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- /*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #include "include/core/SkCanvas.h"
- #include "include/core/SkColorFilter.h"
- #include "include/core/SkMaskFilter.h"
- #include "include/core/SkPath.h"
- #include "include/core/SkString.h"
- #include "include/core/SkVertices.h"
- #include "include/private/SkColorData.h"
- #include "include/utils/SkRandom.h"
- #include "include/utils/SkShadowUtils.h"
- #include "src/core/SkBlurMask.h"
- #include "src/core/SkDevice.h"
- #include "src/core/SkDrawShadowInfo.h"
- #include "src/core/SkEffectPriv.h"
- #include "src/core/SkPathPriv.h"
- #include "src/core/SkRasterPipeline.h"
- #include "src/core/SkResourceCache.h"
- #include "src/core/SkTLazy.h"
- #include "src/utils/SkShadowTessellator.h"
- #include <new>
- #if SK_SUPPORT_GPU
- #include "src/gpu/effects/generated/GrBlurredEdgeFragmentProcessor.h"
- #include "src/gpu/geometry/GrShape.h"
- #endif
- /**
- * Gaussian color filter -- produces a Gaussian ramp based on the color's B value,
- * then blends with the color's G value.
- * Final result is black with alpha of Gaussian(B)*G.
- * The assumption is that the original color's alpha is 1.
- */
- class SkGaussianColorFilter : public SkColorFilter {
- public:
- static sk_sp<SkColorFilter> Make() {
- return sk_sp<SkColorFilter>(new SkGaussianColorFilter);
- }
- #if SK_SUPPORT_GPU
- std::unique_ptr<GrFragmentProcessor> asFragmentProcessor(
- GrRecordingContext*, const GrColorSpaceInfo&) const override;
- #endif
- protected:
- void flatten(SkWriteBuffer&) const override {}
- bool onAppendStages(const SkStageRec& rec, bool shaderIsOpaque) const override {
- rec.fPipeline->append(SkRasterPipeline::gauss_a_to_rgba);
- return true;
- }
- private:
- SK_FLATTENABLE_HOOKS(SkGaussianColorFilter)
- SkGaussianColorFilter() : INHERITED() {}
- typedef SkColorFilter INHERITED;
- };
- sk_sp<SkFlattenable> SkGaussianColorFilter::CreateProc(SkReadBuffer&) {
- return Make();
- }
- #if SK_SUPPORT_GPU
- std::unique_ptr<GrFragmentProcessor> SkGaussianColorFilter::asFragmentProcessor(
- GrRecordingContext*, const GrColorSpaceInfo&) const {
- return GrBlurredEdgeFragmentProcessor::Make(GrBlurredEdgeFragmentProcessor::Mode::kGaussian);
- }
- #endif
- ///////////////////////////////////////////////////////////////////////////////////////////////////
- namespace {
- uint64_t resource_cache_shared_id() {
- return 0x2020776f64616873llu; // 'shadow '
- }
- /** Factory for an ambient shadow mesh with particular shadow properties. */
- struct AmbientVerticesFactory {
- SkScalar fOccluderHeight = SK_ScalarNaN; // NaN so that isCompatible will fail until init'ed.
- bool fTransparent;
- SkVector fOffset;
- bool isCompatible(const AmbientVerticesFactory& that, SkVector* translate) const {
- if (fOccluderHeight != that.fOccluderHeight || fTransparent != that.fTransparent) {
- return false;
- }
- *translate = that.fOffset;
- return true;
- }
- sk_sp<SkVertices> makeVertices(const SkPath& path, const SkMatrix& ctm,
- SkVector* translate) const {
- SkPoint3 zParams = SkPoint3::Make(0, 0, fOccluderHeight);
- // pick a canonical place to generate shadow
- SkMatrix noTrans(ctm);
- if (!ctm.hasPerspective()) {
- noTrans[SkMatrix::kMTransX] = 0;
- noTrans[SkMatrix::kMTransY] = 0;
- }
- *translate = fOffset;
- return SkShadowTessellator::MakeAmbient(path, noTrans, zParams, fTransparent);
- }
- };
- /** Factory for an spot shadow mesh with particular shadow properties. */
- struct SpotVerticesFactory {
- enum class OccluderType {
- // The umbra cannot be dropped out because either the occluder is not opaque,
- // or the center of the umbra is visible.
