/*********************************************************************
* This function returns a pointer to the sphere object that the
* ray intersects first; NULL if no intersection. You should decide
* which arguments to use for the function. For exmaple, note that you
* should return the point of intersection to the calling function.
**********************************************************************/
Spheres *intersect_scene(Point o, Vector u, Spheres *sph, Point *hit, int sindex) {
Spheres *closest_sph = NULL;
Point closest_hit;
float min = -1;
while (sph != NULL)
{
// skips this sphere (used for shadows)
if (sph->index == sindex)
{
sph = sph->next;
continue;
}
Point hit;
float intersect;
if (sph->index == 0)
intersect = intersect_board(o, u, sph, &hit);
else
intersect = intersect_sphere(o, u, sph, &hit);
if ( intersect > 0 && (intersect < min || min < 0) )
{
min = intersect;
closest_sph = sph;
closest_hit = hit;
}
sph = sph->next;
}
if (hit != NULL)
*hit = closest_hit;
return closest_sph;
}
int
pick_square(struct position *pos, const struct board_state *state,
const struct matrix *mv, int x, int y)
{
struct ray ray_orig; /* pick ray in world coordinates */
struct ray ray_obj; /* pick ray in object coordinates */
struct matrix inv_mv;
struct vector p;
int i, j;
struct position first_pos;
const unsigned char *ps;
struct hit hit;
int no_hits, hit_level, hit_square;
float closer_t;
/* ray in world coordinates */
get_pick_ray(&ray_orig, x, y);
/* transform ray to game coordinates */
mat_invert_copy(&inv_mv, mv);
mat_transform_ray(&ray_obj, &inv_mv, &ray_orig);
no_hits = 1;
hit_level = hit_square = -1;
closer_t = -1.f;
for (i = 0; i < NUM_MAIN_BOARDS; i++) {
/* intersection with main board */
get_main_board_xyz(&p, i);
get_main_board_position(&first_pos, i);
ps = &state->board[first_pos.level][first_pos.square];
if (intersect_board(&hit, &ray_obj, &p, ps, MAIN_BOARD_SIZE)) {
if (no_hits || hit.t < closer_t) {
closer_t = hit.t;
hit_level = first_pos.level;
hit_square = first_pos.square +
hit.row*BCOLS + hit.col;
no_hits = 0;
}
}
for (j = 0; j < 8; j++) {
if (ATTACK_BOARD_IS_ACTIVE(state, i, j)) {
/* intersection with attack board */
hit.t = -1.f;
get_attack_board_xyz(&p, i, j);
get_attack_board_position(&first_pos, i, j);
ps = &state->board
[first_pos.level][first_pos.square];
if (intersect_board(&hit, &ray_obj, &p, ps,
ATTACK_BOARD_SIZE)) {
if (no_hits || hit.t < closer_t) {
closer_t = hit.t;
hit_level = first_pos.level;
hit_square = first_pos.square +
hit.row*BCOLS + hit.col;
no_hits = 0;
}
}
}
}
}
if (no_hits)
return 0;
pos->level = hit_level;
pos->square = hit_square;
return 1;
}