b5b4549b6d
This fixes a bug where, for a zoom value greater than that of the highest zoom stop, composite function interpolation would return nan. (Blocking a render test over in #8593) * Add failing tests for composite function edge case The failing cases here are: - Should interpolate before the first stop - Should interpolate past the last stop * Fix edge case in composite function interpolation * Hold functions constant outside stop-defined domain
125 lines
4.3 KiB
C++
125 lines
4.3 KiB
C++
#pragma once
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#include <mbgl/style/function/composite_exponential_stops.hpp>
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#include <mbgl/style/function/composite_interval_stops.hpp>
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#include <mbgl/style/function/composite_categorical_stops.hpp>
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#include <mbgl/util/interpolate.hpp>
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#include <mbgl/util/range.hpp>
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#include <mbgl/util/variant.hpp>
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#include <string>
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#include <tuple>
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namespace mbgl {
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class GeometryTileFeature;
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namespace style {
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// A CompositeFunction consists of an outer zoom function whose stop range values are
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// "inner" source functions. It provides the GL Native implementation of
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// "zoom-and-property" functions from the style spec.
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template <class T>
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class CompositeFunction {
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public:
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using InnerStops = std::conditional_t<
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util::Interpolatable<T>,
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variant<
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ExponentialStops<T>,
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IntervalStops<T>,
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CategoricalStops<T>>,
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variant<
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IntervalStops<T>,
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CategoricalStops<T>>>;
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using Stops = std::conditional_t<
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util::Interpolatable<T>,
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variant<
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CompositeExponentialStops<T>,
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CompositeIntervalStops<T>,
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CompositeCategoricalStops<T>>,
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variant<
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CompositeIntervalStops<T>,
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CompositeCategoricalStops<T>>>;
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CompositeFunction(std::string property_, Stops stops_, optional<T> defaultValue_ = {})
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: property(std::move(property_)),
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stops(std::move(stops_)),
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defaultValue(std::move(defaultValue_)) {
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}
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std::tuple<Range<float>, Range<InnerStops>>
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coveringRanges(float zoom) const {
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return stops.match(
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[&] (const auto& s) {
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assert(!s.stops.empty());
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auto minIt = s.stops.lower_bound(zoom);
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auto maxIt = s.stops.upper_bound(zoom);
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// lower_bound yields first element >= zoom, but we want the *last*
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// element <= zoom, so if we found a stop > zoom, back up by one.
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if (minIt != s.stops.begin() && minIt->first > zoom) {
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minIt--;
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}
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return std::make_tuple(
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Range<float> {
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minIt == s.stops.end() ? s.stops.rbegin()->first : minIt->first,
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maxIt == s.stops.end() ? s.stops.rbegin()->first : maxIt->first
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},
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Range<InnerStops> {
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s.innerStops(minIt == s.stops.end() ? s.stops.rbegin()->second : minIt->second),
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s.innerStops(maxIt == s.stops.end() ? s.stops.rbegin()->second : maxIt->second)
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}
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);
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}
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);
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}
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template <class Feature>
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Range<T> evaluate(Range<InnerStops> coveringStops,
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const Feature& feature,
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T finalDefaultValue) const {
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optional<Value> v = feature.getValue(property);
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if (!v) {
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return {
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defaultValue.value_or(finalDefaultValue),
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defaultValue.value_or(finalDefaultValue)
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};
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}
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auto eval = [&] (const auto& s) {
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return s.evaluate(*v).value_or(defaultValue.value_or(finalDefaultValue));
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};
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return Range<T> {
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coveringStops.min.match(eval),
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coveringStops.max.match(eval)
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};
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}
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T evaluate(float zoom, const GeometryTileFeature& feature, T finalDefaultValue) const {
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std::tuple<Range<float>, Range<InnerStops>> ranges = coveringRanges(zoom);
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Range<T> resultRange = evaluate(std::get<1>(ranges), feature, finalDefaultValue);
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// If the covering stop range is constant, just return the output value directly.
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if (resultRange.min == resultRange.max) return resultRange.min;
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// Otherwise, interpolate between the two stops.
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return util::interpolate(
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resultRange.min,
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resultRange.max,
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util::interpolationFactor(1.0f, std::get<0>(ranges), zoom));
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}
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friend bool operator==(const CompositeFunction& lhs,
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const CompositeFunction& rhs) {
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return std::tie(lhs.property, lhs.stops, lhs.defaultValue)
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== std::tie(rhs.property, rhs.stops, rhs.defaultValue);
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}
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std::string property;
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Stops stops;
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optional<T> defaultValue;
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};
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} // namespace style
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} // namespace mbgl
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