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cgConnectParameter

NAME

cgConnectParameter - connect two parameters

SYNOPSIS

  #include <Cg/cg.h>

  void cgConnectParameter( CGparameter from,

                           CGparameter to );

PARAMETERS

from

The source parameter.

to

The destination parameter.

RETURN VALUES

None.

DESCRIPTION

cgConnectParameter connects a source (from) parameter to a destination (to) parameter. The resulting connection forces the value and variability of the destination parameter to be identical to the source parameter. A source parameter may be connected to multiple destination parameters but there may only be one source parameter per destination parameter.

cgConnectParameter may be used to create an arbitrarily deep tree. A runtime error will be thrown if a cycle is inadvertently created. For example, the following code snipped would generate a CG_BIND_CREATES_CYCLE_ERROR :

  CGcontext context = cgCreateContext();

  CGparameter Param1 = cgCreateParameter(context, CG_FLOAT);

  CGparameter Param2 = cgCreateParameter(context, CG_FLOAT);

  CGparameter Param3 = cgCreateParameter(context, CG_FLOAT);

  cgConnectParameter(Param1, Param2);

  cgConnectParameter(Param2, Param3);

  cgConnectParameter(Param3, Param1); /* This will generate the error */

If the source type is a complex type (e.g., struct, or array) the topology and member types of both parameters must be identical. Each correlating member parameter will be connected.

Both parameters must be of the same type unless the source parameter is a struct type, the destination parameter is an interface type, and the struct type implements the interface type. In such a case, a copy of the parameter tree under the source parameter will be duplicated, linked to the orignal tree, and placed under the destination parameter.

If a an array parameter is connected to a resizable array parameter the destination parameter array will automatically be resized to match the source array.

The source parameter may not be a program parameter. Also the variability of the parameters may not be CG_VARYING.

EXAMPLES

  CGparameter TimeParam1 = cgGetNamedParameter(program1, "time");

  CGparameter TimeParam2 = cgGetNamedParameter(program2, "time");

  CGparameter SharedTime = cgCreateParameter(context, 

                                             cgGetParameterType(TimeParam1));

  cgConnectParameter(SharedTime, TimeParam1);

  cgConnectParameter(SharedTime, TimeParam2);

  cgSetParameter1f(SharedTime, 2.0);

ERRORS

CG_INVALID_PARAM_HANDLE_ERROR is generated if either of the from or to parameters are invalid handles.

CG_PARAMETER_IS_NOT_SHARED is generated if the source parameter is a program parameter.

CG_BIND_CREATES_CYCLE_ERROR is generated if the connection will result in a cycle.

CG_PARAMETERS_DO_NOT_MATCH_ERROR is generated if the parameters do not have the same type or the topologies do not match.

CG_ARRAY_TYPES_DO_NOT_MATCH_ERROR is generated if the type of two arrays being connected do not match.

CG_ARRAY_DIMENSIONS_DO_NOT_MATCH_ERROR is generated if the dimensions of two arrays being connected do not match.

HISTORY

cgConnectParameter was introduced in Cg 1.2.

SEE ALSO

the cgGetConnectedParameter manpage, the cgGetConnectedToParameter manpage, the cgDisconnectParameter manpage