prog_parameter: Document the fact that Size may be > 4

Signed-off-by: Nicolai Hähnle <nhaehnle@gmail.com>

src/mesa/shader/prog_parameter.h

@@ -56,7 +56,13 @@ struct gl_program_parameter
    const char *Name;        /**< Null-terminated string */
    gl_register_file Type;   /**< PROGRAM_NAMED_PARAM, CONSTANT or STATE_VAR */
    GLenum DataType;         /**< GL_FLOAT, GL_FLOAT_VEC2, etc */
-   GLuint Size;             /**< Number of components (1..4) */
+   /**
+    * Number of components (1..4), or more.
+    * If the number of components is greater than 4,
+    * this parameter is part of a larger uniform like a GLSL matrix or array.
+    * The next program parameter's Size will be Size-4 of this parameter.
+    */
+   GLuint Size;
    GLboolean Used;          /**< Helper flag for GLSL uniform tracking */
    GLboolean Initialized;   /**< Has the ParameterValue[] been set? */
    GLbitfield Flags;        /**< Bitmask of PROG_PARAM_*_BIT */