MapLibreParticleLab/src/mbgl/renderer/sources/render_image_source.cpp

#include <mbgl/map/transform_state.hpp>
#include <mbgl/math/log2.hpp>
#include <mbgl/renderer/buckets/raster_bucket.hpp>
#include <mbgl/renderer/paint_parameters.hpp>
#include <mbgl/renderer/render_tile.hpp>
#include <mbgl/renderer/sources/render_image_source.hpp>
#include <mbgl/renderer/tile_parameters.hpp>
#include <mbgl/renderer/render_static_data.hpp>
#include <mbgl/gfx/cull_face_mode.hpp>
#include <mbgl/util/constants.hpp>
#include <mbgl/util/instrumentation.hpp>
#include <mbgl/util/logging.hpp>
#include <mbgl/util/tile_coordinate.hpp>
#include <mbgl/util/tile_cover.hpp>

namespace mbgl {

using namespace style;

ImageSourceRenderData::~ImageSourceRenderData() = default;

void ImageSourceRenderData::upload(gfx::UploadPass& uploadPass) const {
    if (bucket && bucket->needsUpload()) {
        bucket->upload(uploadPass);
    }
}

RenderImageSource::RenderImageSource(Immutable<style::ImageSource::Impl> impl_)
    : RenderSource(std::move(impl_)) {}

RenderImageSource::~RenderImageSource() = default;

const style::ImageSource::Impl& RenderImageSource::impl() const {
    return static_cast<const style::ImageSource::Impl&>(*baseImpl);
}

bool RenderImageSource::isLoaded() const {
    return !!bucket;
}

std::unique_ptr<RenderItem> RenderImageSource::createRenderItem() {
    assert(renderData);
    return std::move(renderData);
}

void RenderImageSource::prepare(const SourcePrepareParameters& parameters) {
    MLN_TRACE_FUNC();
    assert(!renderData);
    if (!isLoaded()) {
        renderData = std::make_unique<ImageSourceRenderData>(bucket, std::vector<mat4>{}, baseImpl->id);
        return;
    }

    std::vector<mat4> matrices{tileIds.size(), mat4()};
    const auto& transformParams = parameters.transform;
    for (size_t i = 0u; i < tileIds.size(); ++i) {
        mat4& matrix = matrices[i];
        matrix::identity(matrix);
        transformParams.state.matrixFor(matrix, tileIds[i]);
    }
    renderData = std::make_unique<ImageSourceRenderData>(bucket, std::move(matrices), baseImpl->id);
}

std::unordered_map<std::string, std::vector<Feature>> RenderImageSource::queryRenderedFeatures(
    const ScreenLineString&,
    const TransformState&,
    const std::unordered_map<std::string, const RenderLayer*>&,
    const RenderedQueryOptions&,
    const mat4&) const {
    return std::unordered_map<std::string, std::vector<Feature>>{};
}

std::vector<Feature> RenderImageSource::querySourceFeatures(const SourceQueryOptions&) const {
    return {};
}

void RenderImageSource::update(Immutable<style::Source::Impl> baseImpl_,
                               const std::vector<Immutable<LayerProperties>>&,
                               const bool needsRendering,
                               const bool,
                               const TileParameters& parameters) {
    enabled = needsRendering;
    if (!needsRendering) {
        return;
    }

    auto transformState = parameters.transformState;
    std::swap(baseImpl, baseImpl_);

    auto coords = impl().getCoordinates();
    std::shared_ptr<PremultipliedImage> image = impl().getImage();

    if (!image || !image->valid()) {
        enabled = false;
        return;
    }

    // Compute the z0 tile coordinates for the given LatLngs
    TileCoordinatePoint nePoint = {-INFINITY, -INFINITY};
    TileCoordinatePoint swPoint = {INFINITY, INFINITY};
    std::vector<TileCoordinatePoint> tileCoordinates;
    for (LatLng latLng : coords) {
        auto point = TileCoordinate::fromLatLng(0, latLng).p;
        tileCoordinates.push_back(point);
        swPoint.x = std::min(swPoint.x, point.x);
        nePoint.x = std::max(nePoint.x, point.x);
        swPoint.y = std::min(swPoint.y, point.y);
        nePoint.y = std::max(nePoint.y, point.y);
    }

