lg_mesh_v1.h

/*
 *      LibGame - Copyright (C) Emmanuel Thomas-Maurin 2011-2025
 *      All rights reserved
 */
 
#ifndef LG_MESH_H
#define LG_MESH_H
 
#define LG_MESH_NAME_MAX_LEN    (64 - 1)
#define MAT_NAME_MAX_LEN        (64 - 1)
#define N_MAX_MAT_PER_OBJ       64              /* Or N_MAX_MAT_PER_MTL ? */
#define N_MAX_USEMTL_PER_OBJ    256             /* 4096 ? */
 
#define LG_FLOAT_EPSILON        (1e-6)          /* 1e-6 or 1e-8 ? */
 
#define LG_VBO_CACHE            "vbo_cache"
#define MAX_FILE_EXT_LEN        64              /* Extension length must not exceed that */
#define LG_MESH_INFO_EXT        ".info"
#define LG_MESH_VBO_EXT         ".vbo"
#define LG_MESH_IBO_EXT         ".ibo"
 
#define LG_OBJ_CACHE            "obj_cache"     /* Only used on Android so far */
 
#define LG_OBJ_FILE_MAXSIZE     ((size_t)50 * (size_t)(1024 * 1024))    /* 50 MiB */
 
#define CHECK_PATH(_z_)         INFO_OUT("DEBUG: [%s %d]: %s() -> %s\n", basename2(__FILE__), __LINE__, __func__, _z_)
 
#define LG_MESH_IS_RH           1
#define LG_MESH_IS_LH           2
 
/* Mesh original format, ie from OBJ/FBX file or whatever */
typedef enum {
        LG_MESH_OBJ,
        LG_MESH_FBX,
        LG_MESH_TERRAIN,
        LG_MESH_SKYBOX,
        LG_MESH_OTHER
} lg_mesh_type;
 
/*
- Use LG_String for LG_Material ?
        typedef struct {
                char            name[64];       -> LG_String ?
                uint32_t        indice;
                LG_Texture      *texture;
                char            tex_path[128];  -> LG_String ?
        } LG_Material;
 
        sizeof(LG_Terrain)          = 2.0 MiB   <- big elevation array
        sizeof(LG_Mesh)             = 52.7 KiB  -> 7.0 KiB - with LG_String
        sizeof(LG_DrawElements_Cmd) = 6.0 KiB
        sizeof(LG_SceneNode)        = 2.6 KiB
        sizeof(LG_Env)              = 1.4 KiB
        sizeof(LG_ErrorContext)     = 1.1 KiB
        sizeof(LG_Material)         = 208 bytes
        sizeof(LG_Material2)        = 28 bytes
 
        MATS_WIH_LG_STRING
        name ----> name->data
        tex_path ----> tex_path->data
 
        is_lg_string()
        lg_string_new()
        lg_string_get_data()
        lg_string_remove()
 
        mesh->materials[i].name)
        mesh->materials[i].tex_path
 
  BUT (BIG ONE): strings will be lost when mesh is saved to file
        Or using these funcs ?
        zboolean lg_string_save_all_to_file(const char *)
        zboolean lg_string_load_all_from_file(const char *)
*/
 
typedef struct /*__attribute__((packed, aligned(4)))*/ {
        LG_String       *name;
        uint32_t        indice;         // Material face indice in VBO (uint32_t with GL_OES_element_index_uint extension)
        LG_Texture      *texture;
        LG_String       *tex_path;      // Used by lg_mesh_reload_mats()
} LG_Material;
 
/* Axis-aligned bounding box */
typedef struct {
        float   min_x;
        float   max_x;
        float   min_y;
        float   max_y;
        float   min_z;
        float   max_z;
} LG_BBox;
 
/*
 * === Triangle mesh ===
 *
 * We want the same type sizes in binary files on all suppored platforms
 * (ie Linux and Android so far) to avoid portability issues, so we now
 * use fixed-size types (uint32_t, int32_t, ...) a lot for vertices structs
 * and buffer objects.
 *
 * In OBJ file:
 *      - 'mtllib'      -> obj_file.mtl
 *      - 'usemtl'      -> material name
 *
 * In MTL file:
 *      - 'newmtl'      -> material name
 *      - 'map_K*'      -> texture path
 */
typedef struct {
        int32_t         type;                                   /* lg_mesh_type */
        char            name[LG_MESH_NAME_MAX_LEN + 1];         /* OBJ/FBX basename */
        zboolean        skinned;
        /* Generated VBO and IBO */
        union {
          Vertex_uv_n   *vbo_data;                              /* VBO (with interleaved vertex data) - sizeof(Vertex_uv_n) = 24 */
          Vertex_uvn_iw *vbo_data_iw;                           /* VBO (with interleaved vertex data) - sizeof(Vertex_uvn_iw) = 36 */
        };
        uint32_t        *ibo_data;                              /* IBO (indices start at 0) - sizeof(uint32_t) = 4 */
        uint32_t        vbo_size;                               /* previously size_t */
        uint32_t        ibo_size;                               /* previously size_t */
        /* Read from obj file */
        int32_t         n_v;                                    /* Num of coords vertices */
        int32_t         n_vt;                                   /* Num of texture coords */
        int32_t         n_vn;                                   /* Num of normals */
        int32_t         n_f;                                    /* Num of faces */
        /* Materials */
        char            mtl_file[LG_MESH_NAME_MAX_LEN + 1];     /* The MTL file path */
        int32_t         n_mat;                                  /* Num of materials (with textures) in MTL file */
        int32_t         n_usemtl;                               /* Num of usemtl tags in OBJ file */
        LG_Material     materials[N_MAX_USEMTL_PER_OBJ];        /* Materials referenced by usemtl tags */
        LG_BBox         bbox;
        LG_Cuboid       b_cuboid;                               /* Bounding cuboid */
        Lines3D_VB      b_cuboid_l3d_vb;                        /* Lines3D_VB from bounding box cuboid */
        zboolean        xyz_normalized;
        double          normalize_k;
        zboolean        horiz_centered;                         /* Horizontally centered -> x, z*/
        zboolean        vert_centered;                          /* Vertically centered -> y */
        zboolean        vert_bottom;                            /* Vertically at bottom -> y - set mesh origin at bottom, override do_vert_center */
} LG_Mesh;
 
LG_Mesh *lg_load_vbo(const char *, zboolean, zboolean, zboolean, zboolean, zboolean, zboolean);
 
LG_Mesh *lg_mesh_new_from_objfile(const char *, zboolean, zboolean, zboolean, zboolean, zboolean);
 
LG_Mesh *lg_mesh_new_from_fbxfile(const char *, zboolean, zboolean, zboolean, zboolean, zboolean);
 
void    lg_mesh_free(LG_Mesh *);
 
void    lg_mesh_info(LG_Mesh *);
 
int     lg_obj_file_save_to_cache(void *, const char *, size_t, size_t *);
 
void    *lg_obj_file_open_from_cache(const char *);
 
int     lg_vbo_save_to_file(const char *, LG_Mesh *);
 
int     lg_vbo_load_from_file(const char *, LG_Mesh **);
 
int     lg_mesh_reload_mats(LG_Mesh *);
 
#endif /* LG_MESH_H */