axmol/chipmunk/src/cpSpaceHash.c

535 lines
13 KiB
C

/* Copyright (c) 2007 Scott Lembcke
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <math.h>
#include <stdlib.h>
#include "chipmunk_private.h"
#include "prime.h"
static cpHandle*
cpHandleInit(cpHandle *hand, void *obj)
{
hand->obj = obj;
hand->retain = 0;
hand->stamp = 0;
return hand;
}
static inline void cpHandleRetain(cpHandle *hand){hand->retain++;}
static inline void
cpHandleRelease(cpHandle *hand, cpArray *pooledHandles)
{
hand->retain--;
if(hand->retain == 0) cpArrayPush(pooledHandles, hand);
}
cpSpaceHash*
cpSpaceHashAlloc(void)
{
return (cpSpaceHash *)cpcalloc(1, sizeof(cpSpaceHash));
}
// Frees the old table, and allocate a new one.
static void
cpSpaceHashAllocTable(cpSpaceHash *hash, int numcells)
{
cpfree(hash->table);
hash->numcells = numcells;
hash->table = (cpSpaceHashBin **)cpcalloc(numcells, sizeof(cpSpaceHashBin *));
}
// Equality function for the handleset.
static int handleSetEql(void *obj, cpHandle *hand){return (obj == hand->obj);}
// Transformation function for the handleset.
static void *
handleSetTrans(void *obj, cpSpaceHash *hash)
{
if(hash->pooledHandles->num == 0){
// handle pool is exhausted, make more
int count = CP_BUFFER_BYTES/sizeof(cpHandle);
cpAssert(count, "Buffer size is too small.");
cpHandle *buffer = (cpHandle *)cpcalloc(1, CP_BUFFER_BYTES);
cpArrayPush(hash->allocatedBuffers, buffer);
for(int i=0; i<count; i++) cpArrayPush(hash->pooledHandles, buffer + i);
}
cpHandle *hand = cpHandleInit((cpHandle *) cpArrayPop(hash->pooledHandles), obj);
cpHandleRetain(hand);
return hand;
}
cpSpaceHash*
cpSpaceHashInit(cpSpaceHash *hash, cpFloat celldim, int numcells, cpSpaceHashBBFunc bbfunc)
{
cpSpaceHashAllocTable(hash, next_prime(numcells));
hash->celldim = celldim;
hash->bbfunc = bbfunc;
hash->handleSet = cpHashSetNew(0, (cpHashSetEqlFunc)handleSetEql, (cpHashSetTransFunc)handleSetTrans);
hash->pooledHandles = cpArrayNew(0);
hash->pooledBins = NULL;
hash->allocatedBuffers = cpArrayNew(0);
hash->stamp = 1;
return hash;
}
cpSpaceHash*
cpSpaceHashNew(cpFloat celldim, int cells, cpSpaceHashBBFunc bbfunc)
{
return cpSpaceHashInit(cpSpaceHashAlloc(), celldim, cells, bbfunc);
}
static inline void
recycleBin(cpSpaceHash *hash, cpSpaceHashBin *bin)
{
bin->next = hash->pooledBins;
hash->pooledBins = bin;
}
static inline void
clearHashCell(cpSpaceHash *hash, int idx)
{
cpSpaceHashBin *bin = hash->table[idx];
while(bin){
cpSpaceHashBin *next = bin->next;
cpHandleRelease(bin->handle, hash->pooledHandles);
recycleBin(hash, bin);
bin = next;
}
hash->table[idx] = NULL;
}
// Clear all cells in the hashtable.
