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fglGetLight(3G)		       OpenGL Reference		       fglGetLight(3G)

NAME
     fglGetLightfv, fglGetLightiv - return light source parameter values

FORTRAN SPECIFICATION
     SUBROUTINE fglGetLightfv( INTEGER*4 light,
			       INTEGER*4 pname,
			       CHARACTER*8 params )
     SUBROUTINE fglGetLightiv( INTEGER*4 light,
			       INTEGER*4 pname,
			       CHARACTER*8 params )

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_LIGHTi 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
     fglGetLight 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_LIGHTi 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

									Page 1

fglGetLight(3G)		       OpenGL Reference		       fglGetLight(3G)

			 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 fglLight, unless
			 the modelview matrix was identity at the time
			 fglLight 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 fglLight, unless
			 the modelview matrix was identity at the time
			 fglLight 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.

									Page 2

fglGetLight(3G)		       OpenGL Reference		       fglGetLight(3G)

     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_LIGHTi = 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 fglGetLight is executed between the
     execution of fglBegin and the corresponding execution of fglEnd.

SEE ALSO
     fglLight

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