Simple Entity type in C macros.

Entity.c

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

#pragma pack(1)

typedef struct
{
	int32_t x, y;
} Vect2D_s32;

typedef struct _ent_t
{
	Vect2D_s32 position;
	Vect2D_s32 acceleration;
	struct _ent_t *next, *prev;
	void (*update)();
} Entity;

typedef struct
{
	uint32_t startFrame : 10; //	the base frame
	uint32_t frameCount : 5;	//	how many frames are there ?
	uint32_t delay : 5;				//	delay
	uint16_t noloop : 1;			//	set this if we want to not loop
} Animation;

typedef struct
{
	Animation *anim;			 //	ptr to animation
	uint16_t timer : 5;		 //	individual info , timer
	uint16_t frameInd : 5; //	current frame inside the scope
	uint16_t ended : 1;		 //	set this flag when we hit the end
	uint16_t frame;				 //	the actual frame ( base->startFrame + frameInd )
} Entity_Animation;

typedef struct
{
	Entity super;
	Entity_Animation animation;
	int health;
} Player;

// Animation
//	tick down timer, when timer = 0 next frame or loop or stop
#define anim_update(_anim) ({                                  \
	register Entity_Animation *anim = (Entity_Animation *)_anim; \
	register Animation *base = anim->anim;                       \
	anim->ended = 0;                                             \
	if (anim->timer == 0)                                        \
	{                                                            \
		anim->frameInd++;                                          \
		if (anim->frameInd > base->frameCount)                     \
		{                                                          \
			if (base->noloop == 0)                                   \
			{                                                        \
				anim->frameInd = 0;                                    \
			}                                                        \
			else                                                     \
			{                                                        \
				anim->frameInd--                                       \
			};                                                       \
			anim->ended = 1;                                         \
		}                                                          \
		anim->timer = base->delay;                                 \
		anim->frame = base->startFrame + anim->frameInd;           \
	}                                                            \
	else                                                         \
	{                                                            \
		anim->timer--;                                             \
	}                                                            \
})

typedef struct
{
	Entity super;
	int life;
} Particle;

//	Add to list
#define list_add(list, obj) ({  \
	((Entity *)obj)->next = list; \
	((Entity *)obj)->prev = NULL; \
	if (list != NULL)             \
		list->prev = obj;           \
	list = (Entity *)obj;         \
})

//	Remove from list
#define list_del(list, obj) ({                           \
	if (((Entity *)obj)->next)                             \
		((Entity *)obj)->next->prev = ((Entity *)obj)->prev; \
	if (((Entity *)obj)->prev)                             \
		((Entity *)obj)->prev->next = ((Entity *)obj)->next; \
	else                                                   \
		list = ((Entity *)obj)->next;                        \
})

//	for loop from this list
#define list_for(_list) for (self = _list; self != NULL; self = self->next)

//	entity move
#define ent_move(obj) ({                                          \
	((Entity *)obj)->position.x += ((Entity *)obj)->acceleration.x; \
	((Entity *)obj)->position.y += ((Entity *)obj)->acceleration.y; \
})

//	set all properties
#define ent_set_all(obj, _x, _y, _ax, _ay, _update) ({ \
	((Entity *)obj)->position.x = _x;                    \
	((Entity *)obj)->position.y = _y;                    \
	((Entity *)obj)->acceleration.x = _ax;               \
	((Entity *)obj)->acceleration.y = _ay;               \
	((Entity *)obj)->update = _update;                   \
})

//	set just X & Y
#define ent_set_xy(obj, _x, _y) ({  \
	((Entity *)obj)->position.x = _x; \
	((Entity *)obj)->position.y = _y; \
})

//	set just acceleration
#define ent_set_acceleration(obj, _x, _y) ({ \
	((Entity *)obj)->acceleration.x = _x;      \
	((Entity *)obj)->acceleration.y = _y;      \
})

//	set the update function
#define ent_set_update(obj, _update) ({ \
	((Entity *)obj)->update = _update;    \
})

//	apply force to acceleration ( doesn't move )
#define ent_apply_force(obj, _x, _y) ({  \
	((Entity *)obj)->acceleration.x += _x; \
	((Entity *)obj)->acceleration.y += _y; \
})

//	debugging
#define ent_print(obj) ({                                     \
	printf("x=%x y=%x vx=%x vy=%x prev=%x next=%x update=%x\n", \
				 ((Entity *)obj)->position.x,                         \
				 ((Entity *)obj)->position.y,                         \
				 ((Entity *)obj)->acceleration.x,                     \
				 ((Entity *)obj)->acceleration.y,                     \
				 ((Entity *)obj)->prev,                               \
				 ((Entity *)obj)->next,                               \
				 ((Entity *)obj)->update);                            \
})

//	test data
Animation hero_walk = {32, 5, 7, 0};
Animation hero_run = {65, 31, 1, 1}; //	never loop test
Player heroes[2];
Particle prts[16];
Entity *list = NULL;

register Entity *self asm("r12");

void Hero()
{
	register Player *player = (Player *)self;
	ent_move(self);
	ent_apply_force(self, 0, 1);
	//	player->animation.anim = &hero_walk;
	player->health++;
	anim_update((Entity_Animation *)&player->animation);
	//	Animate(&player->animation);
	if (player->animation.ended == 1)
	{
		printf("health = %d\n", player->health);
	}
	printf("end trigger %d\n", player->animation.frame);
	ent_print(self);
}

void main()
{
	self = (Entity *)&heroes[0];
	heroes[0].health = 100;
	heroes[1].health = 10;
	heroes[0].animation.anim = &hero_run;
	heroes[1].animation.anim = &hero_walk;

	printf("try list_add\n");

	list_add(list, (Entity *)&prts[0]);
	list_add(list, (Entity *)&prts[1]);
	list_add(list, (Entity *)&heroes[1]);
	list_add(list, (Entity *)&prts[2]);
	list_add(list, (Entity *)&heroes[0]);

	printf("try ent_set_all\n");

	ent_set_all(&heroes[0], 0, 1, 2, 3, Hero);
	ent_set_all(&heroes[1], 0, 1, 2, 3, Hero);

	//
	printf("self = first ent in list\n");
	ent_print(self);
	ent_apply_force(self, 3, 3);
	ent_print(self);
	ent_set_acceleration(self, 3, 3);
	ent_print(self);
	ent_move(self);
	ent_print(self);

	self = self->next;

	printf("self = next\n");
	ent_print(self);
	ent_apply_force(self, 3, 3);
	ent_print(self);
	ent_set_acceleration(self, 3, 3);
	ent_print(self);
	ent_move(self);
	ent_print(self);

	printf("try for print\n");
	list_for(list)
			ent_print(self);

	printf("try delete\n");

	list_del(list, &prts[1]);
	list_del(list, &prts[2]);

	printf("try for print\n");

	list_for(list)
			ent_print(self);

	list_del(list, &prts[0]);

	printf("try for\n");

	for (int q = 0; q < 100; q++)
	{
		list_for(list)
		{
			if (self->update != NULL)
				self->update();
		}
	}

	/*
	ent_init( (Entity*)&heroes[0] , 0 , 1, 2, 3);
	ent_print( (Entity*)&heroes[0] );
	ent_applyForce( (Entity*)&heroes[0], 3,3);
	ent_print( (Entity*)&heroes[0] );
	ent_setForce( (Entity*)&heroes[0], 3,3);
	ent_print( (Entity*)&heroes[0] );

	ent_move( (Entity*)&heroes[0] );
	ent_print( (Entity*)&heroes[0] );
//	gbapal("ruff16.pal.bin");	
*/
}