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authorAnsis Brammanis <brammanis@gmail.com>2017-06-30 15:38:43 -0400
committerAnsis Brammanis <brammanis@gmail.com>2017-07-11 09:10:25 -0700
commitd661b4ba61a7bd7770c96464c190bfadf9a42414 (patch)
treebdec86a0a786028b44c64b308e875fc3fea9e218
parente514138b691615be24f484986c40f486223df82a (diff)
downloadqtlocation-mapboxgl-d661b4ba61a7bd7770c96464c190bfadf9a42414.tar.gz
[core] port pitch-label collision hack
https://github.com/mapbox/mapbox-gl-js/pull/4781/commits/81363951ed56c54f331ffc8d88e4e5079226a224
-rw-r--r--src/mbgl/text/collision_feature.cpp30
-rw-r--r--src/mbgl/text/collision_feature.hpp9
-rw-r--r--src/mbgl/text/collision_tile.cpp29
-rw-r--r--src/mbgl/text/collision_tile.hpp2
4 files changed, 50 insertions, 20 deletions
diff --git a/src/mbgl/text/collision_feature.cpp b/src/mbgl/text/collision_feature.cpp
index 58a7949a8e..022ee50644 100644
--- a/src/mbgl/text/collision_feature.cpp
+++ b/src/mbgl/text/collision_feature.cpp
@@ -42,7 +42,7 @@ CollisionFeature::CollisionFeature(const GeometryCoordinates& line,
bboxifyLabel(line, anchorPoint, anchor.segment, length, height);
}
} else {
- boxes.emplace_back(anchor.point, x1, y1, x2, y2, std::numeric_limits<float>::infinity());
+ boxes.emplace_back(anchor.point, Point<float>{ 0, 0 }, x1, y1, x2, y2, std::numeric_limits<float>::infinity());
}
}
@@ -50,10 +50,10 @@ void CollisionFeature::bboxifyLabel(const GeometryCoordinates& line, GeometryCoo
const int segment, const float labelLength, const float boxSize) {
const float step = boxSize / 2;
const int nBoxes = std::floor(labelLength / step);
- // We calculate line collision boxes out to 150% of what would normally be our
+ // We calculate line collision boxes out to 300% of what would normally be our
// max size, to allow collision detection to work on labels that expand as
// they move into the distance
- const int nPitchPaddingBoxes = std::floor(nBoxes / 4);
+ const int nPitchPaddingBoxes = std::floor(nBoxes / 2);
// offset the center of the first box by half a box so that the edge of the
// box is at the edge of the label.
@@ -90,7 +90,13 @@ void CollisionFeature::bboxifyLabel(const GeometryCoordinates& line, GeometryCoo
for (int i = -nPitchPaddingBoxes; i < nBoxes + nPitchPaddingBoxes; i++) {
// the distance the box will be from the anchor
- const float boxDistanceToAnchor = labelStartDistance + i * step;
+ const float boxOffset = i * step;
+ float boxDistanceToAnchor = labelStartDistance + boxOffset;
+
+ // make the distance between pitch padding boxes bigger
+ if (boxOffset < 0) boxDistanceToAnchor += boxOffset;
+ if (boxOffset > labelLength) boxDistanceToAnchor += boxOffset - labelLength;
+
if (boxDistanceToAnchor < anchorDistance) {
// The line doesn't extend far enough back for this box, skip it
// (This could allow for line collisions on distant tiles)
@@ -143,8 +149,22 @@ void CollisionFeature::bboxifyLabel(const GeometryCoordinates& line, GeometryCoo
maxScale = std::min(maxScale, 0.99f);
}
- boxes.emplace_back(boxAnchor, -boxSize / 2, -boxSize / 2, boxSize / 2, boxSize / 2, maxScale);
+ boxes.emplace_back(boxAnchor, boxAnchor - convertPoint<float>(anchorPoint), -boxSize / 2, -boxSize / 2, boxSize / 2, boxSize / 2, maxScale);
}
}
+float CollisionBox::adjustedMaxScale(const std::array<float, 4>& rotationMatrix, const float yStretch) const {
+ // When the map is pitched the distance covered by a line changes.
+ // Adjust the max scale by (approximatePitchedLength / approximateRegularLength)
+ // to compensate for this.
