diff --git a/effects/boxblur.frag b/effects/boxblur.frag
index 3683a469e..626cc1f7e 100644
--- a/effects/boxblur.frag
+++ b/effects/boxblur.frag
@@ -18,10 +18,12 @@ void main(void) {
 		float divider = 1.0;
 		if (horiz_blur) divider /= rad;
 		if (vert_blur) divider /= rad;
+		vec4 color = vec4(0.0);
 		for (float x=-x_rad+0.5;x<=x_rad;x+=2.0) {					
 			for (float y=-y_rad+0.5;y<=y_rad;y+=2.0) {
-				gl_FragColor += texture2D(image, (vec2(gl_FragCoord.x+x, gl_FragCoord.y+y))/resolution)*(divider);
+				color += texture2D(image, (vec2(gl_FragCoord.x+x, gl_FragCoord.y+y))/resolution)*(divider);
 			}
 		}
+		gl_FragColor = color;
 	}
 }
\ No newline at end of file
diff --git a/effects/directionalblur.frag b/effects/directionalblur.frag
index 1d549ed6d..e04d350ed 100644
--- a/effects/directionalblur.frag
+++ b/effects/directionalblur.frag
@@ -17,11 +17,13 @@ void main(void) {
 		float sin_angle = sin(radians);
 		float cos_angle = cos(radians);
 
+		vec4 color = vec4(0.0);
 		for (float i=-ceillen+0.5;i<=ceillen;i+=2.0) {
 			float y = sin_angle * i;
 			float x = cos_angle * i;
-			gl_FragColor += texture2D(image, vec2(gl_FragCoord.x+x, gl_FragCoord.y+y)/resolution)*(divider);
+			color += texture2D(image, vec2(gl_FragCoord.x+x, gl_FragCoord.y+y)/resolution)*(divider);
 		}
+		gl_FragColor = color;
 	} else {
 		gl_FragColor = texture2D(image, gl_FragCoord.xy/resolution);
 	}
diff --git a/effects/gaussianblur.frag b/effects/gaussianblur.frag
index f2d76caf2..b5dd4e8c9 100644
--- a/effects/gaussianblur.frag
+++ b/effects/gaussianblur.frag
@@ -36,11 +36,13 @@ void main(void) {
 			}
 		}
 
+		vec4 color = vec4(0.0);
 		for (float x=-x_rad+0.5;x<=x_rad;x+=2.0) {
 			for (float y=-y_rad+0.5;y<=y_rad;y+=2.0) {
 				float weight = (gaussian2(x, y, sigma)/sum);
-				gl_FragColor += texture2D(image, (vec2(gl_FragCoord.x+x, gl_FragCoord.y+y))/resolution)*(weight);
+				color += texture2D(image, (vec2(gl_FragCoord.x+x, gl_FragCoord.y+y))/resolution)*(weight);
 			}
 		}
+		gl_FragColor = color;
 	}	
 }
\ No newline at end of file
diff --git a/effects/radialblur.frag b/effects/radialblur.frag
index 2101480f2..e32cfb662 100644
--- a/effects/radialblur.frag
+++ b/effects/radialblur.frag
@@ -22,11 +22,15 @@ void main(void) {
 		float limit = ceil(radius * multiplier);
 
 		float divider = 1.0 / limit;
+
+		vec4 color = vec4(0.0);
+
 		for (float i=-limit+0.5;i<=limit;i+=2.0) {
 			float y = sin_angle * i;
 			float x = cos_angle * i;
-			gl_FragColor += texture2D(image, vec2(gl_FragCoord.x+x, gl_FragCoord.y+y)/resolution)*(divider);
+			color += texture2D(image, vec2(gl_FragCoord.x+x, gl_FragCoord.y+y)/resolution)*(divider);
 		}
+		gl_FragColor = color;
 	} else {
 		gl_FragColor = texture2D(image, gl_FragCoord.xy/resolution);
 	}