import { BufferGeometry } from '../core/BufferGeometry.js';
import { Float32BufferAttribute } from '../core/BufferAttribute.js';
import { Vector3 } from '../math/Vector3.js';
class WireframeGeometry extends BufferGeometry {
constructor( geometry = null ) {
super();
this.type = 'WireframeGeometry';
this.parameters = {
geometry: geometry
};
if ( geometry !== null ) {
// buffer
const vertices = [];
const edges = new Set();
// helper variables
const start = new Vector3();
const end = new Vector3();
if ( geometry.index !== null ) {
// indexed BufferGeometry
const position = geometry.attributes.position;
const indices = geometry.index;
let groups = geometry.groups;
if ( groups.length === 0 ) {
groups = [ { start: 0, count: indices.count, materialIndex: 0 } ];
}
// create a data structure that contains all edges without duplicates
for ( let o = 0, ol = groups.length; o < ol; ++ o ) {
const group = groups[ o ];
const groupStart = group.start;
const groupCount = group.count;
for ( let i = groupStart, l = ( groupStart + groupCount ); i < l; i += 3 ) {
for ( let j = 0; j < 3; j ++ ) {
const index1 = indices.getX( i + j );
const index2 = indices.getX( i + ( j + 1 ) % 3 );
start.fromBufferAttribute( position, index1 );
end.fromBufferAttribute( position, index2 );
if ( isUniqueEdge( start, end, edges ) === true ) {
vertices.push( start.x, start.y, start.z );
vertices.push( end.x, end.y, end.z );
}
}
}
}
} else {
// non-indexed BufferGeometry
const position = geometry.attributes.position;
for ( let i = 0, l = ( position.count / 3 ); i < l; i ++ ) {
for ( let j = 0; j < 3; j ++ ) {
// three edges per triangle, an edge is represented as (index1, index2)
// e.g. the first triangle has the following edges: (0,1),(1,2),(2,0)
const index1 = 3 * i + j;
const index2 = 3 * i + ( ( j + 1 ) % 3 );
start.fromBufferAttribute( position, index1 );
end.fromBufferAttribute( position, index2 );
if ( isUniqueEdge( start, end, edges ) === true ) {
vertices.push( start.x, start.y, start.z );
vertices.push( end.x, end.y, end.z );
}
}
}
}
// build geometry
this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
}
}
}
function isUniqueEdge( start, end, edges ) {
const hash1 = `${start.x},${start.y},${start.z}-${end.x},${end.y},${end.z}`;
const hash2 = `${end.x},${end.y},${end.z}-${start.x},${start.y},${start.z}`; // coincident edge
if ( edges.has( hash1 ) === true || edges.has( hash2 ) === true ) {
return false;
} else {
edges.add( hash1 );
edges.add( hash2 );
return true;
}
}
export { WireframeGeometry };