- kTransparent,
- // The umbra can be dropped where it is occluded.
- kOpaquePartialUmbra,
- // It is known that the entire umbra is occluded.
- kOpaqueNoUmbra
- };
- SkVector fOffset;
- SkPoint fLocalCenter;
- SkScalar fOccluderHeight = SK_ScalarNaN; // NaN so that isCompatible will fail until init'ed.
- SkPoint3 fDevLightPos;
- SkScalar fLightRadius;
- OccluderType fOccluderType;
- bool isCompatible(const SpotVerticesFactory& that, SkVector* translate) const {
- if (fOccluderHeight != that.fOccluderHeight || fDevLightPos.fZ != that.fDevLightPos.fZ ||
- fLightRadius != that.fLightRadius || fOccluderType != that.fOccluderType) {
- return false;
- }
- switch (fOccluderType) {
- case OccluderType::kTransparent:
- case OccluderType::kOpaqueNoUmbra:
- // 'this' and 'that' will either both have no umbra removed or both have all the
- // umbra removed.
- *translate = that.fOffset;
- return true;
- case OccluderType::kOpaquePartialUmbra:
- // In this case we partially remove the umbra differently for 'this' and 'that'
- // if the offsets don't match.
- if (fOffset == that.fOffset) {
- translate->set(0, 0);
- return true;
- }
- return false;
- }
- SK_ABORT("Uninitialized occluder type?");
- return false;
- }
- sk_sp<SkVertices> makeVertices(const SkPath& path, const SkMatrix& ctm,
- SkVector* translate) const {
- bool transparent = OccluderType::kTransparent == fOccluderType;
- SkPoint3 zParams = SkPoint3::Make(0, 0, fOccluderHeight);
- if (ctm.hasPerspective() || OccluderType::kOpaquePartialUmbra == fOccluderType) {
- translate->set(0, 0);
- return SkShadowTessellator::MakeSpot(path, ctm, zParams,
- fDevLightPos, fLightRadius, transparent);
- } else {
- // pick a canonical place to generate shadow, with light centered over path
- SkMatrix noTrans(ctm);
- noTrans[SkMatrix::kMTransX] = 0;
- noTrans[SkMatrix::kMTransY] = 0;
- SkPoint devCenter(fLocalCenter);
- noTrans.mapPoints(&devCenter, 1);
- SkPoint3 centerLightPos = SkPoint3::Make(devCenter.fX, devCenter.fY, fDevLightPos.fZ);
- *translate = fOffset;
- return SkShadowTessellator::MakeSpot(path, noTrans, zParams,
- centerLightPos, fLightRadius, transparent);
- }
- }
- };
- /**
- * This manages a set of tessellations for a given shape in the cache. Because SkResourceCache
- * records are immutable this is not itself a Rec. When we need to update it we return this on
- * the FindVisitor and let the cache destroy the Rec. We'll update the tessellations and then add
- * a new Rec with an adjusted size for any deletions/additions.
