glGetLight man page on OpenBSD

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GLGETLIGHT(3G)							GLGETLIGHT(3G)

NAME
       glGetLightfv, glGetLightiv - return light source parameter values

C SPECIFICATION
       void glGetLightfv( GLenum light,
	    GLenum pname,
	    GLfloat *params )
       void glGetLightiv( GLenum light,
	    GLenum pname,
	    GLint *params )

       delim $$

PARAMETERS
       light  Specifies a light source.	 The number of possible lights depends
	      on the implementation, but at least eight lights are supported.
	      They are identified by symbolic names of the form GL_LIGHT$i$
	      where 0 <= $ i $ < GL_MAX_LIGHTS.

       pname  Specifies a light source parameter for light.  Accepted symbolic
	      names are GL_AMBIENT, GL_DIFFUSE, GL_SPECULAR, GL_POSITION,
	      GL_SPOT_DIRECTION, GL_SPOT_EXPONENT, GL_SPOT_CUTOFF,
	      GL_CONSTANT_ATTENUATION, GL_LINEAR_ATTENUATION, and
	      GL_QUADRATIC_ATTENUATION.

       params Returns the requested data.

DESCRIPTION
       glGetLight returns in params the value or values of a light source
       parameter.  light names the light and is a symbolic name of the form
       GL_LIGHT$i$ for 0 <= $i$ < GL_MAX_LIGHTS, where GL_MAX_LIGHTS is an
       implementation dependent constant that is greater than or equal to
       eight.  pname specifies one of ten light source parameters, again by
       symbolic name.

       The following parameters are defined:

       GL_AMBIENT	   params returns four integer or floating-point
			   values representing the ambient intensity of the
			   light source.  Integer values, when requested, are
			   linearly mapped from the internal floating-point
			   representation such that 1.0 maps to the most
			   positive representable integer value, and -1.0 maps
			   to the most negative representable integer value.
			   If the internal value is outside the range [-1, 1],
			   the corresponding integer return value is
			   undefined. The initial value is (0, 0, 0, 1).

       GL_DIFFUSE	   params returns four integer or floating-point
			   values representing the diffuse intensity of the
			   light source.  Integer values, when requested, are
			   linearly mapped from the internal floating-point
			   representation such that 1.0 maps to the most
			   positive representable integer value, and -1.0 maps
			   to the most negative representable integer value.
			   If the internal value is outside the range [-1, 1],
			   the corresponding integer return value is
			   undefined. The initial value for GL_LIGHT0 is (1,
			   1, 1, 1); for other lights, the initial value is
			   (0, 0, 0, 0).

       GL_SPECULAR	   params returns four integer or floating-point
			   values representing the specular intensity of the
			   light source.  Integer values, when requested, are
			   linearly mapped from the internal floating-point
			   representation such that 1.0 maps to the most
			   positive representable integer value, and -1.0 maps
			   to the most negative representable integer value.
			   If the internal value is outside the range [-1, 1],
			   the corresponding integer return value is
			   undefined. The initial value for GL_LIGHT0 is (1,
			   1, 1, 1); for other lights, the initial value is
			   (0, 0, 0, 0).

       GL_POSITION	   params returns four integer or floating-point
			   values representing the position of the light
			   source.  Integer values, when requested, are
			   computed by rounding the internal floating-point
			   values to the nearest integer value.	 The returned
			   values are those maintained in eye coordinates.
			   They will not be equal to the values specified
			   using glLight, unless the modelview matrix was
			   identity at the time glLight was called. The
			   initial value is (0, 0, 1, 0).

       GL_SPOT_DIRECTION   params returns three integer or floating-point
			   values representing the direction of the light
			   source.  Integer values, when requested, are
			   computed by rounding the internal floating-point
			   values to the nearest integer value.	 The returned
			   values are those maintained in eye coordinates.
			   They will not be equal to the values specified
			   using glLight, unless the modelview matrix was
			   identity at the time glLight was called.  Although
			   spot direction is normalized before being used in
			   the lighting equation, the returned values are the
			   transformed versions of the specified values prior
			   to normalization. The initial value is (0, 0, -1).

       GL_SPOT_EXPONENT	   params returns a single integer or floating-point
			   value representing the spot exponent of the light.
			   An integer value, when requested, is computed by
			   rounding the internal floating-point representation
			   to the nearest integer. The initial value is 0.

       GL_SPOT_CUTOFF	   params returns a single integer or floating-point
			   value representing the spot cutoff angle of the
			   light.  An integer value, when requested, is
			   computed by rounding the internal floating-point
			   representation to the nearest integer. The initial
			   value is 180.

       GL_CONSTANT_ATTENUATION
			   params returns a single integer or floating-point
			   value representing the constant (not
			   distance-related) attenuation of the light.	An
			   integer value, when requested, is computed by
			   rounding the internal floating-point representation
			   to the nearest integer. The initial value is 1.

       GL_LINEAR_ATTENUATION
			   params returns a single integer or floating-point
			   value representing the linear attenuation of the
			   light.  An integer value, when requested, is
			   computed by rounding the internal floating-point
			   representation to the nearest integer. The initial
			   value is 0.

       GL_QUADRATIC_ATTENUATION
			   params returns a single integer or floating-point
			   value representing the quadratic attenuation of the
			   light.  An integer value, when requested, is
			   computed by rounding the internal floating-point
			   representation to the nearest integer. The initial
			   value is 0.

NOTES
       It is always the case that GL_LIGHT$i$ = GL_LIGHT0 + $i$.

       If an error is generated, no change is made to the contents of params.

ERRORS
       GL_INVALID_ENUM is generated if light or pname is not an accepted
       value.

       GL_INVALID_OPERATION is generated if glGetLight is executed between the
       execution of glBegin and the corresponding execution of glEnd.

SEE ALSO
       glLight(3G)

								 March 1, 2011
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