[cogl/cogl-1.18] Add a COGL_EXT_IN_GLES3 option to specify extensions that are in GLES3

[Neil Roberts <nroberts src gnome org>]

commit eb7c37812a82ede1e683346c188678da24dd507a
Author: Neil Roberts <neil linux intel com>
Date:   Tue Apr 1 14:54:38 2014 +0100

    Add a COGL_EXT_IN_GLES3 option to specify extensions that are in GLES3
    
    Some features that were previously available as an extension in GLES2
    are now in core in GLES3 so we should be able to specify that with the
    gles_availability mask of COGL_EXT_BEGIN so that GL implementations
    advertising GLES3 don't have to additionally advertise the extension
    for us to take advantage of it.
    
    Reviewed-by: Robert Bragg <robert bragg intel com>
    (cherry picked from commit 4d892cd97558da61ba526f947ac0555ebab632d2)

 cogl/cogl-feature-private.c            |   28 +++++++++++++++++++---
 cogl/cogl-feature-private.h            |    3 +-
 cogl/driver/gl/cogl-util-gl-private.h  |   11 +++++++++
 cogl/driver/gl/cogl-util-gl.c          |   33 +++++++++++++++++++++++++++
 cogl/driver/gl/gl/cogl-driver-gl.c     |   39 +++----------------------------
 cogl/driver/gl/gles/cogl-driver-gles.c |   30 +++++++++++++++++++++++-
 6 files changed, 102 insertions(+), 42 deletions(-)
---
diff --git a/cogl/cogl-feature-private.c b/cogl/cogl-feature-private.c
index 67d304a..7c160c3 100644
--- a/cogl/cogl-feature-private.c
+++ b/cogl/cogl-feature-private.c
@@ -53,18 +53,38 @@ _cogl_feature_check (CoglRenderer *renderer,
 {
   const char *suffix = NULL;
   int func_num;
+  CoglExtGlesAvailability gles_availability = 0;
   CoglBool in_core;
 
+  switch (driver)
+    {
+    case COGL_DRIVER_GLES1:
+      gles_availability = COGL_EXT_IN_GLES;
+      break;
+    case COGL_DRIVER_GLES2:
+      gles_availability = COGL_EXT_IN_GLES2;
+
+      if (COGL_CHECK_GL_VERSION (gl_major, gl_minor, 3, 0))
+        gles_availability |= COGL_EXT_IN_GLES3;
+      break;
+    case COGL_DRIVER_ANY:
+      g_assert_not_reached ();
+    case COGL_DRIVER_WEBGL:
+      /* FIXME: WebGL should probably have its own COGL_EXT_IN_WEBGL flag */
+      break;
+    case COGL_DRIVER_NOP:
+    case COGL_DRIVER_GL:
+    case COGL_DRIVER_GL3:
+      break;
+    }
+
   /* First check whether the functions should be directly provided by
      GL */
   if (((driver == COGL_DRIVER_GL ||
         driver == COGL_DRIVER_GL3) &&
        COGL_CHECK_GL_VERSION (gl_major, gl_minor,
                               data->min_gl_major, data->min_gl_minor)) ||
-      (driver == COGL_DRIVER_GLES1 &&
-       (data->gles_availability & COGL_EXT_IN_GLES)) ||
-      (driver == COGL_DRIVER_GLES2 &&
-       (data->gles_availability & COGL_EXT_IN_GLES2)))
+      (data->gles_availability & gles_availability))
     {
       suffix = "";
       in_core = TRUE;
diff --git a/cogl/cogl-feature-private.h b/cogl/cogl-feature-private.h
index 02714b7..a342d23 100644
--- a/cogl/cogl-feature-private.h
+++ b/cogl/cogl-feature-private.h
@@ -42,7 +42,8 @@
 typedef enum
 {
   COGL_EXT_IN_GLES = (1 << 0),
-  COGL_EXT_IN_GLES2 = (1 << 1)
+  COGL_EXT_IN_GLES2 = (1 << 1),
+  COGL_EXT_IN_GLES3 = (1 << 2)
 } CoglExtGlesAvailability;
 
