Visualization 2: STL data display

The first task is to draw STL data OpenGL, which can be rotated, scaled, picked up (after picking, display the title number, node number), move the vertex position to change the shape of the object; the first stage: read and show how to read STL files generated by Solidworks model in STL:
ASCII format of STL Files

The ASCII format STL file provides the geometric information of the triangle surface line by line. Each line starts with one or two keywords. In the STL file, the information unit facet of the triangle surface is a triangle surface with vector direction. The STL model is composed of a group of such triangle surfaces. In an STL file, each facet is composed of seven rows of data, and the fifth row is the amount of data lost due to the triangle surface pointing to the external object, and the third row indicates the subsequent 3, 4, the five rows of data are the three vertices of the triangle, which are arranged in the clockwise direction along the normal vector (1st rows of data) pointing to the external body. The ASCII format STL file structure is as follows:
Solid filename STL folder file path and file name
Facet normal x y z x
Outer Loop
Vertex x y z coordinate of the first vertex of the Triangle Surface
Vertex x y z coordinate of the second vertex of the Triangle Surface
Vertex x y z coordinate of the third vertex of the Triangle Surface
Endloop
The first triangle surface of endfacet watermark is defined.
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The VC code for reading STL Files in OpenGL is as follows: File * fp = NULL;
Fp = fopen (".. \ Active synchronization Belt Wheel. STL", "R ");
If (FP)
{
Cstring strline;
Cstring strhead;
Glfloat normal [3];
Glfloat vertex [3];

Glnewlist (3, gl_compile );
Glpushmatrix ();
// Gldisable (gl_lighting );
Glenable (gl_depth_test );
Glable (gl_lighting );
Glable (gl_line_smooth );
Glscalef (0.001, 0.001, 0.001 );

While (1)
{
Fscanf (FP, "% s \ n", strhead. getbuffer (20 ));
Strhead. trimleft ();

If (strhead = "solid ")
{
Fscanf (FP, "% s \ n", strline. getbuffer (20 ));
Continue;
}
Else if (strhead = "facet ")
{
Fscanf (FP, "% s \ n", strline. getbuffer (20 ));
Fscanf (FP, "% F \ n", normal, normal + 1, normal + 2 );
Glnormal3fv (normal );
}
If (strhead = "outer ")
{
Fscanf (FP, "% s \ n", strline. getbuffer (20 ));

Glbegin (gl_polygon );

For (INT I = 0; I <3; I ++)
{
Fscanf (FP, "% s \ n", strline. getbuffer (20 ));
Strline. trimleft ();
If (strline = "vertex ")
{
Fscanf (FP, "% F \ n", vertex, vertex + 1, vertex + 2 );
Glvertex3d (vertex [0], vertex [1], vertex [2]);
}
}

Glend ();

Continue;
}
Else if (strhead = "endloop" | strhead = "endfacet ")
{
Continue;
}
Else if (strhead = "endsolid ")
{
Break;
}
}

// Glable (gl_depth_test );
// Glenable (gl_lighting );
Gldisable (gl_line_smooth );
Glpopmatrix ();
Glendlist ();

Fclose (FP );
} The above is the code segment that reads STL and displays in;

Visualization 2: STL data display