Ethan Nicholas | 0274b30 | 2017-07-14 16:17:04 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2017 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
Ethan Nicholas | aae47c8 | 2017-11-10 15:34:03 -0500 | [diff] [blame] | 8 | enum class Mode { |
| 9 | kGaussian = 0, |
| 10 | kSmoothStep = 1 |
| 11 | }; |
Ethan Nicholas | 0274b30 | 2017-07-14 16:17:04 -0400 | [diff] [blame] | 12 | |
Ethan Nicholas | aae47c8 | 2017-11-10 15:34:03 -0500 | [diff] [blame] | 13 | layout(key) in Mode mode; |
Ethan Nicholas | 0274b30 | 2017-07-14 16:17:04 -0400 | [diff] [blame] | 14 | |
| 15 | void main() { |
Ethan Nicholas | f7b8820 | 2017-09-18 14:10:39 -0400 | [diff] [blame] | 16 | half factor = 1.0 - sk_InColor.a; |
Ethan Nicholas | 0274b30 | 2017-07-14 16:17:04 -0400 | [diff] [blame] | 17 | @switch (mode) { |
Ethan Nicholas | aae47c8 | 2017-11-10 15:34:03 -0500 | [diff] [blame] | 18 | case Mode::kGaussian: |
Ethan Nicholas | 0274b30 | 2017-07-14 16:17:04 -0400 | [diff] [blame] | 19 | factor = exp(-factor * factor * 4.0) - 0.018; |
| 20 | break; |
Ethan Nicholas | aae47c8 | 2017-11-10 15:34:03 -0500 | [diff] [blame] | 21 | case Mode::kSmoothStep: |
Ethan Nicholas | 0274b30 | 2017-07-14 16:17:04 -0400 | [diff] [blame] | 22 | factor = smoothstep(1.0, 0.0, factor); |
| 23 | break; |
| 24 | } |
Ethan Nicholas | f7b8820 | 2017-09-18 14:10:39 -0400 | [diff] [blame] | 25 | sk_OutColor = half4(factor); |
Ethan Nicholas | 0274b30 | 2017-07-14 16:17:04 -0400 | [diff] [blame] | 26 | } |