broad_phase.h

// SPDX-FileCopyrightText: 2023 Erin Catto
// SPDX-License-Identifier: MIT

#pragma once

#include "dynamic_tree.h"
#include "table.h"

#include "box2d/collision.h"
#include "box2d/types.h"

typedef struct b2Shape b2Shape;
typedef struct b2Stack b2Stack;
typedef struct b2World b2World;

// Store the proxy type in the lower 2 bits of the proxy key. This leaves 30 bits for the id.
#define B2_PROXY_TYPE( KEY ) ( (b2BodyType)( ( KEY ) & 3 ) )
#define B2_PROXY_ID( KEY ) ( ( KEY ) >> 2 )
#define B2_PROXY_KEY( ID, TYPE ) ( ( ( ID ) << 2 ) | ( TYPE ) )

/// The broad-phase is used for computing pairs and performing volume queries and ray casts.
/// This broad-phase does not persist pairs. Instead, this reports potentially new pairs.
/// It is up to the client to consume the new pairs and to track subsequent overlap.
typedef struct b2BroadPhase
{
	// One tree for each body type.
	b2DynamicTree trees[b2_bodyTypeCount];

	// The moved siblings gathered from the dynamic body tree.
	int* movedSiblings;

	// Tracks shape pairs that have a b2Contact
	b2HashSet pairSet;
} b2BroadPhase;

void b2CreateBroadPhase( b2BroadPhase* bp, const b2Capacity* capacity );
void b2DestroyBroadPhase( b2BroadPhase* bp );

int b2BroadPhase_CreateProxy( b2BroadPhase* bp, b2BodyType proxyType, b2AABB aabb, uint64_t categoryBits, int shapeIndex,
							  bool forcePairCreation );
void b2BroadPhase_DestroyProxy( b2BroadPhase* bp, int proxyKey );

void b2BroadPhase_MoveProxy( b2BroadPhase* bp, int proxyKey, b2AABB aabb );

void b2UpdateBroadPhasePairs( b2World* world );

void b2RadixSortKeys( uint64_t* keys, uint64_t* tempKeys, int count );

void b2ValidateBroadphase( const b2BroadPhase* bp );
void b2ValidateNoEnlarged( const b2BroadPhase* bp );

static inline void b2BroadPhase_MarkProxyMovedSerial( b2BroadPhase* bp, int proxyKey )
{
	b2BodyType proxyType = B2_PROXY_TYPE( proxyKey );
	int proxyId = B2_PROXY_ID( proxyKey );
	b2DynamicTree_MarkProxyMovedSerial( bp->trees + proxyType, proxyId );
}

static inline void b2BroadPhase_MarkProxyMoved( b2BroadPhase* bp, int proxyKey, b2AABB aabb )
{
	b2BodyType proxyType = B2_PROXY_TYPE( proxyKey );
	int proxyId = B2_PROXY_ID( proxyKey );
	b2DynamicTree_MarkProxyMoved( bp->trees + proxyType, proxyId, aabb );
}