constexpr int quality = 20;

static Vertex_t verts[quality];

for ( int i = 0; i < quality; i++ ) {
    float angle = ((float)i / -quality) * MATH_TAU;

    verts[i].x = cir.pos.x + (cir.radius * sin( angle ));
    verts[i].y = cir.pos.y + (cir.radius * cos( angle ));
}