• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2  * Copyright 2010 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 "src/gpu/SkGr.h"
9 
10 #include "include/core/SkCanvas.h"
11 #include "include/core/SkColorFilter.h"
12 #include "include/core/SkData.h"
13 #include "include/core/SkPixelRef.h"
14 #include "include/effects/SkRuntimeEffect.h"
15 #include "include/gpu/GrContext.h"
16 #include "include/gpu/GrTypes.h"
17 #include "include/private/GrRecordingContext.h"
18 #include "include/private/SkImageInfoPriv.h"
19 #include "include/private/SkTemplates.h"
20 #include "src/core/SkAutoMalloc.h"
21 #include "src/core/SkBlendModePriv.h"
22 #include "src/core/SkColorSpacePriv.h"
23 #include "src/core/SkImagePriv.h"
24 #include "src/core/SkMaskFilterBase.h"
25 #include "src/core/SkMessageBus.h"
26 #include "src/core/SkMipMap.h"
27 #include "src/core/SkPaintPriv.h"
28 #include "src/core/SkResourceCache.h"
29 #include "src/core/SkTraceEvent.h"
30 #include "src/gpu/GrBitmapTextureMaker.h"
31 #include "src/gpu/GrCaps.h"
32 #include "src/gpu/GrColorSpaceXform.h"
33 #include "src/gpu/GrContextPriv.h"
34 #include "src/gpu/GrGpuResourcePriv.h"
35 #include "src/gpu/GrPaint.h"
36 #include "src/gpu/GrProxyProvider.h"
37 #include "src/gpu/GrRecordingContextPriv.h"
38 #include "src/gpu/GrTextureProxy.h"
39 #include "src/gpu/GrXferProcessor.h"
40 #include "src/gpu/effects/GrBicubicEffect.h"
41 #include "src/gpu/effects/GrPorterDuffXferProcessor.h"
42 #include "src/gpu/effects/GrSkSLFP.h"
43 #include "src/gpu/effects/GrXfermodeFragmentProcessor.h"
44 #include "src/gpu/effects/generated/GrClampFragmentProcessor.h"
45 #include "src/gpu/effects/generated/GrConstColorProcessor.h"
46 #include "src/image/SkImage_Base.h"
47 #include "src/shaders/SkShaderBase.h"
48 
49 GR_FP_SRC_STRING SKSL_DITHER_SRC = R"(
50 // This controls the range of values added to color channels
51 in int rangeType;
52 
53 void main(float2 p, inout half4 color) {
54     half value;
55     half range;
56     @switch (rangeType) {
57         case 0:
58             range = 1.0 / 255.0;
59             break;
60         case 1:
61             range = 1.0 / 63.0;
62             break;
63         default:
64             // Experimentally this looks better than the expected value of 1/15.
65             range = 1.0 / 15.0;
66             break;
67     }
68     @if (sk_Caps.integerSupport) {
69         // This ordered-dither code is lifted from the cpu backend.
70         uint x = uint(p.x);
71         uint y = uint(p.y);
72         uint m = (y & 1) << 5 | (x & 1) << 4 |
73                  (y & 2) << 2 | (x & 2) << 1 |
74                  (y & 4) >> 1 | (x & 4) >> 2;
75         value = half(m) * 1.0 / 64.0 - 63.0 / 128.0;
76     } else {
77         // Simulate the integer effect used above using step/mod. For speed, simulates a 4x4
78         // dither pattern rather than an 8x8 one.
79         half4 modValues = mod(half4(half(p.x), half(p.y), half(p.x), half(p.y)), half4(2.0, 2.0, 4.0, 4.0));
80         half4 stepValues = step(modValues, half4(1.0, 1.0, 2.0, 2.0));
81         value = dot(stepValues, half4(8.0 / 16.0, 4.0 / 16.0, 2.0 / 16.0, 1.0 / 16.0)) - 15.0 / 32.0;
82     }
83     // For each color channel, add the random offset to the channel value and then clamp
84     // between 0 and alpha to keep the color premultiplied.
