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[core] Reuse flyTo constant screen velocity calculation for easeTo implementation.

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When using flyTo for easeTo:
Limit zoom out to min(startZoom, targetZoom).
Reduce cinematic zoom in animation at the end of transition,
Linear zoom interpolation.

The patch also sets linear interpolation for flyTo edgeInsets animation, as it looks more appropriate to follow the approach taken for pitch and bearing.

Fixes: #15144
This commit is contained in:
Aleksandar Stojiljkovic
2019-08-02 12:13:46 +03:00
parent 9ed6a84df6
commit 8cf5103452
2 changed files with 26 additions and 18 deletions
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34
src/mbgl/map/transform.cpp
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@@ -82,6 +82,11 @@ void Transform::jumpTo(const CameraOptions& camera) {
* values for any options not included in `options`.
*/
void Transform::easeTo(const CameraOptions& camera, const AnimationOptions& animation) {
Duration duration = animation.duration ? *animation.duration : Duration::zero();
if (state.bounds == LatLngBounds::unbounded() && !isGestureInProgress() && duration != Duration::zero()) {
// reuse flyTo, without exaggerated animation, to achieve constant ground speed.
return flyTo(camera, animation, true);
}
const EdgeInsets& padding = camera.padding.value_or(state.edgeInsets);
LatLng startLatLng = getLatLng(LatLng::Unwrapped);
const LatLng& unwrappedLatLng = camera.center.value_or(startLatLng);
@@ -118,8 +123,6 @@ void Transform::easeTo(const CameraOptions& camera, const AnimationOptions& anim
bearing = _normalizeAngle(bearing, state.bearing);
state.bearing = _normalizeAngle(state.bearing, bearing);
Duration duration = animation.duration ? *animation.duration : Duration::zero();
const double startZoom = state.getZoom();
const double startBearing = state.bearing;
const double startPitch = state.pitch;
@@ -161,7 +164,7 @@ void Transform::easeTo(const CameraOptions& camera, const AnimationOptions& anim
Where applicable, local variable documentation begins with the associated
variable or function in van Wijk (2003). */
void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &animation) {
void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &animation, bool linearZoomInterpolation) {
const EdgeInsets& padding = camera.padding.value_or(state.edgeInsets);
const LatLng& latLng = camera.center.value_or(getLatLng(LatLng::Unwrapped)).wrapped();
double zoom = camera.zoom.value_or(getZoom());
@@ -208,16 +211,16 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
1.42 is the average value selected by participants in the user study in
van Wijk (2003). A value of 6<sup>¼</sup> would be equivalent to the
root mean squared average velocity, V<sub>RMS</sub>. A value of 1 would
produce a circular motion. */
root mean squared average velocity, V<sub>RMS</sub>. A value of 1
produces a circular motion. */
double rho = 1.42;
if (animation.minZoom) {
double minZoom = util::min(*animation.minZoom, startZoom, zoom);
if (animation.minZoom || linearZoomInterpolation) {
double minZoom = util::min(animation.minZoom.value_or(startZoom), startZoom, zoom);
minZoom = util::clamp(minZoom, state.getMinZoom(), state.getMaxZoom());
/// w<sub>m</sub>: Maximum visible span, measured in pixels with respect
/// to the initial scale.
double wMax = w0 / state.zoomScale(minZoom - startZoom);
rho = std::sqrt(wMax / u1 * 2);
rho = u1 != 0 ? std::sqrt(wMax / u1 * 2) : 1.0;
}
/// ρ²
double rho2 = rho * rho;
@@ -232,8 +235,8 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
};
/// r₀: Zoom-out factor during ascent.
double r0 = r(0);
double r1 = r(1);
double r0 = u1 != 0 ? r(0) : INFINITY; // Silence division by 0 on sanitize bot.
double r1 = u1 != 0 ? r(1) : INFINITY;
// When u₀ = u₁, the optimal path doesn’t require both ascent and descent.
bool isClose = std::abs(u1) < 0.000001 || !std::isfinite(r0) || !std::isfinite(r1);
@@ -288,7 +291,8 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
// Calculate the current point and zoom level along the flight path.
Point<double> framePoint = util::interpolate(startPoint, endPoint, us);
double frameZoom = startZoom + state.scaleZoom(1 / w(s));
double frameZoom = linearZoomInterpolation ? util::interpolate(startZoom, zoom, k)
: startZoom + state.scaleZoom(1 / w(s));
// Zoom can be NaN if size is empty.
if (std::isnan(frameZoom)) {
@@ -305,10 +309,10 @@ void Transform::flyTo(const CameraOptions &camera, const AnimationOptions &anima
if (padding != startEdgeInsets) {
// Interpolate edge insets
state.edgeInsets = {
util::interpolate(startEdgeInsets.top(), padding.top(), us),
util::interpolate(startEdgeInsets.left(), padding.left(), us),
util::interpolate(startEdgeInsets.bottom(), padding.bottom(), us),
util::interpolate(startEdgeInsets.right(), padding.right(), us)
util::interpolate(startEdgeInsets.top(), padding.top(), k),
util::interpolate(startEdgeInsets.left(), padding.left(), k),
util::interpolate(startEdgeInsets.bottom(), padding.bottom(), k),
util::interpolate(startEdgeInsets.right(), padding.right(), k)
};
}
auto maxPitch = getMaxPitchForEdgeInsets(state.edgeInsets);