PC PowerPlay 22/PCPP #22.iso/Quake2/q2source_12_11/utils3/common/l3dslib.c

C/C++ Source or Header | 1997-06-28 | 5.2 KB | 280 lines

//
// l3dslib.c: library for loading triangles from an Alias triangle file
//

#include <stdio.h>
#include "cmdlib.h"
#include "mathlib.h"
#include "trilib.h"
#include "l3dslib.h"

#define MAIN3DS       0x4D4D
#define EDIT3DS       0x3D3D  // this is the start of the editor config
#define EDIT_OBJECT   0x4000
#define OBJ_TRIMESH   0x4100
#define TRI_VERTEXL   0x4110
#define TRI_FACEL1    0x4120

#define MAXVERTS    2000

typedef struct {
    int    v[4];
} tri;

float    fverts[MAXVERTS][3];
tri        tris[MAXTRIANGLES];

int    bytesread, level, numtris, totaltris;
int    vertsfound, trisfound;

triangle_t    *ptri;


// Alias stores triangles as 3 explicit vertices in .tri files, so even though we
// start out with a vertex pool and vertex indices for triangles, we have to convert
// to raw, explicit triangles
void StoreAliasTriangles (void)
{
    int        i, j, k;

    if ((totaltris + numtris) > MAXTRIANGLES)
        Error ("Error: Too many triangles");

    for (i=0; i<numtris ; i++)
    {
        for (j=0 ; j<3 ; j++)
        {
            for (k=0 ; k<3 ; k++)
            {
                ptri[i+totaltris].verts[j][k] = fverts[tris[i].v[j]][k];
            }
        }
    }

    totaltris += numtris;
    numtris = 0;
    vertsfound = 0;
    trisfound = 0;
}


int ParseVertexL (FILE *input)
{
    int                i, j, startbytesread, numverts;
    unsigned short    tshort;

    if (vertsfound)
        Error ("Error: Multiple vertex chunks");

    vertsfound = 1;
    startbytesread = bytesread;

    if (feof(input))
        Error ("Error: unexpected end of file");

    fread(&tshort, sizeof(tshort), 1, input);
    bytesread += sizeof(tshort);
    numverts = (int)tshort;

    if (numverts > MAXVERTS)
        Error ("Error: Too many vertices");

    for (i=0 ; i<numverts ; i++)
    {
        for (j=0 ; j<3 ; j++)
        {
            if (feof(input))
                Error ("Error: unexpected end of file");

            fread(&fverts[i][j], sizeof(float), 1, input);
            bytesread += sizeof(float);
        }
    }

    if (vertsfound && trisfound)
        StoreAliasTriangles ();

    return bytesread - startbytesread;
}


int ParseFaceL1 (FILE *input)
{

    int                i, j, startbytesread;
    unsigned short    tshort;

    if (trisfound)
        Error ("Error: Multiple face chunks");

    trisfound = 1;
    startbytesread = bytesread;

    if (feof(input))
        Error ("Error: unexpected end of file");

    fread(&tshort, sizeof(tshort), 1, input);
    bytesread += sizeof(tshort);
    numtris = (int)tshort;

    if (numtris > MAXTRIANGLES)
        Error ("Error: Too many triangles");

    for (i=0 ; i<numtris ; i++)
    {
        for (j=0 ; j<4 ; j++)
        {
            if (feof(input))
                Error ("Error: unexpected end of file");

            fread(&tshort, sizeof(tshort), 1, input);
            bytesread += sizeof(tshort);
            tris[i].v[j] = (int)tshort;
        }
    }

    if (vertsfound && trisfound)
        StoreAliasTriangles ();

    return bytesread - startbytesread;
}


int ParseChunk (FILE *input)
{
#define BLOCK_SIZE    4096
    char            temp[BLOCK_SIZE];
    unsigned short    type;
    int                i, length, w, t, retval;

    level++;
    retval = 0;

// chunk type
    if (feof(input))
        Error ("Error: unexpected end of file");

    fread(&type, sizeof(type), 1, input);
    bytesread += sizeof(type);

// chunk length
    if (feof(input))
        Error ("Error: unexpected end of file");

    fread (&length, sizeof(length), 1, input);
    bytesread += sizeof(length);
    w = length - 6;

// process chunk if we care about it, otherwise skip it
    switch (type)
    {
    case TRI_VERTEXL:
        w -= ParseVertexL (input);
        goto ParseSubchunk;

    case TRI_FACEL1:
        w -= ParseFaceL1 (input);
        goto ParseSubchunk;

    case EDIT_OBJECT:
    // read the name
        i = 0;

        do
        {
            if (feof(input))
                Error ("Error: unexpected end of file");

            fread (&temp[i], 1, 1, input);
            i++;
            w--;
            bytesread++;
        } while (temp[i-1]);

    case MAIN3DS:
    case OBJ_TRIMESH:
    case EDIT3DS:
    // parse through subchunks
ParseSubchunk:
        while (w > 0)
        {
            w -= ParseChunk (input);
        }

        retval = length;
        goto Done;

    default:
    // skip other chunks
        while (w > 0)
        {
            t = w;

            if (t > BLOCK_SIZE)
                t = BLOCK_SIZE;

            if (feof(input))
                Error ("Error: unexpected end of file");

            fread (&temp, t, 1, input);
            bytesread += t;

            w -= t;
        }

        retval = length;
        goto Done;
    }

Done:
    level--;
    return retval;
}


void Load3DSTriangleList (char *filename, triangle_t **pptri, int *numtriangles)
{
    FILE        *input;
    short int    tshort;

    bytesread = 0;
    level = 0;
    numtris = 0;
    totaltris = 0;
    vertsfound = 0;
    trisfound = 0;

    if ((input = fopen(filename, "rb")) == 0) {
        fprintf(stderr,"reader: could not open file '%s'\n", filename);
        exit(0);
    }

    fread(&tshort, sizeof(tshort), 1, input);

// should only be MAIN3DS, but some files seem to start with EDIT3DS, with
// no MAIN3DS
    if ((tshort != MAIN3DS) && (tshort != EDIT3DS)) {
        fprintf(stderr,"File is not a 3DS file.\n");
        exit(0);
    }

// back to top of file so we can parse the first chunk descriptor
    fseek(input, 0, SEEK_SET);

    ptri = malloc (MAXTRIANGLES * sizeof(triangle_t));

    *pptri = ptri;

// parse through looking for the relevant chunk tree (MAIN3DS | EDIT3DS | EDIT_OBJECT |
// OBJ_TRIMESH | {TRI_VERTEXL, TRI_FACEL1}) and skipping other chunks
    ParseChunk (input);

    if (vertsfound || trisfound)
        Error ("Incomplete triangle set");

    *numtriangles = totaltris;

    fclose (input);
}