    // Calculate the optimum zoom level to determine the tile ids to use for transforms
    const auto dx = nePoint.x - swPoint.x;
    const auto dy = nePoint.y - swPoint.y;
    const auto dMax = std::max(dx, dy);
    const auto zoom = static_cast<uint8_t>(std::max(0.0, std::floor(-util::log2(dMax))));

    // Only enable if the long side of the image is > 2 pixels. Resulting in a
    // display of at least 2 x 1 px image
    // A tile coordinate unit represents the length of one tile (tileSize) at a given zoom.
    // To convert a tile coordinate to pixels, multiply by tileSize.
    // Here dMax is in z0 tile units, so we also scale by 2^z to match current zoom.
    enabled = dMax * std::pow(2.0, transformState.getZoom()) * util::tileSize_D > 2.0;
    if (!enabled) {
        return;
    }

    auto imageBounds = LatLngBounds::hull(coords[0], coords[1]);
    imageBounds.extend(coords[2]);
    imageBounds.extend(coords[3]);
    auto tileCover = util::tileCover(imageBounds, zoom);
    tileIds.clear();
    tileIds.push_back(tileCover[0]);

    bool hasVisibleTile = false;
    // Add additional wrapped tile ids if neccessary
    auto idealTiles = util::tileCover({.transformState = transformState,
                                       .tileLodMinRadius = parameters.tileLodMinRadius,
                                       .tileLodScale = parameters.tileLodScale,
                                       .tileLodPitchThreshold = parameters.tileLodPitchThreshold},
                                      static_cast<uint8_t>(transformState.getZoom()));
    for (auto tile : idealTiles) {
        if (tile.wrap != 0 && tileCover[0].canonical.isChildOf(tile.canonical)) {
            tileIds.emplace_back(tile.wrap, tileCover[0].canonical);
            hasVisibleTile = true;
        } else if (!hasVisibleTile) {
            for (auto coveringTile : tileCover) {
                if (coveringTile.canonical == tile.canonical || coveringTile.canonical.isChildOf(tile.canonical) ||
                    tile.canonical.isChildOf(coveringTile.canonical)) {
                    hasVisibleTile = true;
                }
            }
        }
    }

    enabled = hasVisibleTile;
    if (!enabled) {
        return;
    }

    // Calculate Geometry Coordinates based on tile cover at ideal zoom
    GeometryCoordinates geomCoords;
    for (auto tileCoords : tileCoordinates) {
        auto gc = TileCoordinate::toGeometryCoordinate(tileIds[0], tileCoords);
        geomCoords.push_back(gc);
    }
    if (!bucket) {
        bucket = std::make_shared<RasterBucket>(image);
    } else {
        bucket->clear();
        if (image != bucket->image) {
            bucket->setImage(image);
        }
    }

    // Set Bucket Vertices, Indices, and segments
    bucket->vertices.emplace_back(RasterBucket::layoutVertex({geomCoords[0].x, geomCoords[0].y}, {0, 0}));
    bucket->vertices.emplace_back(RasterBucket::layoutVertex({geomCoords[1].x, geomCoords[1].y}, {util::EXTENT, 0}));
    bucket->vertices.emplace_back(RasterBucket::layoutVertex({geomCoords[3].x, geomCoords[3].y}, {0, util::EXTENT}));
    bucket->vertices.emplace_back(
        RasterBucket::layoutVertex({geomCoords[2].x, geomCoords[2].y}, {util::EXTENT, util::EXTENT}));

    bucket->indices.emplace_back(0, 1, 2);
    bucket->indices.emplace_back(1, 2, 3);

    bucket->segments.emplace_back(0, 0, 4, 6);
}

void RenderImageSource::dumpDebugLogs() const {
    Log::Info(Event::General, "RenderImageSource::id: " + impl().id);
    Log::Info(Event::General, "RenderImageSource::loaded: " + std::string(isLoaded() ? "yes" : "no"));
}

} // namespace mbgl