StencilTest Class Reference
[Scene Graph]

#include <lvt/State.h>

Inheritance diagram for StencilTest:

[legend]List of all members.

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Detailed Description

Controls stencil testing.

The StencilTest class controls both stencil testing, the stencil operation and writes to the stencil buffer. Disabling the class (via State::Disable) will disable both stencil testing and stencil writes. To disable stencil testing, but leave stencil writes enabled, set the stencil test function to GL_ALWAYS:

    StencilTest *st = new StencilTest;
    st->SetStencilFunc(GL_ALWAYS);

The StencilTest class supports two-sided stencil via OpenGL 2.0 core, ATI_separate_stencil, and EXT_stencil_two_side. StencilTest does not support separate stencil buffer masks for front and back polygons as EXT_stencil_two_side does. StencilTest will first try the OpenGL 2.0 core entry points. Failing that, it will try ATI_separate_stencil. ATI_separate_stencil does not support separate reference values and masks in the call to SetStencilFunc, so the reference value and mask for front faces is also used for back faces. If no two-sided stencil extension is present, StencilTest will fall back to one-sided stencil using the parameters set for front faces.

Public Member Functions
GLenum	GetStencilFailOp (GLenum face) const
	Returns the current fail stencil operation for the specified face.
GLenum	GetStencilFunc (GLenum face) const
	Returns the current stencil function for the specified face.
GLuint	GetStencilMask () const
	Returns the current stencil mask.
GLenum	GetStencilZFailOp (GLenum face) const
	Returns the current zfail stencil operation for the specified face.
GLenum	GetStencilZPassOp (GLenum face) const
	Returns the current zpass stencil operation for the specified face.
bool	HasTwoSidedStencil () const
	Returns true if the implementation has some support for two-sided stencil.
virtual void	Render ()
	Activates the State.
void	SetStencilFunc (GLenum face, GLenum func, GLint ref, GLuint mask)
	Sets the current stencil function.
void	SetStencilMask (GLuint mask)
	Sets the current stencil mask.
void	SetStencilOp (GLenum face, GLenum fail, GLenum zfail, GLenum zpass)
	Sets the current stencil operation.

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Member Function Documentation

GLenum GetStencilFailOp (  GLenum  face  )  const

Returns the current fail stencil operation for the specified face. If two-sided stencil is not supported by the current implementation, the face parameter is ignored.

GLenum GetStencilFunc (  GLenum  face  )  const

Returns the current stencil function for the specified face. If two-sided stencil is not supported by the current implementation, the face parameter is ignored.

GLuint GetStencilMask (   )  const [inline]

Returns the current stencil mask.

GLenum GetStencilZFailOp (  GLenum  face  )  const

Returns the current zfail stencil operation for the specified face. If two-sided stencil is not supported by the current implementation, the face parameter is ignored.

GLenum GetStencilZPassOp (  GLenum  face  )  const

Returns the current zpass stencil operation for the specified face. If two-sided stencil is not supported by the current implementation, the face parameter is ignored.

bool HasTwoSidedStencil (   )  const

Returns true if the implementation has some support for two-sided stencil.

virtual void Render (   )  [virtual]

Activates the State. If the State is enabled, the corresponding piece of OpenGL state is enabled and its value is set, if appropriate. If the State object is disabled, the corresponding piece of OpenGL state is disabled. Implements State.

void SetStencilFunc (  GLenum  face, GLenum  func, GLint  ref, GLuint  mask )

Sets the current stencil function. If two-sided stencil is not supported by the current implementation, the face parameter is ignored.

void SetStencilMask (  GLuint  mask  )  [inline]

Sets the current stencil mask. Set the stencil mask to 0 to disable writes to the stencil buffer. The default is all 1s (i.e. ~0).

void SetStencilOp (  GLenum  face, GLenum  fail, GLenum  zfail, GLenum  zpass )

Sets the current stencil operation. Parameters: face  The polygon type to apply the stencil operation to one of GL_FRONT, GL_BACK, or GL_FRONT_AND_BACK fail  Action to take when the stencil test fails. zfail  Action to take when the stencil test passes but the depth test fails. zpass  Action to take when both the stencil test and the depth test pass. See the man page for glStencilOp or the OpenGL Red Book for more information about the values accepted for fail, zfail, and zpass. The default for all three actions is GL_KEEP. If two-sided stencil is not supported by the current implementation, the face parameter is ignored.

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