166 lines
4.9 KiB
C
166 lines
4.9 KiB
C
/*
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* common/trilib.c
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*
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* library for loading triangles from an Alias triangle file
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*
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*/
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#include <stdio.h>
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#include <common/cmdlib.h>
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#include <common/mathlib.h>
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#include <common/trilib.h>
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/* on disk representation of a face */
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#define FLOAT_START 99999.0
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#define FLOAT_END -FLOAT_START
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#define MAGIC 123322
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/* #define NOISY 1 */
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typedef struct {
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float v[3];
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} vector;
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typedef struct {
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vector n; /* normal */
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vector p; /* point */
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vector c; /* color */
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float u; /* u */
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float v; /* v */
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} aliaspoint_t;
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typedef struct {
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aliaspoint_t pt[3];
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} tf_triangle;
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void
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ByteSwapTri(tf_triangle * tri)
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{
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int i;
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for (i = 0; i < sizeof(tf_triangle) / 4; i++) {
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((int *)tri)[i] = BigLong(((int *)tri)[i]);
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}
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}
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void
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LoadTriangleList(char *filename, triangle_t ** pptri, int *numtriangles)
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{
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FILE *input;
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float start;
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char name[256], tex[256];
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int i, count, magic;
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tf_triangle tri;
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triangle_t *ptri;
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int iLevel;
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int exitpattern;
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float t;
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t = -FLOAT_START;
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*((unsigned char *)&exitpattern + 0) = *((unsigned char *)&t + 3);
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*((unsigned char *)&exitpattern + 1) = *((unsigned char *)&t + 2);
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*((unsigned char *)&exitpattern + 2) = *((unsigned char *)&t + 1);
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*((unsigned char *)&exitpattern + 3) = *((unsigned char *)&t + 0);
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if ((input = fopen(filename, "rb")) == 0) {
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fprintf(stderr, "reader: could not open file '%s'\n", filename);
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exit(0);
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}
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iLevel = 0;
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fread(&magic, sizeof(int), 1, input);
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if (BigLong(magic) != MAGIC) {
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fprintf(stderr, "File is not a Alias object separated triangle file,"
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" magic number is wrong.\n");
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exit(0);
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}
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ptri = malloc(MAXTRIANGLES * sizeof(triangle_t));
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*pptri = ptri;
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while (feof(input) == 0) {
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fread(&start, sizeof(float), 1, input);
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*(int *)&start = BigLong(*(int *)&start);
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if (*(int *)&start != exitpattern) {
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if (start == FLOAT_START) {
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/* Start of an object or group of objects. */
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i = -1;
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do {
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/* There are probably better ways to read a string from */
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/* a file, but this does allow you to do error checking */
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/* (which I'm not doing) on a per character basis. */
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++i;
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fread(&(name[i]), sizeof(char), 1, input);
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} while (name[i] != '\0');
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/* indent(); */
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/* fprintf(stdout,"OBJECT START: %s\n",name); */
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fread(&count, sizeof(int), 1, input);
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count = BigLong(count);
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++iLevel;
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if (count != 0) {
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/* indent(); */
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/* fprintf(stdout,"NUMBER OF TRIANGLES: %d\n",count); */
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i = -1;
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do {
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++i;
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fread(&(tex[i]), sizeof(char), 1, input);
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} while (tex[i] != '\0');
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/* indent(); */
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/* fprintf(stdout," Object texture name: '%s'\n",tex); */
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}
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/* Else (count == 0) this is the start of a group, and */
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/* no texture name is present. */
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} else if (start == FLOAT_END) {
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/* End of an object or group. Yes, the name should be */
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/* obvious from context, but it is in here just to be */
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/* safe and to provide a little extra information for */
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/* those who do not wish to write a recursive reader. */
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/* Mia culpa. */
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--iLevel;
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i = -1;
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do {
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++i;
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fread(&(name[i]), sizeof(char), 1, input);
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} while (name[i] != '\0');
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/* indent(); */
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/* fprintf(stdout,"OBJECT END: %s\n",name); */
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continue;
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}
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}
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/* read the triangles */
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for (i = 0; i < count; ++i) {
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int j;
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fread(&tri, sizeof(tf_triangle), 1, input);
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ByteSwapTri(&tri);
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for (j = 0; j < 3; j++) {
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int k;
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for (k = 0; k < 3; k++) {
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ptri->verts[j][k] = tri.pt[j].p.v[k];
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}
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}
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ptri++;
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if ((ptri - *pptri) >= MAXTRIANGLES)
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Error("Error: too many triangles; increase MAXTRIANGLES\n");
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}
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}
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*numtriangles = ptri - *pptri;
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fclose(input);
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}
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