Face Class Reference

This reference page is linked to from the following overview topics: Mesh Related Classes, 3DXI Mesh.

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Detailed Description

This class represents a single triangular face.

The class maintains three indices into the vertex list for the face, a 32-bit smoothing group for the face, and 32-bits of face flags. The flags also store information about the visibility of the face, the visibility of the three edges, and whether or not the face has texture vertices present. The most significant 16-bits of the face flags store the material index. All methods of this class are implemented by the system.

See also:

Class Mesh.

#include <mesh.h>

Inheritance diagram for Face:

List of all members.

Public Member Functions
	Face ()
	Constructor.
MtlID	getMatID ()
	Retrieves the zero based material ID for this face.
void	setMatID (MtlID id)
	Sets the material ID for this face.
void	setSmGroup (DWORD i)
	Sets the smoothing group bits for this face.
DWORD	getSmGroup (void)
	Returns the smoothing group bits for this face.
DllExport void	setVerts (DWORD *vrt)
	Sets the vertices of this face.
void	setVerts (int a, int b, int c)
	Sets the vertices of this face.
DllExport void	setEdgeVis (int edge, int visFlag)
	Sets the visibility of the specified edge.
DllExport void	setEdgeVisFlags (int va, int vb, int vc)
	Sets the visibility of the all the edges.
int	getEdgeVis (int edge)
	Retrieves the edge visibility for the specified edge.
DWORD	getVert (int index)
	Returns the index into the mesh vertex array of the specified vertex.
DWORD *	getAllVerts (void)
	Retrieves a pointer to the vertex array.
BOOL	Hidden ()
	Determines if the face is hidden or visible.
void	Hide ()
	Hides this face (makes it invisible in the viewports).
void	Show ()
	Shows this face (makes it visible in the viewports).
void	SetHide (BOOL hide)
	Sets the hidden state of this face.
BOOL	InForeground ()
void	PushToForeground ()
void	PushToBackground ()
void	SetInForegound (BOOL foreground)
BOOL	IsBackFacing ()
void	SetBackFacing ()
void	SetFrontFacing ()
void	SetBackFacing (BOOL backFacing)
DllExport DWORD	GetOtherIndex (DWORD v0, DWORD v1)
	Returns the first vertex in the face that isn't v0 or v1.
DllExport DWORD	GetEdgeIndex (DWORD v0, DWORD v1)
	Returns the index of the edge in the face that goes from v0 to v1, or v1 to v0.
DllExport int	Direction (DWORD v0, DWORD v1)
	Indicates order in which vertices v0 and v1 appear in the face.
DllExport DWORD	GetVertIndex (DWORD v0)
	Returns the index of the specified vertex in this face's vertex list (0, 1 or 2).
DllExport void	OrderVerts (DWORD &v0, DWORD &v1)
	This method switches v0,v1 if needed to put them in face-order.
Public Attributes
DWORD	v [3]
	These are zero-based indices into a mesh object's array of vertices.
DWORD	smGroup
	Smoothing group bits for the face.
DWORD	flags
	The Face Flags: Can be from the following list:

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Constructor & Destructor Documentation

Face

(

)

[inline]

Constructor.

The smoothing groups and face flags are initialized to zero.

{ smGroup = flags = 0; }

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Member Function Documentation

MtlID getMatID

(

)

[inline]

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Retrieves the zero based material ID for this face.

Note: typedef unsigned short MtlID;

{ return (int)( ( flags >> FACE_MATID_SHIFT ) & FACE_MATID_MASK); }

void setMatID

(

MtlID

id

)

[inline]

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Sets the material ID for this face.

Parameters:

id	Specifies the zero based material index.

{flags &= 0xFFFF; flags |= (DWORD)(id<<FACE_MATID_SHIFT);}

void setSmGroup

(

DWORD

i

)

[inline]

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Sets the smoothing group bits for this face.

Parameters:

i	Specifies the smoothing group bits for this face.

{ smGroup = i; }

DWORD getSmGroup

(

void

)

[inline]

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Returns the smoothing group bits for this face.

{ return smGroup; }

DllExport void setVerts

(

DWORD *

vrt

)

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Sets the vertices of this face.

Parameters:

vrt	An array of the 3 vertices to store. These are zero based indices into the mesh object's array of vertices.

void setVerts	(	int	a,
		int	b,
		int	c
	)		[inline]

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Sets the vertices of this face.

The specified indexes are zero based indices into the mesh object's array of vertices.

Parameters:

a	Specifies the first vertex.
b	Specifies the second vertex.
c	Specifies the third vertex.

{ v[0]=a; v[1]=b; v[2]=c; }

DllExport void setEdgeVis	(	int	edge,
		int	visFlag
	)

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Sets the visibility of the specified edge.

Parameters:

edge	Specifies the edge to set the visibility of. You may use 0, 1, or 2.
visFlag	One of the following values: EDGE_VIS Sets the edge as visible. EDGE_INVIS Sets the edge as invisible.

DllExport void setEdgeVisFlags	(	int	va,
		int	vb,
		int	vc
	)

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Sets the visibility of the all the edges.

