glValidateProgram — validate a program object
glValidateProgram checks to see whether the executables contained in
program can execute given the current OpenGL state. The information generated by the validation process will be stored in
program's information log. The validation information may consist of an empty string, or it may be a string containing information about how the current program object interacts with the rest of current OpenGL state. This provides a way for OpenGL implementers to convey more information about why the current program is inefficient, suboptimal, failing to execute, and so on.
The status of the validation operation will be stored as part of the program object's state. This value will be set to
GL_TRUE if the validation succeeded, and
GL_FALSE otherwise. It can be queried by calling glGetProgramiv with arguments
GL_VALIDATE_STATUS. If validation is successful,
program is guaranteed to execute given the current state. Otherwise,
program is guaranteed to not execute.
This function is typically useful only during application development. The informational string stored in the information log is completely implementation dependent; therefore, an application should not expect different OpenGL implementations to produce identical information strings.
This function mimics the validation operation that OpenGL implementations must perform when rendering commands are issued while programmable shaders are part of current state. The error
GL_INVALID_OPERATION will be generated by glDrawArrays or glDrawElements if any two active samplers in the current program object are of different types, but refer to the same texture image unit.
It may be difficult or cause a performance degradation for applications to catch these errors when rendering commands are issued. Therefore, applications are advised to make calls to
glValidateProgram to detect these issues during application development.
GL_INVALID_VALUE is generated if
program is not a value generated by OpenGL.
GL_INVALID_OPERATION is generated if
program is not a program object.
glGetProgramiv with arguments
glGetProgramInfoLog with argument
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