draw intersection of cutting planes with the bounding box

Graphics/Draw.cpp

-// $Id: Draw.cpp,v 1.59 2004-06-04 02:07:06 geuzaine Exp $
+// $Id: Draw.cpp,v 1.60 2004-07-22 19:32:02 geuzaine Exp $
 //
 // Copyright (C) 1997-2004 C. Geuzaine, J.-F. Remacle
 //
@@ -294,3 +294,4 @@ void myZoom(GLdouble X1, GLdouble X2, GLdouble Y1, GLdouble Y2,
   InitPosition();
   Draw();
 }
+

Graphics/Draw.h

@@ -76,6 +76,7 @@ void Draw_Vector(int Type, int Fill,
 		 double relHeadRadius, double relStemLength, double relStemRadius,
 		 double x, double y, double z, double dx, double dy, double dz,
 		 double Raise[3][8], int light);
+
 void Draw_Mesh(Mesh *M);
 void Draw_Mesh_Volume(void *a, void *b);
 void Draw_Mesh_Surface(void *a, void *b);
@@ -91,6 +92,10 @@ void Draw_Mesh_Prism(void *a, void *b);
 void Draw_Mesh_Pyramid(void *a, void *b);
 void Draw_Mesh_Array(VertexArray *va, int faces, int edges);
 
+void Draw_PlaneInBoundingBox(double xmin, double ymin, double zmin,
+			     double xmax, double ymax, double zmax,
+			     double a, double b, double c, double d);
+
 void Draw_ScalarPoint(Post_View *View, int preproNormals,
 		      double ValMin, double ValMax, 
 		      double *X, double *Y, double *Z, double *V);

Graphics/Entity.cpp

-// $Id: Entity.cpp,v 1.43 2004-07-05 15:20:06 geuzaine Exp $
+// $Id: Entity.cpp,v 1.44 2004-07-22 19:32:02 geuzaine Exp $
 //
 // Copyright (C) 1997-2004 C. Geuzaine, J.-F. Remacle
 //
@@ -363,3 +363,88 @@ void Draw_Vector(int Type, int Fill,
   }
 
 }
+
+void Draw_PlaneInBoundingBox(double xmin, double ymin, double zmin,
+			     double xmax, double ymax, double zmax,
+			     double a, double b, double c, double d)
+{
+  class point{
+  public:
+    double x, y, z;
+    bool valid;
+    point() : x(0.), y(0.), z(0.), valid(false) {;};
+    point(double xi, double yi, double zi) :
+      x(xi), y(yi), z(zi), valid(true) {;};
+  };
+  
+  class plane{
+  private:
+    double _a, _b, _c, _d;
+  public:
+    plane(double a, double b, double c, double d) :
+      _a(a), _b(b), _c(c), _d(d) {;};
+    double val(point &p){
+      return _a*p.x + _b*p.y + _c*p.z + _d;
+    };
+    point intersect(point &p1, point &p2){
+      double v1 = val(p1), v2 = val(p2);
+      if(fabs(v1) < 1.e-12)
+	return point(p1.x, p1.y, p1.z);
+      else if(fabs(v2) < 1.e-12)
+	return point(p2.x, p2.y, p2.z);
+      else if(v1 * v2 < 0.){
+	double coef = - v1 / (v2 - v1);
+	return point(coef * (p2.x - p1.x) + p1.x,
+		     coef * (p2.y - p1.y) + p1.y,
+		     coef * (p2.z - p1.z) + p1.z);
+      }
+      else
+	return point();
+    };
+  };
+
+  plane pl(a, b, c, d);
+  point p1(xmin, ymin, zmin), p2(xmax, ymin, zmin);
+  point p3(xmax, ymax, zmin), p4(xmin, ymax, zmin);
+  point p5(xmin, ymin, zmax), p6(xmax, ymin, zmax);
+  point p7(xmax, ymax, zmax), p8(xmin, ymax, zmax);
+
+  point edge[12];
+  edge[0] = pl.intersect(p1, p2);
+  edge[1] = pl.intersect(p1, p4);
+  edge[2] = pl.intersect(p1, p5);
+  edge[3] = pl.intersect(p2, p3);
+  edge[4] = pl.intersect(p2, p6);
+  edge[5] = pl.intersect(p3, p4);
+  edge[6] = pl.intersect(p3, p7);
+  edge[7] = pl.intersect(p4, p8);
+  edge[8] = pl.intersect(p5, p6);
+  edge[9] = pl.intersect(p5, p8);
+  edge[10] = pl.intersect(p6, p7);
+  edge[11] = pl.intersect(p7, p8);
+
+  int face[6][4] = {
+    {0, 2, 4, 8},
+    {0, 1, 3, 5},
+    {1, 2, 7, 9},
+    {3, 4, 6, 10},
+    {5, 6, 7, 11},
+    {8, 9, 10, 11}
+  };
+  
+  for(int i = 0; i < 6; i++){
+    int nb = 0;
+    point p[4];
+    for(int j = 0; j < 4; j++){
+      if(edge[face[i][j]].valid == true)
+	p[nb++] = edge[face[i][j]];
+    }
+    if(nb > 1){
+      glColor3d(1.,0.,0.);
+      glBegin(GL_LINE_STRIP);
+      for(int j = 0; j < nb; j++)
+	glVertex3d(p[j].x, p[j].y, p[j].z);	
+      glEnd();
+    }
+  }
+}