+ const Point<float> rotatedOffset = util::matrixMultiply(rotationMatrix, offset);
+ const float xSqr = rotatedOffset.x * rotatedOffset.x;
+ const float ySqr = rotatedOffset.y * rotatedOffset.y;
+ const float yStretchSqr = ySqr * yStretch * yStretch;
+ const float adjustmentFactor = xSqr + ySqr != 0 ?
+ std::sqrt((xSqr + yStretchSqr) / (xSqr + ySqr)) :
+ 1.0f;
+ return maxScale * adjustmentFactor;
+}
+
} // namespace mbgl
diff --git a/src/mbgl/text/collision_feature.hpp b/src/mbgl/text/collision_feature.hpp
index c94ec23513..3b6e461a26 100644
--- a/src/mbgl/text/collision_feature.hpp
+++ b/src/mbgl/text/collision_feature.hpp
@@ -11,11 +11,16 @@ namespace mbgl {
class CollisionBox {
public:
- CollisionBox(Point<float> _anchor, float _x1, float _y1, float _x2, float _y2, float _maxScale) :
- anchor(std::move(_anchor)), x1(_x1), y1(_y1), x2(_x2), y2(_y2), maxScale(_maxScale) {}
+ CollisionBox(Point<float> _anchor, Point<float> _offset, float _x1, float _y1, float _x2, float _y2, float _maxScale) :
+ anchor(std::move(_anchor)), offset(_offset), x1(_x1), y1(_y1), x2(_x2), y2(_y2), maxScale(_maxScale) {}
+
+ float adjustedMaxScale(const std::array<float, 4>& rotationMatrix, const float yStretch) const;
// the box is centered around the anchor point
Point<float> anchor;
+
+ // the offset of the box from the label's anchor point
+ Point<float> offset;
// distances to the edges from the anchor
float x1;
diff --git a/src/mbgl/text/collision_tile.cpp b/src/mbgl/text/collision_tile.cpp
index 520f66ead8..b3fbe6f8a3 100644
--- a/src/mbgl/text/collision_tile.cpp
+++ b/src/mbgl/text/collision_tile.cpp
@@ -34,7 +34,7 @@ CollisionTile::CollisionTile(PlacementConfig config_) : config(std::move(config_
}
-float CollisionTile::findPlacementScale(const Point<float>& anchor, const CollisionBox& box, const Point<float>& blockingAnchor, const CollisionBox& blocking) {
+float CollisionTile::findPlacementScale(const Point<float>& anchor, const CollisionBox& box, const float boxMaxScale, const Point<float>& blockingAnchor, const CollisionBox& blocking) {
float minPlacementScale = minScale;
// Find the lowest scale at which the two boxes can fit side by side without overlapping.
@@ -55,10 +55,10 @@ float CollisionTile::findPlacementScale(const Point<float>& anchor, const Collis
collisionFreeScale = blocking.maxScale;
}
- if (collisionFreeScale > box.maxScale) {
+ if (collisionFreeScale > boxMaxScale) {
// If the box can only be shown after it is visible, then the box can never be shown.
// But the label can be shown after this box is not visible.
- collisionFreeScale = box.maxScale;
+ collisionFreeScale = boxMaxScale;
}
if (collisionFreeScale > minPlacementScale &&
@@ -77,13 +77,13 @@ float CollisionTile::placeFeature(const CollisionFeature& feature, bool allowOve
static const float infinity = std::numeric_limits<float>::infinity();
static const std::array<CollisionBox, 4> edges {{
// left
- CollisionBox(Point<float>(0, 0), 0, -infinity, 0, infinity, infinity),
+ CollisionBox(Point<float>(0, 0), { 0, 0 }, 0, -infinity, 0, infinity, infinity),
// right
- CollisionBox(Point<float>(util::EXTENT, 0), 0, -infinity, 0, infinity, infinity),
+ CollisionBox(Point<float>(util::EXTENT, 0), { 0, 0 }, 0, -infinity, 0, infinity, infinity),
// top
- CollisionBox(Point<float>(0, 0), -infinity, 0, infinity, 0, infinity),
+ CollisionBox(Point<float>(0, 0), { 0, 0 }, -infinity, 0, infinity, 0, infinity),
// bottom
- CollisionBox(Point<float>(0, util::EXTENT), -infinity, 0, infinity, 0, infinity)
