From d0c103fa8f0bade2be56d50a745f16b4e9ed6b29 Mon Sep 17 00:00:00 2001 From: Mikko Pulkki Date: Mon, 23 Mar 2020 18:21:13 +0200 Subject: Refactor tileCover to support lod tiles --- src/mbgl/algorithm/update_renderables.hpp | 18 +- src/mbgl/map/transform_state.cpp | 10 +- src/mbgl/map/transform_state.hpp | 2 + .../renderer/layers/render_background_layer.cpp | 7 +- src/mbgl/renderer/tile_pyramid.cpp | 17 +- src/mbgl/util/bounding_volumes.cpp | 283 +++++++++++++++++++++ src/mbgl/util/bounding_volumes.hpp | 68 +++++ src/mbgl/util/mat3.hpp | 1 + src/mbgl/util/tile_cover.cpp | 145 +++++++++-- src/mbgl/util/tile_cover.hpp | 4 +- 10 files changed, 511 insertions(+), 44 deletions(-) create mode 100644 src/mbgl/util/bounding_volumes.cpp create mode 100644 src/mbgl/util/bounding_volumes.hpp (limited to 'src') diff --git a/src/mbgl/algorithm/update_renderables.hpp b/src/mbgl/algorithm/update_renderables.hpp index 316ada8269..91eb058638 100644 --- a/src/mbgl/algorithm/update_renderables.hpp +++ b/src/mbgl/algorithm/update_renderables.hpp @@ -21,19 +21,18 @@ void updateRenderables(GetTileFn getTile, RenderTileFn renderTile, const IdealTileIDs& idealTileIDs, const Range& zoomRange, - const uint8_t dataTileZoom, const optional& maxParentOverscaleFactor = nullopt) { std::unordered_set checked; bool covered; int32_t overscaledZ; // 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); + for (const auto& idealDataTileID : idealTileIDs) { + assert(idealDataTileID.canonical.z >= zoomRange.min); + assert(idealDataTileID.canonical.z <= zoomRange.max); + assert(idealDataTileID.overscaledZ >= idealDataTileID.canonical.z); - const OverscaledTileID idealDataTileID(dataTileZoom, idealRenderTileID.wrap, idealRenderTileID.canonical); + const UnwrappedTileID idealRenderTileID = idealDataTileID.toUnwrapped(); auto tile = getTile(idealDataTileID); if (!tile) { tile = createTile(idealDataTileID); @@ -56,7 +55,7 @@ void updateRenderables(GetTileFn getTile, // The tile isn't loaded yet, but retain it anyway because it's an ideal tile. retainTile(*tile, TileNecessity::Required); covered = true; - overscaledZ = dataTileZoom + 1; + overscaledZ = idealDataTileID.overscaledZ + 1; if (overscaledZ > zoomRange.max) { // We're looking for an overzoomed child tile. const auto childDataTileID = idealDataTileID.scaledTo(overscaledZ); @@ -85,11 +84,12 @@ void updateRenderables(GetTileFn getTile, if (!covered) { // We couldn't find child tiles that entirely cover the ideal tile. - for (overscaledZ = dataTileZoom - 1; overscaledZ >= zoomRange.min; --overscaledZ) { + for (overscaledZ = idealDataTileID.overscaledZ - 1; overscaledZ >= zoomRange.min; --overscaledZ) { const auto parentDataTileID = idealDataTileID.scaledTo(overscaledZ); // Request / render parent tile only if it's overscale factor is less than defined maximum. - if (maxParentOverscaleFactor && (dataTileZoom - overscaledZ) > *maxParentOverscaleFactor) { + if (maxParentOverscaleFactor && + (idealDataTileID.overscaledZ - overscaledZ) > *maxParentOverscaleFactor) { break; } diff --git a/src/mbgl/map/transform_state.cpp b/src/mbgl/map/transform_state.cpp index b5513f3d83..1894c59e2b 100644 --- a/src/mbgl/map/transform_state.cpp +++ b/src/mbgl/map/transform_state.cpp @@ -171,9 +171,12 @@ void TransformState::updateMatricesIfNeeded() const { getProjMatrix(projectionMatrix); coordMatrix = coordinatePointMatrix(projectionMatrix); - bool err = matrix::invert(invertedMatrix, coordMatrix); + bool err = matrix::invert(invProjectionMatrix, projectionMatrix); + if (err) throw std::runtime_error("failed to invert