Graphics/Mesh.cpp

-// $Id: Mesh.cpp,v 1.104 2004-07-22 05:47:46 geuzaine Exp $
+// $Id: Mesh.cpp,v 1.105 2004-07-22 19:32:02 geuzaine Exp $
 //
 // Copyright (C) 1997-2004 C. Geuzaine, J.-F. Remacle
 //
@@ -173,6 +173,18 @@ void Draw_Mesh(Mesh * M)
 		  CTX.max[2] + offset / CTX.s[0]);
     sprintf(label, "(%g,%g,%g)", CTX.max[0], CTX.max[1], CTX.max[2]);
     Draw_String(label);
+
+    for(int i = 0; i < 6; i++)
+      if(CTX.clip[i] & 1 || CTX.clip[i] & 2)
+	Draw_PlaneInBoundingBox(CTX.min[0], CTX.min[1], CTX.min[2],
+				CTX.max[0], CTX.max[1], CTX.max[2],
+				CTX.clip_plane[i][0], CTX.clip_plane[i][1], 
+				CTX.clip_plane[i][2], CTX.clip_plane[i][3]);
+    if(CTX.mesh.use_cut_plane)
+      Draw_PlaneInBoundingBox(CTX.min[0], CTX.min[1], CTX.min[2],
+			      CTX.max[0], CTX.max[1], CTX.max[2],
+			      CTX.mesh.cut_planea, CTX.mesh.cut_planeb, 
+			      CTX.mesh.cut_planec, CTX.mesh.cut_planed);
   }
   
   // draw the mesh

Graphics/Post.cpp

-// $Id: Post.cpp,v 1.74 2004-07-22 05:47:47 geuzaine Exp $
+// $Id: Post.cpp,v 1.75 2004-07-22 19:32:02 geuzaine Exp $
 //
 // Copyright (C) 1997-2004 C. Geuzaine, J.-F. Remacle
 //
@@ -355,6 +355,13 @@ void Draw_Post(void)
 		      v->BBox[5] + offset / CTX.s[0]);
 	sprintf(label, "(%g,%g,%g)", v->BBox[1], v->BBox[3], v->BBox[5]);
 	Draw_String(label);
+
+	for(int i = 0; i < 6; i++)
+	  if(CTX.clip[i] & (1<<(2+iView)))
+	    Draw_PlaneInBoundingBox(v->BBox[0], v->BBox[2], v->BBox[4],
+				    v->BBox[1], v->BBox[3], v->BBox[5],
+				    CTX.clip_plane[i][0], CTX.clip_plane[i][1], 
+				    CTX.clip_plane[i][2], CTX.clip_plane[i][3]);
       }
     }
   }