feat: liquid glass, пока-что скрыт.

shaders/liquid_glass.frag

@@ -0,0 +1,104 @@
+#version 460 core
+
+#include <flutter/runtime_effect.glsl>
+
+precision highp float;
+
+uniform vec2 uSize;
+uniform vec2 uRectOrigin;
+uniform vec2 uRectSize;
+uniform float uRadius;
+uniform float uSpread;
+uniform float uRefraction;
+uniform float uChroma;
+uniform float uSpecular;
+uniform vec4 uTint;
+uniform vec2 uLight;
+uniform float uTintFeather;
+uniform float uRimWidth;
+
+uniform sampler2D uBackdrop;
+
+out vec4 fragColor;
+
+float roundedBoxSdf(vec2 p, vec2 halfSize, float radius) {
+  vec2 q = abs(p) - halfSize + radius;
+  return min(max(q.x, q.y), 0.0) + length(max(q, vec2(0.0))) - radius;
+}
+
+vec2 surfaceNormal(vec2 p, vec2 halfSize, float radius) {
+  vec2 unit = vec2(1.0, 0.0);
+  float dx = roundedBoxSdf(p + unit.xy, halfSize, radius) -
+             roundedBoxSdf(p - unit.xy, halfSize, radius);
+  float dy = roundedBoxSdf(p + unit.yx, halfSize, radius) -
+             roundedBoxSdf(p - unit.yx, halfSize, radius);
+  return normalize(vec2(dx, dy) + vec2(1e-6));
+}
+
+const int TAPS = 5;
+
+float displacement(float distance, float reach) {
+  float bevel = 1.0 - clamp(-distance / reach, 0.0, 1.0);
+  return uRefraction * bevel * bevel * (1.0 + bevel);
+}
+
+vec3 sampleBackdrop(vec2 coord) {
+  vec2 uv = coord / uSize;
+#ifdef IMPELLER_TARGET_OPENGLES
+  uv.y = 1.0 - uv.y;
+#endif
+  return texture(uBackdrop, clamp(uv, vec2(0.0), vec2(1.0))).rgb;
+}
+
+void main() {
+  vec2 fragCoord = FlutterFragCoord().xy;
+  vec2 halfSize = uRectSize * 0.5;
+  vec2 center = uRectOrigin + halfSize;
+  vec2 p = fragCoord - center;
+
+  float radius = min(uRadius, min(halfSize.x, halfSize.y));
+  float sd = roundedBoxSdf(p, halfSize, radius);
+
+  if (sd > 0.0) {
+    fragColor = vec4(sampleBackdrop(fragCoord), 1.0);
+    return;
+  }
+
+  vec2 normal = surfaceNormal(p, halfSize, radius);
+  float reach = max(uSpread * min(halfSize.x, halfSize.y), 1.0);
+  float shift = displacement(sd, reach);
+  float lens = shift / max(uRefraction, 1e-6);
+
+  float slope = displacement(sd + 1.0, reach) - displacement(sd - 1.0, reach);
+  float footprint = clamp(abs(1.0 + slope * 0.5), 1.0, 24.0);
+  float aberration = uChroma * lens;
+
+  vec3 refracted = vec3(0.0);
+  for (int i = 0; i < TAPS; i++) {
+    float offset = (float(i) / float(TAPS - 1) - 0.5) * footprint;
+    vec2 base = fragCoord + normal * (shift + offset);
+    if (aberration > 0.0) {
+      refracted.r += sampleBackdrop(base + normal * shift * aberration).r;
+      refracted.g += sampleBackdrop(base).g;
+      refracted.b += sampleBackdrop(base - normal * shift * aberration).b;
+    } else {
+      refracted += sampleBackdrop(base);
+    }
+  }
+  refracted /= float(TAPS);
+
+  float veil = smoothstep(0.0, 1.0, clamp(-sd / max(uTintFeather, 1.0), 0.0, 1.0));
+  vec3 color = mix(refracted, uTint.rgb, uTint.a * veil);
+
+  vec2 light = normalize(uLight + vec2(1e-6));
+  float facing = dot(normal, light);
+  float rim = 1.0 - clamp(-sd / max(uRimWidth, 1.0), 0.0, 1.0);
+  rim = rim * rim;
+  float highlight = pow(max(facing, 0.0), 5.0) * rim * uSpecular;
+  float shade = pow(max(-facing, 0.0), 4.0) * rim * uSpecular * 0.35;
+
+  color += vec3(highlight);
+  color = mix(color, color * 0.72, shade);
+
+  fragColor = vec4(clamp(color, vec3(0.0), vec3(1.0)), 1.0);
+}