6 * From page 17 (page 23 of the PDF) of the GLSL 1.20 spec:
8 * "Samplers cannot be treated as l-values; hence cannot be used
9 * as out or inout function parameters..."
11 * The GLSL 1.10 spec does not state this rule specifically, but it is
12 * clear from context that it is intended.
25 gl_FragColor = vec4(1.0);