RaycastCallback.cpp

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#include "Engine/Collision/RaycastCallback.hpp"
#include "Engine/engine.hpp"

namespace Engine
{
    RayCastClosestCallback::RayCastClosestCallback() : hit(false), detectionLayers(CollisionLayer::SOLID)
    {
    }

    RayCastClosestCallback::RayCastClosestCallback(const CollisionLayer detectLayers) : hit(false), detectionLayers(detectLayers)
    {
    }

    float32 RayCastClosestCallback::ReportFixture(b2Fixture* fixture, const b2Vec2& point, const b2Vec2& normal, float32 fraction)
    {
        const bool isDetectable = uint16(detectionLayers) & fixture->GetFilterData().categoryBits;
        if (isDetectable == false)
            return 1.0f;

        // Record hit data
        hit = true;
        this->point = point;
        this->normal = normal;

        // Record Hit Entity
        const uint64_t entityID = uint64_t(fixture->GetUserData());
        entity = Engine::GetEngine().lock()->GetEntitySystem().lock()->GetEntity(entityID);

        // BOX2D Comment - By returning the current fraction, we instruct the calling code to clip the ray and
        // continue the ray-cast to the next fixture. WARNING: do not assume that fixtures
        // are reported in order. However, by clipping, we can always get the closest fixture.
        return fraction;
    }

    RayCastMultipleCallback::RayCastMultipleCallback() : detectionLayers(CollisionLayer::SOLID), count(0)
    {
    }

    RayCastMultipleCallback::RayCastMultipleCallback(const CollisionLayer detectLayers) : detectionLayers(detectLayers), count(0)
    {
    }

    float32 RayCastMultipleCallback::ReportFixture(b2Fixture* fixture, const b2Vec2& point, const b2Vec2& normal, float32)
    {
        const bool isDetectable = uint16(detectionLayers) & fixture->GetFilterData().categoryBits;
        if (isDetectable == false)
            return 1.0f;

        b2Assert(count < MAX_COUNT);

        // Record hit data
        points[count] = point;
        normals[count] = normal;
        ++count;

        if (count == MAX_COUNT)
        {
            // At this point the buffer is full.
            // By returning 0, we instruct the calling code to terminate the ray-cast.
            return 0.0f;
        }

        // By returning 1, we instruct the caller to continue without clipping the ray.
        return 1.0f;
    }
} // namespace Engine