72 lines
2.1 KiB
C++
72 lines
2.1 KiB
C++
#include <mbgl/map/tile_id.hpp>
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#include <mbgl/util/string.hpp>
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#include <mbgl/util/constants.hpp>
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#include <cassert>
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namespace mbgl {
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float TileID::pixelsToTileUnits(float pixelValue, float zoom) const {
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return pixelValue * (util::EXTENT / (util::tileSize * overscaleFactor() * std::pow(2, zoom - z)));
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}
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TileID TileID::parent(uint8_t parent_z, uint8_t sourceMaxZoom) const {
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assert(parent_z < z);
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auto newX = x;
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auto newY = y;
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for (auto newZ = z; newZ > parent_z; newZ--) {
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if (newZ > sourceMaxZoom) {
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// the id represents an overscaled tile, return the same coordinates with a lower z
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// do nothing
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} else {
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newX = newX / 2;
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newY = newY / 2;
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}
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}
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return TileID{parent_z, newX, newY, parent_z > sourceMaxZoom ? sourceMaxZoom : parent_z};
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}
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std::forward_list<TileID> TileID::children(uint8_t sourceMaxZoom) const {
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auto childZ = z + 1;
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std::forward_list<TileID> child_ids;
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if (z >= sourceMaxZoom) {
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// return a single tile id representing a an overscaled tile
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child_ids.emplace_front(childZ, x, y, sourceMaxZoom);
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} else {
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auto childX = x * 2;
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auto childY = y * 2;
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child_ids.emplace_front(childZ, childX, childY, childZ);
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child_ids.emplace_front(childZ, childX + 1, childY, childZ);
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child_ids.emplace_front(childZ, childX, childY + 1, childZ);
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child_ids.emplace_front(childZ, childX + 1, childY + 1, childZ);
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}
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return child_ids;
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}
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TileID TileID::normalized() const {
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int32_t dim = std::pow(2, sourceZ);
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int32_t nx = x, ny = y;
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while (nx < 0) nx += dim;
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while (nx >= dim) nx -= dim;
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return TileID { z, nx, ny, sourceZ};
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}
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bool TileID::isChildOf(const TileID &parent_id) const {
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if (parent_id.z >= z || parent_id.w != w) {
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return false;
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}
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int32_t scale = std::pow(2, z - parent_id.z);
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return parent_id.x == ((x < 0 ? x - scale + 1 : x) / scale) &&
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parent_id.y == y / scale;
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}
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TileID::operator std::string() const {
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return util::toString(z) + "/" + util::toString(x) + "/" + util::toString(y);
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}
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} // namespace mbgl
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