- */
- class CachedTessellations : public SkRefCnt {
- public:
- size_t size() const { return fAmbientSet.size() + fSpotSet.size(); }
- sk_sp<SkVertices> find(const AmbientVerticesFactory& ambient, const SkMatrix& matrix,
- SkVector* translate) const {
- return fAmbientSet.find(ambient, matrix, translate);
- }
- sk_sp<SkVertices> add(const SkPath& devPath, const AmbientVerticesFactory& ambient,
- const SkMatrix& matrix, SkVector* translate) {
- return fAmbientSet.add(devPath, ambient, matrix, translate);
- }
- sk_sp<SkVertices> find(const SpotVerticesFactory& spot, const SkMatrix& matrix,
- SkVector* translate) const {
- return fSpotSet.find(spot, matrix, translate);
- }
- sk_sp<SkVertices> add(const SkPath& devPath, const SpotVerticesFactory& spot,
- const SkMatrix& matrix, SkVector* translate) {
- return fSpotSet.add(devPath, spot, matrix, translate);
- }
- private:
- template <typename FACTORY, int MAX_ENTRIES>
- class Set {
- public:
- size_t size() const { return fSize; }
- sk_sp<SkVertices> find(const FACTORY& factory, const SkMatrix& matrix,
- SkVector* translate) const {
- for (int i = 0; i < MAX_ENTRIES; ++i) {
- if (fEntries[i].fFactory.isCompatible(factory, translate)) {
- const SkMatrix& m = fEntries[i].fMatrix;
- if (matrix.hasPerspective() || m.hasPerspective()) {
- if (matrix != fEntries[i].fMatrix) {
- continue;
- }
- } else if (matrix.getScaleX() != m.getScaleX() ||
- matrix.getSkewX() != m.getSkewX() ||
- matrix.getScaleY() != m.getScaleY() ||
- matrix.getSkewY() != m.getSkewY()) {
- continue;
- }
- return fEntries[i].fVertices;
- }
- }
- return nullptr;
- }
- sk_sp<SkVertices> add(const SkPath& path, const FACTORY& factory, const SkMatrix& matrix,
- SkVector* translate) {
- sk_sp<SkVertices> vertices = factory.makeVertices(path, matrix, translate);
- if (!vertices) {
- return nullptr;
- }
- int i;
- if (fCount < MAX_ENTRIES) {
- i = fCount++;
- } else {
- i = fRandom.nextULessThan(MAX_ENTRIES);
- fSize -= fEntries[i].fVertices->approximateSize();
- }
- fEntries[i].fFactory = factory;
- fEntries[i].fVertices = vertices;
- fEntries[i].fMatrix = matrix;
- fSize += vertices->approximateSize();
- return vertices;
- }
- private:
- struct Entry {
- FACTORY fFactory;
- sk_sp<SkVertices> fVertices;
- SkMatrix fMatrix;
- };
- Entry fEntries[MAX_ENTRIES];
- int fCount = 0;
- size_t fSize = 0;
- SkRandom fRandom;
- };
- Set<AmbientVerticesFactory, 4> fAmbientSet;
- Set<SpotVerticesFactory, 4> fSpotSet;
- };
- /**
- * A record of shadow vertices stored in SkResourceCache of CachedTessellations for a particular
- * path. The key represents the path's geometry and not any shadow params.
- */
- class CachedTessellationsRec : public SkResourceCache::Rec {
- public:
- CachedTessellationsRec(const SkResourceCache::Key& key,
- sk_sp<CachedTessellations> tessellations)
- : fTessellations(std::move(tessellations)) {
- fKey.reset(new uint8_t[key.size()]);
- memcpy(fKey.get(), &key, key.size());
- }
- const Key& getKey() const override {
- return *reinterpret_cast<SkResourceCache::Key*>(fKey.get());
- }
- size_t bytesUsed() const override { return fTessellations->size(); }
- const char* getCategory() const override { return "tessellated shadow masks"; }
- sk_sp<CachedTessellations> refTessellations() const { return fTessellations; }
- template <typename FACTORY>
- sk_sp<SkVertices> find(const FACTORY& factory, const SkMatrix& matrix,
- SkVector* translate) const {
- return fTessellations->find(factory, matrix, translate);
- }
- private:
- std::unique_ptr<uint8_t[]> fKey;
- sk_sp<CachedTessellations> fTessellations;
- };
- /**
- * Used by FindVisitor to determine whether a cache entry can be reused and if so returns the
- * vertices and a translation vector. If the CachedTessellations does not contain a suitable
- * mesh then we inform SkResourceCache to destroy the Rec and we return the CachedTessellations
- * to the caller. The caller will update it and reinsert it back into the cache.