projectionMatrix"); + err = matrix::invert(invertedMatrix, coordMatrix); if (err) throw std::runtime_error("failed to invert coordinatePointMatrix"); + requestMatricesUpdate = false; } @@ -182,6 +185,11 @@ const mat4& TransformState::getProjectionMatrix() const { return projectionMatrix; } +const mat4& TransformState::getInvProjectionMatrix() const { + updateMatricesIfNeeded(); + return invProjectionMatrix; +} + const mat4& TransformState::getCoordMatrix() const { updateMatricesIfNeeded(); return coordMatrix; diff --git a/src/mbgl/map/transform_state.hpp b/src/mbgl/map/transform_state.hpp index b7fa97eea6..69f0eebd40 100644 --- a/src/mbgl/map/transform_state.hpp +++ b/src/mbgl/map/transform_state.hpp @@ -216,6 +216,7 @@ public: void constrain(double& scale, double& x, double& y) const; const mat4& getProjectionMatrix() const; + const mat4& getInvProjectionMatrix() const; private: bool rotatedNorth() const; @@ -282,6 +283,7 @@ private: mutable bool requestMatricesUpdate{true}; mutable mat4 projectionMatrix; + mutable mat4 invProjectionMatrix; mutable mat4 coordMatrix; mutable mat4 invertedMatrix; }; diff --git a/src/mbgl/renderer/layers/render_background_layer.cpp b/src/mbgl/renderer/layers/render_background_layer.cpp index 3e12b74db9..c791a394a1 100644 --- a/src/mbgl/renderer/layers/render_background_layer.cpp +++ b/src/mbgl/renderer/layers/render_background_layer.cpp @@ -116,14 +116,15 @@ void RenderBackgroundLayer::render(PaintParameters& parameters) { uint32_t i = 0; for (const auto& tileID : util::tileCover(parameters.state, parameters.state.getIntegerZoom())) { + const UnwrappedTileID unwrappedTileID = tileID.toUnwrapped(); draw(parameters.programs.getBackgroundLayerPrograms().backgroundPattern, - BackgroundPatternProgram::layoutUniformValues(parameters.matrixForTile(tileID), + BackgroundPatternProgram::layoutUniformValues(parameters.matrixForTile(unwrappedTileID), evaluated.get(), parameters.patternAtlas.getPixelSize(), *imagePosA, *imagePosB, crossfade, - tileID, + unwrappedTileID, parameters.state), BackgroundPatternProgram::TextureBindings{ textures::image::Value{parameters.patternAtlas.textureBinding()}, @@ -141,7 +142,7 @@ void RenderBackgroundLayer::render(PaintParameters& parameters) { for (const auto& tileID : util::tileCover(parameters.state, parameters.state.getIntegerZoom())) { draw(parameters.programs.getBackgroundLayerPrograms().background, BackgroundProgram::LayoutUniformValues{ - uniforms::matrix::Value(parameters.matrixForTile(tileID)), + uniforms::matrix::Value(parameters.matrixForTile(tileID.toUnwrapped())), uniforms::color::Value(evaluated.get()), uniforms::opacity::Value(evaluated.get()), }, diff --git a/src/mbgl/renderer/tile_pyramid.cpp b/src/mbgl/renderer/tile_pyramid.cpp index c456bf6e24..57086cb915 100644 --- a/src/mbgl/renderer/tile_pyramid.cpp +++ b/src/mbgl/renderer/tile_pyramid.cpp @@ -91,8 +91,8 @@ void TilePyramid::update(const std::vector>& l int32_t tileZoom = overscaledZoom; int32_t panZoom = zoomRange.max; - std::vector idealTiles; - std::vector panTiles; + std::vector idealTiles; + std::vector panTiles; if (overscaledZoom >= zoomRange.min) { int32_t idealZoom = std::min(zoomRange.max, overscaledZoom); @@ -118,7 +118,7 @@ void TilePyramid::update(const std::vector>& l } } - idealTiles = util::tileCover(parameters.transformState, idealZoom); + idealTiles = util::tileCover(parameters.transformState, idealZoom, tileZoom); } // Stores a list of all the tiles that we're definitely going to retain. There are two @@ -185,18 +185,11 @@ void TilePyramid::update(const std::vector>& l [](const