Of course, uniform variables can be any valid GLSL type, including complex types such as arrays or structures. OpenGL provides a glUniform function with the usual suffixes, appropriate for each type. For example, to assign to a variable of the vec3 type, one would use glUniform3f or glUniform3fv.
For arrays, one can use the functions ending in v to initialize multiple values within the array. Note that if it is desired, one can query for the location of a particular element of the uniform array using the [] operator. For example, to query for the location of the second element of MyArray:
GLuint location = glGetUniformLocation( programHandle, "MyArray[1]" );
For structures, the members of the structure must be initialized ...
