graphics: use dummy GLESv1 by default

Newer Ubuntu systems tend to not provide a libGLESv1_CM.so.1 anymore. As
we're not required to have a GLESv1 implementation (only a few older
Android apps are using GLESv1) we can as easy fix avoid loading a real
GLESv1 implementation and assign dummy functions instead to all relevant
GLESv1 API calls. In the future we want to switch to a GLESv1->GLESv2
translator as the Android emulator does.

external/android-emugl/host/libs/libOpenGLESDispatch/GLESv1Dispatch.cpp

@@ -25,24 +25,40 @@ extern EGLDispatch s_egl;
 
 static emugl::SharedLibrary *s_gles1_lib = NULL;
 
-// An unimplemented function which prints out an error message.
-// To make it consistent with the guest, all GLES1 functions not supported by
-// the driver should be redirected to this function.
-
 static void gles1_unimplemented() {
     fprintf(stderr, "Called unimplemented GLESv1 API\n");
 }
 
-//
-// This function is called only once during initialiation before
-// any thread has been created - hence it should NOT be thread safe.
-//
+static void gles1_dummy() {}
+
+#define ASSIGN_DUMMY(return_type, function_name, signature, call_args) do { \
+    dispatch_table-> function_name = reinterpret_cast<function_name ## _t>(gles1_dummy); \
+  } while(0);
+
+
+#define LOOKUP_SYMBOL(return_type,function_name,signature,callargs) \
+    dispatch_table-> function_name = reinterpret_cast< function_name ## _t >( \
+            s_gles1_lib->findSymbol(#function_name));
+
+#define LOOKUP_EXT_SYMBOL(return_type,function_name,signature,callargs) \
+    dispatch_table-> function_name = reinterpret_cast< function_name ## _t >( \
+            s_egl.eglGetProcAddress(#function_name));
 
 namespace {
 constexpr const char *glesv1_lib_env_var{"ANBOX_GLESv1_LIB"};
 }
 
 bool gles1_dispatch_init(const char *path, GLESv1Dispatch* dispatch_table) {
+    if (!dispatch_table)
+        return false;
+
+    // If no path is given we assign dummy functions to all GL calls
+    // we would have loaded from a real implementation.
+    if (!path) {
+        LIST_GLES1_FUNCTIONS(ASSIGN_DUMMY, ASSIGN_DUMMY);
+        return true;
+    }
+
     const char* libName = getenv(glesv1_lib_env_var);
     if (!libName)
       libName = path;
@@ -57,17 +73,6 @@ bool gles1_dispatch_init(const char *path, GLESv1Dispatch* dispatch_table) {
         return false;
     }
 
-    //
-    // init the GLES dispatch table
-    //
-#define LOOKUP_SYMBOL(return_type,function_name,signature,callargs) \
-    dispatch_table-> function_name = reinterpret_cast< function_name ## _t >( \
-            s_gles1_lib->findSymbol(#function_name));
-
-#define LOOKUP_EXT_SYMBOL(return_type,function_name,signature,callargs) \
-    dispatch_table-> function_name = reinterpret_cast< function_name ## _t >( \
-            s_egl.eglGetProcAddress(#function_name));
-
     LIST_GLES1_FUNCTIONS(LOOKUP_SYMBOL,LOOKUP_EXT_SYMBOL)
 
     dispatch_table->initialized = true;

src/anbox/graphics/emugl/RenderApi.cpp

@@ -40,10 +40,6 @@ namespace emugl {
 std::vector<GLLibrary> default_gl_libraries() {
   return std::vector<GLLibrary>{
     {GLLibrary::Type::EGL, default_egl_lib},
-    // If environment doesn't provide a GLESv1 .so file we use the GLESv2
-    // implementation instead. If our stack allows it we can try to get
-    // rid of GLESv1 completely at a later point.
-    {GLLibrary::Type::GLESv1, default_glesv1_lib},
     {GLLibrary::Type::GLESv2, default_glesv2_lib},
   };
 }
@@ -75,7 +71,15 @@ bool initialize(const std::vector<GLLibrary> &libs, emugl_logger_struct *log_fun
     }
   }
 
-  if (!s_egl.initialized || !s_gles1.initialized || !s_gles2.initialized)
+  // If we are not provided with a link to a OpenGL ES v1 implementation
+  // we assign dummy functions to all of the functions we would call.
+  // This allows us to still manage the major chunk of Android applications
+  // which are all >= GLESv2 until we have a proper GLESv1->GLESv2
+  // translation mechanism in place.
+  if (!s_gles1.initialized)
+    gles1_dispatch_init(nullptr, &s_gles1);
+
+  if (!s_egl.initialized || !s_gles2.initialized)
     return false;
 
   return true;