- */
- template <typename FACTORY>
- struct FindContext {
- FindContext(const SkMatrix* viewMatrix, const FACTORY* factory)
- : fViewMatrix(viewMatrix), fFactory(factory) {}
- const SkMatrix* const fViewMatrix;
- // If this is valid after Find is called then we found the vertices and they should be drawn
- // with fTranslate applied.
- sk_sp<SkVertices> fVertices;
- SkVector fTranslate = {0, 0};
- // If this is valid after Find then the caller should add the vertices to the tessellation set
- // and create a new CachedTessellationsRec and insert it into SkResourceCache.
- sk_sp<CachedTessellations> fTessellationsOnFailure;
- const FACTORY* fFactory;
- };
- /**
- * Function called by SkResourceCache when a matching cache key is found. The FACTORY and matrix of
- * the FindContext are used to determine if the vertices are reusable. If so the vertices and
- * necessary translation vector are set on the FindContext.
- */
- template <typename FACTORY>
- bool FindVisitor(const SkResourceCache::Rec& baseRec, void* ctx) {
- FindContext<FACTORY>* findContext = (FindContext<FACTORY>*)ctx;
- const CachedTessellationsRec& rec = static_cast<const CachedTessellationsRec&>(baseRec);
- findContext->fVertices =
- rec.find(*findContext->fFactory, *findContext->fViewMatrix, &findContext->fTranslate);
- if (findContext->fVertices) {
- return true;
- }
- // We ref the tessellations and let the cache destroy the Rec. Once the tessellations have been
- // manipulated we will add a new Rec.
- findContext->fTessellationsOnFailure = rec.refTessellations();
- return false;
- }
- class ShadowedPath {
- public:
- ShadowedPath(const SkPath* path, const SkMatrix* viewMatrix)
- : fPath(path)
- , fViewMatrix(viewMatrix)
- #if SK_SUPPORT_GPU
- , fShapeForKey(*path, GrStyle::SimpleFill())
- #endif
- {}
- const SkPath& path() const { return *fPath; }
- const SkMatrix& viewMatrix() const { return *fViewMatrix; }
- #if SK_SUPPORT_GPU
- /** Negative means the vertices should not be cached for this path. */
- int keyBytes() const { return fShapeForKey.unstyledKeySize() * sizeof(uint32_t); }
- void writeKey(void* key) const {
- fShapeForKey.writeUnstyledKey(reinterpret_cast<uint32_t*>(key));
- }
- bool isRRect(SkRRect* rrect) { return fShapeForKey.asRRect(rrect, nullptr, nullptr, nullptr); }
- #else
- int keyBytes() const { return -1; }
- void writeKey(void* key) const { SK_ABORT("Should never be called"); }
- bool isRRect(SkRRect* rrect) { return false; }
- #endif
- private:
- const SkPath* fPath;
- const SkMatrix* fViewMatrix;
- #if SK_SUPPORT_GPU
- GrShape fShapeForKey;
- #endif
- };
- // This creates a domain of keys in SkResourceCache used by this file.
- static void* kNamespace;
- // When the SkPathRef genID changes, invalidate a corresponding GrResource described by key.
- class ShadowInvalidator : public SkPathRef::GenIDChangeListener {
- public:
- ShadowInvalidator(const SkResourceCache::Key& key) {
- fKey.reset(new uint8_t[key.size()]);
- memcpy(fKey.get(), &key, key.size());
- }
- private:
- const SkResourceCache::Key& getKey() const {
- return *reinterpret_cast<SkResourceCache::Key*>(fKey.get());
- }
- // always purge
- static bool FindVisitor(const SkResourceCache::Rec&, void*) {
- return false;
- }
- void onChange() override {
- SkResourceCache::Find(this->getKey(), ShadowInvalidator::FindVisitor, nullptr);
- }
- std::unique_ptr<uint8_t[]> fKey;
- };
- /**
- * Draws a shadow to 'canvas'. The vertices used to draw the shadow are created by 'factory' unless
- * they are first found in SkResourceCache.
