+
+ // If we're the last phase and need to flip the picture to compensate for
+ // the origin, tell the vertex shader so.
+ if (phase->output_node->outgoing_links.empty() && output_origin == OUTPUT_ORIGIN_TOP_LEFT) {
+ const string needle = "#define FLIP_ORIGIN 0";
+ size_t pos = vert_shader.find(needle);
+ assert(pos != string::npos);
+
+ vert_shader[pos + needle.size() - 1] = '1';
+ }
+