glgettransformfeedbackvarying(3g) [osx man page]
GLGETTRANSFORMFEEDBA(3G) OpenGL 3.3 GLGETTRANSFORMFEEDBA(3G) NAME
glGetTransformFeedbackVarying - retrieve information about varying variables selected for transform feedback C SPECIFICATION
void glGetTransformFeedbackVarying(GLuintprogram, GLuintindex, GLsizeibufSize, GLsizei *length, GLsizeisize, GLenum *type, char *name); PARAMETERS
program The name of the target program object. index The index of the varying variable whose information to retrieve. bufSize The maximum number of characters, including the null terminator, that may be written into name. length The address of a variable which will receive the number of characters written into name, excluding the null-terminator. If length is NULL no length is returned. size The address of a variable that will receive the size of the varying. type The address of a variable that will recieve the type of the varying. name The address of a buffer into which will be written the name of the varying. DESCRIPTION
Information about the set of varying variables in a linked program that will be captured during transform feedback may be retrieved by calling glGetTransformFeedbackVarying. glGetTransformFeedbackVarying provides information about the varying variable selected by index. An index of 0 selects the first varying variable specified in the varyings array passed to glTransformFeedbackVaryings(), and an index of GL_TRANSFORM_FEEDBACK_VARYINGS-1 selects the last such variable. The name of the selected varying is returned as a null-terminated string in name. The actual number of characters written into name, excluding the null terminator, is returned in length. If length is NULL, no length is returned. The maximum number of characters that may be written into name, including the null terminator, is specified by bufSize. The length of the longest varying name in program is given by GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH, which can be queried with glGetProgram(). For the selected varying variable, its type is returned into type. The size of the varying is returned into size. The value in size is in units of the type returned in type. The type returned can be any of the scalar, vector, or matrix attribute types returned by glGetActiveAttrib(). If an error occurred, the return parameters length, size, type and name will be unmodified. This command will return as much information about the varying variables as possible. If no information is available, length will be set to zero and name will be an empty string. This situation could arise if glGetTransformFeedbackVarying is called after a failed link. ERRORS
GL_INVALID_VALUE is generated if program is not the name of a program object. GL_INVALID_VALUE is generated if index is greater or equal to the value of GL_TRANSFORM_FEEDBACK_VARYINGS. GL_INVALID_OPERATION is generated program has not been linked. ASSOCIATED GETS
glGetProgram() with argument GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH. SEE ALSO
glBeginTransformFeedback(), glEndTransformFeedback(), glTransformFeedbackVaryings(), glGetProgram() COPYRIGHT
Copyright (C) 2010 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/. OpenGL 3.3 03/08/2011 GLGETTRANSFORMFEEDBA(3G)
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GLBINDFRAGDATALOCATI(3G) OpenGL 3.3 GLBINDFRAGDATALOCATI(3G) NAME
glBindFragDataLocationIndexed - bind a user-defined varying out variable to a fragment shader color number and index C SPECIFICATION
void glBindFragDataLocationIndexed(GLuint program, GLuint colorNumber, GLuint index, const char *name); PARAMETERS
program The name of the program containing varying out variable whose binding to modify colorNumber The color number to bind the user-defined varying out variable to index The index of the color input to bind the user-defined varying out variable to name The name of the user-defined varying out variable whose binding to modify DESCRIPTION
glBindFragDataLocationIndexed specifies that the varying out variable name in program should be bound to fragment color colorNumber when the program is next linked. index may be zero or one to specify that the color be used as either the first or second color input to the blend equation, respectively. The bindings specified by glBindFragDataLocationIndexed have no effect until program is next linked. Bindings may be specified at any time after program has been created. Specifically, they may be specified before shader objects are attached to the program. Therefore, any name may be specified in name, including a name that is never used as a varying out variable in any fragment shader object. Names beginning with gl_ are reserved by the GL. If name was bound previously, its assigned binding is replaced with colorNumber and index. name must be a null-terminated string. index must be less than or equal to one, and colorNumber must be less than the value of GL_MAX_DRAW_BUFFERS if index is zero, and less than the value of GL_MAX_DUAL_SOURCE_DRAW_BUFFERS if index is greater than or equal to one. In addition to the errors generated by glBindFragDataLocationIndexed, the program program will fail to link if: o The number of active outputs is greater than the value GL_MAX_DRAW_BUFFERS. o More than one varying out variable is bound to the same color number. NOTES
Varying out varyings may have locations assigned explicitly in the shader text using a location layout qualifier. If a shader statically assigns a location to a varying out variable in the shader text, that location is used and any location assigned with glBindFragDataLocation is ignored. ERRORS
GL_INVALID_VALUE is generated if colorNumber is greater than or equal to GL_MAX_DRAW_BUFFERS. GL_INVALID_VALUE is generated if colorNumber is greater than or equal to GL_MAX_DUAL_SOURCE_DRAW_BUFERS and index is greater than or equal to one. GL_INVALID_VALUE is generated if index is greater than one. GL_INVALID_OPERATION is generated if name starts with the reserved gl_ prefix. GL_INVALID_OPERATION is generated if program is not the name of a program object. ASSOCIATED GETS
glGetFragDataLocation() with a valid program object and the the name of a user-defined varying out variable glGetFragDataIndex() with a valid program object and the the name of a user-defined varying out variable SEE ALSO
glCreateProgram(), glLinkProgram() glGetFragDataLocation(), glGetFragDataIndex() glBindFragDataLocation() COPYRIGHT
Copyright (C) 2010 Khronos Group. This material may be distributed subject to the terms and conditions set forth in the Open Publication License, v 1.0, 8 June 1999. http://opencontent.org/openpub/. OpenGL 3.3 03/08/2011 GLBINDFRAGDATALOCATI(3G)