static void
clearHash(cpSpaceHash *hash)
{
for(int i=0; i<hash->numcells; i++)
clearHashCell(hash, i);
}
static void freeWrap(void *ptr, void *unused){cpfree(ptr);}
void
cpSpaceHashDestroy(cpSpaceHash *hash)
{
if(hash->table) clearHash(hash);
cpfree(hash->table);
cpHashSetFree(hash->handleSet);
if(hash->allocatedBuffers) cpArrayEach(hash->allocatedBuffers, freeWrap, NULL);
cpArrayFree(hash->allocatedBuffers);
cpArrayFree(hash->pooledHandles);
}
void
cpSpaceHashFree(cpSpaceHash *hash)
{
if(hash){
cpSpaceHashDestroy(hash);
cpfree(hash);
}
}
void
cpSpaceHashResize(cpSpaceHash *hash, cpFloat celldim, int numcells)
{
// Clear the hash to release the old handle locks.
clearHash(hash);
hash->celldim = celldim;
cpSpaceHashAllocTable(hash, next_prime(numcells));
}
// Return true if the chain contains the handle.
static inline cpBool
containsHandle(cpSpaceHashBin *bin, cpHandle *hand)
{
while(bin){
if(bin->handle == hand) return cpTrue;
bin = bin->next;
}
return cpFalse;
}
// Get a recycled or new bin.
static inline cpSpaceHashBin *
getEmptyBin(cpSpaceHash *hash)
{
cpSpaceHashBin *bin = hash->pooledBins;
if(bin){
hash->pooledBins = bin->next;
return bin;
} else {
// Pool is exhausted, make more
int count = CP_BUFFER_BYTES/sizeof(cpSpaceHashBin);
cpAssert(count, "Buffer size is too small.");
cpSpaceHashBin *buffer = (cpSpaceHashBin *)cpcalloc(1, CP_BUFFER_BYTES);
cpArrayPush(hash->allocatedBuffers, buffer);
// push all but the first one, return the first instead
for(int i=1; i<count; i++) recycleBin(hash, buffer + i);
return buffer;
}
}
// The hash function itself.
static inline cpHashValue
hash_func(cpHashValue x, cpHashValue y, cpHashValue n)
{
return (x*1640531513ul ^ y*2654435789ul) % n;
}
// Much faster than (int)floor(f)
// Profiling showed floor() to be a sizable performance hog
static inline int
floor_int(cpFloat f)
{
int i = (int)f;
return (f < 0.0f && f != i ? i - 1 : i);
}
static inline void
hashHandle(cpSpaceHash *hash, cpHandle *hand, cpBB bb)
{
// Find the dimensions in cell coordinates.
cpFloat dim = hash->celldim;
int l = floor_int(bb.l/dim); // Fix by ShiftZ
int r = floor_int(bb.r/dim);
int b = floor_int(bb.b/dim);
int t = floor_int(bb.t/dim);
int n = hash->numcells;
for(int i=l; i<=r; i++){
for(int j=b; j<=t; j++){
int idx = hash_func(i,j,n);
cpSpaceHashBin *bin = hash->table[idx];
// Don't add an object twice to the same cell.
if(containsHandle(bin, hand)) continue;
cpHandleRetain(hand);
// Insert a new bin for the handle in this cell.
cpSpaceHashBin *newBin = getEmptyBin(hash);
newBin->handle = hand;
newBin->next = bin;
hash->table[idx] = newBin;
}
}
}
void
cpSpaceHashInsert(cpSpaceHash *hash, void *obj, cpHashValue hashid, cpBB _deprecated_unused)
{
cpHandle *hand = (cpHandle *)cpHashSetInsert(hash->handleSet, hashid, obj, hash);
hashHandle(hash, hand, hash->bbfunc(obj));
}
void
cpSpaceHashRehashObject(cpSpaceHash *hash, void *obj, cpHashValue hashid)
{
cpHandle *hand = (cpHandle *)cpHashSetRemove(hash->handleSet, hashid, obj);
if(hand){
hand->obj = NULL;
cpHandleRelease(hand, hash->pooledHandles);
cpSpaceHashInsert(hash, obj, hashid, cpBBNew(0.0f, 0.0f, 0.0f, 0.0f));
}
}
static void handleRehashHelper(cpHandle *hand, cpSpaceHash *hash){hashHandle(hash, hand, hash->bbfunc(hand->obj));}
void
cpSpaceHashRehash(cpSpaceHash *hash)
{
clearHash(hash);
cpHashSetEach(hash->handleSet, (cpHashSetIterFunc)handleRehashHelper, hash);
}
void
cpSpaceHashRemove(cpSpaceHash *hash, void *obj, cpHashValue hashid)
{
cpHandle *hand = (cpHandle *)cpHashSetRemove(hash->handleSet, hashid, obj);
if(hand){
hand->obj = NULL;
cpHandleRelease(hand, hash->pooledHandles);
}
}
typedef struct eachPair {
cpSpaceHashIterator func;
void *data;
} eachPair;
static void eachHelper(cpHandle *hand, eachPair *pair){pair->func(hand->obj, pair->data);}
// Iterate over the objects in the spatial hash.
