inline plane_orientation classify_simplex_to_plane(const Simplex& smplx, const Hyperplane& plane, const NumberComparisonPolicy& cmp)
{
// Loop over all polygon vertices and count how many vertices
// lie in front of and how many lie behind of the thickened plane
auto numInFront = 0, numBehind = 0;
auto numVerts = number_vertices(smplx);
for (auto i = 0; i < numVerts; ++i)
{
auto p = get_vertex(smplx, i);
switch (classify_point_to_plane(p, plane, cmp))
{
case plane_orientation::in_front_of_plane:
++numInFront;
break;
case plane_orientation::in_back_of_plane:
++numBehind;
break;
}
}
// If vertices on both sides of the plane, the polygon is straddling
if (numBehind != 0 && numInFront != 0)
return plane_orientation::straddling_plane;
// If one or more vertices in front of the plane and no vertices behind
// the plane, the polygon lies in front of the plane
if (numInFront != 0)
return plane_orientation::in_front_of_plane;
// Ditto, the polygon lies behind the plane if no vertices in front of
// the plane, and one or more vertices behind the plane
if (numBehind != 0)
return plane_orientation::in_back_of_plane;
// All vertices lie on the plane so the polygon is coplanar with the plane
return plane_orientation::coplanar_with_plane;
}
void
cleanup_game(struct Game *game)
{
SDL_Quit();
destroy_vertices_array(screen_vertices(), 4);
destroy_vertices_array(number_vertices(), 4);
deconstruct_polygon(game->player);
deconstruct_polygon_array(game->asteroids, MAX_ASTEROIDS);
deconstruct_polygon_array(game->stars, MAX_STARS);
}
void
display_number(struct Game *game, int number)
{
char string[8];
sprintf(string, "%d", number);
int i;
int digit;
int offset;
float kerning;
int length = strlen(string);
for (i = 0; i < length; i++) {
digit = (int) string[i] - 48;
kerning = 1.5 + (float) i;
glPushMatrix();
glTranslatef(kerning, 0.6f, 0.0f);
display_quad(game->graphics.number_textures[digit], 0, 0, number_vertices());
glPopMatrix();
}
}