85     color = half4(clamp(color.rgb + value * range, 0.0, color.a), color.a);
86 }
87 )";
88 
GrMakeKeyFromImageID(GrUniqueKey * key,uint32_t imageID,const SkIRect & imageBounds)89 void GrMakeKeyFromImageID(GrUniqueKey* key, uint32_t imageID, const SkIRect& imageBounds) {
90     SkASSERT(key);
91     SkASSERT(imageID);
92     SkASSERT(!imageBounds.isEmpty());
93     static const GrUniqueKey::Domain kImageIDDomain = GrUniqueKey::GenerateDomain();
94     GrUniqueKey::Builder builder(key, kImageIDDomain, 5, "Image");
95     builder[0] = imageID;
96     builder[1] = imageBounds.fLeft;
97     builder[2] = imageBounds.fTop;
98     builder[3] = imageBounds.fRight;
99     builder[4] = imageBounds.fBottom;
100 }
101 
102 ////////////////////////////////////////////////////////////////////////////////
103 
GrInstallBitmapUniqueKeyInvalidator(const GrUniqueKey & key,uint32_t contextUniqueID,SkPixelRef * pixelRef)104 void GrInstallBitmapUniqueKeyInvalidator(const GrUniqueKey& key, uint32_t contextUniqueID,
105                                          SkPixelRef* pixelRef) {
106     class Invalidator : public SkPixelRef::GenIDChangeListener {
107     public:
108         explicit Invalidator(const GrUniqueKey& key, uint32_t contextUniqueID)
109                 : fMsg(key, contextUniqueID) {}
110 
111     private:
112         GrUniqueKeyInvalidatedMessage fMsg;
113 
114         void onChange() override { SkMessageBus<GrUniqueKeyInvalidatedMessage>::Post(fMsg); }
115     };
116 
117     pixelRef->addGenIDChangeListener(new Invalidator(key, contextUniqueID));
118 }
119 
GrCopyBaseMipMapToTextureProxy(GrRecordingContext * ctx,GrSurfaceProxy * baseProxy,GrSurfaceOrigin origin,GrColorType srcColorType)120 GrSurfaceProxyView GrCopyBaseMipMapToTextureProxy(GrRecordingContext* ctx,
121                                                   GrSurfaceProxy* baseProxy,
122                                                   GrSurfaceOrigin origin,
123                                                   GrColorType srcColorType) {
124     SkASSERT(baseProxy);
125 
126     if (!ctx->priv().caps()->isFormatCopyable(baseProxy->backendFormat())) {
127         return {};
128     }
129     GrSurfaceProxyView view = GrSurfaceProxy::Copy(ctx, baseProxy, origin, srcColorType,
130                                                    GrMipMapped::kYes, SkBackingFit::kExact,
131                                                    SkBudgeted::kYes);
132     SkASSERT(!view.proxy() || view.asTextureProxy());
133     return view;
134 }
135 
GrRefCachedBitmapView(GrRecordingContext * ctx,const SkBitmap & bitmap,GrSamplerState params,SkScalar scaleAdjust[2])136 GrSurfaceProxyView GrRefCachedBitmapView(GrRecordingContext* ctx, const SkBitmap& bitmap,
137                                          GrSamplerState params, SkScalar scaleAdjust[2]) {
138     GrBitmapTextureMaker maker(ctx, bitmap, GrBitmapTextureMaker::Cached::kYes);
139     return maker.viewForParams(params, scaleAdjust);
140 }
141 
GrMakeCachedBitmapProxyView(GrRecordingContext * context,const SkBitmap & bitmap,SkBackingFit fit)142 GrSurfaceProxyView GrMakeCachedBitmapProxyView(GrRecordingContext* context, const SkBitmap& bitmap,
143                                                SkBackingFit fit) {
144     if (!bitmap.peekPixels(nullptr)) {
145         return {};
146     }
147 
148     GrBitmapTextureMaker maker(context, bitmap, GrBitmapTextureMaker::Cached::kYes, fit);
149     auto[view, grCT] = maker.view(GrMipMapped::kNo);
150     return view;
151 }
152 
153 ///////////////////////////////////////////////////////////////////////////////
154 
SkColorToPMColor4f(SkColor c,const GrColorInfo & colorInfo)155 SkPMColor4f SkColorToPMColor4f(SkColor c, const GrColorInfo& colorInfo) {
156     SkColor4f color = SkColor4f::FromColor(c);
157     if (auto* xform = colorInfo.colorSpaceXformFromSRGB()) {
158         color = xform->apply(color);
159     }
160     return color.premul();
161 }
162 
SkColor4fPrepForDst(SkColor4f color,const GrColorInfo & colorInfo)163 SkColor4f SkColor4fPrepForDst(SkColor4f color, const GrColorInfo& colorInfo) {
164     if (auto* xform = colorInfo.colorSpaceXformFromSRGB()) {
165         color = xform->apply(color);
166     }
167     return color;
168 }
169 