- */
- template <typename FACTORY>
- bool draw_shadow(const FACTORY& factory,
- std::function<void(const SkVertices*, SkBlendMode, const SkPaint&,
- SkScalar tx, SkScalar ty, bool)> drawProc, ShadowedPath& path, SkColor color) {
- FindContext<FACTORY> context(&path.viewMatrix(), &factory);
- SkResourceCache::Key* key = nullptr;
- SkAutoSTArray<32 * 4, uint8_t> keyStorage;
- int keyDataBytes = path.keyBytes();
- if (keyDataBytes >= 0) {
- keyStorage.reset(keyDataBytes + sizeof(SkResourceCache::Key));
- key = new (keyStorage.begin()) SkResourceCache::Key();
- path.writeKey((uint32_t*)(keyStorage.begin() + sizeof(*key)));
- key->init(&kNamespace, resource_cache_shared_id(), keyDataBytes);
- SkResourceCache::Find(*key, FindVisitor<FACTORY>, &context);
- }
- sk_sp<SkVertices> vertices;
- bool foundInCache = SkToBool(context.fVertices);
- if (foundInCache) {
- vertices = std::move(context.fVertices);
- } else {
- // TODO: handle transforming the path as part of the tessellator
- if (key) {
- // Update or initialize a tessellation set and add it to the cache.
- sk_sp<CachedTessellations> tessellations;
- if (context.fTessellationsOnFailure) {
- tessellations = std::move(context.fTessellationsOnFailure);
- } else {
- tessellations.reset(new CachedTessellations());
- }
- vertices = tessellations->add(path.path(), factory, path.viewMatrix(),
- &context.fTranslate);
- if (!vertices) {
- return false;
- }
- auto rec = new CachedTessellationsRec(*key, std::move(tessellations));
- SkPathPriv::AddGenIDChangeListener(path.path(), sk_make_sp<ShadowInvalidator>(*key));
- SkResourceCache::Add(rec);
- } else {
- vertices = factory.makeVertices(path.path(), path.viewMatrix(),
- &context.fTranslate);
- if (!vertices) {
- return false;
- }
- }
- }
- SkPaint paint;
- // Run the vertex color through a GaussianColorFilter and then modulate the grayscale result of
- // that against our 'color' param.
- paint.setColorFilter(
- SkColorFilters::Blend(color, SkBlendMode::kModulate)->makeComposed(
- SkGaussianColorFilter::Make()));
- drawProc(vertices.get(), SkBlendMode::kModulate, paint,
- context.fTranslate.fX, context.fTranslate.fY, path.viewMatrix().hasPerspective());
- return true;
- }
- }
- static bool tilted(const SkPoint3& zPlaneParams) {
- return !SkScalarNearlyZero(zPlaneParams.fX) || !SkScalarNearlyZero(zPlaneParams.fY);
- }
- static SkPoint3 map(const SkMatrix& m, const SkPoint3& pt) {
- SkPoint3 result;
- m.mapXY(pt.fX, pt.fY, (SkPoint*)&result.fX);
- result.fZ = pt.fZ;
- return result;
- }
- void SkShadowUtils::ComputeTonalColors(SkColor inAmbientColor, SkColor inSpotColor,
- SkColor* outAmbientColor, SkColor* outSpotColor) {
- // For tonal color we only compute color values for the spot shadow.
- // The ambient shadow is greyscale only.
- // Ambient
- *outAmbientColor = SkColorSetARGB(SkColorGetA(inAmbientColor), 0, 0, 0);
- // Spot
- int spotR = SkColorGetR(inSpotColor);
- int spotG = SkColorGetG(inSpotColor);
- int spotB = SkColorGetB(inSpotColor);
- int max = SkTMax(SkTMax(spotR, spotG), spotB);
- int min = SkTMin(SkTMin(spotR, spotG), spotB);
- SkScalar luminance = 0.5f*(max + min)/255.f;
- SkScalar origA = SkColorGetA(inSpotColor)/255.f;
- // We compute a color alpha value based on the luminance of the color, scaled by an
- // adjusted alpha value. We want the following properties to match the UX examples
- // (assuming a = 0.25) and to ensure that we have reasonable results when the color
- // is black and/or the alpha is 0:
- // f(0, a) = 0
- // f(luminance, 0) = 0
- // f(1, 0.25) = .5
- // f(0.5, 0.25) = .4
- // f(1, 1) = 1
- // The following functions match this as closely as possible.