void
cpSpaceHashEach(cpSpaceHash *hash, cpSpaceHashIterator func, void *data)
{
eachPair pair = {func, data};
cpHashSetEach(hash->handleSet, (cpHashSetIterFunc)eachHelper, &pair);
}
static inline void
removeOrphanedHandles(cpSpaceHash *hash, cpSpaceHashBin **bin_ptr)
{
cpSpaceHashBin *bin = *bin_ptr;
while(bin){
cpHandle *hand = bin->handle;
cpSpaceHashBin *next = bin->next;
if(!hand->obj){
// orphaned handle, unlink and recycle the bin
(*bin_ptr) = bin->next;
recycleBin(hash, bin);
cpHandleRelease(hand, hash->pooledHandles);
} else {
bin_ptr = &bin->next;
}
bin = next;
}
}
// Calls the callback function for the objects in a given chain.
static inline void
query(cpSpaceHash *hash, cpSpaceHashBin **bin_ptr, void *obj, cpSpaceHashQueryFunc func, void *data)
{
restart:
for(cpSpaceHashBin *bin = *bin_ptr; bin; bin = bin->next){
cpHandle *hand = bin->handle;
void *other = hand->obj;
if(hand->stamp == hash->stamp || obj == other){
continue;
} else if(other){
func(obj, other, data);
hand->stamp = hash->stamp;
} else {
// The object for this handle has been removed
// cleanup this cell and restart the query
removeOrphanedHandles(hash, bin_ptr);
goto restart; // GCC not smart enough/able to tail call an inlined function.
}
}
}
void
cpSpaceHashPointQuery(cpSpaceHash *hash, cpVect point, cpSpaceHashQueryFunc func, void *data)
{
cpFloat dim = hash->celldim;
int idx = hash_func(floor_int(point.x/dim), floor_int(point.y/dim), hash->numcells); // Fix by ShiftZ
query(hash, &hash->table[idx], &point, func, data);
hash->stamp++;
}
void
cpSpaceHashQuery(cpSpaceHash *hash, void *obj, cpBB bb, cpSpaceHashQueryFunc func, void *data)
{
// Get the dimensions in cell coordinates.
cpFloat dim = hash->celldim;
int l = floor_int(bb.l/dim); // Fix by ShiftZ
int r = floor_int(bb.r/dim);
int b = floor_int(bb.b/dim);
int t = floor_int(bb.t/dim);
int n = hash->numcells;
cpSpaceHashBin **table = hash->table;
// Iterate over the cells and query them.
for(int i=l; i<=r; i++){
for(int j=b; j<=t; j++){
query(hash, &table[hash_func(i,j,n)], obj, func, data);
}
}
hash->stamp++;
}
// Similar to struct eachPair above.
typedef struct queryRehashPair {
cpSpaceHash *hash;
cpSpaceHashQueryFunc func;
void *data;
} queryRehashPair;
// Hashset iterator func used with cpSpaceHashQueryRehash().
static void
handleQueryRehashHelper(void *elt, void *data)
{
cpHandle *hand = (cpHandle *)elt;
// Unpack the user callback data.