UnwrappedTileID&, Tile&) {}, panTiles, zoomRange, - panZoom, maxParentTileOverscaleFactor); } - algorithm::updateRenderables(getTileFn, - createTileFn, - retainTileFn, - renderTileFn, - idealTiles, - zoomRange, - tileZoom, - maxParentTileOverscaleFactor); + algorithm::updateRenderables( + getTileFn, createTileFn, retainTileFn, renderTileFn, idealTiles, zoomRange, maxParentTileOverscaleFactor); for (auto previouslyRenderedTile : previouslyRenderedTiles) { Tile& tile = previouslyRenderedTile.second; diff --git a/src/mbgl/util/bounding_volumes.cpp b/src/mbgl/util/bounding_volumes.cpp new file mode 100644 index 0000000000..8d34f9bd62 --- /dev/null +++ b/src/mbgl/util/bounding_volumes.cpp @@ -0,0 +1,283 @@ +#include + +#include +#include +#include + +namespace mbgl { +namespace { + +vec3 toVec3(const vec4& v) { + return vec3{v[0], v[1], v[2]}; +} + +vec3 vec3Sub(const vec3& a, const vec3& b) { + return vec3{a[0] - b[0], a[1] - b[1], a[2] - b[2]}; +} + +vec3 vec3Scale(const vec3& a, double s) { + return vec3{a[0] * s, a[1] * s, a[2] * s}; +} + +vec3 vec3Cross(const vec3& a, const vec3& b) { + return vec3{a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0]}; +} + +double vec3Dot(const vec3& a, const vec3& b) { + return a[0] * b[0] + a[1] * b[1] + a[2] * b[2]; +} + +double vec3LengthSq(const vec3& a) { + return vec3Dot(a, a); +} + +double vec3Length(const vec3& a) { + return std::sqrt(vec3LengthSq(a)); +} + +vec3 vec3Normalize(const vec3& a) { + return vec3Scale(a, 1.0 / vec3Length(a)); +} + +double vec4Dot(const vec4& a, const vec4& b) { + return a[0] * b[0] + a[1] * b[1] + a[2] * b[2] + a[3] * b[3]; +} + +template +static Point ProjectPointsToAxis(const std::array& points, const vec3& origin, const vec3& axis) { + double min = std::numeric_limits::max(); + double max = -std::numeric_limits::max(); + + for (const vec3& point : points) { + double projectedPoint = vec3Dot(vec3Sub(point, origin), axis); + min = std::min(projectedPoint, min); + max = std::max(projectedPoint, max); + } + + return {min, max}; +} + +} // namespace + +namespace util { + +AABB::AABB() : min({0, 0, 0}), max({0, 0, 0}) {} + +AABB::AABB(const vec3& min_, const vec3& max_) : min(min_), max(max_) {} + +vec3 AABB::closestPoint(const vec3& point) const { + return {std::max(std::min(max[0], point[0]), min[0]), + std::max(std::min(max[1], point[1]), min[1]), + std::max(std::min(max[2], point[2]), min[2])}; +} + +vec3 AABB::distanceXYZ(const vec3& point) const { + vec3 vec = vec3Sub(closestPoint(point), point); + + vec[0] = std::abs(vec[0]); + vec[1] = std::abs(vec[1]); + vec[2] = std::abs(vec[2]); + + return vec; +} + +AABB AABB::quadrant(int idx) const { + assert(idx >= 0 && idx < 4); + vec3 quadrantMin = min; + vec3 quadrantMax = max; + const double xCenter = 0.5 * (max[0] + min[0]); + const double yCenter = 0.5 * (max[1] + min[1]); + + // This aabb is split into 4 quadrants. For each axis define in which side of the split "idx" is + // The result for indices 0, 1, 2, 3 is: { 0, 0 }, { 1, 0 }, { 0, 1 }, { 1, 1 } + const std::array xSplit = {0, 1, 0, 1}; + const std::array ySplit = {0, 0, 1, 1}; + + quadrantMin[0] = xSplit[idx] ? xCenter : quadrantMin[0]; + quadrantMax[0] = xSplit[idx] ? quadrantMax[0] : xCenter; + + quadrantMin[1] = ySplit[idx] ? yCenter : quadrantMin[1]; + quadrantMax[1] = ySplit[idx] ? quadrantMax[1] : yCenter; + + return {quadrantMin, quadrantMax}; +} + +bool AABB::intersects(const AABB& aabb) const { + if (min[0] > aabb.max[0] || aabb.min[0] > max[0]) return false; + if (min[1] > aabb.max[1] || aabb.min[1] > max[1]) return false; + if (min[2] > aabb.max[2] || aabb.min[2] > max[2]) return false; + return true; +} + +bool AABB::operator==(const AABB& aabb) const { + return min == aabb.min && max == aabb.max; +} + +bool AABB::operator!