1 /*
2 * Copyright 2021 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
8 #include "include/core/SkData.h"
9 #include "include/core/SkRefCnt.h"
10 #include "include/core/SkString.h"
11 #include "include/effects/SkRuntimeEffect.h"
12 #include "include/private/base/SkAssert.h"
13 #include "modules/skottie/src/Adapter.h"
14 #include "modules/skottie/src/SkottiePriv.h"
15 #include "modules/skottie/src/SkottieValue.h"
16 #include "modules/skottie/src/effects/Effects.h"
17 #include "modules/sksg/include/SkSGColorFilter.h"
18 #include "modules/sksg/include/SkSGRenderNode.h"
19
20 #include <cstddef>
21 #include <utility>
22
23 namespace skjson {
24 class ArrayValue;
25 }
26
27 namespace skottie::internal {
28 namespace {
29
30 // Convert to black & white, based on input luminance and a threshold uniform.
31 static constexpr char gThresholdSkSL[] =
32 "uniform half t;"
33
34 "half4 main(half4 color) {"
35 "half4 c = unpremul(color);"
36
37 "half lum = dot(c.rgb, half3(0.2126, 0.7152, 0.0722)),"
38 "bw = step(t, lum);"
39
40 "return bw.xxx1 * c.a;"
41 "}"
42 ;
43
threshold_effect()44 static sk_sp<SkRuntimeEffect> threshold_effect() {
45 static const SkRuntimeEffect* effect =
46 SkRuntimeEffect::MakeForColorFilter(SkString(gThresholdSkSL), {}).effect.release();
47 SkASSERT(effect);
48
49 return sk_ref_sp(effect);
50 }
51
52 class ThresholdAdapter final : public DiscardableAdapterBase<ThresholdAdapter,
53 sksg::ExternalColorFilter> {
54 public:
ThresholdAdapter(const skjson::ArrayValue & jprops,sk_sp<sksg::RenderNode> layer,const AnimationBuilder & abuilder)55 ThresholdAdapter(const skjson::ArrayValue& jprops,
56 sk_sp<sksg::RenderNode> layer,
57 const AnimationBuilder& abuilder)
58 : INHERITED(sksg::ExternalColorFilter::Make(std::move(layer)))
59 {
60 enum : size_t {
61 kLevel_Index = 0,
62 };
63
64 EffectBinder(jprops, abuilder, this).bind(kLevel_Index, fLevel);
65 }
66
67 private:
onSync()68 void onSync() override {
69 auto cf =
70 threshold_effect()->makeColorFilter(SkData::MakeWithCopy(&fLevel, sizeof(fLevel)));
71
72 this->node()->setColorFilter(std::move(cf));
73 }
74
75 ScalarValue fLevel = 0;
76
77 using INHERITED = DiscardableAdapterBase<ThresholdAdapter, sksg::ExternalColorFilter>;
78 };
79
80 } // namespace
81
attachThresholdEffect(const skjson::ArrayValue & jprops,sk_sp<sksg::RenderNode> layer) const82 sk_sp<sksg::RenderNode> EffectBuilder::attachThresholdEffect(const skjson::ArrayValue& jprops,
83 sk_sp<sksg::RenderNode> layer) const {
84 return fBuilder->attachDiscardableAdapter<ThresholdAdapter>(jprops,
85 std::move(layer),
86 *fBuilder);
87 }
88
89 } // namespace skottie::internal
90