queryRehashPair *pair = (queryRehashPair *)data;
cpSpaceHash *hash = pair->hash;
cpSpaceHashQueryFunc func = pair->func;
cpFloat dim = hash->celldim;
int n = hash->numcells;
void *obj = hand->obj;
cpBB bb = hash->bbfunc(obj);
int l = floor_int(bb.l/dim);
int r = floor_int(bb.r/dim);
int b = floor_int(bb.b/dim);
int t = floor_int(bb.t/dim);
cpSpaceHashBin **table = hash->table;
for(int i=l; i<=r; i++){
for(int j=b; j<=t; j++){
int idx = hash_func(i,j,n);
cpSpaceHashBin *bin = table[idx];
if(containsHandle(bin, hand)) continue;
cpHandleRetain(hand); // this MUST be done first in case the object is removed in func()
query(hash, &bin, obj, func, pair->data);
cpSpaceHashBin *newBin = getEmptyBin(hash);
newBin->handle = hand;
newBin->next = bin;
table[idx] = newBin;
}
}
// Increment the stamp for each object hashed.
hash->stamp++;
}
void
cpSpaceHashQueryRehash(cpSpaceHash *hash, cpSpaceHashQueryFunc func, void *data)
{
clearHash(hash);
queryRehashPair pair = {hash, func, data};
cpHashSetEach(hash->handleSet, &handleQueryRehashHelper, &pair);
}
static inline cpFloat
segmentQuery(cpSpaceHash *hash, cpSpaceHashBin **bin_ptr, void *obj, cpSpaceHashSegmentQueryFunc func, void *data)
{
cpFloat t = 1.0f;
restart:
for(cpSpaceHashBin *bin = *bin_ptr; bin; bin = bin->next){
cpHandle *hand = bin->handle;
void *other = hand->obj;
// Skip over certain conditions
if(hand->stamp == hash->stamp){
continue;
} else if(other){
t = cpfmin(t, func(obj, other, data));
hand->stamp = hash->stamp;
} else {
// The object for this handle has been removed
// cleanup this cell and restart the query
removeOrphanedHandles(hash, bin_ptr);
goto restart; // GCC not smart enough/able to tail call an inlined function.
}
}
return t;
}
// modified from http://playtechs.blogspot.com/2007/03/raytracing-on-grid.html
void cpSpaceHashSegmentQuery(cpSpaceHash *hash, void *obj, cpVect a, cpVect b, cpFloat t_exit, cpSpaceHashSegmentQueryFunc func, void *data)
{
a = cpvmult(a, 1.0f/hash->celldim);
b = cpvmult(b, 1.0f/hash->celldim);
int cell_x = floor_int(a.x), cell_y = floor_int(a.y);
cpFloat t = 0;
int x_inc, y_inc;
cpFloat temp_v, temp_h;
if (b.x > a.x){
x_inc = 1;
temp_h = (cpffloor(a.x + 1.0f) - a.x);
} else {
x_inc = -1;
temp_h = (a.x - cpffloor(a.x));
}
if (b.y > a.y){
y_inc = 1;
temp_v = (cpffloor(a.y + 1.0f) - a.y);
} else {
y_inc = -1;
temp_v = (a.y - cpffloor(a.y));
}
// Division by zero is *very* slow on ARM
cpFloat dx = cpfabs(b.x - a.x), dy = cpfabs(b.y - a.y);
cpFloat dt_dx = (dx ? 1.0f/dx : INFINITY), dt_dy = (dy ? 1.0f/dy : INFINITY);
// fix NANs in horizontal directions
cpFloat next_h = (temp_h ? temp_h*dt_dx : dt_dx);
cpFloat next_v = (temp_v ? temp_v*dt_dy : dt_dy);
cpSpaceHashBin **table = hash->table;
int n = hash->numcells;
while(t < t_exit){
int idx = hash_func(cell_x, cell_y, n);
t_exit = cpfmin(t_exit, segmentQuery(hash, &table[idx], obj, func, data));
if (next_v < next_h){
cell_y += y_inc;
t = next_v;
next_v += dt_dy;
} else {
cell_x += x_inc;
t = next_h;
next_h += dt_dx;
}
}
hash->stamp++;
}