=(const AABB& aabb) const { + return !(*this == aabb); +} + +// Named index values for frustum::points array +enum { + near_tl = 0, + near_tr = 1, + near_br = 2, + near_bl = 3, + far_tl = 4, + far_tr = 5, + far_br = 6, + far_bl = 7, +}; + +Frustum::Frustum(const std::array& points_, const std::array& planes_) + : points(points_), planes(planes_) { + const Point xBounds = ProjectPointsToAxis(points, {0, 0, 0}, {1, 0, 0}); + const Point yBounds = ProjectPointsToAxis(points, {0, 0, 0}, {0, 1, 0}); + const Point zBounds = ProjectPointsToAxis(points, {0, 0, 0}, {0, 0, 1}); + + bounds = AABB({xBounds.x, yBounds.x, zBounds.x}, {xBounds.y, yBounds.y, zBounds.y}); + + // Precompute a set of separating axis candidates for precise intersection tests. + // Remaining axes not covered in basic intersection tests are: axis[] = (edges of aabb) x (edges of frustum) + std::array frustumEdges = {vec3Sub(points[near_br], points[near_bl]), + vec3Sub(points[near_tl], points[near_bl]), + vec3Sub(points[far_tl], points[near_tl]), + vec3Sub(points[far_tr], points[near_tr]), + vec3Sub(points[far_br], points[near_br]), + vec3Sub(points[far_bl], points[near_bl])}; + + for (size_t i = 0; i < frustumEdges.size(); i++) { + // Cross product [1, 0, 0] x [a, b, c] == [0, -c, b] + // Cross product [0, 1, 0] x [a, b, c] == [c, 0, -a] + const vec3 axis0 = {0.0, -frustumEdges[i][2], frustumEdges[i][1]}; + const vec3 axis1 = {frustumEdges[i][2], 0.0, -frustumEdges[i][0]}; + + projections[i * 2] = {axis0, ProjectPointsToAxis(points, points[0], axis0)}; + projections[i * 2 + 1] = {axis1, ProjectPointsToAxis(points, points[0], axis1)}; + } +} + +Frustum Frustum::fromInvProjMatrix(const mat4& invProj, double worldSize, double zoom, bool flippedY) { + // Define frustum corner points in normalized clip space + std::array cornerCoords = {vec4{-1.0, 1.0, -1.0, 1.0}, + vec4{1.0, 1.0, -1.0, 1.0}, + vec4{1.0, -1.0, -1.0, 1.0}, + vec4{-1.0, -1.0, -1.0, 1.0}, + vec4{-1.0, 1.0, 1.0, 1.0}, + vec4{1.0, 1.0, 1.0, 1.0}, + vec4{1.0, -1.0, 1.0, 1.0}, + vec4{-1.0, -1.0, 1.0, 1.0}}; + + const double scale = std::pow(2.0, zoom); + + // Transform points to tile space + for (auto& coord : cornerCoords) { + matrix::transformMat4(coord, coord, invProj); + for (auto& component : coord) component *= 1.0 / coord[3] / worldSize * scale; + } + + std::array frustumPlanePointIndices = { + vec3i{near_bl, near_br, far_br}, // bottom + vec3i{near_tl, near_bl, far_bl}, // left + vec3i{near_br, near_tr, far_tr}, // right + vec3i{near_tl, far_tl, far_tr}, // top + vec3i{near_tl, near_tr, near_br}, // near + vec3i{far_br, far_tr, far_tl} // far + }; + + if (flippedY) { + std::for_each(frustumPlanePointIndices.begin(), frustumPlanePointIndices.end(), [](vec3i& tri) { + std::swap(tri[1], tri[2]); + }); + } + + std::array frustumPlanes; + + for (std::size_t i = 0; i < frustumPlanePointIndices.size(); i++) { + const vec3i indices = frustumPlanePointIndices[i]; + + // Compute plane equation using 3 points on the plane + const vec3 p0 = toVec3(cornerCoords[indices[0]]); + const vec3 p1 = toVec3(cornerCoords[indices[1]]); + const vec3 p2 = toVec3(cornerCoords[indices[2]]); + + const vec3 a = vec3Sub(p0, p1); + const vec3 b = vec3Sub(p2, p1); + const vec3 n = vec3Normalize(vec3Cross(a, b)); + + frustumPlanes[i] = {n[0], n[1], n[2], -vec3Dot(n, p1)}; + } + + std::array frustumPoints; + + for (size_t i = 0; i < cornerCoords.size(); i++) frustumPoints[i] = toVec3(cornerCoords[i]); + + return {frustumPoints, frustumPlanes}; +} + +IntersectionResult Frustum::intersects(const AABB& aabb) const { + // Execute separating axis test between two convex objects to find intersections + // Each frustum plane together with 3 major axes define the separating axes + // This implementation is conservative as it's not checking all possible axes. + // False positive rate is ~0.5% of all cases (see intersectsPrecise). + // Note: test only 4 points as both min and max points have zero elevation + assert(aabb.min[2] == 0.0 && aabb.max[2] == 0.0); + + if (!bounds.intersects(aabb)) return IntersectionResult::Separate; + + const std::array aabbPoints = { + vec4{aabb.min[0], aabb.min[1], 0.0, 1.0}, + vec4{aabb.max[0], aabb.min[1], 0.0, 1.0}, + vec4{aabb.max[0], aabb.max[1], 0.0, 1.0}, + vec4{aabb.min[0], aabb.max[1], 0.0, 1.0}, + }; + + bool fullyInside = true; + + for (const vec4& plane : planes) { + size_t pointsInside = 0; + + pointsInside += vec4Dot(plane, aabbPoints[0]) >= 0.0; + pointsInside += vec4Dot(plane, aabbPoints[1]) >= 0.0; + pointsInside += vec4Dot(plane, aabbPoints[2]) >= 0.0; + pointsInside += vec4Dot(plane, aabbPoints[3]) >= 0.0; + + if (!pointsInside) { + // Separating axis found, no intersection + return IntersectionResult::Separate; + } + + if (pointsInside != aabbPoints.size()) fullyInside = false; + } + + return fullyInside ? IntersectionResult::Contains : IntersectionResult::Intersects; +} + +IntersectionResult Frustum::intersectsPrecise(const AABB& aabb, bool edgeCasesOnly) const { + if (!edgeCasesOnly) { + IntersectionResult result = intersects(aabb); + + if (result == IntersectionResult::Separate) return result; + } + + const std::array aabbPoints = {vec3{aabb.min[0], aabb.min[1], 0.0}, + vec3{aabb.max[0], aabb.min[1], 0.0}, + vec3{aabb.max[0], aabb.max[1], 0.0}, + vec3{aabb.min[0], aabb.max[1], 0.0}}; + + // For a precise SAT-test all edge cases needs to be covered + // Projections of the frustum on separating axis candidates have been precomputed already + for (const Projection& proj : projections) { + Point projectedAabb = ProjectPointsToAxis(aabbPoints, points[0], proj.axis); + const Point& projectedFrustum = proj.projection; + + if (projectedFrustum.y < projectedAabb.x || projectedFrustum.x > projectedAabb.y) { + return IntersectionResult::Separate; + } + } + + return IntersectionResult::Intersects; +} + +} // namespace util +} // namespace mbgl \ No newline at end of file diff --git a/src/mbgl/util/bounding_volumes.hpp b/src/mbgl/util/bounding_volumes.hpp new file mode 100644 index 0000000000..bca183d842 --- /dev/null +++ b/src/mbgl/util/bounding_volumes.hpp @@ -0,0 +1,68 @@ +#pragma once + +#include +#include +#include + +namespace mbgl { +namespace util { + +enum class IntersectionResult : int { + Separate, + Intersects, + Contains, +}; + +class AABB { +public: + AABB(); + AABB(const vec3& min_, const vec3& max_); + + vec3 closestPoint(const vec3& point) const; + + // Computes the shortest manhattan distance to the provided point + vec3 distanceXYZ(const vec3& point) const; + + // Creates an aabb covering one quadrant of the aabb on XZ-plane. + AABB quadrant(int idx) const; + + bool intersects(const AABB& aabb) const; + + bool operator==(const AABB& aabb) const; + bool operator!