Once it is determined what
action each character wants to perform, that action
must be validated. Characters moving around can’t walk through other players
(except for PCs, who can walk through other PCs). Also, depending on your
levels,
you use a function to determine character-to-map collisions. These two
validation
functions are as follows:
///////////////////////////////////////////////////////////////////////////////////////////////////
bool cCharController::check_move(sCharacter* character, float* x_move, float* y_move, float* z_move)
{
if(character == NULL)
return false;
float pos_x = character->pos_x + (*x_move);
float pos_y = character->pos_y + (*y_move);
float pos_z = character->pos_z + (*z_move);
float min_x, min_z, max_x, max_z;
character->object.get_bounds(&min_x, NULL, &min_z, &max_x, NULL, &max_z, NULL);
float radius1 = max(max_x - min_x, max_z - min_z) * 0.5;
// check movement against other characters
for(sCharacter* char_ptr = m_root_char; char_ptr != NULL; char_ptr = char_ptr->next)
{
// do not check against self or disabled characters
if(character != char_ptr && char_ptr->update_enable)
{
// do not check against other PC characters
if(character->type == CHAR_PC && char_ptr->type == CHAR_PC)
break;
// get distance between characters
float x_diff = fabs(pos_x - char_ptr->pos_x);
float y_diff = fabs(pos_y - char_ptr->pos_y);
float z_diff = fabs(pos_z - char_ptr->pos_z);
float dist = x_diff * x_diff + y_diff * y_diff + z_diff * z_diff;
char_ptr->object.get_bounds(&min_x, NULL, &min_z, &max_x, NULL, &max_z, NULL);
float radius2 = max(max_x - min_x, max_z - min_z) * 0.5f;
// do not allow movement if intersecting
if(dist <= (radius1 * radius1 + radius2 * radius2))
return false;
}
}
// check custom collisions (map, etc)
return validate_move(character, x_move, y_move, z_move);
}
///////////////////////////////////////////////////////////////////////////////////////////////////
virtual bool validate_move(sCharacter* character, float* x_move, float* y_move, float* z_move)
{
// validate for outside bounds checking against character movements.
return true;
}
Both of the preceding functions (check_move
and validate_move) take a pointer to the
character being updated, as well as the character’s intended amount of movement
in each direction. Each function modifies these values appropriately. When the
character’s moves and actions have been validated, another function wraps up the
actions and actually updates the character positions and actions.
///////////////////////////////////////////////////////////////////////////////////////////////////
void cCharController::process_update(sCharacter* character, float x_move, float y_move, float z_move)
{
// move character
character->pos_x += x_move;
character->pos_y += y_move;
character->pos_z += z_move;
// move object and point in direction
character->object.move(character->pos_x, character->pos_y, character->pos_z);
character->object.rotate(0.0f, character->direction, 0.0f);
// set new animation
if(character->last_anim != character->action)
{
character->last_anim = character->action;
if(m_num_char_anim != 0 && m_char_anim)
{
character->last_anim_time = timeGetTime() / 30;
character->object.set_anim_set(
&m_mesh_anim[character->char_def.mesh_index].anim,
m_char_anim[character->action].name,
character->last_anim_time);
}
}
}
Whenever characters start battling
it out, some are sure to die. The controller can
quickly handle dying NPCs and monsters by removing their respective structures
from the list. As for PCs though, death can mean the end of the game, so it’s up
to
the main application to handle them. That’s the reasoning behind pc_death, which
takes a single argument, the pointer to the dying PC:
virtual void
pc_death(sCharacter* character)
{
}
Speaking of characters dying,
any time a monster dies, it has a chance of dropping
an item, as well as all the money it is carrying. Because your main application
handles
all items in the maps, it’s your job to determine when a monster drops an item
or gold and to add the appropriate item to the map’s list of items. Overriding
the
following two functions will help you out anytime a monster drops something by
giving you the exact coordinates where the monster perished, the item dropped,
and the amount of money dropped.
virtual bool
drop_money(float pos_x, float pos_y, float pos_z, long quantity)
{
return true;
}
virtual bool drop_item(float pos_x, float pos_y, float pos_z, long item_index)
{
return true;
}