Generate inbetween nodes between bmesh key nodes

README.md

@@ -21,18 +21,20 @@ 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 ~ Dec 19, 2016)   
+- [ ] Implement B-Mesh algorithm (Dec 18, 2016 ~ Dec 20, 2016)   
 *Drawing Skeletal Shape Balls*  
 Draw shape ball is easy, no need to rotate, I just need scale it along the ball's radius.
 Draw the cylinder which connects two shape balls is more difficult, I need do some math to rotate it. [Here](http://www.thjsmith.com/40/cylinder-between-two-points-opengl-c) described it.  
 *Camera Control*  
 Camera rotate/zoom implemented, [here](http://www.songho.ca/opengl/gl_transform.html) is a good article which explained the theory of OpenGL Transformation. Most important is that the demo app is very beautiful.  
 Added x,z axis, looks better than last screenshot.   
-I have to use the GLU library, the previous implementation of drawSphere and drawCylinder looks not good, and take too much time to debug.
-<img src="screenshot/dust3d_node_edge_with_glu.png">
+I have to use the GLU library, the previous implementation of drawSphere and drawCylinder looks not good, and take too much time to debug.  
+<img src="screenshot/dust3d_node_edge_with_glu.png" style="width:170px; height:140px;">  
 *B-Mesh data struct*  
-I created the test nodes's geometry information from Blender. Here is the render result of `data/bmesh_test_1.h`
-<img src="screenshot/dust3d_bmesh_nodes.png">
+I created the test nodes's geometry information from Blender. Here is the render result of `data/bmesh_test_1.h`  
+<img src="screenshot/dust3d_bmesh_nodes.png" style="width:206px; height:164px;">  
+*Generate Inbetween Nodes*  
+<img src="screenshot/dust3d_bmesh_skeleton.png" style="width:124px; height:128px;">  <img src="screenshot/dust3d_bmesh_inbetween.png" style="width:124px; height:128px;">  
 - [ ] Export Wavefront .obj  
 - [ ] Render B-Mesh result  
 - [ ] Design UI for monster parts configuration  

data/bmesh_test_1.h

@@ -1,9 +1,9 @@
-const float bmeshTest1Nodes[][4] = {
-  {0, -2.07575, 1.53902, 0.04122},                                          {1, 2.40837, 2.34882, 0.48585},
-      {2, -0.91403, 0.77069, 0.62299},            {3, 2.25224, 0.74973, 0.85115},
-                                    {4, 0, 0, 0},
-                               {5, 0.00920, -0.66115, -2.04601},
-                               {6, 0.01726, -0.88224, -2.87471}
+const float bmeshTest1Nodes[][6] = {
+  {0, -2.07575, 1.53902, 0.04122, 0.25},                                          {1, 2.40837, 2.34882, 0.48585, 0.3},
+      {2, -0.91403, 0.77069, 0.62299, 0.5},            {3, 2.25224, 0.74973, 0.85115, 0.5},
+                                    {4, 0, 0, 0, 0.8, 1},
+                               {5, 0.00920, -0.66115, -2.04601, 0.5},
+                               {6, 0.01726, -0.88224, -2.87471, 0.2}
 };
 
 const int bmeshTest1Edges[][2] = {

src/bmesh.c

@@ -73,3 +73,39 @@ int bmeshAddEdge(bmesh *bm, bmeshEdge *edge) {
   memcpy(arrayGetItem(bm->edgeArray, index), edge, sizeof(bmeshEdge));
   return index;
 }
+
+static int bmeshAddInbetweenNodeBetween(bmesh *bm,
+    bmeshNode *firstNode, bmeshNode *secondNode, float frac) {
+  bmeshNode newNode;
+  memset(&newNode, 0, sizeof(newNode));
+  newNode.type = BMESH_NODE_TYPE_INBETWEEN;
+  newNode.radius = firstNode->radius * (1 - frac) +
+    secondNode->radius * frac;
+  vec3Lerp(&firstNode->position, &secondNode->position, frac,
+    &newNode.position);
+  return bmeshAddNode(bm, &newNode);
+}
+
+int bmeshGenerateInbetweenNodes(bmesh *bm) {
+  int edgeIdx;
+  for (edgeIdx = 0; edgeIdx < bmeshGetEdgeNum(bm); ++edgeIdx) {
+    bmeshEdge *edge = bmeshGetEdge(bm, edgeIdx);
+    bmeshNode *firstNode = bmeshGetNode(bm, edge->firstNode);
+    bmeshNode *secondNode = bmeshGetNode(bm, edge->secondNode);
+    float step = 0.5;
+    float distance = vec3Distance(&firstNode->position, &secondNode->position);
+    if (distance > 0) {
+      float offset = step;
+      if (offset + step <= distance) {
+        while (offset + step <= distance) {
+          float frac = offset / distance;
+          bmeshAddInbetweenNodeBetween(bm, firstNode, secondNode, frac);
+          offset += step;
+        }
+      } else if (distance > step) {
+        bmeshAddInbetweenNodeBetween(bm, firstNode, secondNode, 0.5);
+      }
+    }
+  }
+  return 0;
+}