Parameters:

va	Specifies the visibility for edge 0. Use either EDGE_VIS or EDGE_INVIS.
vb	Specifies the visibility for edge 1. Use either EDGE_VIS or EDGE_INVIS.
vc	Specifies the visibility for edge 2. Use either EDGE_VIS or EDGE_INVIS.

int getEdgeVis

(

int

edge

)

[inline]

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Retrieves the edge visibility for the specified edge.

Parameters:

edge	Specifies the edge.

Returns:

Nonzero if the edge is visible, zero if the edge is invisible.

{ return flags & (VIS_BIT << edge); }

DWORD getVert

(

int

index

)

[inline]

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Returns the index into the mesh vertex array of the specified vertex.

Parameters:

index

Specifies the vertex to retrieve. You may use 0, 1 or 2.

{ return v[index]; }

DWORD* getAllVerts

(

void

)

[inline]

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Retrieves a pointer to the vertex array.

Returns:

A pointer to the vertex array.

{ return v; }

BOOL Hidden

(

)

[inline]

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Determines if the face is hidden or visible.

Returns:

TRUE if the face is hidden; otherwise FALSE.

{return flags&FACE_HIDDEN?TRUE:FALSE;}

void Hide

(

)

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Hides this face (makes it invisible in the viewports).

{flags|=FACE_HIDDEN;}

void Show

(

)

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Shows this face (makes it visible in the viewports).

{flags&=~FACE_HIDDEN;}

void SetHide

(

BOOL

hide

)

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Sets the hidden state of this face.

Parameters:

hide	Specifies the hidden state for the face. Pass TRUE to hide the face; FALSE to show it.

{if (hide) Hide(); else Show();}

BOOL InForeground

(

)

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{return flags&FACE_INFOREGROUND?TRUE:FALSE;}

void PushToForeground

(

)

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{flags|=FACE_INFOREGROUND;}

void PushToBackground

(

)

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{flags&=~FACE_INFOREGROUND;}

void SetInForegound

(

BOOL

foreground

)

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{if (foreground) PushToForeground(); else PushToBackground();}

BOOL IsBackFacing

(

)

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{return flags&FACE_BACKFACING?TRUE:FALSE;}

void SetBackFacing

(

)

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{flags|=FACE_BACKFACING;}

void SetFrontFacing

(

)

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{flags&=~FACE_BACKFACING;}

void SetBackFacing

(

BOOL

backFacing

)

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{if (backFacing) SetBackFacing(); else SetFrontFacing();}

DllExport DWORD GetOtherIndex	(	DWORD	v0,
		DWORD	v1
	)

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Returns the first vertex in the face that isn't v0 or v1.

Parameters:

v0	The zero based index of one of the vertices to check.
v1	The zero based index of the other vertex to check.

Returns:

The zero based index of the vertex found in the Mesh's vertex list.

DllExport DWORD GetEdgeIndex	(	DWORD	v0,
		DWORD	v1
	)

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Returns the index of the edge in the face that goes from v0 to v1, or v1 to v0.

Parameters:

v0	The zero based index of the vertex at one end of the edge.
v1	The zero based index of the vertex at the other end of the edge.

Returns:

The zero based index of the edge found in the Mesh's edge list.

DllExport int Direction	(	DWORD	v0,
		DWORD	v1
	)

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Indicates order in which vertices v0 and v1 appear in the face.

Parameters:

v0	One vertex on this face.
v1	Another vertex on this face.

Returns:

1 if v1 follows v0 in sequence (This includes e.g. when Face::v[2] == v0 and Face::v[0] == v1.) -1 if v0 follows v1 in sequence 0 if v0 or v1 are not on the face.

DllExport DWORD GetVertIndex

(

DWORD

v0

)

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Returns the index of the specified vertex in this face's vertex list (0, 1 or 2).

If not found 3 is returned.

Parameters:

v0	The zero based index of the vertex to check.

DllExport void OrderVerts	(	DWORD &	v0,
		DWORD &	v1
	)

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This method switches v0,v1 if needed to put them in face-order.

If v0 and v1 are in the order in which they appear in the face, or if one or both of them are not actually on the face, nothing happens. If however v0 follows v1, the values of the parameters are switched, so that they are then in the correct order for this face. Sample Code:

        Face & f = mesh.faces[edge.f[0]];
        DWORD v0 = edge.v[0];
        DWORD v1 = edge.v[1];
        // Switch v0, v1 if needed to match orientation in selected face.
        f.OrderVerts(v0,v1);

Parameters:

v0	One vertex on this face.
v1	Another vertex on this face.

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Member Data Documentation

DWORD v[3]

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These are zero-based indices into a mesh object's array of vertices.

DWORD smGroup

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Smoothing group bits for the face.

Each bit of this 32 bit value represents membership in a smoothing group. The least significant bit represents smoothing group #1 while the most significant bit represents group #32. If two adjacent faces are assigned the same smoothing group bit, the edge between them is rendered smoothly.

DWORD flags

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The Face Flags: Can be from the following list:

• The flags in Edge Visibility Flags
• The FACE_HIDDEN flag (Face visibility bit: if the bit is 1, the face is hidden).
• The Mesh::mapSupport() function (should be used instead of the obsolete HAS_TVERTS flag).
• Material ID Masks to access the Material ID (which is stored in the HIWORD of the face flags).