Techneck/code/source-c/entity.c

#include "entity.h"
#include "state.h"

#include <stdlib.h>
#include <string.h>

tc_entity_registry_s tc_init_entity_registry()
{
    tc_entity_registry_s        registry;
    registry.types_capacity         = 64;
    registry.num_types              = 0;
    registry.types                  = calloc(sizeof(tc_entity_type_s), registry.types_capacity);
    registry.intervals_capacity     = 256;
    registry.num_intervals          = 0;
    registry.intervals              = calloc(sizeof(tc_interval_s *), registry.intervals_capacity);
    registry.pool                   = tc_create_entity_pool(512);
    
    return registry;
}

void tc_register_entity_type(tc_entity_type_s type)
{
    if(tc_game_state_g.entity_registry.num_types
        >=
       tc_game_state_g.entity_registry.types_capacity
    ) {
        tc_game_state_g.entity_registry.types_capacity         *= 2;
        tc_game_state_g.entity_registry.types                   =
          realloc(
            tc_game_state_g.entity_registry.types,
            tc_game_state_g.entity_registry.types_capacity
          );
    }
    
    if(type.instances_capacity == 0) type.instances_capacity         = 64;
    type.instances                  = calloc(sizeof(tc_entity_s *), type.instances_capacity);
    type.num_instances              = 0;
    
    tc_game_state_g.entity_registry.types[tc_game_state_g.entity_registry.num_types] = type;
    
    ++tc_game_state_g.entity_registry.num_types;
}

tc_entity_type_s * tc_get_entity_type_with_name(char *internal_name)
{
    u32_t            num_types           = tc_game_state_g.entity_registry.num_types;
    tc_entity_type_s   *types               = tc_game_state_g.entity_registry.types;
    
    u32_t            index               = 0;
    while(index < num_types)
    {
        if(!strcmp(types[index].internal_name, internal_name)) return &types[index];
        ++index;
    }
    return NULL;
}

i32_t tc_find_entity_instance_index_in_type(tc_entity_type_s *type, tc_entity_s *entity)
{
    u32_t        index       = 0;
    while(index < type->num_instances)
    {
        if(type->instances[index] == entity) return index;
        ++index;
    }
    return -1;
}

void tc_add_entity_instance_to_type(tc_entity_type_s *type, tc_entity_s *entity)
{
    if(type->num_instances >= type->instances_capacity)
    {
        type->instances_capacity   *= 2;
        type->instances             = realloc(type->instances, type->instances_capacity);
    }
    type->instances[type->num_instances]       = entity;
    ++type->num_instances;
}

tc_entity_s * tc_create_entity(char *type)
{
    tc_entity_type_s *type_struct = tc_get_entity_type_with_name(type);
    if(type_struct == NULL) return NULL;
    
    tc_entity_s        *entity      = tc_allocate_entity();
    entity->type                    = type_struct;
    entity->num_attributes          = 0;
    entity->attributes_capacity     = 8;
    entity->attributes              =
        calloc(sizeof(tc_entity_attribute_s), entity->attributes_capacity);
    
    type_struct->functions.fn_create(entity);
    
    tc_add_entity_instance_to_type(type_struct, entity);
    
    return entity;
}

void tc_spawn_entity(tc_entity_s *entity, tc_location_s location)
{
    entity->type->functions.fn_spawn(entity, location);
}

void tc_teleport_entity(tc_entity_s *entity, tc_location_s location)
{
    entity->type->functions.fn_teleport(entity, location);
}

void tc_draw_entity(tc_entity_s *entity)
{
    entity->type->functions.fn_draw(entity);
}

void tc_delete_entity(tc_entity_s *entity)
{
    tc_entity_type_s        *type       = entity->type;
    
    i32_t         instance_index      =
        tc_find_entity_instance_index_in_type(type, entity);
    
    if(instance_index == -1)
    {
        puts("Entity can't be found as an instance of it's type?!");
    }
    else
    {
        --type->num_instances;
        type->instances[instance_index]     = type->instances[type->num_instances];
    }
    
    entity->type->functions.fn_delete(entity);
    tc_deallocate_entity(entity);
}



tc_entity_attribute_s * tc_get_entity_attribute_with_name(tc_entity_s *entity, char *name)
{
    u32_t        attribute_index         = 0;
    while(attribute_index < entity->attributes_capacity)
    {
        tc_entity_attribute_s attribute               = entity->attributes[attribute_index];
        if(attribute.name == NULL)
        {
            ++attribute_index;
            continue;
        }
        
        if(!strcmp(attribute.name, name)) return &entity->attributes[attribute_index];
        ++attribute_index;
    }
    return NULL;
}

tc_entity_attribute_s * tc_allocate_entity_attribute(tc_entity_s *entity)
{
    if(entity->num_attributes >= entity->attributes_capacity)
    {
        entity->attributes_capacity        *= 2;
        entity->attributes                  = realloc(entity->attributes, sizeof(tc_entity_attribute_s) * entity->attributes_capacity);
    }
    ++entity->num_attributes;
    return &entity->attributes[entity->num_attributes-1];
}

tc_entity_attribute_s * tc_get_or_allocate_entity_attribute_with_name(tc_entity_s *entity, char *name)
{
    tc_entity_attribute_s  *attribute;
    if((attribute = tc_get_entity_attribute_with_name(entity, name)) == NULL)
    {
        attribute = tc_allocate_entity_attribute(entity);
        attribute->name = name;
    }
    return attribute;
}



void tc_set_pointer_for_entity(tc_entity_s *entity, char *attr_name, void *pointer)
{
    tc_get_or_allocate_entity_attribute_with_name(entity, attr_name)->value.pointer = pointer;
}

