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/*
* Copyright 2021 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "modules/skottie/src/effects/Effects.h"
#include "include/core/SkCanvas.h"
#include "include/effects/SkRuntimeEffect.h"
#include "include/utils/SkRandom.h"
#include "modules/skottie/src/Adapter.h"
#include "modules/skottie/src/SkottieJson.h"
#include "modules/skottie/src/SkottieValue.h"
#include "modules/sksg/include/SkSGRenderNode.h"
#include <cmath>
namespace skottie::internal {
#ifdef SK_ENABLE_SKSL
namespace {
// An implementation of the ADBE Fractal Noise effect:
//
// - multiple noise sublayers (octaves) are combined using a weighted average
// - each layer is subject to a (cumulative) transform, filter and post-sampling options
//
// Parameters:
//
// * Noise Type -- controls noise layer post-sampling filtering
// (Block, Linear, Soft Linear, Spline)
// * Fractal Type -- determines a noise layer post-filtering transformation
// (Basic, Turbulent Smooth, Turbulent Basic, etc)
// * Transform -- offset/scale/rotate the noise effect (local matrix)
//
// * Complexity -- number of sublayers;
// can be fractional, where the fractional part modulates the last layer
// * Evolution -- controls noise topology in a gradual manner (can be animated for smooth
// noise transitions)
// * Sub Influence -- relative amplitude weight for sublayers (cumulative)
//
// * Sub Scaling/Rotation/Offset -- relative scale for sublayers (cumulative)
//
// * Invert -- invert noise values
//
// * Contrast -- apply a contrast to the noise result
//
// * Brightness -- apply a brightness effect to the noise result
//
//
// TODO:
// - Invert
// - Contrast/Brightness
static constexpr char gNoiseEffectSkSL[] =
"uniform float3x3 u_submatrix;" // sublayer transform
"uniform float2 u_noise_planes;" // noise planes computed based on evolution params
"uniform float u_noise_weight," // noise planes lerp weight
"u_octaves," // number of octaves (can be fractional)
"u_persistence;" // relative octave weight
// Hash based on hash13 (https://www.shadertoy.com/view/4djSRW).
"float hash(float3 v) {"
"v = fract(v*0.1031);"
"v += dot(v, v.zxy + 31.32);"
"return fract((v.x + v.y)*v.z);"
"}"
// The general idea is to compute a coherent hash for two planes in discretized (x,y,e) space,
// and interpolate between them. This yields gradual changes when animating |e| - which is the
// desired outcome.
"float sample_noise(float2 xy) {"
"xy = floor(xy);"
"float n0 = hash(float3(xy, u_noise_planes.x)),"
"n1 = hash(float3(xy, u_noise_planes.y));"
// Note: Ideally we would use 4 samples (-1, 0, 1, 2) and cubic interpolation for
// better results -- but that's significantly more expensive than lerp.
"return mix(n0, n1, u_noise_weight);"
"}"
// filter() placeholder
"%s"
// fractal() placeholder
"%s"
// Generate ceil(u_octaves) noise layers and combine based on persistentce and sublayer xform.
"float4 main(vec2 xy) {"
"float oct = u_octaves," // initial octave count (this is the effective loop counter)
"amp = 1," // initial layer amplitude
"wacc = 0," // weight accumulator
"n = 0;" // noise accumulator
// Constant loop counter chosen to be >= ceil(u_octaves).
// The logical counter is actually 'oct'.
"for (float i = 0; i < %u; ++i) {"
// effective layer weight computed to accommodate fixed loop counters
//
// -- for full octaves: layer amplitude
// -- for fractional octave: layer amplitude modulated by fractional part
// -- for octaves > ceil(u_octaves): 0
//
// e.g. for 6 loops and u_octaves = 2.3, this generates the sequence [1,1,.3,0,0]
"float w = amp*saturate(oct);"
"n += w*fractal(filter(xy));"
"wacc += w;"
"amp *= u_persistence;"
"oct -= 1;"
"xy = (u_submatrix*float3(xy,1)).xy;"
"}"
"n /= wacc;"
// TODO: fractal functions
"return float4(n,n,n,1);"
"}";
static constexpr char gFilterNearestSkSL[] =
"float filter(float2 xy) {"
"return sample_noise(xy);"
"}";
static constexpr char gFilterLinearSkSL[] =
"float filter(float2 xy) {"
"xy -= 0.5;"
"float n00 = sample_noise(xy + float2(0,0)),"
"n10 = sample_noise(xy + float2(1,0)),"
"n01 = sample_noise(xy + float2(0,1)),"
"n11 = sample_noise(xy + float2(1,1));"
"float2 t = fract(xy);"
"return mix(mix(n00, n10, t.x), mix(n01, n11, t.x), t.y);"
"}";
static constexpr char gFilterSoftLinearSkSL[] =
"float filter(float2 xy) {"
"xy -= 0.5;"
"float n00 = sample_noise(xy + float2(0,0)),"
"n10 = sample_noise(xy + float2(1,0)),"
"n01 = sample_noise(xy + float2(0,1)),"
"n11 = sample_noise(xy + float2(1,1));"
"float2 t = smoothstep(0, 1, fract(xy));"
"return mix(mix(n00, n10, t.x), mix(n01, n11, t.x), t.y);"
"}";
static constexpr char gFractalBasicSkSL[] =
"float fractal(float n) {"
"return n;"
"}";
static constexpr char gFractalTurbulentBasicSkSL[] =
"float fractal(float n) {"
"return 2*abs(0.5 - n);"
"}";
static constexpr char gFractalTurbulentSmoothSkSL[] =
"float fractal(float n) {"
"n = 2*abs(0.5 - n);"
"return n*n;"
"}";
static constexpr char gFractalTurbulentSharpSkSL[] =
"float fractal(float n) {"
"return sqrt(2*abs(0.5 - n));"
"}";
enum class NoiseFilter {
kNearest,
kLinear,
kSoftLinear,
// TODO: kSpline?
