buildnavjs

"use strict";

var fs = require("fs");
var recast = require("../haxerecast/js/recast/recast");

var THREE = require("../armory_tools/threejs/three.tools");

var path_mesh = '';
if(process.argv.length > 2){
    path_mesh = './' + process.argv[2] + '.obj';
    recast.OBJLoader(path_mesh, function() {
        var rcPolyMesh = {};
        var rcPolyMeshDetail = {};
        var settings;
        
        if (process.argv[3] !== undefined) {
            settings = JSON.parse(process.argv[3]);
            recast.settings(settings);
        }

        recast.buildSolo();
        
        recast.get_rcPolyMesh( recast.cb( function ( rcpolymesh ) {
            rcPolyMesh = rcpolymesh;
        }));

        recast.get_rcPolyMeshDetail( recast.cb( function ( rcpolymeshdetail ) {
            rcPolyMeshDetail = rcpolymeshdetail;
        }));
        if (rcPolyMesh !== undefined && rcPolyMeshDetail !== undefined) {
            var navObject = createMeshFromVertices( rcPolyMesh, rcPolyMeshDetail);

            var navMesh = mergeGeometry(navObject);

            var navMeshObj = saveGeometryToObj(navMesh);

            fs.writeFile(path_mesh, navMeshObj, function (err) {
                if (err) throw err;
            });    
        }    
    });
}
//https://stackoverflow.com/questions/19559395/merging-an-entire-object3d-mesh-hierarchy-together
function mergeGeometry (obj){
    var newGeo = new THREE.Geometry();
    obj.traverse(function(child){
        if(child.parent){
            child.updateMatrixWorld();
            child.applyMatrix(child.parent.matrixWorld);    
        }
        THREE.GeometryUtils.merge(newGeo, child);
    });
    return newGeo;
}

function saveGeometryToObj (geometry) {
    var buffer = '';
    
    var verts = geometry.vertices;
    for (var i in verts) buffer += 'v ' + (verts[i].x) + ' ' + verts[i].y + ' ' + verts[i].z + '\n';

    var faces = geometry.faces;
    for (var i in faces) {
        buffer += 'f ' + (faces[i].a + 1) + ' ' + (faces[i].b + 1) + ' ' + (faces[i].c + 1);    
        if (faces[i].d !== undefined) buffer += ' ' + (faces[i].d + 1);
        buffer += '\n';
    }

    return buffer;
}

// original script from blender-2.79b/source/blender/editors/mesh/mesh_navmesh.c 
// http://www.letworyinteractive.com/blendercode/dd/de9/mesh__navmesh_8c_source.html#l00292
function createMeshFromVertices (rcpolymesh, rcpolymeshdetail) {

    var nmeshes = rcpolymeshdetail.nmeshes;
    var meshes = rcpolymeshdetail.meshes;

    var parent = new THREE.Object3D();

    var dummyMaterial = new THREE.MeshBasicMaterial();

    var materials = [ dummyMaterial ];

    var new_verts=[];
    var verts = rcpolymesh.verts;
    
    for (var i = 0; i < rcpolymesh.nverts; i++){
        var x = rcpolymesh.boundbox.bmin[0] + verts[(i * 3) + 0] * rcpolymesh.cell.cs;
        var y = rcpolymesh.boundbox.bmin[1] + verts[(i * 3) + 1] * rcpolymesh.cell.ch;
        var z = rcpolymesh.boundbox.bmin[2] + verts[(i * 3) + 2] * rcpolymesh.cell.cs;
        new_verts.push({'x':x,'y':z,'z':y});
    }

    for (var i = 0; i < nmeshes; i++) {
        
        var uniquevbase = new_verts.length;
        var nvp = rcpolymesh.nvp;
        var vbase = meshes[4 * i + 0];
		var ndv = meshes[4 * i + 1];
		var tribase = meshes[4 * i + 2];
		var trinum = meshes[4 * i + 3];
		var p = (i * nvp * 2);
        var nv = 0;
        
        for (j = 0; j < nvp; ++j) {
			if (rcpolymesh.polys[p + j] == 0xffff) break;
			nv++;
        }

        for (var j = nv; j < ndv; j++) {
            var x = rcpolymeshdetail.verts[3 * (vbase + j) + 0];
            var y = rcpolymeshdetail.verts[3 * (vbase + j) + 1];
            var z = rcpolymeshdetail.verts[3 * (vbase + j) + 2];
            new_verts.push({'x':x,'y':z,'z':y});
        }

        for (var j = 0; j < trinum; j++) {
            var tri = (4 * (tribase + j));
            var face = [];
			for (var k = 0; k < 3; k++) {
				if (rcpolymeshdetail.tris[tri + k] < nv)
					face.push(rcpolymesh.polys[p + rcpolymeshdetail.tris[tri + k]]);  /* shared vertex */
				else
					face.push(uniquevbase + rcpolymeshdetail.tris[tri + k] - nv);  /* unique vertex */
            }

            var geometry = new THREE.ConvexGeometry([
                new THREE.Vector3( new_verts[face[0]].x, new_verts[face[0]].y, new_verts[face[0]].z ), 
                new THREE.Vector3( new_verts[face[2]].x, new_verts[face[2]].y, new_verts[face[2]].z ),
                new THREE.Vector3( new_verts[face[1]].x, new_verts[face[1]].y, new_verts[face[1]].z )
            ]);
    
            var child = THREE.SceneUtils.createMultiMaterialObject(geometry, materials);
            parent.add(child);
		}
    }  
    return parent;
}
// https://github.com/vincent/recastjs-editor/blob/master/threejs/BufferGeometryUtils.js