void tc_set_string_for_entity(tc_entity_s *entity, char *attr_name, char *string)
{
    tc_get_or_allocate_entity_attribute_with_name(entity, attr_name)->value.string = string;
}

void tc_set_integer_for_entity(tc_entity_s *entity, char *attr_name, int64_t integer)
{
    tc_get_or_allocate_entity_attribute_with_name(entity, attr_name)->value.integer = integer;
}

void tc_set_float_for_entity(tc_entity_s *entity, char *attr_name, double floating)
{
    tc_get_or_allocate_entity_attribute_with_name(entity, attr_name)->value.floating = floating;
}



void * tc_get_pointer_from_entity(tc_entity_s *entity, char *attr_name)
{
    return tc_get_or_allocate_entity_attribute_with_name(entity, attr_name)->value.pointer;
}

char * tc_get_string_from_entity(tc_entity_s *entity, char *attr_name)
{
    return tc_get_or_allocate_entity_attribute_with_name(entity, attr_name)->value.string;
}

int64_t tc_get_integer_from_entity(tc_entity_s *entity, char *attr_name)
{
    return tc_get_or_allocate_entity_attribute_with_name(entity, attr_name)->value.integer;
}

double tc_get_float_from_entity(tc_entity_s *entity, char *attr_name)
{
    return tc_get_or_allocate_entity_attribute_with_name(entity, attr_name)->value.floating;
}



void tc_forget_entity_attribute(tc_entity_s *entity, char *attr_name)
{
    u32_t        attribute_index         = 0;
    while(attribute_index < entity->attributes_capacity)
    {
        tc_entity_attribute_s *attribute               = &entity->attributes[attribute_index];
        if(attribute->name == NULL)
        {
            ++attribute_index;
            continue;
        }
        
        if(!strcmp(attribute->name, attr_name))
        {
            entity->attributes[attribute_index]         = entity->attributes[entity->num_attributes];
            --entity->num_attributes;
            break;
        }
        ++attribute_index;
    }
    return;
}



i32_t tc_find_index_of_entity_in_intervals(tc_entity_s *entity)
{
    u32_t            interval_index        = 0;
    while(interval_index < tc_game_state_g.entity_registry.num_intervals)
    {
        if(tc_game_state_g.entity_registry.intervals[interval_index].entity == entity)
            return interval_index;
        
        ++interval_index;
    }
    return -1;
}

u32_t tc_allocate_interval()
{
    if(
      tc_game_state_g.entity_registry.num_intervals
        >=
      tc_game_state_g.entity_registry.intervals_capacity
    ) {
        tc_game_state_g.entity_registry.intervals_capacity *= 2;
        tc_game_state_g.entity_registry.intervals =
            realloc(
              tc_game_state_g.entity_registry.intervals,
              sizeof(tc_interval_s) * tc_game_state_g.entity_registry.intervals_capacity
            );
    }
    u32_t            last        = tc_game_state_g.entity_registry.num_intervals;
    tc_game_state_g.entity_registry.intervals[last].last_invocation = 0.0f;
    ++tc_game_state_g.entity_registry.num_intervals;
    
    return last;
}

void tc_schedule_interval(tc_entity_s *entity, float wanted_delta, void (*fn_interval)(tc_entity_s *entity))
{
    i32_t         interval_index;
    if((interval_index = tc_find_index_of_entity_in_intervals(entity)) == -1)
    {
        interval_index          = tc_allocate_interval();
    }
    tc_interval_s entry;
    entry.entity                = entity;
    entry.wanted_delta          = wanted_delta;
    entry.fn_interval           = fn_interval;
    tc_game_state_g.entity_registry.intervals[interval_index]  = entry;
}

void tc_send_pointer_to_entity(tc_entity_s *entity, char *event_name, void *pointer)
{
    tc_entity_event_s event;
    event.identifier        = event_name;
    event.value.pointer     = pointer;
    entity->type->functions.fn_send_event(entity, event);
}

void tc_send_string_to_entity(tc_entity_s *entity, char *event_name, char *string)
{
    tc_entity_event_s event;
    event.identifier        = event_name;
    event.value.string      = string;
    entity->type->functions.fn_send_event(entity, event);
}

void tc_send_integer_to_entity(tc_entity_s *entity, char *event_name, int64_t integer)
{
    tc_entity_event_s event;
    event.identifier        = event_name;
    event.value.integer     = integer;
    entity->type->functions.fn_send_event(entity, event);
}

void tc_send_float_to_entity(tc_entity_s *entity, char *event_name, double  floating)
{
    tc_entity_event_s event;
    event.identifier        = event_name;
    event.value.floating    = floating;
    entity->type->functions.fn_send_event(entity, event);
}

void tc_tick_intervals()
{
    uint64_t                    current_ms      =  SDL_GetTicks64();
    tc_entity_registry_s        registry        = tc_game_state_g.entity_registry;
    
    u32_t                    interval_index  = 0;
    while(interval_index < registry.num_intervals)
    {
        tc_interval_s        interval        = registry.intervals[interval_index];
        u32_t                    elapsed_time    = current_ms - interval.last_invocation;
        if(elapsed_time >= interval.wanted_delta)
        {
            if(interval.fn_interval == NULL)
            {
                ++interval_index;
                continue;
            }
            interval.fn_interval(interval.entity);
        }
        ++interval_index;
    }
}


void tc_draw_all_entities_of_type(char *name)
{
    tc_entity_type_s           *type            = tc_get_entity_type_with_name(name);
    
    u32_t                    drawn_entities  = 0;
    u32_t                    entity_index    = 0;
    while(entity_index < type->num_instances)
    {
        tc_entity_s            *entity          = type->instances[entity_index];
        tc_draw_entity(entity);
        ++drawn_entities;
        
        ++entity_index;
    }
}