cmodel.c

Quake 2 Source code for students by Theerthan You can also download from idsoftwares.com

	if (!buf)
		Com_Error (ERR_DROP, "Couldn't load %s", name);

	last_checksum = LittleLong (Com_BlockChecksum (buf, length));
	*checksum = last_checksum;

	header = *(dheader_t *)buf;
	for (i=0 ; i<sizeof(dheader_t)/4 ; i++)
		((int *)&header)[i] = LittleLong ( ((int *)&header)[i]);

	if (header.version != BSPVERSION)
		Com_Error (ERR_DROP, "CMod_LoadBrushModel: %s has wrong version number (%i should be %i)"
		, name, header.version, BSPVERSION);

	cmod_base = (byte *)buf;

	// load into heap
	CMod_LoadSurfaces (&header.lumps[LUMP_TEXINFO]);
	CMod_LoadLeafs (&header.lumps[LUMP_LEAFS]);
	CMod_LoadLeafBrushes (&header.lumps[LUMP_LEAFBRUSHES]);
	CMod_LoadPlanes (&header.lumps[LUMP_PLANES]);
	CMod_LoadBrushes (&header.lumps[LUMP_BRUSHES]);
	CMod_LoadBrushSides (&header.lumps[LUMP_BRUSHSIDES]);
	CMod_LoadSubmodels (&header.lumps[LUMP_MODELS]);
	CMod_LoadNodes (&header.lumps[LUMP_NODES]);
	CMod_LoadAreas (&header.lumps[LUMP_AREAS]);
	CMod_LoadAreaPortals (&header.lumps[LUMP_AREAPORTALS]);
	CMod_LoadVisibility (&header.lumps[LUMP_VISIBILITY]);
	CMod_LoadEntityString (&header.lumps[LUMP_ENTITIES]);

	FS_FreeFile (buf);

	CM_InitBoxHull ();

	memset (portalopen, 0, sizeof(portalopen));
	FloodAreaConnections ();

	strcpy (map_name, name);

	return &map_cmodels[0];
}

/*
==================
CM_InlineModel
==================
*/
cmodel_t	*CM_InlineModel (char *name)
{
	int		num;

	if (!name || name[0] != '*')
		Com_Error (ERR_DROP, "CM_InlineModel: bad name");
	num = atoi (name+1);
	if (num < 1 || num >= numcmodels)
		Com_Error (ERR_DROP, "CM_InlineModel: bad number");

	return &map_cmodels[num];
}

int		CM_NumClusters (void)
{
	return numclusters;
}

int		CM_NumInlineModels (void)
{
	return numcmodels;
}

char	*CM_EntityString (void)
{
	return map_entitystring;
}

int		CM_LeafContents (int leafnum)
{
	if (leafnum < 0 || leafnum >= numleafs)
		Com_Error (ERR_DROP, "CM_LeafContents: bad number");
	return map_leafs[leafnum].contents;
}

int		CM_LeafCluster (int leafnum)
{
	if (leafnum < 0 || leafnum >= numleafs)
		Com_Error (ERR_DROP, "CM_LeafCluster: bad number");
	return map_leafs[leafnum].cluster;
}

int		CM_LeafArea (int leafnum)
{
	if (leafnum < 0 || leafnum >= numleafs)
		Com_Error (ERR_DROP, "CM_LeafArea: bad number");
	return map_leafs[leafnum].area;
}

//=======================================================================


cplane_t	*box_planes;
int			box_headnode;
cbrush_t	*box_brush;
cleaf_t		*box_leaf;

