загрузчик *.3DS

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <io.h>
#include "3dsloader.h"
/**********************************************************
 *
 * FUNCTION Load3DS (obj_type_ptr, char *)
 *
 * This function loads a mesh from a 3ds file.
 * Please note that we are loading only the vertices, polygons and mapping lists.
 * If you need to load meshes with advanced features as for example: 
 * multi objects, materials, lights and so on, you must insert other chunk parsers.
 *
 *********************************************************/
 
char Load3DS (obj_type_ptr p_object, char *p_filename)
{
    int i; //Index variable
    
    FILE *l_file; //File pointer
    
    unsigned short l_chunk_id; //Chunk identifier
    unsigned int l_chunk_lenght; //Chunk lenght
 
    unsigned char l_char; //Char variable
    unsigned short l_qty; //Number of elements in each chunk
 
    unsigned short l_face_flags; //Flag that stores some face information
 
    if ((l_file=fopen (p_filename, "rb"))== NULL) return 0; //Open the file
 
    while (ftell (l_file) < filelength (fileno (l_file))) //Loop to scan the whole file 
    {
        //getche(); //Insert this command for debug (to wait for keypress for each chuck reading)
 
        fread (&l_chunk_id, 2, 1, l_file); //Read the chunk header
        printf("ChunkID: %x\n",l_chunk_id); 
        fread (&l_chunk_lenght, 4, 1, l_file); //Read the lenght of the chunk
        printf("ChunkLenght: %x\n",l_chunk_lenght);
 
        switch (l_chunk_id)
        {
            //----------------- MAIN3DS -----------------
            // Description: Main chunk, contains all the other chunks
            // Chunk ID: 4d4d 
            // Chunk Lenght: 0 + sub chunks
            //-------------------------------------------
            case 0x4d4d: 
            break;    
 
            //----------------- EDIT3DS -----------------
            // Description: 3D Editor chunk, objects layout info 
            // Chunk ID: 3d3d (hex)
            // Chunk Lenght: 0 + sub chunks
            //-------------------------------------------
            case 0x3d3d:
            break;
            
            //--------------- EDIT_OBJECT ---------------
            // Description: Object block, info for each object
            // Chunk ID: 4000 (hex)
            // Chunk Lenght: len(object name) + sub chunks
            //-------------------------------------------
            case 0x4000: 
                i=0;
                do
                {
                    fread (&l_char, 1, 1, l_file);
                    p_object->name[i]=l_char;
                    i++;
                }while(l_char != '\0' && i<20);
            break;
 
            //--------------- OBJ_TRIMESH ---------------
            // Description: Triangular mesh, contains chunks for 3d mesh info
            // Chunk ID: 4100 (hex)
            // Chunk Lenght: 0 + sub chunks
            //-------------------------------------------
            case 0x4100:
            break;
            
            //--------------- TRI_VERTEXL ---------------
            // Description: Vertices list
            // Chunk ID: 4110 (hex)
            // Chunk Lenght: 1 x unsigned short (number of vertices) 
            //             + 3 x float (vertex coordinates) x (number of vertices)
            //             + sub chunks
            //-------------------------------------------
            case 0x4110: 
                fread (&l_qty, sizeof (unsigned short), 1, l_file);
                p_object->vertices_qty = l_qty;
                printf("Number of vertices: %d\n",l_qty);
                for (i=0; i<l_qty; i++)
                {
                    fread (&p_object->vertex[i].x, sizeof(float), 1, l_file);
                    printf("Vertices list x: %f\n",p_object->vertex[i].x);
                    fread (&p_object->vertex[i].y, sizeof(float), 1, l_file);
                    printf("Vertices list y: %f\n",p_object->vertex[i].y);
                    fread (&p_object->vertex[i].z, sizeof(float), 1, l_file);
                    printf("Vertices list z: %f\n",p_object->vertex[i].z);
                }
                break;
 
            //--------------- TRI_FACEL1 ----------------
            // Description: Polygons (faces) list
            // Chunk ID: 4120 (hex)
            // Chunk Lenght: 1 x unsigned short (number of polygons) 
            //             + 3 x unsigned short (polygon points) x (number of polygons)
            //             + sub chunks
            //-------------------------------------------
            case 0x4120:
                fread (&l_qty, sizeof (unsigned short), 1, l_file);
                p_object->polygons_qty = l_qty;
                printf("Number of polygons: %d\n",l_qty); 
                for (i=0; i<l_qty; i++)
                {
                    fread (&p_object->polygon[i].a, sizeof (unsigned short), 1, l_file);
                    printf("Polygon point a: %d\n",p_object->polygon[i].a);
                    fread (&p_object->polygon[i].b, sizeof (unsigned short), 1, l_file);
                    printf("Polygon point b: %d\n",p_object->polygon[i].b);
                    fread (&p_object->polygon[i].c, sizeof (unsigned short), 1, l_file);
                    printf("Polygon point c: %d\n",p_object->polygon[i].c);
                    fread (&l_face_flags, sizeof (unsigned short), 1, l_file);
                    printf("Face flags: %x\n",l_face_flags);
                }
                break;
 
            //------------- TRI_MAPPINGCOORS ------------
            // Description: Vertices list
            // Chunk ID: 4140 (hex)
            // Chunk Lenght: 1 x unsigned short (number of mapping points) 
            //             + 2 x float (mapping coordinates) x (number of mapping points)
            //             + sub chunks
            //-------------------------------------------
            case 0x4140:
                fread (&l_qty, sizeof (unsigned short), 1, l_file);
                for (i=0; i<l_qty; i++)
                {
                    fread (&p_object->mapcoord[i].u, sizeof (float), 1, l_file);
                    printf("Mapping list u: %f\n",p_object->mapcoord[i].u);
                    fread (&p_object->mapcoord[i].v, sizeof (float), 1, l_file);
                    printf("Mapping list v: %f\n",p_object->mapcoord[i].v);
                }
                break;
 
            //----------- Skip unknow chunks ------------
            //We need to skip all the chunks that currently we don't use
            //We use the chunk lenght information to set the file pointer
            //to the same level next chunk
            //-------------------------------------------
            default:
                 fseek(l_file, l_chunk_lenght-6, SEEK_CUR);
        } 
    }
    fclose (l_file); // Closes the file stream
    return (1); // Returns ok
}