170 ///////////////////////////////////////////////////////////////////////////////
171 
blend_requires_shader(const SkBlendMode mode)172 static inline bool blend_requires_shader(const SkBlendMode mode) {
173     return SkBlendMode::kDst != mode;
174 }
175 
176 #ifndef SK_IGNORE_GPU_DITHER
dither_range_type_for_config(GrColorType dstColorType)177 static inline int32_t dither_range_type_for_config(GrColorType dstColorType) {
178     switch (dstColorType) {
179         case GrColorType::kUnknown:
180         case GrColorType::kGray_8:
181         case GrColorType::kRGBA_8888:
182         case GrColorType::kRGB_888x:
183         case GrColorType::kRG_88:
184         case GrColorType::kBGRA_8888:
185         case GrColorType::kRG_1616:
186         case GrColorType::kRGBA_16161616:
187         case GrColorType::kRG_F16:
188         case GrColorType::kRGBA_8888_SRGB:
189         case GrColorType::kRGBA_1010102:
190         case GrColorType::kAlpha_F16:
191         case GrColorType::kRGBA_F32:
192         case GrColorType::kRGBA_F16:
193         case GrColorType::kRGBA_F16_Clamped:
194         case GrColorType::kAlpha_8:
195         case GrColorType::kAlpha_8xxx:
196         case GrColorType::kAlpha_16:
197         case GrColorType::kAlpha_F32xxx:
198         case GrColorType::kGray_8xxx:
199         case GrColorType::kRGB_888:
200         case GrColorType::kR_8:
201         case GrColorType::kR_16:
202         case GrColorType::kR_F16:
203         case GrColorType::kGray_F16:
204             return 0;
205         case GrColorType::kBGR_565:
206             return 1;
207         case GrColorType::kABGR_4444:
208             return 2;
209     }
210     SkUNREACHABLE;
211 }
212 #endif
213 
skpaint_to_grpaint_impl(GrRecordingContext * context,const GrColorInfo & dstColorInfo,const SkPaint & skPaint,const SkMatrix & viewM,std::unique_ptr<GrFragmentProcessor> * shaderProcessor,SkBlendMode * primColorMode,GrPaint * grPaint)214 static inline bool skpaint_to_grpaint_impl(GrRecordingContext* context,
215                                            const GrColorInfo& dstColorInfo,
216                                            const SkPaint& skPaint,
217                                            const SkMatrix& viewM,
218                                            std::unique_ptr<GrFragmentProcessor>* shaderProcessor,
219                                            SkBlendMode* primColorMode,
220                                            GrPaint* grPaint) {
221     // Convert SkPaint color to 4f format in the destination color space
222     SkColor4f origColor = SkColor4fPrepForDst(skPaint.getColor4f(), dstColorInfo);
223 
224     GrFPArgs fpArgs(context, &viewM, skPaint.getFilterQuality(), &dstColorInfo);
225 
226     // Setup the initial color considering the shader, the SkPaint color, and the presence or not
227     // of per-vertex colors.
228     std::unique_ptr<GrFragmentProcessor> shaderFP;
229     if (!primColorMode || blend_requires_shader(*primColorMode)) {
230         fpArgs.fInputColorIsOpaque = origColor.isOpaque();
231         if (shaderProcessor) {
232             shaderFP = std::move(*shaderProcessor);
233         } else if (const auto* shader = as_SB(skPaint.getShader())) {
234             shaderFP = shader->asFragmentProcessor(fpArgs);
235             if (!shaderFP) {
236                 return false;
237             }
238         }
239     }
240 
241     // Set this in below cases if the output of the shader/paint-color/paint-alpha/primXfermode is
242     // a known constant value. In that case we can simply apply a color filter during this
243     // conversion without converting the color filter to a GrFragmentProcessor.
244     bool applyColorFilterToPaintColor = false;
245     if (shaderFP) {
246         if (primColorMode) {
247             // There is a blend between the primitive color and the shader color. The shader sees
248             // the opaque paint color. The shader's output is blended using the provided mode by
249             // the primitive color. The blended color is then modulated by the paint's alpha.
250 
251             // The geometry processor will insert the primitive color to start the color chain, so
252             // the GrPaint color will be ignored.