+ CollisionBox(Point<float>(0, util::EXTENT), { 0, 0 }, -infinity, 0, infinity, 0, infinity)
}};
float minPlacementScale = minScale;
@@ -91,12 +91,14 @@ float CollisionTile::placeFeature(const CollisionFeature& feature, bool allowOve
for (auto& box : feature.boxes) {
const auto anchor = util::matrixMultiply(rotationMatrix, box.anchor);
+ const float boxMaxScale = box.adjustedMaxScale(rotationMatrix, yStretch);
+
if (!allowOverlap) {
for (auto it = tree.qbegin(bgi::intersects(getTreeBox(anchor, box))); it != tree.qend(); ++it) {
const CollisionBox& blocking = std::get<1>(*it);
Point<float> blockingAnchor = util::matrixMultiply(rotationMatrix, blocking.anchor);
- minPlacementScale = util::max(minPlacementScale, findPlacementScale(anchor, box, blockingAnchor, blocking));
+ minPlacementScale = util::max(minPlacementScale, findPlacementScale(anchor, box, boxMaxScale, blockingAnchor, blocking));
if (minPlacementScale >= maxScale) return minPlacementScale;
}
}
@@ -107,14 +109,15 @@ float CollisionTile::placeFeature(const CollisionFeature& feature, bool allowOve
const Point<float> rbl = util::matrixMultiply(reverseRotationMatrix, { box.x1, box.y2 });
const Point<float> rbr = util::matrixMultiply(reverseRotationMatrix, { box.x2, box.y2 });
CollisionBox rotatedBox(box.anchor,
+ box.offset,
util::min(rtl.x, rtr.x, rbl.x, rbr.x),
util::min(rtl.y, rtr.y, rbl.y, rbr.y),
util::max(rtl.x, rtr.x, rbl.x, rbr.x),
util::max(rtl.y, rtr.y, rbl.y, rbr.y),
- box.maxScale);
+ boxMaxScale);
for (auto& blocking : edges) {
- minPlacementScale = util::max(minPlacementScale, findPlacementScale(box.anchor, rotatedBox, blocking.anchor, blocking));
+ minPlacementScale = util::max(minPlacementScale, findPlacementScale(box.anchor, rotatedBox, boxMaxScale, blocking.anchor, blocking));
if (minPlacementScale >= maxScale) return minPlacementScale;
}
}
@@ -131,7 +134,9 @@ void CollisionTile::insertFeature(CollisionFeature& feature, float minPlacementS
if (minPlacementScale < maxScale) {
std::vector<CollisionTreeBox> treeBoxes;
for (auto& box : feature.boxes) {
- treeBoxes.emplace_back(getTreeBox(util::matrixMultiply(rotationMatrix, box.anchor), box), box, feature.indexedFeature);
+ CollisionBox adjustedBox = box;
+ box.maxScale = box.adjustedMaxScale(rotationMatrix, yStretch);
+ treeBoxes.emplace_back(getTreeBox(util::matrixMultiply(rotationMatrix, box.anchor), box), std::move(adjustedBox), feature.indexedFeature);
}
if (ignorePlacement) {
ignoredTree.insert(treeBoxes.begin(), treeBoxes.end());
@@ -215,7 +220,7 @@ std::vector<IndexedSubfeature> CollisionTile::queryRenderedSymbols(const Geometr
// Check if feature is rendered (collision free) at current scale.
auto visibleAtScale = [&] (const CollisionTreeBox& treeBox) -> bool {
const CollisionBox& box = std::get<1>(treeBox);
- return roundedScale >= box.placementScale && roundedScale <= box.maxScale;
+ return roundedScale >= box.placementScale && roundedScale <= box.adjustedMaxScale(rotationMatrix, yStretch);
};
// Check if query polygon intersects with the feature box at current scale.
diff --git a/src/mbgl/text/collision_tile.hpp b/src/mbgl/text/collision_tile.hpp
index dbff6a007b..9868266aa2 100644
--- a/src/mbgl/text/collision_tile.hpp
+++ b/src/mbgl/text/collision_tile.hpp
@@ -58,7 +58,7 @@ public:
private:
float findPlacementScale(
- const Point<float>& anchor, const CollisionBox& box,
+ const Point<float>& anchor, const CollisionBox& box, const float boxMaxScale,
const Point<float>& blockingAnchor, const CollisionBox& blocking);
Box getTreeBox(const Point<float>& anchor, const CollisionBox& box, const float scale = 1.0);