ajout d'effet de post processing et réparation des graines

common/vfx/materials/shaders/blur_vignette.gdshader

@@ -0,0 +1,33 @@
+shader_type canvas_item;
+
+uniform sampler2D screen_texture: hint_screen_texture, repeat_disable, filter_linear_mipmap;
+uniform float blur_radius : hint_range(0, 1) = 0.2; // Radius of the blur effect
+uniform float blur_amount : hint_range(0, 5) = 1.0; // Strength of the blur effect
+uniform float blur_inner : hint_range(0, 1) = 0.6; // Inner edge of the blur effect
+uniform float blur_outer : hint_range(0, 1) = 0.66; // Outer edge of the blur effect
+
+void fragment() {
+    // Original color of the pixel from the screen
+    vec4 pixelColor = texture(screen_texture, UV);
+    
+    // Color with blur effect from the screen
+    vec4 blurColor = textureLod(screen_texture, SCREEN_UV, blur_amount);
+
+    // Calculate distance from the center of the screen
+    float distance = length(UV - vec2(0.5, 0.5));
+
+    // Apply smoothstep function to control transition between areas
+    float blur = smoothstep(blur_inner - blur_radius, blur_outer, distance);
+
+    // Mix colors of the blur effect and the original color based on the smoothstep value
+    pixelColor.rgb = mix(blurColor.rgb, COLOR.rgb, -blur);
+
+    // Set the alpha component of the blur effect to the smoothstep value
+    blurColor.a = blur;
+
+    // Mix colors of the blur effect with white for an additional effect
+    blurColor.rgb = mix(blurColor.rgb, vec3(1.0), 0.1);
+
+    // Set the final color to the modified color of the blur effect
+    COLOR = blurColor;
+}