 typedef struct _CoglFeatureFunction CoglFeatureFunction;
diff --git a/cogl/driver/gl/cogl-util-gl-private.h b/cogl/driver/gl/cogl-util-gl-private.h
index 8ef26e6..dcc61c0 100644
--- a/cogl/driver/gl/cogl-util-gl-private.h
+++ b/cogl/driver/gl/cogl-util-gl-private.h
@@ -79,4 +79,15 @@ _cogl_gl_util_get_texture_target_string (CoglTextureType texture_type,
                                          const char **target_string_out,
                                          const char **swizzle_out);
 
+/* Parses a GL version number stored in a string. @version_string must
+ * point to the beginning of the version number (ie, it can't point to
+ * the "OpenGL ES" part on GLES). The version number can be followed
+ * by the end of the string, a space or a full stop. Anything else
+ * will be treated as invalid. Returns TRUE and sets major_out and
+ * minor_out if it is succesfully parsed or FALSE otherwise. */
+CoglBool
+_cogl_gl_util_parse_gl_version (const char *version_string,
+                                int *major_out,
+                                int *minor_out);
+
 #endif /* _COGL_UTIL_GL_PRIVATE_H_ */
diff --git a/cogl/driver/gl/cogl-util-gl.c b/cogl/driver/gl/cogl-util-gl.c
index e1df485..814621a 100644
--- a/cogl/driver/gl/cogl-util-gl.c
+++ b/cogl/driver/gl/cogl-util-gl.c
@@ -146,3 +146,36 @@ _cogl_gl_util_get_texture_target_string (CoglTextureType texture_type,
   if (swizzle_out)
     *swizzle_out = tex_coord_swizzle;
 }
+
+CoglBool
+_cogl_gl_util_parse_gl_version (const char *version_string,
+                                int *major_out,
+                                int *minor_out)
+{
+  const char *major_end, *minor_end;
+  int major = 0, minor = 0;
+
+  /* Extract the major number */
+  for (major_end = version_string; *major_end >= '0'
+         && *major_end <= '9'; major_end++)
+    major = (major * 10) + *major_end - '0';
+  /* If there were no digits or the major number isn't followed by a
+     dot then it is invalid */
+  if (major_end == version_string || *major_end != '.')
+    return FALSE;
+
+  /* Extract the minor number */
+  for (minor_end = major_end + 1; *minor_end >= '0'
+         && *minor_end <= '9'; minor_end++)
+    minor = (minor * 10) + *minor_end - '0';
+  /* If there were no digits or there is an unexpected character then
+     it is invalid */
+  if (minor_end == major_end + 1
+      || (*minor_end && *minor_end != ' ' && *minor_end != '.'))
+    return FALSE;
+
+  *major_out = major;
+  *minor_out = minor;
+
+  return TRUE;
+}
diff --git a/cogl/driver/gl/gl/cogl-driver-gl.c b/cogl/driver/gl/gl/cogl-driver-gl.c
index b4de51b..0bcb9ce 100644
--- a/cogl/driver/gl/gl/cogl-driver-gl.c
+++ b/cogl/driver/gl/gl/cogl-driver-gl.c
@@ -290,39 +290,6 @@ _cogl_driver_pixel_format_to_gl (CoglContext *context,
 }
 
