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#include "world.hpp"
extern "C" {
#include "memory.h"
#include "plat.h"
}
#include <string.h>
static int component_sizes[max_components];
void Pool::init(Arena* a, Component_Mask m) {
int i, coff;
next = 0;
size = 0;
mask = m;
count = 0;
for (i = 0, coff = 0; i < max_components; i++) {
if (m & ((Component_Mask)1 << i)) {
offsets[i] = coff;
coff += component_sizes[i];
}
}
size = coff;
data = arena_alloc(a, size * pool_cap);
}
void* Pool::add(Arena* a, Entity_Id eid) {
int idx;
if (next)
return next->add(a, eid);
if (count >= pool_cap) {
next = (Pool*)arena_alloc(a, sizeof *next);
next->init(a, mask);
return next->add(a, eid);
}
idx = count++;
entities[idx] = eid;
mapping[entity_index(eid)] = idx;
return &((char*)data)[idx * size];
}
void Pool::remove(Entity_Id eid) {
int eind = entity_index(eid);
int end = count - 1;
assert(eid == entities[mapping[eind]]);
memmove(
(char*)data + eind * size,
(char*)data + end * size,
size
);
entities[eind] = entities[count];
mapping[end] = eind;
count = end;
}
void* Pool::get(Entity_Id eid, int cid) {
int eind = entity_index(eid);
char* e = &((char*)data)[mapping[eind] * size];
assert(eid == entities[mapping[eind]]);
return &e[offsets[cid]];
}
void* Pool::get(Entity_Id eid) {
int eind = entity_index(eid);
void* e = &((char*)data)[mapping[eind] * size];
assert(eid == entities[mapping[eind]]);
return e;
}
int get_new_component_id(int size) {
static int id = 0;
int i = id++;
component_sizes[i] = size;
return i;
}
int entity_version(Entity_Id e) {
return e & 0xff;
}
int entity_index(Entity_Id e) {
return (e >> 8) & 0xffffff;
}
Entity_Id entity_id(int index, int version) {
return ((index & 0xffffff) << 8) | (version & 0xff);
}
void World::init(Arena* a) {
int i;
arena = a;
count = 0;
free_count = 0;
for (i = 0; i < max_entities; i++)
versions[i] = 1;
for (i = 0; i < max_pools; i++)
pools[i].mask = 0;
}
uint64_t World::hash_mask(Component_Mask m) {
uint64_t h = (uint64_t)m;
h = (h ^ (h >> 30)) * UINT64_C(0xbf58476d1ce4e5b9);
h = (h ^ (h >> 27)) * UINT64_C(0x94d049bb133111eb);
h = (h ^ (h >> 31));
return h;
}
Pool& World::get_pool(Component_Mask m) {
int i, idx;
idx = (int)(hash_mask(m) % max_pools);
for (i = 0; i < max_pools; i++) {
Pool& p = pools[idx];
if (!p.mask) {
p.init(arena, m);
return p;
} else if (p.mask == m)
return p;
idx++;
idx %= max_pools;
}
assert(0);
return pools[0];
}
Entity_Id World::create_entity() {
Entity_Id e;
int ind;
assert(count < max_entities);
if (free_count)
ind = entity_index(freelist[--free_count]);
else
ind = count++;
e = entity_id(ind, versions[ind]);
masks[ind] = 0;
entities[ind] = e;
return e;
}
void* World::add(Entity_Id eid, Component_Mask m) {
int eind = entity_index(eid);
int i;
assert(entity_version(eid) == versions[eind]);
Component_Mask om = masks[eind];
Component_Mask tm = om | m;
assert(om != tm);
Pool& p = get_pool(tm);
p.add(arena, eid);
if (om) {
Pool& op = get_pool(om);
for (i = 0; i < max_components; i++) {
if (om & ((Component_Mask)1 << i)) {
memcpy(
p.get(eid, i),
op.get(eid, i),
component_sizes[i]
);
}
}
op.remove(eid);
}
masks[eind] = tm;
return p.get(eid);
}
void* World::get(Entity_Id eid, int cid) {
int eind = entity_index(eid);
Pool& p = get_pool(masks[eind]);
assert(versions[eind] == entity_version(eid));
assert(p.entities[p.mapping[eind]] == eid);
return p.get(eid, cid);
}
void World::remove(Entity_Id eid, int cid) {
int eind = entity_index(eid), i;
Component_Mask om = masks[eind];
Component_Mask nm = om & ~((Component_Mask)1 << cid);
Pool& s = get_pool(om);
if (nm) {
Pool& d = get_pool(nm);
for (i = 0; i < max_components; i++) {
if (nm & ((uint64_t)1 << i)) {
memcpy(
d.get(eid, i),
s.get(eid, i),
component_sizes[i]
);
}
}
s.remove(eid);
}
s.remove(eid);
masks[eind] = nm;
}
void World::destroy(Entity_Id e) {
int eind = entity_index(e);
Component_Mask m = masks[eind];
Pool& p = get_pool(m);
p.remove(e);
assert(free_count < max_entities);
freelist[free_count++] = e;
versions[entity_index(e)]++;
}
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