RogueLife/src/entities.h

//---
// entities: Objects that move around the map
//---

#pragma once

#include "geometry.h"

//---
// Agents
//---

typedef struct {
	/* Maximum walking speed (m/s) */
	fixed_t max_speed;
	/* Rate a which target speed is approached (1/s) */
	fixed_t propulsion;

	/* Peak dash speed (m/s) */
	fixed_t dash_speed;
	/* Dash duration (s) */
	fixed_t dash_duration;
	/* Dash cooldown (s) */
	fixed_t dash_cooldown;

} entity_movement_params_t;

typedef struct {
	/* Current position */
	fixed_t x, y;
	/* Current speed */
	fixed_t vx, vy;
	/* Dash time remaining (if positive) or cooldown remaining (if negative) */
	fixed_t dash;
	/* Direction currently facing */
	uint8_t facing;
	/* Dash direction */
	uint8_t dash_facing;

} entity_movement_t;

/* Alive agents with hitboxes and movement control */
typedef struct {
	/* Hitbox, centered around (movement.x, movement.y) */
	shape_t hitbox;
	/* Current cinematic situation */
	entity_movement_t movement;
	/* Cinematic parameters */
	entity_movement_params_t const *movement_params;

} entity_t;

/* Entity position */
fpoint_t entity_pos(entity_t const *e);

/* Update walk/sprint movement (stand still if direction == -1); this cinematic
   state can be submitted for collisions and may or may not be accpeted */
entity_movement_t entity_move(entity_t *e, int direction, fixed_t dt);

/* Start dashing in the set direction */
void entity_dash(entity_t *e, int direction);

/* Unit vector in the direction the entity is facing */
fpoint_t entity_facing(entity_t const *e);

//---
// Particles
//---

/* Particles with no interaction but visual effects */
typedef struct {
	/* Location and speed */
	fixed_t x, y;
	fixed_t vx, vy;

} particle_t;