};
enum class NoiseFractal {
kBasic,
kTurbulentBasic,
kTurbulentSmooth,
kTurbulentSharp,
};
sk_sp<SkRuntimeEffect> make_noise_effect(unsigned loops, const char* filter, const char* fractal) {
auto result = SkRuntimeEffect::MakeForShader(
SkStringPrintf(gNoiseEffectSkSL, filter, fractal, loops), {});
return std::move(result.effect);
}
template <unsigned LOOPS, NoiseFilter FILTER, NoiseFractal FRACTAL>
sk_sp<SkRuntimeEffect> noise_effect() {
static constexpr char const* gFilters[] = {
gFilterNearestSkSL,
gFilterLinearSkSL,
gFilterSoftLinearSkSL
};
static constexpr char const* gFractals[] = {
gFractalBasicSkSL,
gFractalTurbulentBasicSkSL,
gFractalTurbulentSmoothSkSL,
gFractalTurbulentSharpSkSL
};
static_assert(static_cast<size_t>(FILTER) < std::size(gFilters));
static_assert(static_cast<size_t>(FRACTAL) < std::size(gFractals));
static const SkRuntimeEffect* effect =
make_noise_effect(LOOPS,
gFilters[static_cast<size_t>(FILTER)],
gFractals[static_cast<size_t>(FRACTAL)])
.release();
SkASSERT(effect);
return sk_ref_sp(effect);
}
class FractalNoiseNode final : public sksg::CustomRenderNode {
public:
explicit FractalNoiseNode(sk_sp<RenderNode> child) : INHERITED({std::move(child)}) {}
SG_ATTRIBUTE(Matrix , SkMatrix , fMatrix )
SG_ATTRIBUTE(SubMatrix , SkMatrix , fSubMatrix )
SG_ATTRIBUTE(NoiseFilter , NoiseFilter , fFilter )
SG_ATTRIBUTE(NoiseFractal , NoiseFractal, fFractal )
SG_ATTRIBUTE(NoisePlanes , SkV2 , fNoisePlanes )
SG_ATTRIBUTE(NoiseWeight , float , fNoiseWeight )
SG_ATTRIBUTE(Octaves , float , fOctaves )
SG_ATTRIBUTE(Persistence , float , fPersistence )
private:
template <NoiseFilter FI, NoiseFractal FR>
sk_sp<SkRuntimeEffect> getEffect() const {
// Bin the loop counter based on the number of octaves (range: [1..20]).
// Low complexities are common, so we maximize resolution for the low end.
