enhance target painting

target.fs

@@ -3,6 +3,9 @@ uniform sampler2D texture;
 varying vec2 vTexCoord;                                                         
 varying vec3 color;                                                            
 void main()                                                                
-{                                                                        
-   gl_FragColor = vec4(color.x,color.y,color.z,texture2D(texture, vTexCoord).w);
+{                                               
+   if(texture2D(texture, vTexCoord).w == 0)
+      discard;
+                               
+   gl_FragColor = vec4(color.x,color.y,color.z,1);
 }