- SkScalar alphaAdjust = (2.6f + (-2.66667f + 1.06667f*origA)*origA)*origA;
- SkScalar colorAlpha = (3.544762f + (-4.891428f + 2.3466f*luminance)*luminance)*luminance;
- colorAlpha = SkTPin(alphaAdjust*colorAlpha, 0.0f, 1.0f);
- // Similarly, we set the greyscale alpha based on luminance and alpha so that
- // f(0, a) = a
- // f(luminance, 0) = 0
- // f(1, 0.25) = 0.15
- SkScalar greyscaleAlpha = SkTPin(origA*(1 - 0.4f*luminance), 0.0f, 1.0f);
- // The final color we want to emulate is generated by rendering a color shadow (C_rgb) using an
- // alpha computed from the color's luminance (C_a), and then a black shadow with alpha (S_a)
- // which is an adjusted value of 'a'. Assuming SrcOver, a background color of B_rgb, and
- // ignoring edge falloff, this becomes
- //
- // (C_a - S_a*C_a)*C_rgb + (1 - (S_a + C_a - S_a*C_a))*B_rgb
- //
- // Assuming premultiplied alpha, this means we scale the color by (C_a - S_a*C_a) and
- // set the alpha to (S_a + C_a - S_a*C_a).
- SkScalar colorScale = colorAlpha*(SK_Scalar1 - greyscaleAlpha);
- SkScalar tonalAlpha = colorScale + greyscaleAlpha;
- SkScalar unPremulScale = colorScale / tonalAlpha;
- *outSpotColor = SkColorSetARGB(tonalAlpha*255.999f,
- unPremulScale*spotR,
- unPremulScale*spotG,
- unPremulScale*spotB);
- }
- // Draw an offset spot shadow and outlining ambient shadow for the given path.
- void SkShadowUtils::DrawShadow(SkCanvas* canvas, const SkPath& path, const SkPoint3& zPlaneParams,
- const SkPoint3& devLightPos, SkScalar lightRadius,
- SkColor ambientColor, SkColor spotColor,
- uint32_t flags) {
- SkMatrix inverse;
- if (!canvas->getTotalMatrix().invert(&inverse)) {
- return;
- }
- SkPoint pt = inverse.mapXY(devLightPos.fX, devLightPos.fY);
- SkDrawShadowRec rec;
- rec.fZPlaneParams = zPlaneParams;
- rec.fLightPos = { pt.fX, pt.fY, devLightPos.fZ };
- rec.fLightRadius = lightRadius;
- rec.fAmbientColor = ambientColor;
- rec.fSpotColor = spotColor;
- rec.fFlags = flags;
- canvas->private_draw_shadow_rec(path, rec);
- }
- static bool validate_rec(const SkDrawShadowRec& rec) {
- return rec.fLightPos.isFinite() && rec.fZPlaneParams.isFinite() &&
- SkScalarIsFinite(rec.fLightRadius);
- }
- void SkBaseDevice::drawShadow(const SkPath& path, const SkDrawShadowRec& rec) {
- auto drawVertsProc = [this](const SkVertices* vertices, SkBlendMode mode, const SkPaint& paint,
- SkScalar tx, SkScalar ty, bool hasPerspective) {
- if (vertices->vertexCount()) {
- // For perspective shadows we've already computed the shadow in world space,
- // and we can't translate it without changing it. Otherwise we concat the
- // change in translation from the cached version.
