pipeline: Move the snippet source loop into a common function

The two loops that generate the functions for the snippets in the
fragend and vertend are very similar so to avoid code duplication this
patch moves the logic to its own function in a new
cogl-pipeline-snippet.c file.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

cogl/cogl-pipeline-snippet-private.h

@@ -0,0 +1,103 @@
+/*
+ * Cogl
+ *
+ * An object oriented GL/GLES Abstraction/Utility Layer
+ *
+ * Copyright (C) 2011 Intel Corporation.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ *
+ *
+ * Authors:
+ *   Neil Roberts <neil@linux.intel.com>
+ */
+
+#ifndef __COGL_PIPELINE_SNIPPET_PRIVATE_H
+#define __COGL_PIPELINE_SNIPPET_PRIVATE_H
+
+#include "cogl-snippet.h"
+#include "cogl-queue.h"
+
+/* Enumeration of all the hook points that a snippet can be attached
+   to within a pipeline. Note that although there are currently only
+   two points that directly correspond to the two state flags, the
+   idea isn't that each new enum here will mean a state flag. The
+   state flags are just intended to mark the split between hooks that
+   affect the fragment shader and hooks that affect the vertex
+   shader. For example, if we add a hook to wrap around the processing
+   for a particular layer then that hook would be part of the fragment
+   snippets state. */
+typedef enum
+{
+  COGL_PIPELINE_SNIPPET_HOOK_VERTEX,
+  COGL_PIPELINE_SNIPPET_HOOK_FRAGMENT
+} CoglPipelineSnippetHook;
+
+typedef struct _CoglPipelineSnippet CoglPipelineSnippet;
+
+COGL_LIST_HEAD (CoglPipelineSnippetList, CoglPipelineSnippet);
+
+struct _CoglPipelineSnippet
+{
+  COGL_LIST_ENTRY (CoglPipelineSnippet) list_node;
+
+  /* Hook where this snippet is attached */
+  CoglPipelineSnippetHook hook;
+
+  CoglSnippet *snippet;
+};
+
+/* Arguments to pass to _cogl_pipeline_snippet_generate_code() */
+typedef struct
+{
+  CoglPipelineSnippetList *snippets;
+
+  /* Only snippets at this hook point will be used */
+  CoglPipelineSnippetHook hook;
+
+  /* The final function to chain on to after all of the snippets code
+     has been run */
+  const char *chain_function;
+
+  /* The name of the final generated function */
+  const char *final_name;
+
+  /* A prefix to insert before each generate function name */
+  const char *function_prefix;
+
+  /* The return type of all of the functions, or NULL to use void */
+  const char *return_type;
+
+  /* A variable to return from the functions. The snippets are
+     expected to modify this variable. Ignored if return_type is
+     NULL */
+  const char *return_variable;
+
+  /* The argument names or NULL if there are none */
+  const char *arguments;
+
+  /* The argument types or NULL */
+  const char *argument_declarations;
+
+  /* The string to generate the source into */
+  GString *source_buf;
+} CoglPipelineSnippetData;
+
+void
+_cogl_pipeline_snippet_generate_code (const CoglPipelineSnippetData *data);
+
+#endif /* __COGL_PIPELINE_SNIPPET_PRIVATE_H */
+