Add trail to bloom

shader/fullscreen/alphaHalve.frag

@@ -0,0 +1,3 @@
+#version 430 core
+out vec4 fColor;
+void main () { fColor = vec4(0,0,0,0.5);}

shader/fullscreen/alphaHalve.vert

@@ -0,0 +1,4 @@
+#version 430 core
+layout (location = 0) in vec2 position;
+void main()
+{ gl_Position = vec4 (position, 0 , 1);}

shader/texture/bloomBlur.frag

@@ -46,7 +46,7 @@ void main()
     float alph = 0.0;
     for (int i = 0; i < 9; i++)
         alph += sampleTex[i].a;
-    alph = sampleTex[5].a + alph/9.0;
+    alph = max(sampleTex[4].a, alph/9.0);
         //
     //fColor = col;
     fColor = vec4(col.rgb/col.a,alph);