| #version 320 es |
| |
| // Copyright 2013 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| precision highp float; |
| |
| layout(location = 0) uniform vec4 u_color; |
| layout(location = 1) uniform float u_alpha; |
| layout(location = 2) uniform vec4 u_sparkle_color; |
| layout(location = 3) uniform float u_sparkle_alpha; |
| layout(location = 4) uniform float u_blur; |
| layout(location = 5) uniform vec2 u_center; |
| layout(location = 6) uniform float u_radius_scale; |
| layout(location = 7) uniform float u_max_radius; |
| layout(location = 8) uniform vec2 u_resolution_scale; |
| layout(location = 9) uniform vec2 u_noise_scale; |
| layout(location = 10) uniform float u_noise_phase; |
| layout(location = 11) uniform vec2 u_circle1; |
| layout(location = 12) uniform vec2 u_circle2; |
| layout(location = 13) uniform vec2 u_circle3; |
| layout(location = 14) uniform vec2 u_rotation1; |
| layout(location = 15) uniform vec2 u_rotation2; |
| layout(location = 16) uniform vec2 u_rotation3; |
| |
| layout(location = 0) out vec4 fragColor; |
| |
| const float PI = 3.1415926535897932384626; |
| const float PI_ROTATE_RIGHT = PI * 0.0078125; |
| const float PI_ROTATE_LEFT = PI * -0.0078125; |
| const float ONE_THIRD = 1./3.; |
| const vec2 TURBULENCE_SCALE = vec2(0.8); |
| |
| float saturate(float x) { |
| return clamp(x, 0.0, 1.0); |
| } |
| |
| float triangle_noise(highp vec2 n) { |
| n = fract(n * vec2(5.3987, 5.4421)); |
| n += dot(n.yx, n.xy + vec2(21.5351, 14.3137)); |
| float xy = n.x * n.y; |
| return fract(xy * 95.4307) + fract(xy * 75.04961) - 1.0; |
| } |
| |
| float threshold(float v, float l, float h) { |
| return step(l, v) * (1.0 - step(h, v)); |
| } |
| |
| mat2 rotate2d(vec2 rad){ |
| return mat2(rad.x, -rad.y, rad.y, rad.x); |
| } |
| |
| float soft_circle(vec2 uv, vec2 xy, float radius, float blur) { |
| float blur_half = blur * 0.5; |
| float d = distance(uv, xy); |
| return 1.0 - smoothstep(1.0 - blur_half, 1.0 + blur_half, d / radius); |
| } |
| |
| float soft_ring(vec2 uv, vec2 xy, float radius, float thickness, float blur) { |
| float circle_outer = soft_circle(uv, xy, radius + thickness, blur); |
| float circle_inner = soft_circle(uv, xy, max(radius - thickness, 0.0), blur); |
| return saturate(circle_outer - circle_inner); |
| } |
| |
| float circle_grid(vec2 resolution, vec2 p, vec2 xy, vec2 rotation, float cell_diameter) { |
| p = rotate2d(rotation) * (xy - p) + xy; |
| p = mod(p, cell_diameter) / resolution; |
| float cell_uv = cell_diameter / resolution.y * 0.5; |
| float r = 0.65 * cell_uv; |
| return soft_circle(p, vec2(cell_uv), r, r * 50.0); |
| } |
| |
| float sparkle(vec2 uv, float t) { |
| float n = triangle_noise(uv); |
| float s = threshold(n, 0.0, 0.05); |
| s += threshold(n + sin(PI * (t + 0.35)), 0.1, 0.15); |
| s += threshold(n + sin(PI * (t + 0.7)), 0.2, 0.25); |
| s += threshold(n + sin(PI * (t + 1.05)), 0.3, 0.35); |
| return saturate(s) * 0.55; |
| } |
| |
| float turbulence(vec2 uv) { |
| vec2 uv_scale = uv * TURBULENCE_SCALE; |
| float g1 = circle_grid(TURBULENCE_SCALE, uv_scale, u_circle1, u_rotation1, 0.17); |
| float g2 = circle_grid(TURBULENCE_SCALE, uv_scale, u_circle2, u_rotation2, 0.2); |
| float g3 = circle_grid(TURBULENCE_SCALE, uv_scale, u_circle3, u_rotation3, 0.275); |
| float v = (g1 * g1 + g2 - g3) * 0.5; |
| return saturate(0.45 + 0.8 * v); |
| } |
| |
| void main() { |
| vec2 p = gl_FragCoord.xy; |
| vec2 uv = p * u_resolution_scale; |
| vec2 density_uv = uv - mod(p, u_noise_scale); |
| float radius = u_max_radius * u_radius_scale; |
| float turbulence = turbulence(uv); |
| float ring = soft_ring(p, u_center, radius, 0.05 * u_max_radius, u_blur); |
| float sparkle = sparkle(density_uv, u_noise_phase) * ring * turbulence * u_sparkle_alpha; |
| float wave_alpha = soft_circle(p, u_center, radius, u_blur) * u_alpha * u_color.a; |
| vec4 wave_color = vec4(u_color.rgb * wave_alpha, wave_alpha); |
| vec4 sparkle_color = vec4(u_sparkle_color.rgb * u_sparkle_color.a, u_sparkle_color.a); |
| fragColor = mix(wave_color, sparkle_color, sparkle); |
| } |