253 
254             SkPMColor4f shaderInput = origColor.makeOpaque().premul();
255             shaderFP = GrFragmentProcessor::OverrideInput(std::move(shaderFP), shaderInput);
256             shaderFP = GrXfermodeFragmentProcessor::MakeFromSrcProcessor(std::move(shaderFP),
257                                                                          *primColorMode);
258 
259             // The above may return null if compose results in a pass through of the prim color.
260             if (shaderFP) {
261                 grPaint->addColorFragmentProcessor(std::move(shaderFP));
262             }
263 
264             // We can ignore origColor here - alpha is unchanged by gamma
265             float paintAlpha = skPaint.getColor4f().fA;
266             if (1.0f != paintAlpha) {
267                 // No gamut conversion - paintAlpha is a (linear) alpha value, splatted to all
268                 // color channels. It's value should be treated as the same in ANY color space.
269                 grPaint->addColorFragmentProcessor(GrConstColorProcessor::Make(
270                     { paintAlpha, paintAlpha, paintAlpha, paintAlpha },
271                     GrConstColorProcessor::InputMode::kModulateRGBA));
272             }
273         } else {
274             // The shader's FP sees the paint *unpremul* color
275             SkPMColor4f origColorAsPM = { origColor.fR, origColor.fG, origColor.fB, origColor.fA };
276             grPaint->setColor4f(origColorAsPM);
277             grPaint->addColorFragmentProcessor(std::move(shaderFP));
278         }
279     } else {
280         if (primColorMode) {
281             // There is a blend between the primitive color and the paint color. The blend considers
282             // the opaque paint color. The paint's alpha is applied to the post-blended color.
283             SkPMColor4f opaqueColor = origColor.makeOpaque().premul();
284             auto processor = GrConstColorProcessor::Make(opaqueColor,
285                                                          GrConstColorProcessor::InputMode::kIgnore);
286             processor = GrXfermodeFragmentProcessor::MakeFromSrcProcessor(std::move(processor),
287                                                                           *primColorMode);
288             if (processor) {
289                 grPaint->addColorFragmentProcessor(std::move(processor));
290             }
291 
292             grPaint->setColor4f(opaqueColor);
293 
294             // We can ignore origColor here - alpha is unchanged by gamma
295             float paintAlpha = skPaint.getColor4f().fA;
296             if (1.0f != paintAlpha) {
297                 // No gamut conversion - paintAlpha is a (linear) alpha value, splatted to all
298                 // color channels. It's value should be treated as the same in ANY color space.
299                 grPaint->addColorFragmentProcessor(GrConstColorProcessor::Make(
300                     { paintAlpha, paintAlpha, paintAlpha, paintAlpha },
301                     GrConstColorProcessor::InputMode::kModulateRGBA));
302             }
303         } else {
304             // No shader, no primitive color.
305             grPaint->setColor4f(origColor.premul());
306             applyColorFilterToPaintColor = true;
307         }
308     }
309 
310     SkColorFilter* colorFilter = skPaint.getColorFilter();
311     if (colorFilter) {
312         if (applyColorFilterToPaintColor) {
313             SkColorSpace* dstCS = dstColorInfo.colorSpace();
314             grPaint->setColor4f(colorFilter->filterColor4f(origColor, dstCS, dstCS).premul());
315         } else {
316             auto cfFP = colorFilter->asFragmentProcessor(context, dstColorInfo);
317             if (cfFP) {
318                 grPaint->addColorFragmentProcessor(std::move(cfFP));
319             } else {
320                 return false;
321             }
322         }
323     }
324 
325     SkMaskFilterBase* maskFilter = as_MFB(skPaint.getMaskFilter());
326     if (maskFilter) {
327         // We may have set this before passing to the SkShader.
328         fpArgs.fInputColorIsOpaque = false;
329         if (auto mfFP = maskFilter->asFragmentProcessor(fpArgs)) {
330             grPaint->addCoverageFragmentProcessor(std::move(mfFP));
331         }
332     }
333 
334     // When the xfermode is null on the SkPaint (meaning kSrcOver) we need the XPFactory field on
335     // the GrPaint to also be null (also kSrcOver).