=(const AABB& aabb) const; + + vec3 min; + vec3 max; +}; + +class Frustum { +public: + Frustum(const std::array& points_, const std::array& planes_); + + static Frustum fromInvProjMatrix(const mat4& invProj, double worldSize, double zoom, bool flippedY = false); + + // Performs conservative intersection test using separating axis theorem. + // Some accuracy is traded for better performance. False positive rate is < 1% + IntersectionResult intersects(const AABB& aabb) const; + + // Performs precise intersection test using separating axis theorem. + // It is possible run only edge cases that were not covered in intersects() + IntersectionResult intersectsPrecise(const AABB& aabb, bool edgeCasesOnly = false) const; + + const std::array& getPoints() const { return points; } + const std::array& getPlanes() const { return planes; } + +private: + struct Projection { + vec3 axis; + Point projection; + }; + + AABB bounds; + std::array points; + std::array planes; + std::array projections; +}; + +} // namespace util +} // namespace mbgl \ No newline at end of file diff --git a/src/mbgl/util/mat3.hpp b/src/mbgl/util/mat3.hpp index c4203c940b..5069e02056 100644 --- a/src/mbgl/util/mat3.hpp +++ b/src/mbgl/util/mat3.hpp @@ -28,6 +28,7 @@ namespace mbgl { using vec3 = std::array; using vec3f = std::array; +using vec3i = std::array; using mat3 = std::array; namespace matrix { diff --git a/src/mbgl/util/tile_cover.cpp b/src/mbgl/util/tile_cover.cpp index cf774abf00..dffee9e841 100644 --- a/src/mbgl/util/tile_cover.cpp +++ b/src/mbgl/util/tile_cover.cpp @@ -1,10 +1,11 @@ -#include +#include +#include +#include #include #include -#include -#include #include -#include +#include +#include #include #include @@ -146,6 +147,128 @@ int32_t coveringZoomLevel(double zoom, style::SourceType type, uint16_t size) { } } +std::vector tileCover(const TransformState& state, uint8_t z, const optional& overscaledZ) { + struct Node { + AABB aabb; + uint8_t zoom; + uint32_t x, y; + int16_t wrap; + bool fullyVisible; + }; + + struct ResultTile { + OverscaledTileID id; + double sqrDist; + }; + + const double numTiles = std::pow(2.0, z); + const double worldSize = Projection::worldSize(state.getScale()); + const uint8_t minZoom = state.getPitch() <= (60.0 / 180.0) * M_PI ? z : 0; + const uint8_t maxZoom = z; + const uint8_t overscaledZoom = overscaledZ.value_or(z); + const bool flippedY = state.getViewportMode() == ViewportMode::FlippedY; + + auto centerPoint = + TileCoordinate::fromScreenCoordinate(state, z, {state.getSize().width / 2.0, state.getSize().height / 2.0}).p; + + vec3 centerCoord = {centerPoint.x, centerPoint.y, 0.0}; + + const Frustum frustum = Frustum::fromInvProjMatrix(state.getInvProjectionMatrix(), worldSize, z, flippedY); + + // There should always be a certain number of maximum zoom level tiles surrounding the center location + const double radiusOfMaxLvlLodInTiles = 3; + + const auto newRootTile = [&](int16_t wrap) -> Node { + return {AABB({wrap * numTiles, 0.0, 0.0}, {(wrap + 1) * numTiles, numTiles, 0.0}), + uint8_t(0), + uint16_t(0), + uint16_t(0), + wrap, + false}; + }; + + // Perform depth-first traversal on tile tree to find visible tiles + std::vector stack; + std::vector result; + stack.reserve(128); + + // World copies shall be rendered three times on both sides from closest to farthest + for (int i = 1; i <= 3; i++) { + stack.push_back(newRootTile(-i)); + stack.push_back(newRootTile(i)); + } + + stack.push_back(newRootTile(0)); + + while (!stack.empty()) { + Node node = stack.back(); + stack.pop_back(); + + // Use cached visibility information of ancestor nodes + if (!node.fullyVisible) { + const IntersectionResult intersection = frustum.intersects(node.aabb); + + if (intersection == IntersectionResult::Separate) continue; + + node.fullyVisible = intersection == IntersectionResult::Contains; + } + + const