// DIRECTION_VERTICAL will be #defined to 1 if we are doing a vertical blur,
// 0 otherwise.
-uniform vec2 PREFIX(samples)[NUM_TAPS / 2 + 1];
+// Implicit uniforms:
+// uniform vec2 PREFIX(samples)[NUM_TAPS / 2 + 1];
vec4 FUNCNAME(vec2 tc) {
vec4 sum = vec4(PREFIX(samples)[0].y) * INPUT(tc);