[Mesa-dev] [RFC 09/21] mesa: Generate a helper function for each extension

[Nanley Chery]

From: Nanley Chery <nanley.g.chery at intel.com>

Generate functions which determine if an extension is supported in the
current context. Initially, enums were going to be explicitly used with
_mesa_extension_supported(). The idea to embed the function and enums
into generated helper functions was suggested by Kristian Høgsberg.

For performance, the function body no longer uses
_mesa_extension_supported() and, as suggested by Chad Versace, the
functions are also declared static inline.

Signed-off-by: Nanley Chery <nanley.g.chery at intel.com>
---
 src/mesa/main/context.h    |  1 +
 src/mesa/main/extensions.c | 22 +---------------------
 src/mesa/main/extensions.h | 39 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 21 deletions(-)

diff --git a/src/mesa/main/context.h b/src/mesa/main/context.h
index 1e7a12c..4798b1f 100644
--- a/src/mesa/main/context.h
+++ b/src/mesa/main/context.h
@@ -50,6 +50,7 @@
 
 
 #include "imports.h"
+#include "extensions.h"
 #include "mtypes.h"
 #include "vbo/vbo.h"
 
diff --git a/src/mesa/main/extensions.c b/src/mesa/main/extensions.c
index 9451085..136313f 100644
--- a/src/mesa/main/extensions.c
+++ b/src/mesa/main/extensions.c
@@ -42,26 +42,6 @@ struct gl_extensions _mesa_extension_override_disables;
 static char *extra_extensions = NULL;
 static char *cant_disable_extensions = NULL;
 
-/**
- * \brief An element of the \c extension_table.
- */
-struct extension {
-   /** Name of extension, such as "GL_ARB_depth_clamp". */
-   const char *name;
-
-   /** Offset (in bytes) of the corresponding member in struct gl_extensions. */
-   size_t offset;
-
-   /** Minimum version the extension requires for the given API
-    * (see gl_api defined in mtypes.h)
-    */
-   GLuint version[API_OPENGL_LAST + 1];
-
-   /** Year the extension was proposed or approved.  Used to sort the 
-    * extension string chronologically. */
-   uint16_t year;
-};
-
 
 /**
  * Given a member \c x of struct gl_extensions, return offset of
@@ -73,7 +53,7 @@ struct extension {
 /**
  * \brief Table of supported OpenGL extensions for all API's.
  */
-static const struct extension extension_table[] = {
+const struct extension extension_table[] = {
 #define EXT(name_str, driver_cap, gll_ver, glc_ver, gles_ver, gles2_ver, yyyy) \
         { .name = "GL_" #name_str, .offset = o(driver_cap), \
           .version = { \
diff --git a/src/mesa/main/extensions.h b/src/mesa/main/extensions.h
index 595512a..24cc04d 100644
--- a/src/mesa/main/extensions.h
+++ b/src/mesa/main/extensions.h
@@ -55,6 +55,45 @@ _mesa_get_extension_count(struct gl_context *ctx);
 extern const GLubyte *
 _mesa_get_enabled_extension(struct gl_context *ctx, GLuint index);
 
+
+/**
+ * \brief An element of the \c extension_table.
+ */
+struct extension {
+   /** Name of extension, such as "GL_ARB_depth_clamp". */
+   const char *name;
+
+   /** Offset (in bytes) of the corresponding member in struct gl_extensions. */
+   size_t offset;
+
+   /** Minimum version the extension requires for the given API
+    * (see gl_api defined in mtypes.h)
+    */
+   GLuint version[API_OPENGL_LAST + 1];
+
+   /** Year the extension was proposed or approved.  Used to sort the 
+    * extension string chronologically. */
+   uint16_t year;
+} extern const extension_table[];
+
+
+/* Generate enums for the functions below */
+enum {
+#define EXT(name_str, ...) MESA_EXTENSION_##name_str,
+#include "extensions_table.h"
+#undef EXT
+};
+
+
+/** Checks if the context suports a user-facing extension */
+#define EXT(name_str, driver_cap, ...) \
+static inline bool _mesa_has_##name_str(const struct gl_context *ctx) { \
+      return ctx->Extensions.driver_cap && (ctx->Version >= \
+             extension_table[MESA_EXTENSION_##name_str].version[ctx->API]); \
+}
+#include "extensions_table.h"
+#undef EXT
+
 extern struct gl_extensions _mesa_extension_override_enables;
 extern struct gl_extensions _mesa_extension_override_disables;
 
-- 
2.6.1