cpp-game-engine/engine/src/entity.cxx

//
//  entity.cxx
//  engine
//
//  Created by Sam Jaffe on 5/20/19.
//  Copyright © 2019 Sam Jaffe. All rights reserved.
//

#include "game/engine/entity.hpp"

#include <json/json.h>

#include "game/engine/serial.hpp"
#include "game/engine/time.hpp"
#include "game/graphics/material.hpp"

using namespace engine;

static unsigned int next_id() {
  static unsigned int id{0};
  return ++id;
}

entity::entity(Json::Value const & json)
    : identity<entity>(next_id()), in_scene(), last_position({-1, -1}),
      velocity(to_vec2(json["velocity"])), acceleration(),
      angular_velocity(0.f), render_info(to_object(json)), frame_index(0),
      frame_texture_coords({make_vector(0.f, 0.f)}),
      scale(json["size"].asFloat()), collides_with(0), collides_as(0) {
  render_info.location.size *= scale;
  render_info.frame.origin = frame_texture_coords[frame_index];
}

void entity::update(tick const & tk) {
  last_position = render_info.location.origin;
  float delta = tk.since.count();
  auto delta_pos = velocity * delta;
  render_info.location.origin += delta_pos;
  render_info.points.ll += delta_pos;
  render_info.points.lr += delta_pos;
  render_info.points.ur += delta_pos;
  render_info.points.ul += delta_pos;
  velocity += acceleration * delta;
  //  render_info.angle += angular_velocity * delta;
}