BSP (Source)/Game-Specific

This page documents some game-specific differences in the BSP file format, compared to the format used for the traditional engine branches.

Alien Swarm and Portal 2

Both games use a slightly different dbrushside_t structure:

struct dbrushside_t
{
	unsigned short		planenum;	// facing out of the leaf
	short			texinfo;
	short			dispinfo;	// displacement info (BSPVERSION 7)
	byte			bevel;		// is the side a bevel plane? (BSPVERSION 7)
	byte			thin;		// is a thin side?
};

Left 4 Dead 2

version and filelen in lump_t are swapped:

struct lump_t
{
	int	version;	// lump format version
	int	fileofs;	// offset into file (bytes)
	int	filelen;	// length of lump(bytes)
	char	fourCC[4];	// lump ident code
};

The Ship

Static props use a modified StaticPropLumpV5_t structure, which contains a target name string.

struct StaticPropLumpV5_ship_t
{
	Vector		m_Origin;
	QAngle		m_Angles;
	unsigned short	m_PropType;
	unsigned short	m_FirstLeaf;
	unsigned short	m_LeafCount;
	unsigned char	m_Solid;
	unsigned char	m_Flags;
	int		m_Skin;
	float		m_FadeMinDist;
	float		m_FadeMaxDist;
	Vector		m_LightingOrigin;
	float		m_flForcedFadeScale;
	char		m_TargetName[128];
};

Vampire: The Masquerade – Bloodlines

Version 17 BSP files contain a substantially modified dface_t structure. The known elements are:

MAXLIGHTMAPS changed from 4 to 8 // 4 lightstyle for day + 4 for night = 8 ( nightime lightmapping system )

struct dface_bsp17_t
{
	colorRGBExp32	m_AvgLightColor[MAXLIGHTMAPS]; // For computing lighting information
	unsigned short	planenum;
	byte		side;	// faces opposite to the node's plane direction
	byte		onNode; // 1 of on node, 0 if in leaf
	int		firstedge;		// we must support > 64k edges
	short		numedges;	
	short		texinfo;
	short		dispinfo;
	short		surfaceFogVolumeID;
	byte		styles[MAXLIGHTMAPS];	// lighting info
	byte		day[MAXLIGHTMAPS];		// Nightime lightmapping system
	byte		night[MAXLIGHTMAPS];		// Nightime lightmapping system
	int		lightofs;		// start of [numstyles*surfsize] samples
	float		area;
	int		m_LightmapTextureMinsInLuxels[2];
	int		m_LightmapTextureSizeInLuxels[2];
	int		origFace;    // reference the original face this face was derived from
	unsigned int	smoothingGroups;
};

The extra data seems to be related to lighting of the face, and makes the length of the structure 104 bytes per face. Both the face lump and the original face lump in version 17 files use this structure.