[PATCH xserver 11/12] glamor_egl: Automatically choose a GLES2 context if desktop GL fails.

[Eric Anholt]

GLES2 support has been requested multiple times, and we've had this
code laying around trying to implement it.  The GLES2 implementation
is not quite there yet (some pixel transfer failures), but it
shouldn't take much fixing at this point.

Signed-off-by: Eric Anholt <eric at anholt.net>
---
 glamor/glamor_egl.c | 85 +++++++++++++++++++++++++++++------------------------
 1 file changed, 46 insertions(+), 39 deletions(-)

diff --git a/glamor/glamor_egl.c b/glamor/glamor_egl.c
index a82c1f790997..647d2efae189 100644
--- a/glamor/glamor_egl.c
+++ b/glamor/glamor_egl.c
@@ -635,22 +635,6 @@ glamor_egl_init(ScrnInfoPtr scrn, int fd)
 {
     struct glamor_egl_screen_private *glamor_egl;
 
-    EGLint config_attribs[] = {
-#ifdef GLAMOR_GLES2
-        EGL_CONTEXT_CLIENT_VERSION, 2,
-#endif
-        EGL_NONE
-    };
-    static const EGLint config_attribs_core[] = {
-        EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR,
-        EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT_KHR,
-        EGL_CONTEXT_MAJOR_VERSION_KHR,
-        GLAMOR_GL_CORE_VER_MAJOR,
-        EGL_CONTEXT_MINOR_VERSION_KHR,
-        GLAMOR_GL_CORE_VER_MINOR,
-        EGL_NONE
-    };
-
     glamor_egl = calloc(sizeof(*glamor_egl), 1);
     if (glamor_egl == NULL)
         return FALSE;
@@ -679,12 +663,6 @@ glamor_egl_init(ScrnInfoPtr scrn, int fd)
         goto error;
     }
 
-#ifndef GLAMOR_GLES2
-    eglBindAPI(EGL_OPENGL_API);
-#else
-    eglBindAPI(EGL_OPENGL_ES_API);
-#endif
-
 #define GLAMOR_CHECK_EGL_EXTENSION(EXT)  \
 	if (!epoxy_has_egl_extension(glamor_egl->display, "EGL_" #EXT)) {  \
 		ErrorF("EGL_" #EXT " required.\n");  \
@@ -699,28 +677,56 @@ glamor_egl_init(ScrnInfoPtr scrn, int fd)
 	}
 
     GLAMOR_CHECK_EGL_EXTENSION(KHR_gl_texture_2D_image);
-#ifdef GLAMOR_GLES2
-    GLAMOR_CHECK_EGL_EXTENSIONS(KHR_surfaceless_context, KHR_surfaceless_gles2);
-#else
-    GLAMOR_CHECK_EGL_EXTENSIONS(KHR_surfaceless_context,
-                                KHR_surfaceless_opengl);
-#endif
 
-#ifndef GLAMOR_GLES2
-    glamor_egl->context = eglCreateContext(glamor_egl->display,
-                                           NULL, EGL_NO_CONTEXT,
-                                           config_attribs_core);
-#else
-    glamor_egl->context = NULL;
-#endif
-    if (!glamor_egl->context) {
+    if (eglBindAPI(EGL_OPENGL_API)) {
+        static const EGLint config_attribs_core[] = {
+            EGL_CONTEXT_OPENGL_PROFILE_MASK_KHR,
+            EGL_CONTEXT_OPENGL_CORE_PROFILE_BIT_KHR,
+            EGL_CONTEXT_MAJOR_VERSION_KHR,
+            GLAMOR_GL_CORE_VER_MAJOR,
+            EGL_CONTEXT_MINOR_VERSION_KHR,
+            GLAMOR_GL_CORE_VER_MINOR,
+            EGL_NONE
+        };
+        static const EGLint config_attribs[] = {
+            EGL_NONE
+        };
+
+        GLAMOR_CHECK_EGL_EXTENSIONS(KHR_surfaceless_context,
+                                    KHR_surfaceless_opengl);
+
         glamor_egl->context = eglCreateContext(glamor_egl->display,
                                                NULL, EGL_NO_CONTEXT,
-                                               config_attribs);
-        if (glamor_egl->context == EGL_NO_CONTEXT) {
-            xf86DrvMsg(scrn->scrnIndex, X_ERROR, "Failed to create EGL context\n");
+                                               config_attribs_core);
+
+        if (glamor_egl->context == EGL_NO_CONTEXT)
+            glamor_egl->context = eglCreateContext(glamor_egl->display,
+                                                   NULL, EGL_NO_CONTEXT,
+                                                   config_attribs);
+    }
+
+    if (glamor_egl->context == EGL_NO_CONTEXT) {
+        static const EGLint config_attribs[] = {
+            EGL_CONTEXT_CLIENT_VERSION, 2,
+            EGL_NONE
+        };
+        if (!eglBindAPI(EGL_OPENGL_ES_API)) {
+            xf86DrvMsg(scrn->scrnIndex, X_ERROR,
+                       "glamor: Failed to bind either GL or GLES APIs.\n");
             goto error;
         }
+
+        GLAMOR_CHECK_EGL_EXTENSIONS(KHR_surfaceless_context,
+                                    KHR_surfaceless_gles2);
+
+        glamor_egl->context = eglCreateContext(glamor_egl->display,
+                                               NULL, EGL_NO_CONTEXT,
+                                               config_attribs);
+    }
+    if (glamor_egl->context == EGL_NO_CONTEXT) {
+        xf86DrvMsg(scrn->scrnIndex, X_ERROR,
+                   "glamor: Failed to create GL or GLES2 contexts\n");
+        goto error;
     }
 
     if (!eglMakeCurrent(glamor_egl->display,
@@ -729,6 +735,7 @@ glamor_egl_init(ScrnInfoPtr scrn, int fd)
                    "Failed to make EGL context current\n");
         goto error;
     }
+
     /*
      * Force the next glamor_make_current call to set the right context
      * (in case of multiple GPUs using glamor)
-- 
2.11.0