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Improve performance of frQuerySpatialHash() by using frBitArray
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@jdeokkim
jdeokkim committed Nov 4, 2024
1 parent edb697c commit f881b88
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Showing 11 changed files with 316 additions and 198 deletions.
27 changes: 16 additions & 11 deletions include/ferox.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -25,7 +25,7 @@

#ifdef __cplusplus
extern "C" {
#endif
#endif // `__cplusplus`

/* Includes ===============================================================> */

Expand Down Expand Up @@ -80,17 +80,19 @@ extern "C" {
/* Macros =================================================================> */

/* Compiler-specific attribute for a function that must be inlined. */
#ifdef _MSC_VER
#define FR_API_INLINE __forceinline
#elif defined(__GNUC__)
#if defined(__STRICT_ANSI__)
#define FR_API_INLINE __inline__ __attribute__((always_inline))
#ifndef FR_API_INLINE
#ifdef _MSC_VER
#define FR_API_INLINE __forceinline
#elif defined(__GNUC__)
#if defined(__STRICT_ANSI__)
#define FR_API_INLINE __inline__ __attribute__((always_inline))
#else
#define FR_API_INLINE inline __attribute__((always_inline))
#endif
#else
#define FR_API_INLINE inline __attribute__((always_inline))
#define FR_API_INLINE inline
#endif
#else
#define FR_API_INLINE inline
#endif
#endif // `FR_API_INLINE`

/* ========================================================================> */

Expand All @@ -104,6 +106,9 @@ typedef struct frVector2_ {
float x, y;
} frVector2;

/* An alias for the `frVector2` data type. */
typedef frVector2 frVector2f;

/* A structure that represents an axis-aligned bounding box. */
typedef struct frAABB_ {
float x, y, width, height;
Expand Down Expand Up @@ -722,6 +727,6 @@ FR_API_INLINE float frUnitsToPixels(float k) {

#ifdef __cplusplus
}
#endif
#endif // `__cplusplus`

#endif // `FEROX_H`
114 changes: 49 additions & 65 deletions src/broad_phase.c
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Original file line number Diff line number Diff line change
Expand Up @@ -22,54 +22,50 @@

/* Includes ===============================================================> */

#include "external/ferox_utils.h"
#include "external/stb_ds.h"

#include "ferox.h"

/* Typedefs ===============================================================> */

/* A structure that represents the key of a spatial hash entry. */
typedef struct frSpatialHashKey_ {
/*
A structure that represents a two-dimensional vector
with `int` coordinates.
*/
typedef struct frVector2i_ {
int x, y;
} frSpatialHashKey;

/* A structure that represents the value of a spatial hash entry. */
typedef int *frSpatialHashValue;
} frVector2i;

/* A structure that represents the key-value pair of a spatial hash.*/
typedef struct frSpatialHashEntry_ {
frSpatialHashKey key;
frSpatialHashValue value;
frVector2i key;
frDynArray(int) value;
} frSpatialHashEntry;

/* A struct that represents a spatial hash. */
struct frSpatialHash_ {
float cellSize, inverseCellSize;
frSpatialHashValue queryResult;
frSpatialHashEntry *entries;
float cellSize, inverseCellSize;
frDynArray(int) queryResult;
frBitArray indexSet;
};

/* Private Function Prototypes ============================================> */

/*
Returns ​a negative integer value if `a` is less than `b`, ​a positive
integer value if `a` is greater than `b` and zero if `a` and `b`
are equivalent.
*/
static int frQSortCompare(const void *a, const void *b);

/* Public Functions =======================================================> */

/* Creates a new spatial hash with the given `cellSize`. */
frSpatialHash *frCreateSpatialHash(float cellSize) {
if (cellSize <= 0.0f) return NULL;

// NOTE: `sh->queryResult` and `sh->entries` must be initialized to `NULL`
frSpatialHash *sh = calloc(1, sizeof *sh);

sh->cellSize = cellSize;
sh->inverseCellSize = 1.0f / cellSize;

sh->indexSet = frCreateBitArray(FR_WORLD_MAX_OBJECT_COUNT);

frInitDynArray(sh->queryResult);

return sh;
}

Expand All @@ -78,19 +74,20 @@ void frReleaseSpatialHash(frSpatialHash *sh) {
if (sh == NULL) return;

for (int i = 0; i < hmlen(sh->entries); i++)
arrfree(sh->entries[i].value);
frReleaseDynArray(sh->entries[i].value);

frReleaseBitArray(sh->indexSet);
frReleaseDynArray(sh->queryResult);

hmfree(sh->entries), arrfree(sh->queryResult), free(sh);
hmfree(sh->entries), free(sh);
}

