[PATCH 3/4] glx: Implement GLX_EXT_create_context_es2_profile

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

This patch builds on the infrastucture put in place for
GLX_ARB_create_context_profile.  If GLX_CONTEXT_ES2_PROFILE_BIT_EXT is
specified and the requested version is 2.0, create a context with the
__DRI_API_GLES2 API.

This change assumes that any DRI2 driver can handle (possibly by saying "no
seeing an API setting other than __DRI_API_OPENGL or __DRI_API_OPENGL_CORE.
This allows enabling the extension any time GLX_ARB_create_context (and
GLX_ARB_create_context_profile) is enabled.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
---
 glx/createcontext.c    |   37 +++++++++++++++++++++++++++++++++++++
 glx/extension_string.c |    1 +
 glx/extension_string.h |    1 +
 glx/glxdri2.c          |    7 +++++++
 4 files changed, 46 insertions(+), 0 deletions(-)

diff --git a/glx/createcontext.c b/glx/createcontext.c
index 6f580f0..8f7dc05 100644
--- a/glx/createcontext.c
+++ b/glx/createcontext.c
@@ -229,6 +229,43 @@ __glXDisp_CreateContextAttribsARB(__GLXclientState * cl, GLbyte * pc)
     case GLX_CONTEXT_CORE_PROFILE_BIT_ARB:
     case GLX_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB:
         break;
+    case GLX_CONTEXT_ES2_PROFILE_BIT_EXT:
+        /* The GLX_EXT_create_context_es2_profile spec says:
+         *
+         *     "... If the version requested is 2.0, and the
+         *     GLX_CONTEXT_ES2_PROFILE_BIT_EXT bit is set in the
+         *     GLX_CONTEXT_PROFILE_MASK_ARB attribute (see below), then the
+         *     context returned will implement OpenGL ES 2.0."
+         *
+         * It also says:
+         *
+         *     "* If attribute GLX_CONTEXT_PROFILE_MASK_ARB has no bits set;
+         *        has any bits set other than
+         *        GLX_CONTEXT_CORE_PROFILE_BIT_ARB,
+         *        GLX_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB, or
+         *        GLX_CONTEXT_ES2_PROFILE_BIT_EXT; has more than one of these
+         *        bits set; or if the implementation does not supported the
+         *        requested profile, then GLXBadProfileARB is generated."
+         *
+         * However, it does not say what is supposed to happen if
+         * GLX_CONTEXT_ES2_PROFILE_BIT_EXT is set but the version requested is
+         * not 2.0.
+         *
+         * We choose to generate GLXBadProfileARB.
+         *
+         * Other options include:
+         *
+         *    * Generate BadMatch.
+         *
+         *    * Ignore the version and create an ES2 context.
+         *
+         *    * Ignore GLX_CONTEXT_ES2_PROFILE_BIT_EXT and create a context
+         *      with the specified version and the default profile for that
+         *      version.
+         */
+        if (major_version != 2 || minor_version != 0)
+            return __glXError(GLXBadProfileARB);
+        break;
     default:
         return __glXError(GLXBadProfileARB);
     }
diff --git a/glx/extension_string.c b/glx/extension_string.c
index 6a1a6c6..2d550a9 100644
--- a/glx/extension_string.c
+++ b/glx/extension_string.c
@@ -72,6 +72,7 @@ static const struct extension_info known_glx_extensions[] = {
     { GLX(ARB_create_context_profile),  VER(0,0), N, },
     { GLX(ARB_multisample),             VER(1,4), Y, },
 
+    { GLX(EXT_create_context_es2_profile), VER(0,0), N, },
     { GLX(EXT_import_context),          VER(0,0), Y, },
     { GLX(EXT_texture_from_pixmap),     VER(0,0), Y, },
     { GLX(EXT_visual_info),             VER(0,0), Y, },
diff --git a/glx/extension_string.h b/glx/extension_string.h
index 947bf89..1704696 100644
--- a/glx/extension_string.h
+++ b/glx/extension_string.h
@@ -39,6 +39,7 @@ enum {
     ARB_create_context_bit = 0,
     ARB_create_context_profile_bit,
     ARB_multisample_bit,
+    EXT_create_context_es2_profile_bit,
     EXT_import_context_bit,
     EXT_texture_from_pixmap_bit,
     EXT_visual_info_bit,
diff --git a/glx/glxdri2.c b/glx/glxdri2.c
index 2827326..e61b13a 100644
--- a/glx/glxdri2.c
+++ b/glx/glxdri2.c
@@ -417,6 +417,9 @@ dri2_convert_glx_attribs(unsigned num_attribs, const uint32_t *attribs,
             case GLX_CONTEXT_COMPATIBILITY_PROFILE_BIT_ARB:
                 *api = __DRI_API_OPENGL;
                 break;
+            case GLX_CONTEXT_ES2_PROFILE_BIT_EXT:
+                *api = __DRI_API_GLES2;
+                break;
             default:
                 *error = __glXError(GLXBadProfileARB);
                 return False;
@@ -814,8 +817,12 @@ initializeExtensions(__GLXDRIscreen * screen)
                              "GLX_ARB_create_context");
         __glXEnableExtension(screen->glx_enable_bits,
                              "GLX_ARB_create_context_profile");
+        __glXEnableExtension(screen->glx_enable_bits,
+                             "GLX_EXT_create_context_es2_profile");
         LogMessage(X_INFO, "AIGLX: enabled GLX_ARB_create_context\n");
         LogMessage(X_INFO, "AIGLX: enabled GLX_ARB_create_context_profile\n");
+        LogMessage(X_INFO,
+                   "AIGLX: enabled GLX_EXT_create_context_es2_profile\n");
     }
 #endif
 
-- 
1.7.6.5