- SkAutoDeviceCTMRestore adr(
- this,
- hasPerspective ? SkMatrix::I()
- : SkMatrix::Concat(this->ctm(), SkMatrix::MakeTrans(tx, ty)));
- this->drawVertices(vertices, nullptr, 0, mode, paint);
- }
- };
- if (!validate_rec(rec)) {
- return;
- }
- SkMatrix viewMatrix = this->ctm();
- SkAutoDeviceCTMRestore adr(this, SkMatrix::I());
- ShadowedPath shadowedPath(&path, &viewMatrix);
- bool tiltZPlane = tilted(rec.fZPlaneParams);
- bool transparent = SkToBool(rec.fFlags & SkShadowFlags::kTransparentOccluder_ShadowFlag);
- bool uncached = tiltZPlane || path.isVolatile();
- SkPoint3 zPlaneParams = rec.fZPlaneParams;
- SkPoint3 devLightPos = map(viewMatrix, rec.fLightPos);
- float lightRadius = rec.fLightRadius;
- if (SkColorGetA(rec.fAmbientColor) > 0) {
- bool success = false;
- if (uncached) {
- sk_sp<SkVertices> vertices = SkShadowTessellator::MakeAmbient(path, viewMatrix,
- zPlaneParams,
- transparent);
- if (vertices) {
- SkPaint paint;
- // Run the vertex color through a GaussianColorFilter and then modulate the
- // grayscale result of that against our 'color' param.
- paint.setColorFilter(
- SkColorFilters::Blend(rec.fAmbientColor,
- SkBlendMode::kModulate)->makeComposed(
- SkGaussianColorFilter::Make()));
- this->drawVertices(vertices.get(), nullptr, 0, SkBlendMode::kModulate, paint);
- success = true;
- }
- }
- if (!success) {
- AmbientVerticesFactory factory;
- factory.fOccluderHeight = zPlaneParams.fZ;
- factory.fTransparent = transparent;
- if (viewMatrix.hasPerspective()) {
- factory.fOffset.set(0, 0);
- } else {
- factory.fOffset.fX = viewMatrix.getTranslateX();
- factory.fOffset.fY = viewMatrix.getTranslateY();
- }
- if (!draw_shadow(factory, drawVertsProc, shadowedPath, rec.fAmbientColor)) {
- // Pretransform the path to avoid transforming the stroke, below.
- SkPath devSpacePath;
- path.transform(viewMatrix, &devSpacePath);
- devSpacePath.setIsVolatile(true);
- // The tesselator outsets by AmbientBlurRadius (or 'r') to get the outer ring of
- // the tesselation, and sets the alpha on the path to 1/AmbientRecipAlpha (or 'a').
- //
- // We want to emulate this with a blur. The full blur width (2*blurRadius or 'f')
- // can be calculated by interpolating:
- //
- // original edge outer edge
- // | |<---------- r ------>|
- // |<------|--- f -------------->|
- // | | |
- // alpha = 1 alpha = a alpha = 0
- //
- // Taking ratios, f/1 = r/a, so f = r/a and blurRadius = f/2.
- //
- // We now need to outset the path to place the new edge in the center of the
- // blur region:
- //
- // original new
- // | |<------|--- r ------>|
- // |<------|--- f -|------------>|
- // | |<- o ->|<--- f/2 --->|
- //
- // r = o + f/2, so o = r - f/2
- //
- // We outset by using the stroker, so the strokeWidth is o/2.
- //
- SkScalar devSpaceOutset = SkDrawShadowMetrics::AmbientBlurRadius(zPlaneParams.fZ);
- SkScalar oneOverA = SkDrawShadowMetrics::AmbientRecipAlpha(zPlaneParams.fZ);
- SkScalar blurRadius = 0.5f*devSpaceOutset*oneOverA;
- SkScalar strokeWidth = 0.5f*(devSpaceOutset - blurRadius);
- // Now draw with blur
- SkPaint paint;
- paint.setColor(rec.fAmbientColor);
- paint.setStrokeWidth(strokeWidth);
- paint.setStyle(SkPaint::kStrokeAndFill_Style);
- SkScalar sigma = SkBlurMask::ConvertRadiusToSigma(blurRadius);
- bool respectCTM = false;
- paint.setMaskFilter(SkMaskFilter::MakeBlur(kNormal_SkBlurStyle, sigma, respectCTM));
- this->drawPath(devSpacePath, paint);
- }
- }
- }
- if (SkColorGetA(rec.fSpotColor) > 0) {
- bool success = false;
- if (uncached) {
- sk_sp<SkVertices> vertices = SkShadowTessellator::MakeSpot(path, viewMatrix,
- zPlaneParams,
- devLightPos, lightRadius,
- transparent);
- if (vertices) {
- SkPaint paint;
- // Run the vertex color through a GaussianColorFilter and then modulate the
- // grayscale result of that against our 'color' param.
