refactor: code cleaning

assets/shaders/distance_field.fs

@@ -0,0 +1,60 @@
+#version 330
+
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+uniform sampler2D texture0;
+uniform sampler2D distanceFieldTex;
+uniform vec2 resolution;
+uniform vec2 mousePos;
+uniform float ballRadius;
+uniform float shapeInfluence;
+
+out vec4 finalColor;
+
+float getBallInfluence(vec2 pos, vec2 center, float radius) {
+    vec2 diff = pos - center;
+    float distSq = dot(diff, diff);
+    float radiusSq = radius * radius;
+    if (distSq > radiusSq) return 0.0;
+    float dist = sqrt(distSq);
+    return 1.0 - (dist / radius);
+}
+
+float getShapeInfluence(vec2 pos) {
+    vec2 uv = pos / resolution;
+    uv.y = 1 - uv.y + 0.045; // invert y and offset to match with wallpaper texture
+    
+    if (any(lessThan(uv, vec2(0.0))) || any(greaterThan(uv, vec2(1.0)))) {
+        return 0.0;
+    }
+    
+    float signedDistance = texture(distanceFieldTex, uv).r * 255.0 - 128.0;
+    
+    float isInside = step(signedDistance, 0.0);
+    float isOutside = 1.0 - isInside;
+    
+    // inside calculation
+    float normalizedDist = abs(signedDistance) * 0.015625; // 1/64
+    float insideInfluence = shapeInfluence * exp(-normalizedDist * 0.5) * 3.0;
+    
+    // outside calculation
+    float adjustedDistance = signedDistance * 0.5;
+    float shapeInfluenceSq = shapeInfluence * shapeInfluence;
+    float outsideInfluence = shapeInfluenceSq / (adjustedDistance * adjustedDistance + shapeInfluence) + 
+                             shapeInfluence * 0.8 * exp(-signedDistance * 0.025); // 1/40
+    
+    return isInside * insideInfluence + isOutside * outsideInfluence;
+}
+
+void main()
+{
+    vec2 pixelPos = fragTexCoord * resolution;
+    
+    float ballValue = getBallInfluence(pixelPos, mousePos, ballRadius);
+    float shapeValue = getShapeInfluence(pixelPos);
+    float totalValue = ballValue + shapeValue * 0.01;
+
+    float mask = step(0.75, totalValue);
+    finalColor = vec4(mask, mask, mask, 1.0);
+}