2D_Engine_SDL3_Core/src/asset_manager.c

#include "asset_manager.h"

#include <SDL2/SDL_render.h>
#include <stdarg.h>
#include <string.h>
#include <stdio.h>
#include "linked_list.h"
#include "memory_alloc.h"
#include "display.h"

asset_t *create_asset(asset_type_t asset_type)
{
    asset_t *asset = malloc(sizeof(asset_t));

    asset->type = asset_type;
    asset->nb_refs = 1;

    return asset;
}

void destroy_asset(asset_t *asset)
{
    free(asset->name);

    switch(asset->type)
    {
      case ASSET_TEXTURE:
        SDL_DestroyTexture(asset->data.texture);

      default:
        break;
    }

    free(asset);
}

void destroy_asset_header_def(asset_header_def_t *asset_header_def)
{
    free(asset_header_def->name);
    free(asset_header_def);
}

void asset_manager_init(asset_manager_t *asset_manager)
{
    linked_list_init(&asset_manager->assets, sizeof(asset_t), (deleter_t)destroy_asset);
    linked_list_init(&asset_manager->assets_header_defs, sizeof(asset_header_def_t), (deleter_t)destroy_asset_header_def);

    asset_manager->asset_file = fopen(ASSET_FILE_NAME, "rb");
    if(!asset_manager->asset_file)
    {
        printf("can't open asset file : %s.\n", ASSET_FILE_NAME);
        return;
    }

    size_t nb_assets;
    size_t ret = fread(&nb_assets, sizeof(nb_assets), 1, asset_manager->asset_file);
    if(ret != 1)
    {
        printf("can't read asset file.");
        return;
    }

    for(size_t i = 0; i < nb_assets; i++)
    {
        elem_t *elem = elem_create(&asset_manager->assets_header_defs);

        size_t cap = 0;

        ret = getdelim(&((asset_header_def_t *)elem->data)->name, &cap, '\0', asset_manager->asset_file);
        if(ret == SIZE_MAX)
        {
            printf("can't read asset file.");
            return;
        }

        ret = fread(&((asset_header_def_t *)elem->data)->start, sizeof(((asset_header_def_t *)elem->data)->start), 1, asset_manager->asset_file);
        if(ret != 1)
        {
            printf("can't read asset file.");
            return;
        }

        linked_list_push_back_elem(&asset_manager->assets_header_defs, elem);
    }
}

void asset_manager_exit(asset_manager_t *asset_manager)
{
    linked_list_clear(&asset_manager->assets_header_defs);
    linked_list_clear(&asset_manager->assets);
    fclose(asset_manager->asset_file);
}

// Only for this file
// No args
static inline bool condition_is_asset_unused(elem_t *elem, va_list args __attribute__((unused)))
{
    return !((asset_t *)elem->data)->nb_refs;
}

inline void asset_manager_collect_garbage(asset_manager_t *asset_manager)
{
    linked_list_remove_if(&asset_manager->assets, condition_is_asset_unused);
}

// Only for this file
// Arg : const char *asset_name
static inline bool condition_is_asset_name(elem_t *elem, va_list args)
{
    return !strcmp(((asset_t *)elem->data)->name, va_arg(args, const char *));
}

//Only for this file
// Arg : const char *asset_name
static inline bool condition_is_asset_header_def_name(elem_t *elem, va_list args)
{
    return !strcmp(((asset_header_def_t *)elem->data)->name, va_arg(args, const char *));
}

static inline void load_texture(asset_manager_t *asset_manager, asset_t *asset, asset_header_def_t *asset_header_def)
{
    if(fseek(asset_manager->asset_file, asset_header_def->start, SEEK_SET))
    {
        printf("Couldn't seek in asset file.");
        return;
    }

    size_t width, height;

    if(fread(&width, sizeof(width), 1, asset_manager->asset_file) != 1)
    {
        printf("Failed to read in asset file.");
        return;
    }

    if(fread(&height, sizeof(height), 1, asset_manager->asset_file) != 1)
    {
        printf("Failed to read in asset file.");
        return;
    }

    SDL_Surface *tmp_surface = SDL_CreateRGBSurfaceWithFormat(0, width, height, 16, SDL_PIXELFORMAT_RGB565);

    if(SDL_LockSurface(tmp_surface))
    {
        printf("Couldn't lock surface : %s\n", SDL_GetError());
        return;
    }

    if(fread(tmp_surface->pixels, sizeof(uint16_t), width * height, asset_manager->asset_file) != width * height)
    {
        printf("Failed to read asset file.");
        return;
    }

    SDL_SetColorKey(tmp_surface, SDL_TRUE, SDL_MapRGB(tmp_surface->format, 0xFF, 0x00, 0xFF));

    asset->data.texture = SDL_CreateTextureFromSurface(renderer, tmp_surface);

    SDL_FreeSurface(tmp_surface);
}

void asset_manager_load_asset(asset_manager_t *asset_manager, const char *asset_name, asset_type_t asset_type)
{
    asset_t *asset = linked_list_get_if(&asset_manager->assets, condition_is_asset_name, asset_name);
    if(asset)
    {
        asset->nb_refs++;
        return;
    }

    asset_header_def_t *asset_header_def = linked_list_get_if(&asset_manager->assets_header_defs, condition_is_asset_header_def_name, asset_name);
    if(!asset_header_def)
    {
        printf("Asset doesn't exist in asset file : %s\n", asset_name);
        return;
    }

    asset = create_asset(asset_type);
    asset->name = malloc(strlen(asset_name) + 1);
    strcpy(asset->name, asset_name);
    asset->type = asset_type;

    switch(asset_type)
    {
      case ASSET_TEXTURE:
        load_texture(asset_manager, asset, asset_header_def);
        break;

      default:
        return;
    }

    linked_list_push_back(&asset_manager->assets, asset);
}

void asset_manager_let_go_asset(asset_manager_t *asset_manager, const char *asset_name)
{
    asset_t *asset = linked_list_get_if(&asset_manager->assets, condition_is_asset_name, asset_name);
    if(asset)
    {
        asset->nb_refs--;
    }
}

texture_t *asset_manager_get_texture(asset_manager_t *asset_manager, const char *asset_name)
{
    asset_t *asset = linked_list_get_if(&asset_manager->assets, condition_is_asset_name, asset_name);
    if(!asset)
        return NULL;

    if(asset->type != ASSET_TEXTURE)
        return NULL;

    return asset->data.texture;
}

void asset_manager_draw_texture(texture_t *texture, rect_t *src_rect, rect_t *dst_rect, bool flip __attribute__((unused)))
{
    SDL_RenderCopy(renderer, texture, src_rect, dst_rect);
}