- paint.setColorFilter(
- SkColorFilters::Blend(rec.fSpotColor,
- SkBlendMode::kModulate)->makeComposed(
- SkGaussianColorFilter::Make()));
- this->drawVertices(vertices.get(), nullptr, 0, SkBlendMode::kModulate, paint);
- success = true;
- }
- }
- if (!success) {
- SpotVerticesFactory factory;
- factory.fOccluderHeight = zPlaneParams.fZ;
- factory.fDevLightPos = devLightPos;
- factory.fLightRadius = lightRadius;
- SkPoint center = SkPoint::Make(path.getBounds().centerX(), path.getBounds().centerY());
- factory.fLocalCenter = center;
- viewMatrix.mapPoints(¢er, 1);
- SkScalar radius, scale;
- SkDrawShadowMetrics::GetSpotParams(zPlaneParams.fZ, devLightPos.fX - center.fX,
- devLightPos.fY - center.fY, devLightPos.fZ,
- lightRadius, &radius, &scale, &factory.fOffset);
- SkRect devBounds;
- viewMatrix.mapRect(&devBounds, path.getBounds());
- if (transparent ||
- SkTAbs(factory.fOffset.fX) > 0.5f*devBounds.width() ||
- SkTAbs(factory.fOffset.fY) > 0.5f*devBounds.height()) {
- // if the translation of the shadow is big enough we're going to end up
- // filling the entire umbra, so we can treat these as all the same
- factory.fOccluderType = SpotVerticesFactory::OccluderType::kTransparent;
- } else if (factory.fOffset.length()*scale + scale < radius) {
- // if we don't translate more than the blur distance, can assume umbra is covered
- factory.fOccluderType = SpotVerticesFactory::OccluderType::kOpaqueNoUmbra;
- } else if (path.isConvex()) {
- factory.fOccluderType = SpotVerticesFactory::OccluderType::kOpaquePartialUmbra;
- } else {
- factory.fOccluderType = SpotVerticesFactory::OccluderType::kTransparent;
- }
- // need to add this after we classify the shadow
- factory.fOffset.fX += viewMatrix.getTranslateX();
- factory.fOffset.fY += viewMatrix.getTranslateY();
- SkColor color = rec.fSpotColor;
- #ifdef DEBUG_SHADOW_CHECKS
- switch (factory.fOccluderType) {
- case SpotVerticesFactory::OccluderType::kTransparent:
- color = 0xFFD2B48C; // tan for transparent
- break;
- case SpotVerticesFactory::OccluderType::kOpaquePartialUmbra:
- color = 0xFFFFA500; // orange for opaque
- break;
- case SpotVerticesFactory::OccluderType::kOpaqueNoUmbra:
- color = 0xFFE5E500; // corn yellow for covered
- break;
- }
- #endif
- if (!draw_shadow(factory, drawVertsProc, shadowedPath, color)) {
- // draw with blur
- SkMatrix shadowMatrix;
- if (!SkDrawShadowMetrics::GetSpotShadowTransform(devLightPos, lightRadius,
- viewMatrix, zPlaneParams,
- path.getBounds(),
- &shadowMatrix, &radius)) {
- return;
- }
- SkAutoDeviceCTMRestore adr(this, shadowMatrix);
- SkPaint paint;
- paint.setColor(rec.fSpotColor);
- SkScalar sigma = SkBlurMask::ConvertRadiusToSigma(radius);
- bool respectCTM = false;
- paint.setMaskFilter(SkMaskFilter::MakeBlur(kNormal_SkBlurStyle, sigma, respectCTM));
- this->drawPath(path, paint);
- }
- }
- }
- }
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