hidden line removal (by lines, not polygon)

I knew how to execute the hidden line removal by polygon mode.
namely…

written by Relic…

glPolygonMode(GL_FRONT, GL_FILL);
glEnable(GL_POLYGON_OFFSET_FILL);
glPolygonOffset((1.0f,1.0f);
glColorMask(GL_FALSE,GL_FALSE,GL_FALSE,GL_FALSE);
glBegin(GL_POLYGON);
glVertex(…) // draw my model as polygons
glEnd();
glColorMask(GL_TRUE,GL_TRUE,GL_TRUE,GL_TRUE);
glDisable(GL_POLYGON_OFFSET_FILL);

// Draw the model as polygons with GL_LINE mode
glPolygonMode(GL_FRONT, GL_LINE);
glBegin(GL_POLYGON);
glColor3ub(set appreciate colors);
glVertex(…) // draw my model as edges
glEnd();
glFinish();

But…

I want to execute the hidden line removal by lines

so…

The part I want to correct

glBegin(GL_POLYGON);
glColor3ub(set appreciate colors);
glVertex(…) // draw my model as edges
glEnd();
glFinish();

--------->

for{
glBegin(GL_LINES);
…
glVertex(the one vertex of two, consisted in one edge);
glVertex(another vertex);
glEnd();
}

Relic said…

The polygon offset works only for polygonal primitives, not for GL_POINTS or GL_LINE…

So…Can’t I implement the hidden line removal by lines’ DB?

Please help me!!

Sure, you can do the second step with lines only and not with polygons. But the first step (drawing the polys in background-color) is needed in order to hide the hidden lines.

You can of course calculate your hidden line model mathematically, but it won’t be fast enough to rotate in realtime.

Kilam.