feat: distance field approach

resources/shaders/basic.fs

@@ -1,50 +0,0 @@
-#version 330
-
-in vec2 fragTexCoord;
-in vec4 fragColor;
-
-uniform vec2 resolution;
-uniform vec2 mouse_pos;
-uniform float ball_radius;
-uniform vec2 polygon_points[6];
-uniform float polygon_influence;
-
-out vec4 finalColor;
-
-float distanceToPolygon(vec2 point, vec2 polyPoints[6]) {
-    float minDist = 100000.0;
-    
-    for (int i = 0; i < 6; i++) {
-        int j = (i + 1) % 6;
-        vec2 a = polyPoints[i];
-        vec2 b = polyPoints[j];
-        
-        vec2 pa = point - a;
-        vec2 ba = b - a;
-        float h = clamp(dot(pa, ba) / dot(ba, ba), 0.0, 1.0);
-        float dist = length(pa - ba * h);
-        minDist = min(minDist, dist);
-    }
-    
-    return minDist;
-}
-
-void main()
-{
-    vec2 pixel_pos = fragTexCoord * resolution;
-    
-    vec2 ball_pixel_pos = mouse_pos;
-    float ball_dist = distance(pixel_pos, ball_pixel_pos);
-    float ball_value = (ball_radius * ball_radius) / (ball_dist * ball_dist + 1.0);
-    
-    float poly_dist = distanceToPolygon(pixel_pos, polygon_points);
-    float poly_value = polygon_influence / (poly_dist * poly_dist + 1.0);
-    
-    float total_value = ball_value + poly_value;
-    
-    if (total_value > 0.7) {
-        finalColor = vec4(1.0, 1.0, 1.0, 1.0); // White
-    } else {
-        finalColor = vec4(0.0, 0.0, 0.0, 1.0); // Black
-    }
-}

resources/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);
+}