glamor: Compute GLSL version from GL_SHADING_LANGUAGE_VERSION (v3)

Use code from Piglit project to compute GLSL version for either GL or
GLES. The Piglit code was originally written by Chad Versace.

v2: bail if the parse fails (requested by Eric Anholt)
v3: Use version 1.20 for GLES until we fix our programs (Eric Anholt)

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Eric Anholt <eric@anholt.net>

1 files changed, 39 insertions, 9 deletions

diff --git a/glamor/glamor.c b/glamor/glamor.c
index 6f4f30927..9d40e3ce5 100644
--- a/glamor/glamor.c
+++ b/glamor/glamor.c
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2008 Intel Corporation
+ * Copyright © 2008,2011 Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -23,7 +23,7 @@
  * Authors:
  *    Eric Anholt <eric@anholt.net>
  *    Zhigang Gong <zhigang.gong@linux.intel.com>
- *
+ *    Chad Versace <chad.versace@linux.intel.com>
  */
 
 /** @file glamor.c
@@ -336,7 +336,11 @@ glamor_init(ScreenPtr screen, unsigned int flags)
 {
     glamor_screen_private *glamor_priv;
     int gl_version;
+    int glsl_major, glsl_minor;
     int max_viewport_size[2];
+    const char *shading_version_string;
+    int shading_version_offset;
+
     PictureScreenPtr ps = GetPictureScreenIfSet(screen);
 
     if (flags & ~GLAMOR_VALID_FLAGS) {
@@ -380,14 +384,40 @@ glamor_init(ScreenPtr screen, unsigned int flags)
 
     gl_version = epoxy_gl_version();
 
-    /* Would be nice to have a cleaner test for GLSL 1.30 support,
-     * but for now this should suffice
-     */
-    if (glamor_priv->gl_flavor == GLAMOR_GL_DESKTOP && gl_version >= 30)
-        glamor_priv->glsl_version = 130;
-    else
-        glamor_priv->glsl_version = 120;
+    shading_version_string = (char *) glGetString(GL_SHADING_LANGUAGE_VERSION);
+
+    if (!shading_version_string) {
+        LogMessage(X_WARNING,
+                   "glamor%d: Failed to get GLSL version\n",
+                   screen->myNum);
+        goto fail;
+    }
 
+    shading_version_offset = 0;
+    if (strncmp("OpenGL ES GLSL ES ", shading_version_string, 18) == 0)
+        shading_version_offset = 18;
+
+    if (sscanf(shading_version_string + shading_version_offset,
+               "%i.%i",
+               &glsl_major,
+               &glsl_minor) != 2) {
+        LogMessage(X_WARNING,
+                   "glamor%d: Failed to parse GLSL version string %s\n",
+                   screen->myNum, shading_version_string);
+        goto fail;
+    }
+    glamor_priv->glsl_version = glsl_major * 100 + glsl_minor;
+
+    if (glamor_priv->gl_flavor == GLAMOR_GL_ES2) {
+        /* Force us back to the base version of our programs on an ES
+         * context, anyway.  Basically glamor only uses desktop 1.20
+         * or 1.30 currently.  1.30's new features are also present in
+         * ES 3.0, but our glamor_program.c constructions use a lot of
+         * compatibility features (to reduce the diff between 1.20 and
+         * 1.30 programs).
+         */
+        glamor_priv->glsl_version = 120;
+    }
 
     /* We'd like to require GL_ARB_map_buffer_range or
      * GL_OES_map_buffer_range, since it offers more information to