fixed blurs causing black frames and added backend for stabilizer

effects/boxblur.frag

@@ -8,7 +8,7 @@ uniform bool horiz_blur;
 uniform bool vert_blur;
 
 void main(void) {
-	float rad = floor(radius);
+	float rad = ceil(radius);
 	float x_rad = (horiz_blur) ? rad : 0.5;
 	float y_rad = (vert_blur) ? rad : 0.5;
 	vec2 texCoord = gl_FragCoord.xy/resolution;

effects/directionalblur.frag

@@ -11,12 +11,13 @@ uniform vec2 resolution;
 
 void main(void) {
 	if (length > 0.0) {
+		float ceillen = ceil(length);
 		float radians = (angle*M_PI)/180.0;
-		float divider = 1.0 / length;
+		float divider = 1.0 / ceillen;
 		float sin_angle = sin(radians);
 		float cos_angle = cos(radians);
 
-		for (float i=-length+0.5;i<=length;i+=2.0) {
+		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);

effects/gaussianblur.frag

@@ -24,7 +24,7 @@ void main(void) {
 	if (radius == 0.0 || sigma == 0.0 || (!horiz_blur && !vert_blur)) {
 		gl_FragColor = texture2D(image, gl_FragCoord.xy/resolution);
 	} else {
-		float rad = floor(radius);
+		float rad = ceil(radius);
 		float x_rad = horiz_blur ? rad : 0.5;
 		float y_rad = vert_blur ? rad : 0.5;