fix: blend mode

Author: lvpengwei

epf/src/main/java/com/daasuu/epf/EPlayerRenderer.java

@@ -77,7 +77,7 @@ public void run() {
 
     @Override
     public void onSurfaceCreated(final EGLConfig config) {
-        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
 
         final int[] args = new int[1];
 
@@ -136,6 +136,8 @@ public void onSurfaceChanged(final int width, final int height) {
 
     @Override
     public void onDrawFrame(final EFramebufferObject fbo) {
+        GLES20.glEnable(GLES20.GL_BLEND);
+        GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
 
         synchronized (this) {
             if (updateSurface) {