--- /dev/null
+#version 150
+
+layout(lines) in;
+layout(line_strip, max_vertices = 5) out;
+
+void main()
+{
+ gl_Position = gl_in[0].gl_Position;
+ EmitVertex();
+ gl_Position = vec4(gl_in[0].gl_Position.x, gl_in[1].gl_Position.y, 0.0, 1.0);
+ EmitVertex();
+ gl_Position = gl_in[1].gl_Position;
+ EmitVertex();
+ gl_Position = vec4(gl_in[1].gl_Position.x, gl_in[0].gl_Position.y, 0.0, 1.0);
+ EmitVertex();
+ gl_Position = gl_in[0].gl_Position;
+ EmitVertex();
+ EndPrimitive();
+}
+