/*
===================
CM_InitBoxHull

Set up the planes and nodes so that the six floats of a bounding box
can just be stored out and get a proper clipping hull structure.
===================
*/
void CM_InitBoxHull (void)
{
	int			i;
	int			side;
	cnode_t		*c;
	cplane_t	*p;
	cbrushside_t	*s;

	box_headnode = numnodes;
	box_planes = &map_planes[numplanes];
	if (numnodes+6 > MAX_MAP_NODES
		|| numbrushes+1 > MAX_MAP_BRUSHES
		|| numleafbrushes+1 > MAX_MAP_LEAFBRUSHES
		|| numbrushsides+6 > MAX_MAP_BRUSHSIDES
		|| numplanes+12 > MAX_MAP_PLANES)
		Com_Error (ERR_DROP, "Not enough room for box tree");

	box_brush = &map_brushes[numbrushes];
	box_brush->numsides = 6;
	box_brush->firstbrushside = numbrushsides;
	box_brush->contents = CONTENTS_MONSTER;

	box_leaf = &map_leafs[numleafs];
	box_leaf->contents = CONTENTS_MONSTER;
	box_leaf->firstleafbrush = numleafbrushes;
	box_leaf->numleafbrushes = 1;

	map_leafbrushes[numleafbrushes] = numbrushes;

	for (i=0 ; i<6 ; i++)
	{
		side = i&1;

		// brush sides
		s = &map_brushsides[numbrushsides+i];
		s->plane = 	map_planes + (numplanes+i*2+side);
		s->surface = &nullsurface;

		// nodes
		c = &map_nodes[box_headnode+i];
		c->plane = map_planes + (numplanes+i*2);
		c->children[side] = -1 - emptyleaf;
		if (i != 5)
			c->children[side^1] = box_headnode+i + 1;
		else
			c->children[side^1] = -1 - numleafs;

		// planes
		p = &box_planes[i*2];
		p->type = i>>1;
		p->signbits = 0;
		VectorClear (p->normal);
		p->normal[i>>1] = 1;

		p = &box_planes[i*2+1];
		p->type = 3 + (i>>1);
		p->signbits = 0;
		VectorClear (p->normal);
		p->normal[i>>1] = -1;
	}	
}


/*
===================
CM_HeadnodeForBox

To keep everything totally uniform, bounding boxes are turned into small
BSP trees instead of being compared directly.
===================
*/
int	CM_HeadnodeForBox (vec3_t mins, vec3_t maxs)
{
	box_planes[0].dist = maxs[0];
	box_planes[1].dist = -maxs[0];
	box_planes[2].dist = mins[0];
	box_planes[3].dist = -mins[0];
	box_planes[4].dist = maxs[1];
	box_planes[5].dist = -maxs[1];
	box_planes[6].dist = mins[1];
	box_planes[7].dist = -mins[1];
	box_planes[8].dist = maxs[2];
	box_planes[9].dist = -maxs[2];
	box_planes[10].dist = mins[2];
	box_planes[11].dist = -mins[2];

	return box_headnode;
}


/*
==================
CM_PointLeafnum_r

==================
*/
int CM_PointLeafnum_r (vec3_t p, int num)
{
	float		d;
	cnode_t		*node;
	cplane_t	*plane;

	while (num >= 0)
	{
		node = map_nodes + num;
		plane = node->plane;
		
		if (plane->type < 3)
			d = p[plane->type] - plane->dist;
		else
			d = DotProduct (plane->normal, p) - plane->dist;
		if (d < 0)
			num = node->children[1];
		else
			num = node->children[0];
	}

	c_pointcontents++;		// optimize counter

	return -1 - num;
}

int CM_PointLeafnum (vec3_t p)
{
	if (!numplanes)
		return 0;		// sound may call this without map loaded
	return CM_PointLeafnum_r (p, 0);
}