if (fOctaves > 8) return noise_effect<20, FI, FR>();
if (fOctaves > 4) return noise_effect< 8, FI, FR>();
if (fOctaves > 3) return noise_effect< 4, FI, FR>();
if (fOctaves > 2) return noise_effect< 3, FI, FR>();
if (fOctaves > 1) return noise_effect< 2, FI, FR>();
return noise_effect<1, FI, FR>();
}
template <NoiseFilter FI>
sk_sp<SkRuntimeEffect> getEffect() const {
switch (fFractal) {
case NoiseFractal::kBasic:
return this->getEffect<FI, NoiseFractal::kBasic>();
case NoiseFractal::kTurbulentBasic:
return this->getEffect<FI, NoiseFractal::kTurbulentBasic>();
case NoiseFractal::kTurbulentSmooth:
return this->getEffect<FI, NoiseFractal::kTurbulentSmooth>();
case NoiseFractal::kTurbulentSharp:
return this->getEffect<FI, NoiseFractal::kTurbulentSharp>();
}
SkUNREACHABLE;
}
sk_sp<SkRuntimeEffect> getEffect() const {
switch (fFilter) {
case NoiseFilter::kNearest : return this->getEffect<NoiseFilter::kNearest>();
case NoiseFilter::kLinear : return this->getEffect<NoiseFilter::kLinear>();
case NoiseFilter::kSoftLinear: return this->getEffect<NoiseFilter::kSoftLinear>();
}
SkUNREACHABLE;
}
sk_sp<SkShader> buildEffectShader() const {
SkRuntimeShaderBuilder builder(this->getEffect());
builder.uniform("u_noise_planes") = fNoisePlanes;
builder.uniform("u_noise_weight") = fNoiseWeight;
builder.uniform("u_octaves" ) = fOctaves;
builder.uniform("u_persistence" ) = fPersistence;
builder.uniform("u_submatrix" ) = std::array<float,9>{
fSubMatrix.rc(0,0), fSubMatrix.rc(1,0), fSubMatrix.rc(2,0),
fSubMatrix.rc(0,1), fSubMatrix.rc(1,1), fSubMatrix.rc(2,1),
fSubMatrix.rc(0,2), fSubMatrix.rc(1,2), fSubMatrix.rc(2,2),
};
return builder.makeShader(&fMatrix);
}
SkRect onRevalidate(sksg::InvalidationController* ic, const SkMatrix& ctm) override {
const auto& child = this->children()[0];
const auto bounds = child->revalidate(ic, ctm);
fEffectShader = this->buildEffectShader();
return bounds;
}
void onRender(SkCanvas* canvas, const RenderContext* ctx) const override {
const auto& bounds = this->bounds();
const auto local_ctx = ScopedRenderContext(canvas, ctx)
.setIsolation(bounds, canvas->getTotalMatrix(), true);
canvas->saveLayer(&bounds, nullptr);
this->children()[0]->render(canvas, local_ctx);
SkPaint effect_paint;
effect_paint.setShader(fEffectShader);
effect_paint.setBlendMode(SkBlendMode::kSrcIn);
canvas->drawPaint(effect_paint);
}
const RenderNode* onNodeAt(const SkPoint&) const override { return nullptr; } // no hit-testing
sk_sp<SkShader> fEffectShader;
SkMatrix fMatrix,
fSubMatrix;
NoiseFilter fFilter = NoiseFilter::kNearest;
NoiseFractal fFractal = NoiseFractal::kBasic;
SkV2 fNoisePlanes = {0,0};
float fNoiseWeight = 0,
fOctaves = 1,
fPersistence = 1;
using INHERITED = sksg::CustomRenderNode;
};
class FractalNoiseAdapter final : public DiscardableAdapterBase<FractalNoiseAdapter,
FractalNoiseNode> {
public:
FractalNoiseAdapter(const skjson::ArrayValue& jprops,
const AnimationBuilder* abuilder,
sk_sp<FractalNoiseNode> node)
: INHERITED(std::move(node))
{
EffectBinder(jprops, *abuilder, this)
.bind( 0, fFractalType )
.bind( 1, fNoiseType )
.bind( 2, fInvert )
.bind( 3, fContrast )
.bind( 4, fBrightness )
// 5 -- overflow
// 6 -- transform begin-group
.bind( 7, fRotation )
.bind( 8, fUniformScaling )
.bind( 9, fScale )
.bind(10, fScaleWidth )
.bind(11, fScaleHeight )
.bind(12, fOffset )
// 13 -- TODO: perspective offset
// 14 -- transform end-group
.bind(15, fComplexity )
// 16 -- sub settings begin-group
.bind(17, fSubInfluence )
.bind(18, fSubScale )
.bind(19, fSubRotation )
.bind(20, fSubOffset )
// 21 -- center subscale
// 22 -- sub settings end-group
.bind(23, fEvolution )
// 24 -- evolution options begin-group
.bind(25, fCycleEvolution )
.bind(26, fCycleRevolutions)
.bind(27, fRandomSeed )
// 28 -- evolution options end-group
.bind(29, fOpacity );
// 30 -- TODO: blending mode
}
private:
std::tuple<SkV2, float> noise() const {
// Constant chosen to visually match AE's evolution rate.
static constexpr auto kEvolutionScale = 0.25f;
// Evolution inputs:
//
// * evolution - main evolution control (degrees)
// * cycle evolution - flag controlling whether evolution cycles
// * cycle revolutions - number of revolutions after which evolution cycles (period)
// * random seed - determines an arbitrary starting plane (evolution offset)
//
// The shader uses evolution floor/ceil to select two noise planes, and the fractional part
// to interpolate between the two -> in order to wrap around smoothly, the cycle/period
// must be integral.
