tr_world.c

3D 游戏界的大牛人 John Carmack 终于放出了 Q3 的源代码

	for ( i = 0 ; i < bmodel->numSurfaces ; i++ ) {
		R_AddWorldSurface( bmodel->firstSurface + i, tr.currentEntity->needDlights );
	}
}


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

	WORLD MODEL

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


/*
================
R_RecursiveWorldNode
================
*/
static void R_RecursiveWorldNode( mnode_t *node, int planeBits, int dlightBits ) {

	do {
		int			newDlights[2];

		// if the node wasn't marked as potentially visible, exit
		if (node->visframe != tr.visCount) {
			return;
		}

		// if the bounding volume is outside the frustum, nothing
		// inside can be visible OPTIMIZE: don't do this all the way to leafs?

		if ( !r_nocull->integer ) {
			int		r;

			if ( planeBits & 1 ) {
				r = BoxOnPlaneSide(node->mins, node->maxs, &tr.viewParms.frustum[0]);
				if (r == 2) {
					return;						// culled
				}
				if ( r == 1 ) {
					planeBits &= ~1;			// all descendants will also be in front
				}
			}

			if ( planeBits & 2 ) {
				r = BoxOnPlaneSide(node->mins, node->maxs, &tr.viewParms.frustum[1]);
				if (r == 2) {
					return;						// culled
				}
				if ( r == 1 ) {
					planeBits &= ~2;			// all descendants will also be in front
				}
			}

			if ( planeBits & 4 ) {
				r = BoxOnPlaneSide(node->mins, node->maxs, &tr.viewParms.frustum[2]);
				if (r == 2) {
					return;						// culled
				}
				if ( r == 1 ) {
					planeBits &= ~4;			// all descendants will also be in front
				}
			}

			if ( planeBits & 8 ) {
				r = BoxOnPlaneSide(node->mins, node->maxs, &tr.viewParms.frustum[3]);
				if (r == 2) {
					return;						// culled
				}
				if ( r == 1 ) {
					planeBits &= ~8;			// all descendants will also be in front
				}
			}

		}

		if ( node->contents != -1 ) {
			break;
		}

		// node is just a decision point, so go down both sides
		// since we don't care about sort orders, just go positive to negative

		// determine which dlights are needed
		newDlights[0] = 0;
		newDlights[1] = 0;
		if ( dlightBits ) {
			int	i;

			for ( i = 0 ; i < tr.refdef.num_dlights ; i++ ) {
				dlight_t	*dl;
				float		dist;

				if ( dlightBits & ( 1 << i ) ) {
					dl = &tr.refdef.dlights[i];
					dist = DotProduct( dl->origin, node->plane->normal ) - node->plane->dist;
					
					if ( dist > -dl->radius ) {
						newDlights[0] |= ( 1 << i );
					}
					if ( dist < dl->radius ) {
						newDlights[1] |= ( 1 << i );
					}
				}
			}
		}

		// recurse down the children, front side first
		R_RecursiveWorldNode (node->children[0], planeBits, newDlights[0] );

		// tail recurse
		node = node->children[1];
		dlightBits = newDlights[1];
	} while ( 1 );

	{
		// leaf node, so add mark surfaces
		int			c;
		msurface_t	*surf, **mark;

		tr.pc.c_leafs++;

		// add to z buffer bounds
		if ( node->mins[0] < tr.viewParms.visBounds[0][0] ) {
			tr.viewParms.visBounds[0][0] = node->mins[0];
		}
		if ( node->mins[1] < tr.viewParms.visBounds[0][1] ) {
			tr.viewParms.visBounds[0][1] = node->mins[1];
		}
		if ( node->mins[2] < tr.viewParms.visBounds[0][2] ) {
			tr.viewParms.visBounds[0][2] = node->mins[2];
		}

		if ( node->maxs[0] > tr.viewParms.visBounds[1][0] ) {
			tr.viewParms.visBounds[1][0] = node->maxs[0];
		}
		if ( node->maxs[1] > tr.viewParms.visBounds[1][1] ) {
			tr.viewParms.visBounds[1][1] = node->maxs[1];
		}
		if ( node->maxs[2] > tr.viewParms.visBounds[1][2] ) {
			tr.viewParms.visBounds[1][2] = node->maxs[2];
		}

		// add the individual surfaces
		mark = node->firstmarksurface;
		c = node->nummarksurfaces;
		while (c--) {
			// the surface may have already been added if it
			// spans multiple leafs
			surf = *mark;
			R_AddWorldSurface( surf, dlightBits );
			mark++;
		}
	}

