first commit

blur.gdshader

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+shader_type canvas_item;
+
+uniform float sigma: hint_range(0.0, 20.0) = 3.3;
+
+float gaussian(float x, float std) {
+    return exp(x * x / (-2.0 * std * std)) / (sqrt(2.0 * PI) * std);
+}
+
+void fragment() {
+    float ksize = round(3.0 * sigma);
+    float std = (sigma != 0.0 ? sigma : 1.0);
+    vec4 col = vec4(0.0);
+    float total_weight = 0.0;
+    for(float i = -ksize ; i <= ksize; ++i) {
+        for(float j = -ksize; j <= ksize; ++j) {
+            float weight = gaussian(i, std) * gaussian(j, std);
+            col += texture(TEXTURE, UV + vec2(i, j) * SCREEN_PIXEL_SIZE) * weight;
+            total_weight += weight;
+        }
+    }
+    COLOR = col / total_weight;
+}