Sphere.cpp

#include "template.h"
#include "scene.h"
#include "Sphere.h"

void Sphere::Move(float deltaTime, Tmpl8::Scene& scene)
{
    m_direction = float3(0, -1, 0);
    m_velocity -= float3(0, 1, 0) * m_acceleration;
    m_center += GetDelta(deltaTime);
    if (m_center.y < 0.f)
    {
        m_center.y = 1.1f;
        m_velocity = 0;
    }

    ResolveCollisions(deltaTime, scene);
}

float3 Sphere::GetDelta(float deltaTime) const
{
    return m_velocity * m_speed * deltaTime;
}

void Sphere::Reflect()
{
    m_velocity.y = -m_velocity.y;
}

void Sphere::ResolveCollisions(float /*deltaTime*/, Tmpl8::Scene& scene)
{
    float3 u, v;
    GetPerpendiculars(m_direction, u, v);
    u *= m_radius;
    v *= m_radius;
    constexpr size_t COUNT = 4;
    float3 checkpoints[COUNT] = {
        u, v, -u, -v
    };

    for (size_t i = 0; i < COUNT; ++i)
    {
        const float3 origin = m_center + m_direction * (m_radius + 0.01f);
        Ray ray(origin + checkpoints[i], m_direction, length(m_velocity));
        scene.FindNearest(ray);
        if (ray.m_length < m_radius)
        {
            m_center -= ray.m_direction * (m_radius - ray.m_length);
            Reflect();
            return;
        }
    }
}