┴──────2/1/3───────────────┤
|
|
// │ │ │
|
|
// │ │ │
|
|
// │ │ │
|
|
// │ 3/2/7 │ 3/3/7 │
|
|
// │ │ │
|
|
// │ │ │
|
|
// │ │ │
|
|
// └─────────────────┴─────────────────┘
|
|
//
|
|
// The TileMask for 2/1/3 thus consists of the tiles 4/4/12, 4/5/12, 4/4/13, 3/2/7, and 3/3/7,
|
|
// but it does *not* include 4/5/13, and 3/3/6, since these are other renderable tiles.
|
|
// A TileMask always contains TileIDs *relative* to the tile it is generated for, so 2/1/3 is
|
|
// "subtracted" from these TileIDs. The final TileMask for 2/1/3 will thus be:
|
|
//
|
|
// ┌────────┬────────┬─────────────────┐
|
|
// │ │ │#################│
|
|
// │ 2/0/0 │ 2/1/0 │#################│
|
|
// │ │ │#################│
|
|
// ├────────┼────────┤#################│
|
|
// │ │########│#################│
|
|
// │ 2/0/1 │########│#################│
|
|
// │ │########│#################│
|
|
// ├────────┴────────┼─────────────────┤
|
|
// │ │ │
|
|
// │ │ │
|
|
// │ │ │
|
|
// │ 1/0/1 │ 1/1/1 │
|
|
// │ │ │
|
|
// │ │ │
|
|
// │ │ │
|
|
// └─────────────────┴─────────────────┘
|
|
//
|
|
// Only other renderable tiles that are *children* of the renderable tile we are generating the mask for will
|
|
// will be considered. For example, adding a renderable tile with TileID 4/8/13 won't affect the TileMask for
|
|
// 2/1/3, since it is not a descendant of it.
|
|
template <typename RenderableTilesMap>
|
|
void updateTileMasks(RenderableTilesMap& renderables) {
|
|
TileMask mask;
|
|
const auto end = renderables.end();
|
|
for (auto it = renderables.begin(); it != end; ++it) {
|
|
const UnwrappedTileID& id = it->first;
|
|
if (!tileNeedsMask(it->second)) {
|
|
continue;
|
|
}
|
|
// Try to add all remaining ids as children. We sorted the tile list
|
|
// by z earlier, so all preceding items cannot be children of the current
|
|
// tile. We also compute the lower bound of the next wrap, because items of the next wrap
|
|
// can never be children of the current wrap.
|
|
auto child_it = std::next(it);
|
|
const auto children_end = std::lower_bound(
|
|
child_it, end,
|
|
UnwrappedTileID{ static_cast<int16_t>(id.wrap + 1), { 0, 0, 0 } },
|
|
[](auto& a, auto& b) { return a.first < b; });
|
|
|
|
mask.clear();
|
|
computeTileMasks(id.canonical, id, child_it, children_end, mask);
|
|
setTileMask(it->second, std::move(mask));
|
|
}
|
|
}
|
|
|
|
} // namespace algorithm
|
|
} // namespace mbgl
|