}


/*
===============
R_PointInLeaf
===============
*/
static mnode_t *R_PointInLeaf( const vec3_t p ) {
	mnode_t		*node;
	float		d;
	cplane_t	*plane;
	
	if ( !tr.world ) {
		ri.Error (ERR_DROP, "R_PointInLeaf: bad model");
	}

	node = tr.world->nodes;
	while( 1 ) {
		if (node->contents != -1) {
			break;
		}
		plane = node->plane;
		d = DotProduct (p,plane->normal) - plane->dist;
		if (d > 0) {
			node = node->children[0];
		} else {
			node = node->children[1];
		}
	}
	
	return node;
}

/*
==============
R_ClusterPVS
==============
*/
static const byte *R_ClusterPVS (int cluster) {
	if (!tr.world || !tr.world->vis || cluster < 0 || cluster >= tr.world->numClusters ) {
		return tr.world->novis;
	}

	return tr.world->vis + cluster * tr.world->clusterBytes;
}

/*
=================
R_inPVS
=================
*/
qboolean R_inPVS( const vec3_t p1, const vec3_t p2 ) {
	mnode_t *leaf;
	byte	*vis;

	leaf = R_PointInLeaf( p1 );
	vis = CM_ClusterPVS( leaf->cluster );
	leaf = R_PointInLeaf( p2 );

	if ( !(vis[leaf->cluster>>3] & (1<<(leaf->cluster&7))) ) {
		return qfalse;
	}
	return qtrue;
}

/*
===============
R_MarkLeaves

Mark the leaves and nodes that are in the PVS for the current
cluster
===============
*/
static void R_MarkLeaves (void) {
	const byte	*vis;
	mnode_t	*leaf, *parent;
	int		i;
	int		cluster;

	// lockpvs lets designers walk around to determine the
	// extent of the current pvs
	if ( r_lockpvs->integer ) {
		return;
	}

	// current viewcluster
	leaf = R_PointInLeaf( tr.viewParms.pvsOrigin );
	cluster = leaf->cluster;

	// if the cluster is the same and the area visibility matrix
	// hasn't changed, we don't need to mark everything again

	// if r_showcluster was just turned on, remark everything 
	if ( tr.viewCluster == cluster && !tr.refdef.areamaskModified 
		&& !r_showcluster->modified ) {
		return;
	}

	if ( r_showcluster->modified || r_showcluster->integer ) {
		r_showcluster->modified = qfalse;
		if ( r_showcluster->integer ) {
			ri.Printf( PRINT_ALL, "cluster:%i  area:%i\n", cluster, leaf->area );
		}
	}

	tr.visCount++;
	tr.viewCluster = cluster;

	if ( r_novis->integer || tr.viewCluster == -1 ) {
		for (i=0 ; i<tr.world->numnodes ; i++) {
			if (tr.world->nodes[i].contents != CONTENTS_SOLID) {
				tr.world->nodes[i].visframe = tr.visCount;
			}
		}
		return;
	}

	vis = R_ClusterPVS (tr.viewCluster);
	
	for (i=0,leaf=tr.world->nodes ; i<tr.world->numnodes ; i++, leaf++) {
		cluster = leaf->cluster;
		if ( cluster < 0 || cluster >= tr.world->numClusters ) {
			continue;
		}

		// check general pvs
		if ( !(vis[cluster>>3] & (1<<(cluster&7))) ) {
			continue;
		}

		// check for door connection
		if ( (tr.refdef.areamask[leaf->area>>3] & (1<<(leaf->area&7)) ) ) {
			continue;		// not visible
		}

		parent = leaf;
		do {
			if (parent->visframe == tr.visCount)
				break;
			parent->visframe = tr.visCount;
			parent = parent->parent;
		} while (parent);
	}
}


/*
=============
R_AddWorldSurfaces
=============
*/
void R_AddWorldSurfaces (void) {
	if ( !r_drawworld->integer ) {
		return;
	}

	if ( tr.refdef.rdflags & RDF_NOWORLDMODEL ) {
		return;
	}

	tr.currentEntityNum = ENTITYNUM_WORLD;
	tr.shiftedEntityNum = tr.currentEntityNum << QSORT_ENTITYNUM_SHIFT;

	// determine which leaves are in the PVS / areamask
	R_MarkLeaves ();

	// clear out the visible min/max
	ClearBounds( tr.viewParms.visBounds[0], tr.viewParms.visBounds[1] );

	// perform frustum culling and add all the potentially visible surfaces
	if ( tr.refdef.num_dlights > 32 ) {
		tr.refdef.num_dlights = 32 ;
	}
	R_RecursiveWorldNode( tr.world->nodes, 15, ( 1 << tr.refdef.num_dlights ) - 1 );
}