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#pragma once
#include <mbgl/tile/tile.hpp>
#include <mbgl/tile/tile_id.hpp>
#include <mbgl/tile/tile_necessity.hpp>
#include <mbgl/util/range.hpp>
#include <unordered_set>
#include <iostream>
namespace mbgl {
namespace algorithm {
template <typename GetTileFn,
typename CreateTileFn,
typename RetainTileFn,
typename RenderTileFn>
bool findBestTile(GetTileFn getTile,
CreateTileFn createTile,
RetainTileFn retainTile,
RenderTileFn renderTile,
const Range<uint8_t>& zoomRange,
const uint8_t dataTileZoom,
const UnwrappedTileID& idealRenderTileID,
const OverscaledTileID& idealDataTileID,
const bool requireFullyRenderable,
std::unordered_set<UnwrappedTileID> checked) {
auto tile = getTile(idealDataTileID);
if (!tile) {
// std::cout << "Create tile: " << idealDataTileID << std::endl;
tile = createTile(idealDataTileID);
assert(tile);
}
bool covered = true;
std::vector<std::pair<UnwrappedTileID,decltype(tile)>> renderTiles;
// if (source has the tile and bucket is loaded) {
if (requireFullyRenderable ? tile->isFullyRenderable() : tile->isRenderable()) {
retainTile(*tile, TileNecessity::Required);
renderTiles.emplace_back(std::make_pair(idealRenderTileID, tile));
} else {
// We are now attempting to load child and parent tiles.
bool parentHasTriedOptional = tile->hasTriedCache();
bool parentIsLoaded = tile->isLoaded();
// The tile isn't loaded yet, but retain it anyway because it's an ideal tile.
retainTile(*tile, TileNecessity::Required); // TODO: Is it fine to retain this twice for both full and partial render?
int32_t overscaledZ = dataTileZoom + 1;
if (overscaledZ > zoomRange.max) {
// We're looking for an overzoomed child tile.
const auto childDataTileID = idealDataTileID.scaledTo(overscaledZ);
tile = getTile(childDataTileID);
if (tile && (requireFullyRenderable ? tile->isFullyRenderable() : tile->isRenderable())) {
retainTile(*tile, TileNecessity::Optional);
renderTiles.emplace_back(std::make_pair(idealRenderTileID, tile));
} else {
covered = false;
}
} else {
// Check all four actual child tiles.
for (const auto& childTileID : idealDataTileID.canonical.children()) {
const OverscaledTileID childDataTileID(overscaledZ, idealRenderTileID.wrap, childTileID);
tile = getTile(childDataTileID);
if (tile && (requireFullyRenderable ? tile->isFullyRenderable() : tile->isRenderable())) {
retainTile(*tile, TileNecessity::Optional);
renderTiles.emplace_back(std::make_pair(childDataTileID.toUnwrapped(), tile));
} else {
// At least one child tile doesn't exist, so we are going to look for
// parents as well.
covered = false;
}
}
}
if (!covered) {
// We couldn't find child tiles that entirely cover the ideal tile.
for (overscaledZ = dataTileZoom - 1; overscaledZ >= zoomRange.min; --overscaledZ) {
const auto parentDataTileID = idealDataTileID.scaledTo(overscaledZ);
const auto parentRenderTileID = parentDataTileID.toUnwrapped();
if (checked.find(parentRenderTileID) != checked.end()) {
// Break parent tile ascent, this route has been checked by another child
// tile before.
break;
} else {
checked.emplace(parentRenderTileID);
}
tile = getTile(parentDataTileID);
// Don't do cache lookups for parents while we're in the "fully renderable" pass:
// Since the cache tiles aren't currently displaying, we don't have to worry about symbol flicker
// And we'd rather get a partially rendered tile closer to our ideal zoom level
if (!tile && !requireFullyRenderable && (parentHasTriedOptional || parentIsLoaded)) {
tile = createTile(parentDataTileID);
}
if (tile) {
if (!parentIsLoaded) {
// We haven't completed loading the child, so we only do an optional
// (cache) request in an attempt to quickly load data that we can show.
retainTile(*tile, TileNecessity::Optional);
} else {
// Now that we've checked the child and know for sure that we can't load
// it, we attempt to load the parent from the network.
retainTile(*tile, TileNecessity::Required);
}
// Save the current values, since they're the parent of the next iteration
// of the parent tile ascent loop.
parentHasTriedOptional = tile->hasTriedCache();
parentIsLoaded = tile->isLoaded();
if ((requireFullyRenderable ? tile->isFullyRenderable() : tile->isRenderable())) {
//std::cout << "Rendering parent zoom change: " << parentRenderTileID.canonical.z - idealRenderTileID.canonical.z << std::endl;
renderTiles.emplace_back(std::make_pair(parentRenderTileID, tile));
covered = true;
// Break parent tile ascent, since we found one.
break;
}
}
}
}
}
if (covered || !requireFullyRenderable) {
// Only add tiles to render tree if we've covered the ideal tile OR we're on our second pass
for (auto tilePair : renderTiles) {
// std::cout << "Rendering tile: " << tilePair.first << std::endl;
renderTile(tilePair.first, *(tilePair.second));
}
} else {
// std::cout << "No tiles added to render tree" << std::endl;
}
return covered;
}
template <typename GetTileFn,
typename CreateTileFn,
typename RetainTileFn,
typename RenderTileFn,
typename IdealTileIDs>
void updateRenderables(GetTileFn getTile,
CreateTileFn createTile,
RetainTileFn retainTile,
RenderTileFn renderTile,
const IdealTileIDs& idealTileIDs,
const Range<uint8_t>& zoomRange,
const uint8_t dataTileZoom) {
std::unordered_set<UnwrappedTileID> checkedPartial;
std::unordered_set<UnwrappedTileID> checkedFull;
//std::cout << "Begin updateRenderables" << std::endl;
// for (all in the set of ideal tiles of the source) {
for (const auto& idealRenderTileID : idealTileIDs) {
assert(idealRenderTileID.canonical.z >= zoomRange.min);
assert(idealRenderTileID.canonical.z <= zoomRange.max);
assert(dataTileZoom >= idealRenderTileID.canonical.z);
const OverscaledTileID idealDataTileID(dataTileZoom, idealRenderTileID.wrap, idealRenderTileID.canonical);
//std::cout << "Ideal tile ID: " << idealDataTileID << std::endl;
// TODO: Two-pass algorithm isn't necessary for tiles that don't have two stage loading (e.g. raster tiles)
// TODO: More efficient to write algorithm as single pass?
if (!findBestTile(getTile, createTile, retainTile, renderTile, zoomRange, dataTileZoom, idealRenderTileID, idealDataTileID, true, checkedFull)) {
findBestTile(getTile, createTile, retainTile, renderTile, zoomRange, dataTileZoom, idealRenderTileID, idealDataTileID, false, checkedPartial);
}
}
}
} // namespace algorithm
} // namespace mbgl
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