 static CoglBool
-parse_gl_version (const char *version_string,
-                  int *major_out,
-                  int *minor_out)
-{
-  const char *major_end, *minor_end;
-  int major = 0, minor = 0;
-
-  /* Extract the major number */
-  for (major_end = version_string; *major_end >= '0'
-        && *major_end <= '9'; major_end++)
-    major = (major * 10) + *major_end - '0';
-  /* If there were no digits or the major number isn't followed by a
-     dot then it is invalid */
-  if (major_end == version_string || *major_end != '.')
-    return FALSE;
-
-  /* Extract the minor number */
-  for (minor_end = major_end + 1; *minor_end >= '0'
-        && *minor_end <= '9'; minor_end++)
-    minor = (minor * 10) + *minor_end - '0';
-  /* If there were no digits or there is an unexpected character then
-     it is invalid */
-  if (minor_end == major_end + 1
-      || (*minor_end && *minor_end != ' ' && *minor_end != '.'))
-    return FALSE;
-
-  *major_out = major;
-  *minor_out = minor;
-
-  return TRUE;
-}
-
-static CoglBool
 _cogl_get_gl_version (CoglContext *ctx,
                       int *major_out,
                       int *minor_out)
@@ -333,7 +300,7 @@ _cogl_get_gl_version (CoglContext *ctx,
   if ((version_string = _cogl_context_get_gl_version (ctx)) == NULL)
     return FALSE;
 
-  return parse_gl_version (version_string, major_out, minor_out);
+  return _cogl_gl_util_parse_gl_version (version_string, major_out, minor_out);
 }
 
 static CoglBool
@@ -444,7 +411,9 @@ _cogl_driver_update_features (CoglContext *ctx,
     {
       const char *glsl_version =
         (char *)ctx->glGetString (GL_SHADING_LANGUAGE_VERSION);
-      parse_gl_version (glsl_version, &ctx->glsl_major, &ctx->glsl_minor);
+      _cogl_gl_util_parse_gl_version (glsl_version,
+                                      &ctx->glsl_major,
+                                      &ctx->glsl_minor);
     }
 
   if (COGL_CHECK_GL_VERSION (ctx->glsl_major, ctx->glsl_minor, 1, 2))
diff --git a/cogl/driver/gl/gles/cogl-driver-gles.c b/cogl/driver/gl/gles/cogl-driver-gles.c
index 989862f..f144ba3 100644
--- a/cogl/driver/gl/gles/cogl-driver-gles.c
+++ b/cogl/driver/gl/gles/cogl-driver-gles.c
@@ -220,6 +220,25 @@ _cogl_driver_pixel_format_to_gl (CoglContext *context,
 }
 
 static CoglBool
+_cogl_get_gl_version (CoglContext *ctx,
+                      int *major_out,
+                      int *minor_out)
+{
+  const char *version_string;
+
+  /* Get the OpenGL version number */
+  if ((version_string = _cogl_context_get_gl_version (ctx)) == NULL)
+    return FALSE;
+
+  if (!g_str_has_prefix (version_string, "OpenGL ES "))
+    return FALSE;
+
+  return _cogl_gl_util_parse_gl_version (version_string + 10,
+                                         major_out,
+                                         minor_out);
+}
+
+static CoglBool
 _cogl_driver_update_features (CoglContext *context,
                               CoglError **error)
 {
@@ -227,6 +246,7 @@ _cogl_driver_update_features (CoglContext *context,
     [COGL_FLAGS_N_LONGS_FOR_SIZE (COGL_N_PRIVATE_FEATURES)] = { 0 };
   CoglFeatureFlags flags = 0;
   char **gl_extensions;
+  int gl_major, gl_minor;
   int i;
 
   /* We have to special case getting the pointer to the glGetString
@@ -263,9 +283,15 @@ _cogl_driver_update_features (CoglContext *context,
 
   _cogl_gpu_info_init (context, &context->gpu);
 
+  if (!_cogl_get_gl_version (context, &gl_major, &gl_minor))
+    {
+      gl_major = 1;
+      gl_minor = 1;
+    }
+
   _cogl_feature_check_ext_functions (context,
-                                     -1 /* GL major version */,
-                                     -1 /* GL minor version */,
+                                     gl_major,
+                                     gl_minor,
                                      gl_extensions);
 
 #ifdef HAVE_COGL_GLES