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 * Portions Copyright (C) 1997-2005 Alias Systems Corp.
 ******************************************************************************
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- Using maya shader state

maya specific shader state items are accessible through 
mayabase_stateitem_get.
mayabase_stateitem_get takes varialbe size arguments,
which should terminate with MBSI_NULL.
The function returns pointers to the specified items.
For example,

miInteger *val1, *val2, *val3;
mayabase_stateitem_get(state,
	MBSI_LIGHTAMBIENT, &val1,
	MBSI_LIGHTDIFFUSE, &val2,
	MBSI_LIGHTSPECULAR, &val3,
	MBSI_NULL
	);
	
val1, val2, val3 points to the shader state items
storing emit ambient, emit diffuse, emit specular 
information respectively.

val1, val2, val3 can be used either to set or to read 
the shader state values.

MbStateItem in mayaapi.h shows 
the full list of shader state items available.

- emit diffuse, emit specular

A light shader may set 
MBSI_LIGHTAMBIENT, MBSI_LIGHTDIFFUSE, MBSI_LIGHTSPECULAR
item in the shader state
to indicate other shaders that
this light emits ambient, diffuse and specular lights.
Other shaders, material shader for instance,
may read these values to compute the final color.

See examples in this directory.

mayaEmitLight_mib_light_point modifies mib_light_point
to set MBSI_LIGHTDIFFUSE and MBSI_LIGHTSPECULAR.

mayaEmitLight_mib_illum_phong modifies mib_illum_phong
to read MBSI_LIGHTDIFFUSE and MBSI_LIGHTSPECULAR.
Diffuse component is added only if MBSI_LIGHTDIFFUSE is set.

mayaShaderState_base.mi
contains declaration for these shaders.
Note that mayaEmitLight_mib_light_point has two extra parameters.

AETemplate files are provided.