[clutter] winsys: Expose environment variable to choose winsys

[Robert Bragg <rbragg src gnome org>]

commit fd42800d008e9153926916e35d0d8927488ff362
Author: Robert Bragg <robert linux intel com>
Date:   Mon Apr 18 16:24:51 2011 +0100

    winsys: Expose environment variable to choose winsys
    
    This makes it possible to override the winsys that cogl uses by setting
    the COGL_RENDERER environment variable e.g. to "GLX" or "EGL"

 clutter/cogl/cogl/cogl-renderer.c              |    8 ++++++++
 clutter/cogl/cogl/winsys/cogl-winsys-egl.c     |    1 +
 clutter/cogl/cogl/winsys/cogl-winsys-glx.c     |    1 +
 clutter/cogl/cogl/winsys/cogl-winsys-private.h |    2 ++
 4 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/clutter/cogl/cogl/cogl-renderer.c b/clutter/cogl/cogl/cogl-renderer.c
index 613b163..93e33a4 100644
--- a/clutter/cogl/cogl/cogl-renderer.c
+++ b/clutter/cogl/cogl/cogl-renderer.c
@@ -28,6 +28,9 @@
 #include "config.h"
 #endif
 
+#include <stdlib.h>
+#include <string.h>
+
 #include "cogl.h"
 #include "cogl-internal.h"
 #include "cogl-object.h"
@@ -168,6 +171,7 @@ cogl_renderer_connect (CoglRenderer *renderer, GError **error)
 {
 #ifdef COGL_HAS_FULL_WINSYS
   int i;
+  char *renderer_name = getenv ("COGL_RENDERER");
 #endif
   GString *error_message;
 
@@ -180,6 +184,10 @@ cogl_renderer_connect (CoglRenderer *renderer, GError **error)
     {
       const CoglWinsysVtable *winsys = _cogl_winsys_vtable_getters[i]();
       GError *tmp_error = NULL;
+
+      if (renderer_name && strcmp (winsys->name, renderer_name) != 0)
+        continue;
+
       if (!winsys->renderer_connect (renderer, &tmp_error))
         {
           g_string_append_c (error_message, '\n');
diff --git a/clutter/cogl/cogl/winsys/cogl-winsys-egl.c b/clutter/cogl/cogl/winsys/cogl-winsys-egl.c
index 46f5842..da39cbd 100644
--- a/clutter/cogl/cogl/winsys/cogl-winsys-egl.c
+++ b/clutter/cogl/cogl/winsys/cogl-winsys-egl.c
@@ -1082,6 +1082,7 @@ _cogl_winsys_context_egl_get_egl_display (CoglContext *context)
 
 static CoglWinsysVtable _cogl_winsys_vtable =
   {
+    .name = "EGL",
     .get_proc_address = _cogl_winsys_get_proc_address,
     .renderer_connect = _cogl_winsys_renderer_connect,
     .renderer_disconnect = _cogl_winsys_renderer_disconnect,
diff --git a/clutter/cogl/cogl/winsys/cogl-winsys-glx.c b/clutter/cogl/cogl/winsys/cogl-winsys-glx.c
index 26ad6e6..b15263c 100644
--- a/clutter/cogl/cogl/winsys/cogl-winsys-glx.c
+++ b/clutter/cogl/cogl/winsys/cogl-winsys-glx.c
@@ -1880,6 +1880,7 @@ _cogl_winsys_texture_pixmap_x11_get_texture (CoglTexturePixmapX11 *tex_pixmap)
 
 static CoglWinsysVtable _cogl_winsys_vtable =
   {
+    .name = "GLX",
     .get_proc_address = _cogl_winsys_get_proc_address,
     .renderer_connect = _cogl_winsys_renderer_connect,
     .renderer_disconnect = _cogl_winsys_renderer_disconnect,
diff --git a/clutter/cogl/cogl/winsys/cogl-winsys-private.h b/clutter/cogl/cogl/winsys/cogl-winsys-private.h
index a610848..856fc8d 100644
--- a/clutter/cogl/cogl/winsys/cogl-winsys-private.h
+++ b/clutter/cogl/cogl/winsys/cogl-winsys-private.h
@@ -54,6 +54,8 @@ typedef enum
 
 typedef struct _CoglWinsysVtable
 {
+  const char *name;
+
   CoglFuncPtr
   (*get_proc_address) (const char *name);