Question

I was thinking of creating a 2×2 array with randomly generated values which then be drawn using glVertex3i, for example:

glBegin(GL_POLYGON);
int x = 5;
int z = 5;
for (int i=0; i<width; i++)
{
    for (int j=0; j<height; j++)
    {
        glVertex3i(x, heightmap[i][j], z);
    }
    x -= 0.5;
    z -= 0.5;
}
glEnd();

The only problem I’m having is that, the map isn’t drawn on the z dimension I think, because all I get is 1 side essentially.

What might be wrong? Obviously the algorithm is basic for now, but its just a starting point.

Answer 1

What might be wrong?

Let’s start here:

glBegin(GL_POLYGON);

A polygon is required to be planar. All of the vertices must lie in a single plane. If they don’t, then OpenGL is not responsible for how it gets rendered. You cannot draw a heightmap as a single polygon and expect to get reasonable results. You must draw triangles, either with a series of GL_TRIANGLE_STRIPs or with GL_TRIANGLES.

Then, there’s what Christian said.