Files
asteroids/collisions.c

88 lines
1.7 KiB
C

#include "collisions.h"
#include "entity.h"
#include <assert.h>
#include <string.h>
typedef struct {
bool valid;
unsigned component_id;
float r;
unsigned priority;
collision_cb_t cb;
} entry_t;
static unsigned max;
static entry_t entries[MAX_ENTITIES];
static void update(unsigned new_entity_id, void *ref)
{
entry_t *old_e = (entry_t *)ref;
entry_t *new_e = entries + new_entity_id;
memcpy(new_e, old_e, sizeof(entry_t));
old_e->valid = false;
entity_update_component(new_entity_id, new_e->component_id, new_e);
}
static void remove(void *ref)
{
entry_t *e = (entry_t *)ref;
e->valid = false;
}
void collisions_init()
{
max = 0;
}
void collisions_update()
{
for (unsigned i = 0; i < max; ++i) {
if (!entries[i].valid)
continue;
for (unsigned j = i + 1; j < max; ++j) {
if (!entries[j].valid)
continue;
const physics_sep_t sep = physics_separation(i, j);
if (sep.dist > entries[i].r + entries[j].r)
continue;
if (sep.va - sep.vb <= 0)
continue;
if (entries[i].priority >= entries[j].priority) {
entries[i].cb(i, j, sep);
} else {
const physics_sep_t flip_sep = {
.dist = sep.dist,
.norm = vec2_scale(sep.norm, -1),
.va = -sep.vb,
.vb = -sep.va,
};
entries[j].cb(j, i, flip_sep);
}
}
}
}
void collisions_add(
unsigned entity, float radius, unsigned priority, collision_cb_t cb)
{
assert(entity < MAX_ENTITIES);
if (entity >= max)
max = entity + 1;
else
assert(!entries[entity].valid);
entry_t *entry = entries + entity;
entry->valid = true;
entry->component_id
= entity_add_component(entity, update, remove, entry);
entry->r = radius;
entry->priority = priority;
entry->cb = cb;
}