Question

I am trying to import .obj files but cant even get a triangle rendered. Here is what I’m trying to do just to test if it can show something.

glBegin(GL_TRIANGLES);
    glColor3f(0.5, 0.5, 0.5);
    glVertex3f(0, 0, 0);
    glVertex3f(1, 1, 1);
    glVertex3f(2, 2, 2);
glEnd();

This doesn’t display anything. However when I change GL_TRIANGLES for GL_LINES it displays the line.

How can I get the triangle to display?

Language: C++

OS: Mac 10.7.3

Answer 1

A triangle where all three points are colinear (in the same line) has zero area. And a triangle renderer only renders the area of a triangle, not the edges of it. So it renders zero pixels.