am d51ecafa: opengl: Ensure we only load the GLES emulation library when the emulator supports it.

* commit 'd51ecafa6875e182346a825ce098e7c5e0b09038':
  opengl: Ensure we only load the GLES emulation library when the emulator supports it.

opengl/libs/EGL/Loader.cpp

@@ -23,6 +23,7 @@
 #include <limits.h>
 
 #include <cutils/log.h>
+#include <cutils/properties.h>
 
 #include <EGL/egl.h>
 
@@ -45,6 +46,39 @@ namespace android {
 
 ANDROID_SINGLETON_STATIC_INSTANCE( Loader )
 
+/* This function is called to check whether we run inside the emulator,
+ * and if this is the case whether GLES GPU emulation is supported.
+ *
+ * Returned values are:
+ *  -1   -> not running inside the emulator
+ *   0   -> running inside the emulator, but GPU emulation not supported
+ *   1   -> running inside the emulator, GPU emulation is supported
+ *          through the "emulation" config.
+ */
+static int
+checkGlesEmulationStatus(void)
+{
+    /* We're going to check for the following kernel parameters:
+     *
+     *    qemu=1                      -> tells us that we run inside the emulator
+     *    android.qemu.gles=<number>  -> tells us the GLES GPU emulation status
+     *
+     * Note that we will return <number> if we find it. This let us support
+     * more additionnal emulation modes in the future.
+     */
+    char  prop[PROPERTY_VALUE_MAX];
+    int   result = -1;
+
+    /* First, check for qemu=1 */
+    property_get("ro.kernel.qemu",prop,"0");
+    if (atoi(prop) != 1)
+        return -1;
+
+    /* We are in the emulator, get GPU status value */
+    property_get("ro.kernel.qemu.gles",prop,"0");
+    return atoi(prop);
+}
+
 // ----------------------------------------------------------------------------
 
 Loader::driver_t::driver_t(void* gles) 
@@ -94,6 +128,15 @@ Loader::Loader()
 {
     char line[256];
     char tag[256];
+
+    /* Special case for GLES emulation */
+    if (checkGlesEmulationStatus() == 0) {
+        LOGD("Emulator without GPU support detected. Fallback to software renderer.");
+        gConfig.add( entry_t(0, 0, "android") );
+        return;
+    }
+
+    /* Otherwise, use egl.cfg */
     FILE* cfg = fopen("/system/lib/egl/egl.cfg", "r");
     if (cfg == NULL) {
         // default config