Merge pull request #4766 from kcoley/objLoaderNegIndices

Add support for loading objs with negative indices

loaders/src/OBJ/babylon.objFileLoader.ts

@@ -226,6 +226,8 @@ module BABYLON {
         public facePattern3 = /f\s+((([\d]{1,}\/[\d]{1,}\/[\d]{1,}[\s]?){3,})+)/;
         // f vertex//normal vertex//normal vertex//normal ...
         public facePattern4 = /f\s+((([\d]{1,}\/\/[\d]{1,}[\s]?){3,})+)/;
+        // f -vertex/-uvs/-normal -vertex/-uvs/-normal -vertex/-uvs/-normal ...
+        public facePattern5 = /f\s+(((-[\d]{1,}\/-[\d]{1,}\/-[\d]{1,}[\s]?){3,})+)/;
 
 
         /**
@@ -428,11 +430,12 @@ module BABYLON {
              * Create triangles from polygons by recursion
              * The best to understand how it works is to draw it in the same time you get the recursion.
              * It is important to notice that a triangle is a polygon
-             * We get 4 patterns of face defined in OBJ File :
+             * We get 5 patterns of face defined in OBJ File :
              * facePattern1 = ["1","2","3","4","5","6"]
              * facePattern2 = ["1/1","2/2","3/3","4/4","5/5","6/6"]
              * facePattern3 = ["1/1/1","2/2/2","3/3/3","4/4/4","5/5/5","6/6/6"]
              * facePattern4 = ["1//1","2//2","3//3","4//4","5//5","6//6"]
+             * facePattern5 = ["-1/-1/-1","-2/-2/-2","-3/-3/-3","-4/-4/-4","-5/-5/-5","-6/-6/-6"]
              * Each pattern is divided by the same method
              * @param face Array[String] The indices of elements
              * @param v Integer The variable to increment
@@ -453,6 +456,7 @@ module BABYLON {
                 //Pattern2 => triangle = ["1/1","2/2","3/3","1/1","3/3","4/4"];
                 //Pattern3 => triangle = ["1/1/1","2/2/2","3/3/3","1/1/1","3/3/3","4/4/4"];
                 //Pattern4 => triangle = ["1//1","2//2","3//3","1//1","3//3","4//4"];
+                //Pattern5 => triangle = ["-1/-1/-1","-2/-2/-2","-3/-3/-3","-1/-1/-1","-3/-3/-3","-4/-4/-4"];
             };
 
             /**
@@ -576,6 +580,37 @@ module BABYLON {
                 triangles = [];
             };
 
+            /**
+             * Create triangles and push the data for each polygon for the pattern 3
+             * In this pattern we get vertice positions, uvs and normals
+             * @param face
+             * @param v
+             */
+            var setDataForCurrentFaceWithPattern5 = (face: Array<string>, v: number) => {
+                //Get the indices of triangles for each polygon
+                getTriangles(face, v);
+
+                for (var k = 0; k < triangles.length; k++) {
+                    //triangle[k] = "-1/-1/-1"
+                    //Split the data for getting position, uv, and normals
+                    var point = triangles[k].split("/"); // ["-1", "-1", "-1"]
+                    // Set position indice
+                    var indicePositionFromObj =  positions.length + parseInt(point[0]);
+                    // Set uv indice
+                    var indiceUvsFromObj =  uvs.length + parseInt(point[1]);
+                    // Set normal indice
+                    var indiceNormalFromObj = normals.length + parseInt(point[2]);
+
+                    setData(
+                        indicePositionFromObj, indiceUvsFromObj, indiceNormalFromObj,
+                        positions[indicePositionFromObj], uvs[indiceUvsFromObj], normals[indiceNormalFromObj] //Set the vector for each component
+                    );
+
+                }
+                //Reset variable for the next line
+                triangles = [];
+            };
+
             var addPreviousObjMesh = () => {
 
                 //Check if it is not the first mesh. Otherwise we don't have data.
@@ -673,6 +708,17 @@ module BABYLON {
                         1
                     );
 
+                } else if ((result = this.facePattern5.exec(line)) !== null) {
+                    //Value of result:
+                    //["f -1/-1/-1 -2/-2/-2 -3/-3/-3", "-1/-1/-1 -2/-2/-2 -3/-3/-3"...]
+
+                    //Set the data for this face
+                    setDataForCurrentFaceWithPattern5(
+                        result[1].trim().split(" "), // ["-1/-1/-1", "-2/-2/-2", "-3/-3/-3"]
+                        1
+                    );
+
+
                 } else if ((result = this.facePattern2.exec(line)) !== null) {
                     //Value of result:
                     //["f 1/1 2/2 3/3", "1/1 2/2 3/3"...]