distance.h

// SPDX-FileCopyrightText: 2023 Erin Catto
// SPDX-License-Identifier: MIT
 
#pragma once
 
#include "constants.h"
#include "types.h"
 
typedef struct b2SegmentDistanceResult
{
    b2Vec2 closest1;
    b2Vec2 closest2;
    float fraction1;
    float fraction2;
    float distanceSquared;
} b2SegmentDistanceResult;
 
BOX2D_API b2SegmentDistanceResult b2SegmentDistance(b2Vec2 p1, b2Vec2 q1, b2Vec2 p2, b2Vec2 q2);
 
typedef struct b2DistanceProxy
{
    b2Vec2 vertices[b2_maxPolygonVertices];
    int32_t count;
    float radius;
} b2DistanceProxy;
 
typedef struct b2DistanceCache
{
    float metric; 
    uint16_t count;
    uint8_t indexA[3]; 
    uint8_t indexB[3]; 
} b2DistanceCache;
 
static const b2DistanceCache b2_emptyDistanceCache = B2_ZERO_INIT;
 
typedef struct b2DistanceInput
{
    b2DistanceProxy proxyA;
    b2DistanceProxy proxyB;
    b2Transform transformA;
    b2Transform transformB;
    bool useRadii;
} b2DistanceInput;
 
typedef struct b2DistanceOutput
{
    b2Vec2 pointA; 
    b2Vec2 pointB; 
    float distance;
    int32_t iterations; 
} b2DistanceOutput;
 
BOX2D_API b2DistanceOutput b2ShapeDistance(b2DistanceCache* cache, const b2DistanceInput* input);
 
typedef struct b2ShapeCastPairInput
{
    b2DistanceProxy proxyA;
    b2DistanceProxy proxyB;
    b2Transform transformA;
    b2Transform transformB;
    b2Vec2 translationB;
    float maxFraction;
} b2ShapeCastPairInput;
 
BOX2D_API b2RayCastOutput b2ShapeCast(const b2ShapeCastPairInput* input);
 
BOX2D_API b2DistanceProxy b2MakeProxy(const b2Vec2* vertices, int32_t count, float radius);
 
typedef struct b2Sweep
{
    b2Vec2 localCenter;
 
    b2Vec2 c1, c2;
 
    float a1, a2;
} b2Sweep;
 
BOX2D_API b2Transform b2GetSweepTransform(const b2Sweep* sweep, float time);
 
typedef struct b2TOIInput
{
    b2DistanceProxy proxyA;
    b2DistanceProxy proxyB;
    b2Sweep sweepA;
    b2Sweep sweepB;
 
    // defines sweep interval [0, tMax]
    float tMax;
} b2TOIInput;
 
typedef enum b2TOIState
{
    b2_toiStateUnknown,
    b2_toiStateFailed,
    b2_toiStateOverlapped,
    b2_toiStateHit,
    b2_toiStateSeparated
} b2TOIState;
 
typedef struct b2TOIOutput
{
    b2TOIState state;
    float t;
} b2TOIOutput;
 
BOX2D_API b2TOIOutput b2TimeOfImpact(const b2TOIInput* input);