rpg-dialogue-js
Version:
A simple roleplay game dialogue engine and editor.
57 lines • 1.88 kB
JavaScript
/**
* @requires Vertex
*
* @author Ikaros Kappler
* @date 2020-12-20
*/
/**
* Remove all duplicate neighbours from the given polygon.
*
* Imagagine a polygon:
* [ [0,0], [10,10], [10,10], [10,10], [20,20], [10,10], [30,30], [0,0] ]
*
* The returned vertex array will then be:
* [ [10,10], [20,20], [10,10], [30,30], [0,0] ]
*
* Duplicate neighbours (and only neightours) of a run of any length will be removed.
*
* @method clearPolygonDuplicateVertices
* @param {Array<Vertex>} vertices - The polygon vertices to use.
* @param {number=0} epsilon - The epsilon area to use around each vertex to check equality.
* @return {Array<Vertex>}
*/
export const clearPolygonDuplicateVertices = (vertices, epsilon) => {
const n = vertices.length;
if (n === 0)
return [];
// Find following up sequence of vertices that are inside the epsilon sphere.
if (typeof epsilon === "undefined")
epsilon = 0;
// Check if the verts a i and j are considered equal
const equalVerts = (i, j) => {
const vertA = vertices[i % n];
const vertB = vertices[j % n];
return (epsilon === 0 && vertA.x === vertB.x && vertA.y === vertB.y)
|| (epsilon !== 0 && vertA.distance(vertB) <= epsilon);
};
// Find the next vertex in the list, starting from 'index', that is different
const findEndOfRun = (index) => {
var b = index;
while (equalVerts(index, b + 1) && b < index + n) {
b++;
}
return b;
};
var start = findEndOfRun(0);
// console.log('starting at', start );
var i = 0;
const result = [];
for (var j = i + 1; j <= n; j++) {
if (!equalVerts(start + i, start + j)) {
result.push(vertices[(start + j) % n]);
i = j;
}
}
return result;
};
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