/*
=============
CM_BoxLeafnums

Fills in a list of all the leafs touched
=============
*/
int		leaf_count, leaf_maxcount;
int		*leaf_list;
float	*leaf_mins, *leaf_maxs;
int		leaf_topnode;

void CM_BoxLeafnums_r (int nodenum)
{
	cplane_t	*plane;
	cnode_t		*node;
	int		s;

	while (1)
	{
		if (nodenum < 0)
		{
			if (leaf_count >= leaf_maxcount)
			{
//				Com_Printf ("CM_BoxLeafnums_r: overflow\n");
				return;
			}
			leaf_list[leaf_count++] = -1 - nodenum;
			return;
		}
	
		node = &map_nodes[nodenum];
		plane = node->plane;
//		s = BoxOnPlaneSide (leaf_mins, leaf_maxs, plane);
		s = BOX_ON_PLANE_SIDE(leaf_mins, leaf_maxs, plane);
		if (s == 1)
			nodenum = node->children[0];
		else if (s == 2)
			nodenum = node->children[1];
		else
		{	// go down both
			if (leaf_topnode == -1)
				leaf_topnode = nodenum;
			CM_BoxLeafnums_r (node->children[0]);
			nodenum = node->children[1];
		}

	}
}

int	CM_BoxLeafnums_headnode (vec3_t mins, vec3_t maxs, int *list, int listsize, int headnode, int *topnode)
{
	leaf_list = list;
	leaf_count = 0;
	leaf_maxcount = listsize;
	leaf_mins = mins;
	leaf_maxs = maxs;

	leaf_topnode = -1;

	CM_BoxLeafnums_r (headnode);

	if (topnode)
		*topnode = leaf_topnode;

	return leaf_count;
}

int	CM_BoxLeafnums (vec3_t mins, vec3_t maxs, int *list, int listsize, int *topnode)
{
	return CM_BoxLeafnums_headnode (mins, maxs, list,
		listsize, map_cmodels[0].headnode, topnode);
}



/*
==================
CM_PointContents

==================
*/
int CM_PointContents (vec3_t p, int headnode)
{
	int		l;

	if (!numnodes)	// map not loaded
		return 0;

	l = CM_PointLeafnum_r (p, headnode);

	return map_leafs[l].contents;
}

/*
==================
CM_TransformedPointContents

Handles offseting and rotation of the end points for moving and
rotating entities
==================
*/
int	CM_TransformedPointContents (vec3_t p, int headnode, vec3_t origin, vec3_t angles)
{
	vec3_t		p_l;
	vec3_t		temp;
	vec3_t		forward, right, up;
	int			l;

	// subtract origin offset
	VectorSubtract (p, origin, p_l);

	// rotate start and end into the models frame of reference
	if (headnode != box_headnode && 
	(angles[0] || angles[1] || angles[2]) )
	{
		AngleVectors (angles, forward, right, up);

		VectorCopy (p_l, temp);
		p_l[0] = DotProduct (temp, forward);
		p_l[1] = -DotProduct (temp, right);
		p_l[2] = DotProduct (temp, up);
	}

	l = CM_PointLeafnum_r (p_l, headnode);

	return map_leafs[l].contents;
}


/*
===============================================================================

BOX TRACING

===============================================================================
*/

// 1/32 epsilon to keep floating point happy
#define	DIST_EPSILON	(0.03125)

vec3_t	trace_start, trace_end;
vec3_t	trace_mins, trace_maxs;
vec3_t	trace_extents;

trace_t	trace_trace;
int		trace_contents;
qboolean	trace_ispoint;		// optimized case

/*
================
CM_ClipBoxToBrush
================
*/
void CM_ClipBoxToBrush (vec3_t mins, vec3_t maxs, vec3_t p1, vec3_t p2,
					  trace_t *trace, cbrush_t *brush)
{
	int			i, j;
	cplane_t	*plane, *clipplane;
	float		dist;
	float		enterfrac, leavefrac;
	vec3_t		ofs;
	float		d1, d2;
	qboolean	getout, startout;
	float		f;
	cbrushside_t	*side, *leadside;

	enterfrac = -1;
	leavefrac = 1;
	clipplane = NULL;

	if (!brush->numsides)
		return;

	c_brush_traces++;

	getout = false;
	startout = false;
	leadside = NULL;

	for (i=0 ; i<brush->numsides ; i++)
	{
		side = &map_brushsides[brush->firstbrushside+i];
		plane = side->plane;

