bullet.c


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#include "bullet.h"
#include "components.h"
#include "error.h"
#include "platform.h"
#include "sprite.h"
#include "world.h"

Entity new_player_bullet(
	World* world,
	int x,
	int y,
	int vx,
	int vy,
	int life
) {
	Entity e;
	CBullet* bullet;
	CPosition* pos;
	CSprite* sprite;
	Sprite_ID sprid;

	e = new_entity(world);

	add_components(
		world,
		e,
		ctype_sprite        |
		ctype_position      |
		ctype_bullet        |
		ctype_player_bullet
	);
	pos = &world->positions[e];
	sprite = &world->sprites[e];
	bullet = &world->bullets[e];
	pos->x = x;
	pos->y = y;

	bullet->vx = vx;
	bullet->vy = vy;
	bullet->life = life;

	if (vx < 0) {
		sprid = sprite_player_bullet_left;
	} else if (vx > 0) {
		sprid = sprite_player_bullet_right;
	} else if (vy < 0) {
		sprid = sprite_player_bullet_up;
	} else if (vy > 0) {
		sprid = sprite_player_bullet_down;
	}
#ifdef DEBUG
	else {
		platform_log("Player bullets must have velocity\n");
		platform_abort(error_gameplay_error);
	}
#endif

	init_csprite(sprite, sprid);

	return e;
}

void bullet_system(World* world) {
	int i;
	unsigned bits;
	CPosition* pos;
	CBullet* bullet;

	for (i = 0; i < world->entity_count; i++) {
		bits = world->bitmask[i];
		if ((bits & ctype_position) && (bits & ctype_bullet)) {
			pos    = &world->positions[i];
			bullet = &world->bullets[i];

			pos->x += bullet->vx;
			pos->y += bullet->vy;
			bullet->life--;

			if (bullet->life <= 0) {
				destroy_entity(world, i);
			}
		}
	}
}