const float
evo_rad = SkDegreesToRadians(fEvolution),
rev_rad = std::max(fCycleRevolutions, 1.0f)*SK_FloatPI*2,
cycle = fCycleEvolution
? SkScalarRoundToScalar(rev_rad*kEvolutionScale)
: SK_ScalarMax,
// Adjust scale when cycling to ensure an integral period (post scaling).
scale = fCycleEvolution
? cycle/rev_rad
: kEvolutionScale,
offset = SkRandom(static_cast<uint32_t>(fRandomSeed)).nextRangeU(0, 100),
evo = evo_rad*scale,
evo_ = std::floor(evo),
weight = evo - evo_;
// We want the GLSL mod() flavor.
auto glsl_mod = [](float x, float y) {
return x - y*std::floor(x/y);
};
const SkV2 noise_planes = {
glsl_mod(evo_ + 0, cycle) + offset,
glsl_mod(evo_ + 1, cycle) + offset,
};
return std::make_tuple(noise_planes, weight);
}
SkMatrix shaderMatrix() const {
static constexpr float kGridSize = 64;
const auto scale = (SkScalarRoundToInt(fUniformScaling) == 1)
? SkV2{fScale, fScale}
: SkV2{fScaleWidth, fScaleHeight};
return SkMatrix::Translate(fOffset.x, fOffset.y)
* SkMatrix::Scale(SkTPin(scale.x, 1.0f, 10000.0f) * 0.01f,
SkTPin(scale.y, 1.0f, 10000.0f) * 0.01f)
* SkMatrix::RotateDeg(fRotation)
* SkMatrix::Scale(kGridSize, kGridSize);
}
SkMatrix subMatrix() const {
const auto scale = 100 / SkTPin(fSubScale, 10.0f, 10000.0f);
return SkMatrix::Translate(-fSubOffset.x * 0.01f, -fSubOffset.y * 0.01f)
* SkMatrix::RotateDeg(-fSubRotation)
* SkMatrix::Scale(scale, scale);
}
NoiseFilter noiseFilter() const {
switch (SkScalarRoundToInt(fNoiseType)) {
case 1: return NoiseFilter::kNearest;
case 2: return NoiseFilter::kLinear;
default: return NoiseFilter::kSoftLinear;
}
SkUNREACHABLE;
}
NoiseFractal noiseFractal() const {
switch (SkScalarRoundToInt(fFractalType)) {
case 1: return NoiseFractal::kBasic;
case 3: return NoiseFractal::kTurbulentSmooth;
case 4: return NoiseFractal::kTurbulentBasic;
default: return NoiseFractal::kTurbulentSharp;
}
SkUNREACHABLE;
}
void onSync() override {
const auto& n = this->node();
const auto [noise_planes, noise_weight] = this->noise();
n->setOctaves(SkTPin(fComplexity, 1.0f, 20.0f));
n->setPersistence(SkTPin(fSubInfluence * 0.01f, 0.0f, 100.0f));
n->setNoisePlanes(noise_planes);
n->setNoiseWeight(noise_weight);
n->setNoiseFilter(this->noiseFilter());
n->setNoiseFractal(this->noiseFractal());
n->setMatrix(this->shaderMatrix());
n->setSubMatrix(this->subMatrix());
}
Vec2Value fOffset = {0,0},
fSubOffset = {0,0};
ScalarValue fFractalType = 0,
fNoiseType = 0,
fRotation = 0,
fUniformScaling = 0,
fScale = 100, // used when uniform scaling is selected
fScaleWidth = 100, // used when uniform scaling is not selected
fScaleHeight = 100, // ^
fComplexity = 1,
fSubInfluence = 100,
fSubScale = 50,
fSubRotation = 0,
fEvolution = 0,
fCycleEvolution = 0,
fCycleRevolutions = 0,
fRandomSeed = 0,
fOpacity = 100, // TODO
fInvert = 0, // TODO
fContrast = 100, // TODO
fBrightness = 0; // TODO
using INHERITED = DiscardableAdapterBase<FractalNoiseAdapter, FractalNoiseNode>;
};
} // namespace
#endif // SK_ENABLE_SKSL
sk_sp<sksg::RenderNode> EffectBuilder::attachFractalNoiseEffect(
const skjson::ArrayValue& jprops, sk_sp<sksg::RenderNode> layer) const {
#ifdef SK_ENABLE_SKSL
auto fractal_noise = sk_make_sp<FractalNoiseNode>(std::move(layer));
return fBuilder->attachDiscardableAdapter<FractalNoiseAdapter>(jprops, fBuilder,
std::move(fractal_noise));
#else
// TODO(skia:12197)
return layer;
#endif
}
} // namespace skottie::internal