halflife-photomode/utils/common/trilib.cpp

/***
*
*	Copyright (c) 1996-2002, Valve LLC. All rights reserved.
*	
*	This product contains software technology licensed from Id 
*	Software, Inc. ("Id Technology").  Id Technology (c) 1996 Id Software, Inc. 
*	All Rights Reserved.
*
****/

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

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

// on disk representation of a face


#define FLOAT_START 99999.0
#define FLOAT_END -FLOAT_START
#define MAGIC 123322

//#define NOISY 1

typedef struct
{
	float v[3];
} vector;

typedef struct
{
	vector n; /* normal */
	vector p; /* point */
	vector c; /* color */
	float u;  /* u */
	float v;  /* v */
} aliaspoint_t;

typedef struct
{
	aliaspoint_t pt[3];
} tf_triangle;


void ByteSwapTri(tf_triangle* tri)
{
	int i;

	for (i = 0; i < sizeof(tf_triangle) / 4; i++)
	{
		((int*)tri)[i] = BigLong(((int*)tri)[i]);
	}
}

void LoadTriangleList(char* filename, triangle_t** pptri, int* numtriangles)
{
	FILE* input;
	float start;
	char name[256], tex[256];
	int i, count, magic;
	tf_triangle tri;
	triangle_t* ptri;
	int iLevel;
	int exitpattern;
	float t;


	t = -FLOAT_START;
	*((unsigned char*)&exitpattern + 0) = *((unsigned char*)&t + 3);
	*((unsigned char*)&exitpattern + 1) = *((unsigned char*)&t + 2);
	*((unsigned char*)&exitpattern + 2) = *((unsigned char*)&t + 1);
	*((unsigned char*)&exitpattern + 3) = *((unsigned char*)&t + 0);

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

	iLevel = 0;

	fread(&magic, sizeof(int), 1, input);
	if (BigLong(magic) != MAGIC)
	{
		fprintf(stderr, "File is not a Alias object separated triangle file, magic number is wrong.\n");
		exit(0);
	}

	ptri = reinterpret_cast<triangle_t*>(malloc(MAXTRIANGLES * sizeof(triangle_t)));

	*pptri = ptri;

	while (feof(input) == 0)
	{
		fread(&start, sizeof(float), 1, input);
		*(int*)&start = BigLong(*(int*)&start);
		if (*(int*)&start != exitpattern)
		{
			if (start == FLOAT_START)
			{
				/* Start of an object or group of objects. */
				i = -1;
				do
				{
					/* There are probably better ways to read a string from */
					/* a file, but this does allow you to do error checking */
					/* (which I'm not doing) on a per character basis.      */
					++i;
					fread(&(name[i]), sizeof(char), 1, input);
				} while (name[i] != '\0');

				//			indent();
				//			fprintf(stdout,"OBJECT START: %s\n",name);
				fread(&count, sizeof(int), 1, input);
				count = BigLong(count);
				++iLevel;
				if (count != 0)
				{
					//				indent();

					//				fprintf(stdout,"NUMBER OF TRIANGLES: %d\n",count);

					i = -1;
					do
					{
						++i;
						fread(&(tex[i]), sizeof(char), 1, input);
					} while (tex[i] != '\0');

					//				indent();
					//				fprintf(stdout,"  Object texture name: '%s'\n",tex);
				}

				/* Else (count == 0) this is the start of a group, and */
				/* no texture name is present. */
			}
			else if (start == FLOAT_END)
			{
				/* End of an object or group. Yes, the name should be */
				/* obvious from context, but it is in here just to be */
				/* safe and to provide a little extra information for */
				/* those who do not wish to write a recursive reader. */
				/* Mia culpa. */
				--iLevel;
				i = -1;
				do
				{
					++i;
					fread(&(name[i]), sizeof(char), 1, input);
				} while (name[i] != '\0');

				//			indent();
				//			fprintf(stdout,"OBJECT END: %s\n",name);
				continue;
			}
		}

		//
		// read the triangles
		//
		for (i = 0; i < count; ++i)
		{
			int j;

			fread(&tri, sizeof(tf_triangle), 1, input);
			ByteSwapTri(&tri);
			for (j = 0; j < 3; j++)
			{
				int k;

				for (k = 0; k < 3; k++)
				{
					ptri->verts[j][k] = tri.pt[j].p.v[k];
				}
			}

			ptri++;

			if ((ptri - *pptri) >= MAXTRIANGLES)
				Error("Error: too many triangles; increase MAXTRIANGLES\n");
		}
	}

	*numtriangles = ptri - *pptri;

	fclose(input);
}