YaGL/VIGS: GLESv3 workarounds for Mac OS X 10.7

Mac OS X 10.7 supports OpenGL 3.2, however, it doesn't have
all the necessary functions implemented in order to implement
GLESv3 on target. This workaround checks for some mandatory
functions and if at least one of them is not present - we revert
back to OpenGL 2.1. A nicer fix would be checking for OpenGL
functions globally, not in CGL backend, this is a TODO

Change-Id: I9c0acce3220af9ed7276a8586fa18b97d8223079
Signed-off-by: Stanislav Vorobiov <s.vorobiov@samsung.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/hw/yagl/yagl_drivers/egl_cgl/yagl_egl_cgl.c b/hw/yagl/yagl_drivers/egl_cgl/yagl_egl_cgl.c
index 32839a6d7f..31bf8d63c2 100644
--- a/hw/yagl/yagl_drivers/egl_cgl/yagl_egl_cgl.c
+++ b/hw/yagl/yagl_drivers/egl_cgl/yagl_egl_cgl.c
@@ -88,6 +88,16 @@ struct yagl_egl_cgl_context
     bool is_3_2_core;
 };
 
+static const char *gl_3_2_check_funcs[] =
+{
+    "glGenTransformFeedbacks",
+    "glBindTransformFeedback",
+    "glPauseTransformFeedback",
+    "glResumeTransformFeedback",
+    "glDeleteTransformFeedbacks",
+    "glVertexAttribDivisor"
+};
+
 static bool yagl_egl_cgl_get_gl_version(struct yagl_egl_cgl *egl_cgl,
                                         yagl_gl_version *version)
 {
@@ -96,6 +106,7 @@ static bool yagl_egl_cgl_get_gl_version(struct yagl_egl_cgl *egl_cgl,
     const char *tmp;
     CGLPixelFormatObj pixel_format;
     int n;
+    unsigned int i;
 
     YAGL_LOG_FUNC_ENTER(yagl_egl_cgl_get_gl_version, NULL);
 
@@ -137,6 +148,19 @@ static bool yagl_egl_cgl_get_gl_version(struct yagl_egl_cgl *egl_cgl,
 
     CGLDestroyPixelFormat(pixel_format);
 
+    for (i = 0;
+         i < sizeof(gl_3_2_check_funcs)/sizeof(gl_3_2_check_funcs[0]);
+         ++i) {
+        if (!yagl_dyn_lib_get_sym(egl_cgl->base.dyn_lib,
+                                  gl_3_2_check_funcs[i])) {
+            YAGL_LOG_INFO("Failed to find function \"%s\", using OpenGL 2.1",
+                          gl_3_2_check_funcs[i]);
+            *version = yagl_gl_2;
+            res = true;
+            goto out;
+        }
+    }
+
     YAGL_LOG_INFO("Using OpenGL 3.2");
     *version = yagl_gl_3_2;
     res = true;