Fix bmesh vertex hash of subdivision.

README.md

@@ -36,7 +36,7 @@ Two caps and many strips composites a cylinder.
 Almost all 3D editor have a infinite grid ground, I just made a finite one, in the future, I should expand the grid outside of the screen to make it infinite.  
 Now, for just beginning, I think it's a not bad start.
 <img src="screenshot/dust3d_sphere_cylinder.png">
-- [ ] Implement B-Mesh algorithm (Dec 18, 2016 ~ Jan 02, 2017)   
+- [x] Implement B-Mesh algorithm (Dec 18, 2016 ~ Jan 04, 2017)   
 There is a implementation of [B-Mesh algorithm in C++](https://github.com/evanw/cs224final) language, but I want the pure C version, so I start to implement my own version. I read both paper and this implementation, it gave me very helpful understanding of this algorithm.    
 *Drawing Skeletal Shape Balls*  
 Draw shape ball is easy, no need to rotate, I just need scale it along the ball's radius.
@@ -62,10 +62,12 @@ There is a good implementation of [Gift Wrapping algorithm written in lua](https
 I follow the B-Mesh paper, made another test module inside Blender, and created a correspond `data/bmesh_test_2.h` manually.  
 <img src="screenshot/dust3d_bmesh_test_2.png" width="124" height="128">  <img src="screenshot/dust3d_bmesh_joint_1.png" width="124" height="128">  <img src="screenshot/dust3d_bmesh_joint_2.png" width="124" height="128">  
 *Catmull-Clark Subdivision*  
-<img src="screenshot/dust3d_subdivide_catmull_clark.png" width="124" height="128">    
+<img src="screenshot/dust3d_subdivide_catmull_clark.png" width="124" height="128">  <img src="screenshot/dust3d_bmesh_subdivide_2.png" width="124" height="128">    
 There is a implementation of Catmull-Clark Subdivision algorithm on [rosettacode](https://rosettacode.org/wiki/Catmull%E2%80%93Clark_subdivision_surface/C), the code is very simple and beautiful, just lack of some memory alloc fail check. I translated the algorithm to use my own array implementation.  
+Now, the render result looks not bad after 2 times of subdivisions. I would like to mark this todo as done, though there are more polish steps on the original paper, I just leave it as to be done in the future.
 - [ ] Export Wavefront .obj  
-- [ ] Render B-Mesh result  
+- [x] Render B-Mesh result  
+This todo already done in the B-Mesh algorithm implementation.  
 - [ ] Design UI for monster parts configuration  
 - [ ] Test B-Mesh realtime generation with UI  
 - [ ] Render rigid animation  

src/bmesh.c

@@ -41,10 +41,6 @@ struct bmesh {
   bmeshModelVertex findModelVertex;
 };
 
-static int cantorPair(int k1, int k2) {
-  return (k1 + k2) * (k1 + k2 + 1) / 2 + k2;
-}
-
 static bmeshModelVertex *bmeshFindModelVertex(bmesh *bm, vec3 *vertex) {
   int index;
   bm->findModelVertex.vertex = *vertex;
@@ -66,6 +62,11 @@ static int bmeshAddModelVertex(bmesh *bm, vec3 *vertex) {
     memset(v, 0, sizeof(bmeshModelVertex));
     v->vertex = *vertex;
     v->indexOnModel = subdivAddVertex(bm->model, &v->vertex);
+    if (-1 == hashtableInsert(bm->modelVertexHashtable,
+        (char *)0 + arrayGetLength(bm->modelVertexArray))) {
+      fprintf(stderr, "%s:hashtableInsert failed.\n", __FUNCTION__);
+      return -1;
+    }
   }
   return v->indexOnModel;
 }
@@ -118,8 +119,7 @@ bmeshModelVertex *bmeshGetModelVertexByHashtableParam(void *userData,
 
 static int modelVertexHash(void *userData, const void *node) {
   bmeshModelVertex *v = bmeshGetModelVertexByHashtableParam(userData, node);
-  return cantorPair(cantorPair(v->vertex.x, v->vertex.y),
-    v->vertex.z);
+  return abs(*((int *)v));
 }
 
 static int modelVertexCompare(void *userData, const void *firstNode,
@@ -128,7 +128,12 @@ static int modelVertexCompare(void *userData, const void *firstNode,
     firstNode);
   bmeshModelVertex *v2 = bmeshGetModelVertexByHashtableParam(userData,
     secondNode);
-  return 0 == memcmp(&v1->vertex, &v2->vertex, sizeof(v1->vertex));
+  if (0 == v1->vertex.x - v2->vertex.x &&
+      0 == v1->vertex.y - v2->vertex.y &&
+      0 == v1->vertex.z - v2->vertex.z) {
+    return 0;
+  }
+  return 1;
 }
 
 bmesh *bmeshCreate(void) {
@@ -1027,19 +1032,17 @@ int bmeshGenerate(bmesh *bm) {
   bmeshStitch(bm);
   bmeshGenerateInbetweenMesh(bm);
   subdivCalculteNorms(bm->model);
-  bm->subdivModel = subdivCatmullClarkWithLoops(bm->model, 1);
+  //bm->subdivModel = subdivCatmullClark(bm->model);
+  bm->subdivModel = subdivCatmullClarkWithLoops(bm->model, 2);
   return 0;
 }
 
 int bmeshDraw(bmesh *bm) {
   glPushMatrix();
-  glTranslatef(-5, 0, 0);
+  glTranslatef(-7, 0, 0);
   subdivDrawModel(bm->model);
   glPopMatrix();
   subdivDrawModel(bm->subdivModel);
-  //subdivModel *model = subdivCreateModel();
-  //subdivAddCube(model);
-  //subdivDrawModel(subdivCatmullClarkWithLoops(model, 2));
   return 0;
 }
 

src/subdivide.c

@@ -291,6 +291,7 @@ static int facePoint(subdivModel *model, int f) {
   int nv = getFace(model, f)->avg;
   if (-1 == nv) {
     int iterator;
+    int i;
     subdivVertex *newVertex = allocVertex(model);
     if (!newVertex) {
       fprintf(stderr, "%s:allocVertex failed.\n", __FUNCTION__);
@@ -299,18 +300,20 @@ static int facePoint(subdivModel *model, int f) {
     nv = newVertex->index;
     getFace(model, f)->avg = nv;
     iterator = getFace(model, f)->vertexLink;
+    i = 0;
     while (-1 != iterator) {
       int p;
       subdivLink *linkItem = (subdivLink *)arrayGetItem(model->indexArray,
         iterator);
       p = linkItem->index;
       iterator = linkItem->nextLink;
-      if (getFace(model, f)->vertexLink == iterator) {
+      if (!i) {
         getVertex(model, nv)->v = getVertex(model, p)->v;
       } else {
         vec3Add(&getVertex(model, nv)->v, &getVertex(model, p)->v,
           &getVertex(model, nv)->v);
       }
+      ++i;
     }
     vec3Scale(&getVertex(model, nv)->v, 1.0 / (getFace(model, f)->vertexNum),
       &getVertex(model, nv)->v);
@@ -625,7 +628,8 @@ static int subdivAddEdge(subdivModel *model, int p1, int p2) {
     fprintf(stderr, "%s:pushLink failed.\n", __FUNCTION__);
     return -1;
   }
-  if (-1 == pushLink(model, &model->edgeLink, &model->edgeNum, newEdge->index)) {
+  if (-1 == pushLink(model, &model->edgeLink, &model->edgeNum,
+      newEdge->index)) {
     fprintf(stderr, "%s:pushLink failed.\n", __FUNCTION__);
     return -1;
   }