336     SkASSERT(!grPaint->getXPFactory());
337     if (!skPaint.isSrcOver()) {
338         grPaint->setXPFactory(SkBlendMode_AsXPFactory(skPaint.getBlendMode()));
339     }
340 
341 #ifndef SK_IGNORE_GPU_DITHER
342     GrColorType ct = dstColorInfo.colorType();
343     if (SkPaintPriv::ShouldDither(skPaint, GrColorTypeToSkColorType(ct)) &&
344         grPaint->numColorFragmentProcessors() > 0) {
345         int32_t ditherRange = dither_range_type_for_config(ct);
346         if (ditherRange >= 0) {
347             static auto effect = std::get<0>(SkRuntimeEffect::Make(SkString(SKSL_DITHER_SRC)));
348             auto ditherFP = GrSkSLFP::Make(context, effect, "Dither",
349                                            SkData::MakeWithCopy(&ditherRange, sizeof(ditherRange)));
350             if (ditherFP) {
351                 grPaint->addColorFragmentProcessor(std::move(ditherFP));
352             }
353         }
354     }
355 #endif
356     if (GrColorTypeClampType(dstColorInfo.colorType()) == GrClampType::kManual) {
357         if (grPaint->numColorFragmentProcessors()) {
358             grPaint->addColorFragmentProcessor(GrClampFragmentProcessor::Make(false));
359         } else {
360             auto color = grPaint->getColor4f();
361             grPaint->setColor4f({SkTPin(color.fR, 0.f, 1.f),
362                                  SkTPin(color.fG, 0.f, 1.f),
363                                  SkTPin(color.fB, 0.f, 1.f),
364                                  SkTPin(color.fA, 0.f, 1.f)});
365         }
366     }
367     return true;
368 }
369 
SkPaintToGrPaint(GrRecordingContext * context,const GrColorInfo & dstColorInfo,const SkPaint & skPaint,const SkMatrix & viewM,GrPaint * grPaint)370 bool SkPaintToGrPaint(GrRecordingContext* context, const GrColorInfo& dstColorInfo,
371                       const SkPaint& skPaint, const SkMatrix& viewM, GrPaint* grPaint) {
372     return skpaint_to_grpaint_impl(context, dstColorInfo, skPaint, viewM, nullptr, nullptr,
373                                    grPaint);
374 }
375 
376 /** Replaces the SkShader (if any) on skPaint with the passed in GrFragmentProcessor. */
SkPaintToGrPaintReplaceShader(GrRecordingContext * context,const GrColorInfo & dstColorInfo,const SkPaint & skPaint,std::unique_ptr<GrFragmentProcessor> shaderFP,GrPaint * grPaint)377 bool SkPaintToGrPaintReplaceShader(GrRecordingContext* context,
378                                    const GrColorInfo& dstColorInfo,
379                                    const SkPaint& skPaint,
380                                    std::unique_ptr<GrFragmentProcessor> shaderFP,
381                                    GrPaint* grPaint) {
382     if (!shaderFP) {
383         return false;
384     }
385     return skpaint_to_grpaint_impl(context, dstColorInfo, skPaint, SkMatrix::I(), &shaderFP,
386                                    nullptr, grPaint);
387 }
388 
389 /** Ignores the SkShader (if any) on skPaint. */
SkPaintToGrPaintNoShader(GrRecordingContext * context,const GrColorInfo & dstColorInfo,const SkPaint & skPaint,GrPaint * grPaint)390 bool SkPaintToGrPaintNoShader(GrRecordingContext* context,
391                               const GrColorInfo& dstColorInfo,
392                               const SkPaint& skPaint,
393                               GrPaint* grPaint) {
394     // Use a ptr to a nullptr to to indicate that the SkShader is ignored and not replaced.
