fix npe release crash

Author: pedroSG94

encoder/src/main/java/com/pedro/encoder/input/gl/render/CameraRender.java

@@ -131,8 +131,8 @@ public void draw() {
   @Override
   public void release() {
     GLES20.glDeleteProgram(program);
-    surfaceTexture.release();
-    surface.release();
+    if (surfaceTexture != null) surfaceTexture.release();
+    if (surface != null) surface.release();
   }
 
   public void updateTexImage() {

encoder/src/main/java/com/pedro/encoder/input/gl/render/filters/AndroidViewFilterRender.java

@@ -184,8 +184,8 @@ public void release() {
     stopRender();
     GLES20.glDeleteProgram(program);
     viewId = new int[] { -1, -1 };
-    surfaceTexture.release();
-    surfaceTexture2.release();
+    if (surfaceTexture != null) surfaceTexture.release();
+    if (surfaceTexture2 != null) surfaceTexture2.release();
   }
 
   public View getView() {

encoder/src/main/java/com/pedro/encoder/input/gl/render/filters/object/SurfaceFilterRender.java

@@ -79,8 +79,8 @@ protected void drawFilter() {
   @Override
   public void release() {
     super.release();
-    surfaceTexture.release();
-    surface.release();
+    if (surfaceTexture != null) surfaceTexture.release();
+    if (surface != null) surface.release();
   }
 
   /**