dxf-parser/src/entities/3dface.ts

Parse dxf files into a readable, logical js object.

import DxfArrayScanner, { IGroup } from '../DxfArrayScanner';
import * as helpers from '../ParseHelpers'

import IGeometry, { IEntity, IPoint } from './geomtry';

export interface I3DfaceEntity extends IEntity {
	shape: boolean;
	hasContinuousLinetypePattern: boolean;
	vertices: IPoint[];
}

export default class ThreeDface implements IGeometry {
	public ForEntityName = '3DFACE' as const;
	public parseEntity(scanner: DxfArrayScanner, curr: IGroup) {
		const entity = { type: curr.value as string, vertices: [] as IPoint[] } as I3DfaceEntity;
		curr = scanner.next();
		while (!scanner.isEOF()) {
			if (curr.code === 0) break;
			switch (curr.code) {
				case 70: // 1 = Closed shape, 128 = plinegen?, 0 = default
					entity.shape = (((curr.value as number) & 1) === 1);
					entity.hasContinuousLinetypePattern = (((curr.value as number) & 128) === 128);
					break;
				case 10: // X coordinate of point
					entity.vertices = parse3dFaceVertices(scanner, curr);
					curr = scanner.lastReadGroup;
					break;
				default:
					helpers.checkCommonEntityProperties(entity, curr, scanner);
					break;
			}
			curr = scanner.next();
		}
		return entity;
	}
}

function parse3dFaceVertices(scanner:DxfArrayScanner, curr:IGroup) {
	var vertices = [];
	var vertexIsStarted = false;
	var vertexIsFinished = false;
	var verticesPer3dFace = 4; // there can be up to four vertices per face, although 3 is most used for TIN

	for (let i = 0; i <= verticesPer3dFace; i++) {
		var vertex = {} as IPoint;
		while (!scanner.isEOF()) {
			if (curr.code === 0 || vertexIsFinished) break;

			switch (curr.code) {
				case 10: // X0
				case 11: // X1
				case 12: // X2
				case 13: // X3
					if (vertexIsStarted) {
						vertexIsFinished = true;
						continue;
					}
					vertex.x = curr.value as number;
					vertexIsStarted = true;
					break;
				case 20: // Y
				case 21:
				case 22:
				case 23:
					vertex.y = curr.value as number;
					break;
				case 30: // Z
				case 31:
				case 32:
				case 33:
					vertex.z = curr.value as number;
					break;
				default:
					// it is possible to have entity codes after the vertices.  
					// So if code is not accounted for return to entity parser where it might be accounted for
					return vertices;
			}
			curr = scanner.next();
		}
		// See https://groups.google.com/forum/#!topic/comp.cad.autocad/9gn8s5O_w6E
		vertices.push(vertex);
		vertexIsStarted = false;
		vertexIsFinished = false;
	}
	scanner.rewind();
	return vertices;
};