emulator: opengl: Back-port GLES emulation from the master tree.

The modules here are only built when BUILD_EMULATOR_OPENGL is defined to true
in your environment or your BoardConfig.mk (see tools/emulator/opengl/Android.mk)

Change-Id: I5f32c35b4452fb5a7b4d5f9fc5870ec1da6032e6

tools/emulator/opengl/host/libs/libOpenglRender/GL2Dispatch.cpp

@@ -0,0 +1,70 @@
+/*
+* Copyright (C) 2011 The Android Open Source Project
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+#ifdef WITH_GLES2
+#include "GL2Dispatch.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include "osDynLibrary.h"
+
+gl2_decoder_context_t s_gl2;
+int                   s_gl2_enabled;
+
+static osUtils::dynLibrary *s_gles2_lib = NULL;
+
+#ifdef _WIN32
+#define DEFAULT_GLES_V2_LIB "libGLES_V2_translator"
+#elif defined(__APPLE__)
+#define DEFAULT_GLES_V2_LIB "libGLES_V2_translator.dylib"
+#else
+#define DEFAULT_GLES_V2_LIB "libGLES_V2_translator.so"
+#endif
+
+//
+// This function is called only once during initialiation before
+// any thread has been created - hence it should NOT be thread safe.
+//
+bool init_gl2_dispatch()
+{
+    const char *libName = getenv("ANDROID_GLESv2_LIB");
+    if (!libName) libName = DEFAULT_GLES_V2_LIB;
+
+    //
+    // Load the GLES library
+    //
+    s_gles2_lib = osUtils::dynLibrary::open(libName);
+    if (!s_gles2_lib) return false;
+
+    //
+    // init the GLES dispatch table
+    //
+    s_gl2.initDispatchByName( gl2_dispatch_get_proc_func, NULL );
+    s_gl2_enabled = true;
+    return true;
+}
+
+//
+// This function is called only during initialiation before
+// any thread has been created - hence it should NOT be thread safe.
+//
+void *gl2_dispatch_get_proc_func(const char *name, void *userData)
+{
+    if (!s_gles2_lib) {
+        return NULL;
+    }
+    return (void *)s_gles2_lib->findSymbol(name);
+}
+
+#endif