/* Erases all elements from `sh`. */
void frClearSpatialHash(frSpatialHash *sh) {
if (sh == NULL) return;

arrsetlen(sh->queryResult, 0);

for (int i = 0; i < hmlen(sh->entries); i++)
arrsetlen(sh->entries[i].value, 0);
frSetDynArrayLength(sh->entries[i].value, 0);
}

/* Returns the cell size of `sh`. */
Expand All @@ -112,16 +109,17 @@ void frInsertIntoSpatialHash(frSpatialHash *sh, frAABB key, int value) {

for (int y = minY; y <= maxY; y++)
for (int x = minX; x <= maxX; x++) {
frSpatialHashKey key = { .x = x, .y = y };
frVector2i key = { .x = x, .y = y };

frSpatialHashEntry *entry = hmgetp_null(sh->entries, key);

if (entry != NULL) {
arrput(entry->value, value);
frDynArrayPush(entry->value, value);
} else {
frSpatialHashEntry newEntry = { .key = key };

arrput(newEntry.value, value);
frInitDynArray(newEntry.value);
frDynArrayPush(newEntry.value, value);

hmputs(sh->entries, newEntry);
}
Expand All @@ -143,59 +141,45 @@ void frQuerySpatialHash(frSpatialHash *sh,
int maxX = (aabb.x + aabb.width) * inverseCellSize;
int maxY = (aabb.y + aabb.height) * inverseCellSize;

arrsetlen(sh->queryResult, 0);
frSetDynArrayLength(sh->queryResult, 0);

for (int y = minY; y <= maxY; y++)
for (int x = minX; x <= maxX; x++) {
frSpatialHashKey key = { .x = x, .y = y };
frVector2i key = { .x = x, .y = y };

frSpatialHashEntry *entry = hmgetp_null(sh->entries, key);

if (entry == NULL) continue;

for (int i = 0; i < arrlen(entry->value); i++)
arrput(sh->queryResult, entry->value[i]);
for (int i = 0; i < frGetDynArrayLength(entry->value); i++)
frDynArrayPush(
sh->queryResult,
frGetDynArrayValue(entry->value, i)
);
}

size_t oldLength = arrlen(sh->queryResult);

if (oldLength > 1) {
// NOTE: Sort the array first, then remove duplicates!
qsort(sh->queryResult,
oldLength,
sizeof *(sh->queryResult),
frQSortCompare);

size_t newLength = 0;
{
frBitArrayClear(sh->indexSet, FR_WORLD_MAX_OBJECT_COUNT);

for (int i = 0; i < oldLength; i++)
if (sh->queryResult[i] != sh->queryResult[i + 1])
sh->queryResult[newLength++] = sh->queryResult[i];
for (int i = 0; i < frGetDynArrayLength(sh->queryResult); i++)
frBitArraySet(sh->indexSet, frGetDynArrayValue(sh->queryResult, i));

if (sh->queryResult[newLength - 1] != sh->queryResult[oldLength - 1])
sh->queryResult[newLength++] = sh->queryResult[oldLength - 1];
frSetDynArrayLength(sh->queryResult, 0);

arrsetlen(sh->queryResult, newLength);
for (int i = 0; i < FR_WORLD_MAX_OBJECT_COUNT; i++)
if (frBitArrayGet(sh->indexSet, i))
frDynArrayPush(sh->queryResult, i);
}

/*
NOTE: For each object in the query result, the callback `func`tion
will be called with the user data pointer `ctx`.
*/
for (int i = 0; i < arrlen(sh->queryResult); i++)
func((frContextNode) { .id = sh->queryResult[i], .ctx = userData });
}

/* Private Functions ======================================================> */

/*
Returns ​a negative integer value if `a` is less than `b`, ​a positive
integer value if `a` is greater than `b` and zero if `a` and `b`
are equivalent.
*/
static int frQSortCompare(const void *a, const void *b) {
const int x = *(const int *) a;
const int y = *(const int *) b;

return (x > y) - (x < y);
}
for (int i = 0; i < frGetDynArrayLength(sh->queryResult); i++)
func(
(frContextNode) {
.id = frGetDynArrayValue(sh->queryResult, i),
.ctx = userData
}
);
}
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