src/bmesh.h

@@ -7,10 +7,10 @@ extern "C" {
 #endif
 
 typedef enum {
-  BMESH_NODE_FLAG_KEY = 0x00000001,
-  BMESH_NODE_FLAG_INBETWEEN = 0x00000002,
-  BMESH_NODE_FLAG_ROOT = 0x00000010,
-} bmeshNodeFlag;
+  BMESH_NODE_TYPE_KEY = 0,
+  BMESH_NODE_TYPE_ROOT = 1,
+  BMESH_NODE_TYPE_INBETWEEN = 2,
+} bmeshNodeType;
 
 typedef struct bmesh bmesh;
 
@@ -18,7 +18,7 @@ typedef struct {
   int index;
   vec3 position;
   float radius;
-  unsigned int flag;
+  int type;
 } bmeshNode;
 
 typedef struct {
@@ -35,6 +35,7 @@ bmeshNode *bmeshGetNode(bmesh *bm, int index);
 bmeshEdge *bmeshGetEdge(bmesh *bm, int index);
 int bmeshAddNode(bmesh *bm, bmeshNode *node);
 int bmeshAddEdge(bmesh *bm, bmeshEdge *edge);
+int bmeshGenerateInbetweenNodes(bmesh *bm);
 
 #ifdef __cplusplus
 }

src/mainwindow.cpp

@@ -6,7 +6,8 @@
 
 MainWindow::MainWindow(void) {
 	render = new Render;
-  resize(QDesktopWidget().availableGeometry(this).size() * 0.7);
+	int size = QDesktopWidget().availableGeometry(this).size().height() * 0.7;
+  resize(QSize(size, size));
 	QHBoxLayout *mainLayout = new QHBoxLayout;
   mainLayout->addWidget(render);
   setLayout(mainLayout);

src/render.cpp

@@ -7,18 +7,24 @@
 #include "bmesh.h"
 #include "matrix.h"
 
+static const float bmeshNodeColors[][3] {
+  {0, 0.78, 1},
+  {1, 0, 0},
+  {1, 1, 1}
+};
+
+static const float bmeshEdgeColor[3] = {1, 1, 0};
+
 static QGLWidget *_this = 0;
 
 static int drawBmeshNode(bmesh *bm, bmeshNode *node) {
-  float color1[3] = {1, 0, 0};
-  glColor3fv(color1);
+  glColor3fv(bmeshNodeColors[node->type]);
   drawSphere(&node->position, node->radius, 36, 24);
   return 0;
 }
 
 static int drawBmeshEdge(bmesh *bm, bmeshEdge *edge) {
-  float color2[3] = {1, 1, 0};
-  glColor3fv(color2);
+  glColor3fv(bmeshEdgeColor);
   bmeshNode *firstNode = bmeshGetNode(bm, edge->firstNode);
   bmeshNode *secondNode = bmeshGetNode(bm, edge->secondNode);
   drawCylinder(&firstNode->position, &secondNode->position, 0.1, 36, 24);
@@ -26,7 +32,10 @@ static int drawBmeshEdge(bmesh *bm, bmeshEdge *edge) {
 }
 
 int drawText(int x, int y, char *text) {
-  _this->renderText(x, y, QString(text));
+  QFont font = QFont("Arial");
+  font.setPointSize(9);
+  font.setBold(false);
+  _this->renderText(x, y, QString(text), font);
   return 0;
 }
 
