129 lines
2.7 KiB
JavaScript
129 lines
2.7 KiB
JavaScript
import { BufferGeometry } from '../core/BufferGeometry.js';
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import { Float32BufferAttribute } from '../core/BufferAttribute.js';
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import { Vector2 } from '../math/Vector2.js';
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import { Vector3 } from '../math/Vector3.js';
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class RingGeometry extends BufferGeometry {
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constructor( innerRadius = 0.5, outerRadius = 1, thetaSegments = 32, phiSegments = 1, thetaStart = 0, thetaLength = Math.PI * 2 ) {
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super();
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this.type = 'RingGeometry';
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this.parameters = {
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innerRadius: innerRadius,
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outerRadius: outerRadius,
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thetaSegments: thetaSegments,
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phiSegments: phiSegments,
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thetaStart: thetaStart,
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thetaLength: thetaLength
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};
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thetaSegments = Math.max( 3, thetaSegments );
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phiSegments = Math.max( 1, phiSegments );
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// buffers
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const indices = [];
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const vertices = [];
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const normals = [];
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const uvs = [];
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// some helper variables
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let radius = innerRadius;
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const radiusStep = ( ( outerRadius - innerRadius ) / phiSegments );
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const vertex = new Vector3();
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const uv = new Vector2();
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// generate vertices, normals and uvs
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for ( let j = 0; j <= phiSegments; j ++ ) {
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for ( let i = 0; i <= thetaSegments; i ++ ) {
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// values are generate from the inside of the ring to the outside
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const segment = thetaStart + i / thetaSegments * thetaLength;
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// vertex
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vertex.x = radius * Math.cos( segment );
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vertex.y = radius * Math.sin( segment );
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vertices.push( vertex.x, vertex.y, vertex.z );
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// normal
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normals.push( 0, 0, 1 );
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// uv
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uv.x = ( vertex.x / outerRadius + 1 ) / 2;
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uv.y = ( vertex.y / outerRadius + 1 ) / 2;
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uvs.push( uv.x, uv.y );
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}
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// increase the radius for next row of vertices
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radius += radiusStep;
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}
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// indices
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for ( let j = 0; j < phiSegments; j ++ ) {
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const thetaSegmentLevel = j * ( thetaSegments + 1 );
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for ( let i = 0; i < thetaSegments; i ++ ) {
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const segment = i + thetaSegmentLevel;
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const a = segment;
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const b = segment + thetaSegments + 1;
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const c = segment + thetaSegments + 2;
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const d = segment + 1;
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// faces
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indices.push( a, b, d );
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indices.push( b, c, d );
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}
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}
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// build geometry
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this.setIndex( indices );
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this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
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this.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );
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this.setAttribute( 'uv', new Float32BufferAttribute( uvs, 2 ) );
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}
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copy( source ) {
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super.copy( source );
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this.parameters = Object.assign( {}, source.parameters );
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return this;
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}
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static fromJSON( data ) {
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return new RingGeometry( data.innerRadius, data.outerRadius, data.thetaSegments, data.phiSegments, data.thetaStart, data.thetaLength );
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}
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}
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export { RingGeometry };
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