#extension GL_ARB_compute_shader : enable
#extension GL_ARB_shader_image_load_store : enable
#extension GL_ARB_shader_image_size : enable
+#ifdef GL_ARB_shading_language_packing
+#extension GL_ARB_shading_language_packing : enable
+#endif
// FIXME this needs to be auto-output or something
uniform restrict writeonly image2D tex_outbuf;