- * Recalculate the \c _Valid flag of a context's shader image units.
- *
- * To be called when the state of any texture bound to an image unit
- * changes.
+ * Get the GL image format class for a shader image format GL enum
+ */
+GLenum
+_mesa_get_image_format_class(GLenum format);
+
+/**
+ * Return whether an image format should be supported based on the current API
+ * version of the context.
+ */
+bool
+_mesa_is_shader_image_format_supported(const struct gl_context *ctx,
+ GLenum format);
+
+/**
+ * Get a single image unit struct with the default state.
+ */
+struct gl_image_unit
+_mesa_default_image_unit(struct gl_context *ctx);
+
+/**
+ * Initialize a context's shader image units to the default state.