help:getting 3Dcoordinates to 2D coordinates and vice versa

(rince__vng) #1

I was wondering if there was a way to get the 3D coordinates to 2D coordinates so that I could have some text properly float. Is there a way to do this in the wolf code?

(zinx) #2

You’ll probably need to do more than just get the coordinates, but here’s some code I wrote for q3/et to convert a single point:


qboolean WorldToScreen(vec3_t point, vec_t world[2])
{
        vec3_t trans;
        vec_t xc, yc;
        vec_t px, py;
        vec_t z;

        px = tan(cg.refdef.fov_x * M_PI / 360.0);
        py = tan(cg.refdef.fov_y * M_PI / 360.0);

        VectorSubtract(point, cg.refdef.vieworg, trans);

        xc = cg.refdef.width / 2.0;
        yc = cg.refdef.height / 2.0;

        z = DotProduct(trans, cg.refdef.viewaxis[0]);
        if (z <= 0.001)
                return qfalse;

        world[0] = xc - DotProduct(trans, cg.refdef.viewaxis[1])*xc/(z*px);
        world[1] = yc - DotProduct(trans, cg.refdef.viewaxis[2])*yc/(z*py);
        return qtrue;
}

It returns ‘true’ if the point might be visible

(rince__vng) #3

interesting, this leads me to another question (more simple than that mysterious formula) : Does anyone know of any sites that have a decent explanation of vectors or vector math or formulas related to vectors ? (Don’t worry, I can do this on my own so don’t feel too guilty if you don’t feel like responding)