@@ -40,7 +49,7 @@ Render::Render(QWidget *parent)
   mouseY = 0;
   cameraAngleX = 20;
   cameraAngleY = -225;
-  cameraDistance = 3;
+  cameraDistance = 7;
 }
 
 Render::~Render(void) {
@@ -99,8 +108,8 @@ void Render::paintGL() {
   glRotatef(cameraAngleY, 0, 1, 0);
 
   glColor3f(0, 0, 0);
-  drawPrintf(0, 10, "cameraAngleX:%f cameraAngleY:%f", cameraAngleX,
-    cameraAngleY);
+  drawPrintf(0, 10, "cameraAngleX:%f cameraAngleY:%f cameraDistance:%f",
+    cameraAngleX, cameraAngleY, cameraDistance);
 
   drawGrid(10, 1);
 
@@ -117,7 +126,8 @@ void Render::paintGL() {
       node.position.x = bmeshTest1Nodes[i][1];
       node.position.y = bmeshTest1Nodes[i][2];
       node.position.z = bmeshTest1Nodes[i][3];
-      node.radius = 0.35;
+      node.radius = bmeshTest1Nodes[i][4];
+      node.type = bmeshTest1Nodes[i][5];
       bmeshAddNode(bm, &node);
     }
 
@@ -127,6 +137,8 @@ void Render::paintGL() {
       edge.secondNode = bmeshTest1Edges[i][1];
       bmeshAddEdge(bm, &edge);
     }
+
+    bmeshGenerateInbetweenNodes(bm);
   }
 
   {
@@ -149,7 +161,7 @@ void Render::resizeGL(int w, int h) {
 
   glMatrixMode(GL_PROJECTION);
   glLoadIdentity();
-  gluPerspective(60.0f, w/(h/2.0f), 1, 100);
+  gluPerspective(60.0f, w/h, 1, 100);
 
   glMatrixMode(GL_MODELVIEW);
   glLoadIdentity();

src/vector3d.c

@@ -1,3 +1,4 @@
+#include <math.h>
 #include "vector3d.h"
 
 float vec3Length(vec3 *p) {
@@ -18,9 +19,13 @@ void vec3Normalize(vec3 *p) {
 }
 
 void vec3Midpoint(vec3 *a, vec3 *b, vec3 *mid) {
-  mid->x = (a->x + b->x) * 0.5;
-  mid->y = (a->y + b->y) * 0.5;
-  mid->z = (a->z + b->z) * 0.5;
+  vec3Lerp(a, b, 0.5, mid);
+}
+
+void vec3Lerp(vec3 *a, vec3 *b, float frac, vec3 *result) {
+  result->x = a->x + (b->x - a->x) * frac;
+  result->y = a->y + (b->y - a->y) * frac;
+  result->z = a->z + (b->z - a->z) * frac;
 }
 
 void vec3Sub(vec3 *a, vec3 *b, vec3 *result) {
@@ -38,3 +43,9 @@ void vec3CrossProduct(vec3 *a, vec3 *b, vec3 *result) {
 float vec3DotProduct(vec3 *a, vec3 *b) {
   return a->x * b->x + a->y * b->y + a->z * b->z;
 }
+
+float vec3Distance(vec3 *a, vec3 *b) {
+  vec3 p;
+  vec3Sub(a, b, &p);
+  return vec3Length(&p);
+}

src/vector3d.h

@@ -13,10 +13,12 @@ typedef struct {
 
 void vec3Normalize(vec3 *p);
 void vec3Midpoint(vec3 *a, vec3 *b, vec3 *mid);
+void vec3Lerp(vec3 *a, vec3 *b, float frac, vec3 *result);
 void vec3CrossProduct(vec3 *a, vec3 *b, vec3 *result);
 void vec3Sub(vec3 *a, vec3 *b, vec3 *result);
 float vec3DotProduct(vec3 *a, vec3 *b);
 float vec3Length(vec3 *p);
+float vec3Distance(vec3 *a, vec3 *b);
 
 #ifdef __cplusplus
 }