How do I display/draw a .ply object in OpenGL? - c++

Question

I'm trying to make OpenGL draw the figure that I'm loading with OPENFILENAME. What I've got right now is: I can display the comments, vertex, how many faces, etc., but I cannot draw the figure and I'm not sure how to do it. I can draw other predetermined figures, but not the ones I'm trying to open.
This is where I'm initializing everything:
case WM_CREATE:
hDC = GetDC(hWnd);
hRC=wglCreateContext(hDC);
wglMakeCurrent(hDC,hRC);
g_hwndDlg = CreateDialog(hInst,MAKEINTRESOURCE(IDD_DIALOG1),hWnd,DialogProc);
Figure = new DrawFigure();
initGL();
break;
This is where I find out what the element I'm opening has:
/* go through each kind of element that we learned is in the file */
/* and read them */
for (i = 0; i < nelems; i++) {
/* get the description of the first element */
elem_name = elist[i];
plist = ply_get_element_description (ply, elem_name, &num_elems, &nprops);
int el=sprintf(szFile,"element %s %d\n", elem_name, num_elems);
/* print the name of the element, for debugging */
TextOut(hDC,150,0+i*20,szFile,el);
/* if we're on vertex elements, read them in */
if (equal_strings ("vertex", elem_name)) {
/* create a vertex list to hold all the vertices */
vlist = (Vertex **) malloc (sizeof (Vertex *) * num_elems);
/* set up for getting vertex elements */
ply_get_property (ply, elem_name, &vert_props[0]);
ply_get_property (ply, elem_name, &vert_props[1]);
ply_get_property (ply, elem_name, &vert_props[2]);
/* grab all the vertex elements */
for (j = 0; j < num_elems; j++) {
int move=10;
/* grab and element from the file */
vlist[j] = (Vertex *) malloc (sizeof (Vertex));
ply_get_element (ply, (void *) vlist[j]);
int vert=sprintf(szFile,"vertex: %g %g %g", vlist[j]->x, vlist[j]->y, vlist[j]->z);
/* print out vertex x,y,z for debugging */
TextOut(hDC,600,move+j*20,szFile,vert);
Figure->Parameters(vlist[j]->x, vlist[j]->y, vlist[j]->z);
}
}
And this is where the class Figure is, where I'm suppossed to draw everything:
Figure::Figure(){
}
void Figure::Parameters(float x,float y,float z)
{
this->x1=x;
this->y1=y;
this->z1=z;
}
void Figure::Draw()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt(0.0,0.0,4.0,0.0,0.0,0.0,0.0,1.0,0.0);
glBegin(GL_TRIANGLES);
glNormal3f(x1,y1,z1);
glVertex3f(x1,y1,z1);
glEnd();
}
x1,y1,z1 are declared in Figure.h
I tried to explain myself the best I could; if you think it still needs more explanation please tell me and I will try to explain it in a different way
Yeah, I forgot to explain I guess the figure I'm trying to draw...well i don't know which figure it would be because I'm using OPENFILENAME to open 1 random figure and draw it i used triangles because i thought that with triangles i could draw anything and also i tried in the class Parameters ask for the number of vertex I'm dealing with and making a "for" in the class Draw but it didn't work

Answer 1

You only specify one vertex between your begin/end.. you need at least 3 to specify a triangle. And many more if you want a whole buncha triangles. You need something more along the lines of this:
void Figure::Parameters(float x, float y, float z)
{
m_vertices.push_back(myVertex(x, y, z));
}
void Figure::Draw()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt(0.0,0.0,4.0,0.0,0.0,0.0,0.0,1.0,0.0);
glBegin(GL_TRIANGLES);
assert(m_vertices.size() % 3 == 0); // since we're drawing triangles
for(size_t i=0; i<m_vertices.size(); i++)
{
glNormal3f(m_vertices[i].x,m_vertices[i].y,m_vertices[i].z);
glVertex3f(m_vertices[i].x,m_vertices[i].y,m_vertices[i].z);
}
glEnd();
}