395     std::unique_ptr<GrFragmentProcessor> nullShaderFP(nullptr);
396     return skpaint_to_grpaint_impl(context, dstColorInfo, skPaint, SkMatrix::I(), &nullShaderFP,
397                                    nullptr, grPaint);
398 }
399 
400 /** Blends the SkPaint's shader (or color if no shader) with a per-primitive color which must
401 be setup as a vertex attribute using the specified SkBlendMode. */
SkPaintToGrPaintWithXfermode(GrRecordingContext * context,const GrColorInfo & dstColorInfo,const SkPaint & skPaint,const SkMatrix & viewM,SkBlendMode primColorMode,GrPaint * grPaint)402 bool SkPaintToGrPaintWithXfermode(GrRecordingContext* context,
403                                   const GrColorInfo& dstColorInfo,
404                                   const SkPaint& skPaint,
405                                   const SkMatrix& viewM,
406                                   SkBlendMode primColorMode,
407                                   GrPaint* grPaint) {
408     return skpaint_to_grpaint_impl(context, dstColorInfo, skPaint, viewM, nullptr, &primColorMode,
409                                    grPaint);
410 }
411 
SkPaintToGrPaintWithTexture(GrRecordingContext * context,const GrColorInfo & dstColorInfo,const SkPaint & paint,const SkMatrix & viewM,std::unique_ptr<GrFragmentProcessor> fp,bool textureIsAlphaOnly,GrPaint * grPaint)412 bool SkPaintToGrPaintWithTexture(GrRecordingContext* context,
413                                  const GrColorInfo& dstColorInfo,
414                                  const SkPaint& paint,
415                                  const SkMatrix& viewM,
416                                  std::unique_ptr<GrFragmentProcessor> fp,
417                                  bool textureIsAlphaOnly,
418                                  GrPaint* grPaint) {
419     std::unique_ptr<GrFragmentProcessor> shaderFP;
420     if (textureIsAlphaOnly) {
421         if (const auto* shader = as_SB(paint.getShader())) {
422             shaderFP = shader->asFragmentProcessor(
423                     GrFPArgs(context, &viewM, paint.getFilterQuality(), &dstColorInfo));
424             if (!shaderFP) {
425                 return false;
426             }
427             std::unique_ptr<GrFragmentProcessor> fpSeries[] = { std::move(shaderFP), std::move(fp) };
428             shaderFP = GrFragmentProcessor::RunInSeries(fpSeries, 2);
429         } else {
430             shaderFP = GrFragmentProcessor::MakeInputPremulAndMulByOutput(std::move(fp));
431         }
432     } else {
433         if (paint.getColor4f().isOpaque()) {
434             shaderFP = GrFragmentProcessor::OverrideInput(std::move(fp), SK_PMColor4fWHITE, false);
435         } else {
436             shaderFP = GrFragmentProcessor::MulChildByInputAlpha(std::move(fp));
437         }
438     }
439 
440     return SkPaintToGrPaintReplaceShader(context, dstColorInfo, paint, std::move(shaderFP),
441                                          grPaint);
442 }
443 
444 ////////////////////////////////////////////////////////////////////////////////////////////////
445 
GrSkFilterQualityToGrFilterMode(int imageWidth,int imageHeight,SkFilterQuality paintFilterQuality,const SkMatrix & viewM,const SkMatrix & localM,bool sharpenMipmappedTextures,bool * doBicubic)446 GrSamplerState::Filter GrSkFilterQualityToGrFilterMode(int imageWidth, int imageHeight,
447                                                        SkFilterQuality paintFilterQuality,
448                                                        const SkMatrix& viewM,
449                                                        const SkMatrix& localM,
450                                                        bool sharpenMipmappedTextures,
451                                                        bool* doBicubic) {
452     *doBicubic = false;
453     if (imageWidth <= 1 && imageHeight <= 1) {
454         return GrSamplerState::Filter::kNearest;
455     }
456     switch (paintFilterQuality) {
457         case kNone_SkFilterQuality:
458             return GrSamplerState::Filter::kNearest;
459         case kLow_SkFilterQuality:
460             return GrSamplerState::Filter::kBilerp;
461         case kMedium_SkFilterQuality: {
462             SkMatrix matrix;
463             matrix.setConcat(viewM, localM);
464             // With sharp mips, we bias lookups by -0.5. That means our final LOD is >= 0 until the
465             // computed LOD is >= 0.5. At what scale factor does a texture get an LOD of 0.5?
466             //
467             // Want:  0       = log2(1/s) - 0.5
468             //        0.5     = log2(1/s)
469             //        2^0.5   = 1/s
470             //        1/2^0.5 = s
471             //        2^0.5/2 = s
472             SkScalar mipScale = sharpenMipmappedTextures ? SK_ScalarRoot2Over2 : SK_Scalar1;
473             if (matrix.getMinScale() < mipScale) {
474                 return GrSamplerState::Filter::kMipMap;
475             } else {
476                 // Don't trigger MIP level generation unnecessarily.
477                 return GrSamplerState::Filter::kBilerp;
478             }
479         }
480         case kHigh_SkFilterQuality: {
481             SkMatrix matrix;
482             matrix.setConcat(viewM, localM);
483             GrSamplerState::Filter textureFilterMode;
484             *doBicubic = GrBicubicEffect::ShouldUseBicubic(matrix, &textureFilterMode);
485             return textureFilterMode;
486         }
487     }
488     SkUNREACHABLE;
489 }
490