		// FIXME: special case for axial

		if (!trace_ispoint)
		{	// general box case

			// push the plane out apropriately for mins/maxs

			// FIXME: use signbits into 8 way lookup for each mins/maxs
			for (j=0 ; j<3 ; j++)
			{
				if (plane->normal[j] < 0)
					ofs[j] = maxs[j];
				else
					ofs[j] = mins[j];
			}
			dist = DotProduct (ofs, plane->normal);
			dist = plane->dist - dist;
		}
		else
		{	// special point case
			dist = plane->dist;
		}

		d1 = DotProduct (p1, plane->normal) - dist;
		d2 = DotProduct (p2, plane->normal) - dist;

		if (d2 > 0)
			getout = true;	// endpoint is not in solid
		if (d1 > 0)
			startout = true;

		// if completely in front of face, no intersection
		if (d1 > 0 && d2 >= d1)
			return;

		if (d1 <= 0 && d2 <= 0)
			continue;

		// crosses face
		if (d1 > d2)
		{	// enter
			f = (d1-DIST_EPSILON) / (d1-d2);
			if (f > enterfrac)
			{
				enterfrac = f;
				clipplane = plane;
				leadside = side;
			}
		}
		else
		{	// leave
			f = (d1+DIST_EPSILON) / (d1-d2);
			if (f < leavefrac)
				leavefrac = f;
		}
	}

	if (!startout)
	{	// original point was inside brush
		trace->startsolid = true;
		if (!getout)
			trace->allsolid = true;
		return;
	}
	if (enterfrac < leavefrac)
	{
		if (enterfrac > -1 && enterfrac < trace->fraction)
		{
			if (enterfrac < 0)
				enterfrac = 0;
			trace->fraction = enterfrac;
			trace->plane = *clipplane;
			trace->surface = &(leadside->surface->c);
			trace->contents = brush->contents;
		}
	}
}

/*
================
CM_TestBoxInBrush
================
*/
void CM_TestBoxInBrush (vec3_t mins, vec3_t maxs, vec3_t p1,
					  trace_t *trace, cbrush_t *brush)
{
	int			i, j;
	cplane_t	*plane;
	float		dist;
	vec3_t		ofs;
	float		d1;
	cbrushside_t	*side;

	if (!brush->numsides)
		return;

	for (i=0 ; i<brush->numsides ; i++)
	{
		side = &map_brushsides[brush->firstbrushside+i];
		plane = side->plane;

		// FIXME: special case for axial

		// general box case

		// push the plane out apropriately for mins/maxs

		// FIXME: use signbits into 8 way lookup for each mins/maxs
		for (j=0 ; j<3 ; j++)
		{
			if (plane->normal[j] < 0)
				ofs[j] = maxs[j];
			else
				ofs[j] = mins[j];
		}
		dist = DotProduct (ofs, plane->normal);
		dist = plane->dist - dist;

		d1 = DotProduct (p1, plane->normal) - dist;

		// if completely in front of face, no intersection
		if (d1 > 0)
			return;

	}

	// inside this brush
	trace->startsolid = trace->allsolid = true;
	trace->fraction = 0;
	trace->contents = brush->contents;
}


/*
================
CM_TraceToLeaf
================
*/
void CM_TraceToLeaf (int leafnum)
{
	int			k;
	int			brushnum;
	cleaf_t		*leaf;
	cbrush_t	*b;

	leaf = &map_leafs[leafnum];
	if ( !(leaf->contents & trace_contents))
		return;
	// trace line against all brushes in the leaf
	for (k=0 ; k<leaf->numleafbrushes ; k++)
	{
		brushnum = map_leafbrushes[leaf->firstleafbrush+k];
		b = &map_brushes[brushnum];
		if (b->checkcount == checkcount)
			continue;	// already checked this brush in another leaf
		b->checkcount = checkcount;

		if ( !(b->contents & trace_contents))
			continue;
		CM_ClipBoxToBrush (trace_mins, trace_maxs, trace_start, trace_end, &trace_trace, b);
		if (!trace_trace.fraction)
			return;
	}