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Don't recalculate bounding box so often

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Wuzzy 2023-10-27 13:05:57 +02:00
parent 2b54ab0985
commit 1f3c1bfdf5
1 changed files with 34 additions and 33 deletions
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67
mibpov.js
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@ -644,40 +644,41 @@ let cachedVoronoiDiagram = null;
/* Given the list of biome points, returns a Voronoi diagram object
(which may have been cached). If recalculate is true, a recalculation is forced. */
function getVoronoiDiagram(points, recalculate) {
// Calculate bounding box, defaults to heat/humidity limits ...
let vbbox = {xl: limit_heat_min, xr: limit_heat_max, yb: limit_humidity_max, yt: limit_humidity_min};
// ... unless a point is out of bounds,
// then we increase the bounding box size
// Calculate by how much to extend the
// bounding box for the given value.
let getBufferZone = function(value) {
// This essentially calculates the "order of magnitude"
// in base-2.
return 2**Math.floor(Math.log2(Math.abs(value)));
// The reason why we do this is due to floating-point arithmetic.
// If we’d add/subtract a constant offset (like 1) from the value,
// the offset might disappear if the value is very large,
// due to floating point rounding, thus effectively adding/subtracting 0.
// This scaling makes sure we'll apply an offset that is
// "in the ballpark" of the origin value
}
for (let p of points) {
if (p.heat < vbbox.xl) {
vbbox.xl = p.heat - getBufferZone(p.heat);
} else if (p.heat > vbbox.xr) {
vbbox.xr = p.heat + getBufferZone(p.heat);
}
if (p.humidity < vbbox.yt) {
vbbox.yt = p.humidity - getBufferZone(p.humidity);
} else if (p.humidity > vbbox.yb) {
vbbox.yb = p.humidity + getBufferZone(p.humidity);
}
}
if ((cachedVoronoiDiagram === null) || recalculate) {
// Calculate bounding box, defaults to heat/humidity limits ...
let vbbox = {xl: limit_heat_min, xr: limit_heat_max, yb: limit_humidity_max, yt: limit_humidity_min};
// ... unless a point is out of bounds,
// then we increase the bounding box size
// Calculate by how much to extend the
// bounding box for the given value.
let getBufferZone = function(value) {
// This essentially calculates the "order of magnitude"
// in base-2.
return 2**Math.floor(Math.log2(Math.abs(value)));
// The reason why we do this is due to floating-point arithmetic.
// If we’d add/subtract a constant offset (like 1) from the value,
// the offset might disappear if the value is very large,
// due to floating point rounding, thus effectively adding/subtracting 0.
// This scaling makes sure we'll apply an offset that is
// "in the ballpark" of the origin value
}
for (let p of points) {
if (p.heat < vbbox.xl) {
vbbox.xl = p.heat - getBufferZone(p.heat);
} else if (p.heat > vbbox.xr) {
vbbox.xr = p.heat + getBufferZone(p.heat);
}
if (p.humidity < vbbox.yt) {
vbbox.yt = p.humidity - getBufferZone(p.humidity);
} else if (p.humidity > vbbox.yb) {
vbbox.yb = p.humidity + getBufferZone(p.humidity);
}
}
let sites = []
for (let p of points) {
sites.push(biomePointToVoronoiPoint(p));