vec3 distanceXyz = node.aabb.distanceXYZ(centerCoord); + const double* longestDim = std::max_element(distanceXyz.data(), distanceXyz.data() + distanceXyz.size()); + assert(longestDim); + + // We're using distance based heuristics to determine if a tile should be split into quadrants or not. + // radiusOfMaxLvlLodInTiles defines that there's always a certain number of maxLevel tiles next to the map + // center. Using the fact that a parent node in quadtree is twice the size of its children (per dimension) we + // can define distance thresholds for each relative level: f(k) = offset + 2 + 4 + 8 + 16 + ... + 2^k. This is + // the same as "offset+2^(k+1)-2" + const double distToSplit = radiusOfMaxLvlLodInTiles + (1 << (maxZoom - node.zoom)) - 2; + + // Have we reached the target depth or is the tile too far away to be any split further? + if (node.zoom == maxZoom || (*longestDim > distToSplit && node.zoom >= minZoom)) { + // Perform precise intersection test between the frustum and aabb. This will cull < 1% false positives + // missed by the original test + if (node.fullyVisible || frustum.intersectsPrecise(node.aabb, true) != IntersectionResult::Separate) { + const OverscaledTileID id = { + node.zoom == maxZoom ? overscaledZoom : node.zoom, node.wrap, node.zoom, node.x, node.y}; + const double dx = node.wrap * numTiles + node.x + 0.5 - centerCoord[0]; + const double dy = node.y + 0.5 - centerCoord[1]; + + result.push_back({id, dx * dx + dy * dy}); + } + continue; + } + + for (int i = 0; i < 4; i++) { + const uint32_t childX = (node.x << 1) + (i % 2); + const uint32_t childY = (node.y << 1) + (i >> 1); + + // Create child node and push to the stack for traversal + Node child = node; + + child.aabb = node.aabb.quadrant(i); + child.zoom = node.zoom + 1; + child.x = childX; + child.y = childY; + + stack.push_back(child); + } + } + + // Sort results by distance + std::sort( + result.begin(), result.end(), [](const ResultTile& a, const ResultTile& b) { return a.sqrDist < b.sqrDist; }); + + std::vector ids; + ids.reserve(result.size()); + + for (const auto& tile : result) { + ids.push_back(tile.id); + } + + return ids; +} + std::vector tileCover(const LatLngBounds& bounds_, uint8_t z) { if (bounds_.isEmpty() || bounds_.south() > util::LATITUDE_MAX || @@ -166,20 +289,6 @@ std::vector tileCover(const LatLngBounds& bounds_, uint8_t z) { z); } -std::vector tileCover(const TransformState& state, uint8_t z) { - assert(state.valid()); - - const double w = state.getSize().width; - const double h = state.getSize().height; - return tileCover( - TileCoordinate::fromScreenCoordinate(state, z, { 0, 0 }).p, - TileCoordinate::fromScreenCoordinate(state, z, { w, 0 }).p, - TileCoordinate::fromScreenCoordinate(state, z, { w, h }).p, - TileCoordinate::fromScreenCoordinate(state, z, { 0, h }).p, - TileCoordinate::fromScreenCoordinate(state, z, { w/2, h/2 }).p, - z); -} - std::vector tileCover(const Geometry& geometry, uint8_t z) { std::vector result; TileCover tc(geometry, z, true); diff --git a/src/mbgl/util/tile_cover.hpp b/src/mbgl/util/tile_cover.hpp index 5ac3537bf6..5e09d8a671 100644 --- a/src/mbgl/util/tile_cover.hpp +++ b/src/mbgl/util/tile_cover.hpp @@ -33,7 +33,9 @@ private: int32_t coveringZoomLevel(double z, style::SourceType type, uint16_t tileSize); -std::vector tileCover(const TransformState&, uint8_t z); +std::vector tileCover(const TransformState&, + uint8_t z, + const optional& overscaledZ = nullopt); std::vector tileCover(const LatLngBounds&, uint8_t z); std::vector tileCover(const Geometry&, uint8_t z); -- cgit v1.2.1