158 lines
4.2 KiB
C
158 lines
4.2 KiB
C
// SPDX-FileCopyrightText: 2023 Erin Catto
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// SPDX-License-Identifier: MIT
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#pragma once
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#include "base.h"
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#include <stdint.h>
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/**
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* @defgroup id Ids
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* These ids serve as handles to internal Box2D objects.
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* These should be considered opaque data and passed by value.
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* Include this header if you need the id types and not the whole Box2D API.
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* All ids are considered null if initialized to zero.
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*
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* For example in C++:
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*
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* @code{.cxx}
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* b2WorldId worldId = {};
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* @endcode
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*
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* Or in C:
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*
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* @code{.c}
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* b2WorldId worldId = {0};
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* @endcode
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*
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* These are both considered null.
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*
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* @warning Do not use the internals of these ids. They are subject to change. Ids should be treated as opaque objects.
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* @warning You should use ids to access objects in Box2D. Do not access files within the src folder. Such usage is unsupported.
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* @{
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*/
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/// World id references a world instance. This should be treated as an opaque handle.
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typedef struct b2WorldId
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{
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uint16_t index1;
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uint16_t generation;
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} b2WorldId;
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/// Body id references a body instance. This should be treated as an opaque handle.
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typedef struct b2BodyId
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{
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int32_t index1;
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uint16_t world0;
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uint16_t generation;
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} b2BodyId;
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/// Shape id references a shape instance. This should be treated as an opaque handle.
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typedef struct b2ShapeId
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{
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int32_t index1;
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uint16_t world0;
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uint16_t generation;
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} b2ShapeId;
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/// Chain id references a chain instances. This should be treated as an opaque handle.
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typedef struct b2ChainId
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{
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int32_t index1;
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uint16_t world0;
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uint16_t generation;
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} b2ChainId;
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/// Joint id references a joint instance. This should be treated as an opaque handle.
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typedef struct b2JointId
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{
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int32_t index1;
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uint16_t world0;
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uint16_t generation;
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} b2JointId;
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/// Use these to make your identifiers null.
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/// You may also use zero initialization to get null.
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static const b2WorldId b2_nullWorldId = B2_ZERO_INIT;
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static const b2BodyId b2_nullBodyId = B2_ZERO_INIT;
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static const b2ShapeId b2_nullShapeId = B2_ZERO_INIT;
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static const b2ChainId b2_nullChainId = B2_ZERO_INIT;
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static const b2JointId b2_nullJointId = B2_ZERO_INIT;
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/// Macro to determine if any id is null.
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#define B2_IS_NULL( id ) ( id.index1 == 0 )
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/// Macro to determine if any id is non-null.
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#define B2_IS_NON_NULL( id ) ( id.index1 != 0 )
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/// Compare two ids for equality. Doesn't work for b2WorldId.
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#define B2_ID_EQUALS( id1, id2 ) ( id1.index1 == id2.index1 && id1.world0 == id2.world0 && id1.generation == id2.generation )
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/// Store a world id into a uint32_t.
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B2_INLINE uint32_t b2StoreWorldId( b2WorldId id )
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{
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return ( (uint32_t)id.index1 << 16 ) | (uint32_t)id.generation;
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}
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/// Load a uint32_t into a world id.
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B2_INLINE b2WorldId b2LoadWorldId( uint32_t x )
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{
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b2WorldId id = { (uint16_t)( x >> 16 ), (uint16_t)( x ) };
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return id;
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}
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/// Store a body id into a uint64_t.
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B2_INLINE uint64_t b2StoreBodyId( b2BodyId id )
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{
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return ( (uint64_t)id.index1 << 32 ) | ( (uint64_t)id.world0 ) << 16 | (uint64_t)id.generation;
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}
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/// Load a uint64_t into a body id.
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B2_INLINE b2BodyId b2LoadBodyId( uint64_t x )
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{
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b2BodyId id = { (int32_t)( x >> 32 ), (uint16_t)( x >> 16 ), (uint16_t)( x ) };
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return id;
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}
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/// Store a shape id into a uint64_t.
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B2_INLINE uint64_t b2StoreShapeId( b2ShapeId id )
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{
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return ( (uint64_t)id.index1 << 32 ) | ( (uint64_t)id.world0 ) << 16 | (uint64_t)id.generation;
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}
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/// Load a uint64_t into a shape id.
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B2_INLINE b2ShapeId b2LoadShapeId( uint64_t x )
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{
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b2ShapeId id = { (int32_t)( x >> 32 ), (uint16_t)( x >> 16 ), (uint16_t)( x ) };
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return id;
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}
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/// Store a chain id into a uint64_t.
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B2_INLINE uint64_t b2StoreChainId( b2ChainId id )
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{
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return ( (uint64_t)id.index1 << 32 ) | ( (uint64_t)id.world0 ) << 16 | (uint64_t)id.generation;
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}
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/// Load a uint64_t into a chain id.
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B2_INLINE b2ChainId b2LoadChainId( uint64_t x )
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{
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b2ChainId id = { (int32_t)( x >> 32 ), (uint16_t)( x >> 16 ), (uint16_t)( x ) };
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return id;
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}
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/// Store a joint id into a uint64_t.
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B2_INLINE uint64_t b2StoreJointId( b2JointId id )
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{
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return ( (uint64_t)id.index1 << 32 ) | ( (uint64_t)id.world0 ) << 16 | (uint64_t)id.generation;
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}
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/// Load a uint64_t into a joint id.
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B2_INLINE b2JointId b2LoadJointId( uint64_t x )
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{
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b2JointId id = { (int32_t)( x >> 32 ), (uint16_t)( x >> 16 ), (uint16_t)( x ) };
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return id;
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}
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/**@}*/
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