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Add maximum triangle size configuration #19

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Add maximum triangle size configuration #19

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905605f
Add maximum triangle size configuration
davenquinn May 19, 2021
7fc6149
Fix typo
davenquinn May 19, 2021
b90ba22
Add semicolons
davenquinn May 19, 2021
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12 changes: 9 additions & 3 deletions index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -92,13 +92,17 @@ class Tile {
}
}

getMesh(maxError = 0) {
getMesh(maxError = 0, maxLength = null) {
const {gridSize: size, indices} = this.martini;
const {errors} = this;
let numVertices = 0;
let numTriangles = 0;
const max = size - 1;

// The maxLength parameter will cause triangles to be generated until the legs are below this length
// It is meant to support cases where a certain mesh density is required to do spherical math on digital globes
const maxScale = maxLength || size;

// use an index grid to keep track of vertices that were already used to avoid duplication
indices.fill(0);

Expand All @@ -110,7 +114,8 @@ class Tile {
const mx = (ax + bx) >> 1;
const my = (ay + by) >> 1;

if (Math.abs(ax - cx) + Math.abs(ay - cy) > 1 && errors[my * size + mx] > maxError) {
const legLength = Math.abs(ax - cx) + Math.abs(ay - cy);
if ((legLength > 1 && errors[my * size + mx] > maxError) || legLength > maxScale) {
countElements(cx, cy, ax, ay, mx, my);
countElements(bx, by, cx, cy, mx, my);
} else {
Expand All @@ -131,7 +136,8 @@ class Tile {
const mx = (ax + bx) >> 1;
const my = (ay + by) >> 1;

if (Math.abs(ax - cx) + Math.abs(ay - cy) > 1 && errors[my * size + mx] > maxError) {
const legLength = Math.abs(ax - cx) + Math.abs(ay - cy);
if ((legLength > 1 && errors[my * size + mx] > maxError) || legLength > maxScale) {
// triangle doesn't approximate the surface well enough; drill down further
processTriangle(cx, cy, ax, ay, mx, my);
processTriangle(bx, by, cx, cy, mx, my);
Expand Down